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Corbet
03-10-2008, 12:49 PM
Whats the consensus on where to mount your antenna on an 80. I know the middle of the roof would be the best but I'm not drilling a hole there. So:

1. Any advantage to mounting on the hood verse rear lift gate?
2. Is there any one model antenna that everyone recommends?
3. Anything else I should know?

Hants
03-10-2008, 01:06 PM
1. Dunno, I'm just a noob. But Dave A. says I can't have any more kids if I transmit at 50W and am closer than 6 feet. :hill: I'm mounting mine on the rear hatch for now. I'm seriously considering removing my roof rack and mounting antenna(s) on the roof (out of the way of my pod).

2. Comet SBB-1NMO is short and flexible -- survives trail (ab)use well. I also have a Diamond SG7500NMO for higher gain.

3. The rain in Spain falls mainly on the plain.

treerootCO
03-10-2008, 01:22 PM
The Wilson brand antenna seem to work better than any other models I have seen for CB.

http://www.wilsonantenna.com/

corsair23
03-10-2008, 01:31 PM
I like Romer's setup...Reminds me of a little cellular antenna attached to the rear gate and it can be folded down parallel to the roof :D

Romer, care to post up the specs on that antenna?

Nathaniel has a nice one too on his 80 that allows the antenna to be removed and a cap screwed on when not in use.

I'm leaning toward something like what Romer has though because unlike my CB and antenna (which are NEVER on unless I'm on a trail) I'll probably actually use the rig just for fun. Case in point was on Saturday when helping Nakman move...Timm and I could have been chatting with Bruce, Romer, and Nakman on the drive :thumb:

The trick antenna is the one that will raise and lower via a motor. Seems to fit the "mold" of a LX :hill:

nuclearlemon
03-10-2008, 03:38 PM
i've got one from hamstick...18" (iirc) nmo mount antenna on a hood lip mount on the 80, mag mount on the front fender on the pig. the one time i listened in, it sounded great. i'm used to running cb antennas on my arb though, so seeing an antenna is nothing for me.

nakman
03-10-2008, 04:02 PM
I'm running a lip mount on the DS of the hood. I wish it was on the PS, which would maybe look funny if I had the radio antenna up, but at least it would always be out of view. Though as it is now I have 3 antennas, if you count the radio & CB, so it's already silly. I know on the roof is best, but then I can't fit inside garages, even with it folded.

I'm thinking of getting a shorter one like 60wag has then put it on the rear hatch, that way I can leave it up all the time and on those few outings where a better dual band antenna is needed, swap it over. Of all our setups, I like Bruce's the best because it's so practical.. sure his range isn't as good with the little guy but 90% of the time either the truck you're talking to is a mile away or you're on a repeater anyway, so bfd..

Romer
03-10-2008, 04:05 PM
I like Romer's setup...Reminds me of a little cellular antenna attached to the rear gate and it can be folded down parallel to the roof :D

Romer, care to post up the specs on that antenna?



http://www.risingsun4x4club.org/forum2/showthread.php?t=5540&highlight=setups

The part numbers are in that thread and then you can go to HRO or gigabyte or hamcity and get the details.

Corbet
03-10-2008, 04:53 PM
Ken, thanks for the link. I did not see any mention of how many, or if any holes had to be drilled in order to do the install on the antenna.

Romer
03-10-2008, 05:23 PM
No holes. Just tighten the two screws on the bracket and it snugs it up against the metal.

nuclearlemon
03-10-2008, 06:02 PM
same here on no holes to drill

Convert
03-10-2008, 09:11 PM
I have mounted mine to the top of the spare tire carrier so that it is 2/3 of its length above the truck. It is a diamond ( cant remember the model at the moment)I know everything you read says not to mount to the bumpers but there are ways to make it work. The bumper is bonded to the body and I am getting great results


PS the CB antenna is right next to it on the opposite side

Shark Bait
03-10-2008, 09:41 PM
Mine is a fold over. Comet, I think. I might as well have not gotten the fold over because I run with the antenna off most of the time and a cap on the NMO mount. :D

Corbet
03-12-2008, 12:25 PM
Thanks for everyone's help. I just ordered the same antenna set-up that Romer posted.

treerootCO
07-18-2008, 12:30 PM
Can someone post up what additional hardware I need after buying one of the dual band Yaesu rigs, an external speaker, and an antenna?

I would like like to run the detachable faceplate above the windshield, the mic next to the console, the guts in back, a speaker in the stock dash location, and an antenna on the rear hatch. Without the equipment, I don't know what needs to be purchased and ran while the headliner and interior is out of the truck. I have already run ought gauge to the rear from the dual batteries to a distribution panel and ought gauge to chassis ground. I read Nathaniel's posts on ground straps to that will be added.

UB mentioned the radio is cat5e and the faceplate is either RJ48 or RJ11...
I assume the junk in back needs clean power and ground.

Hulk
07-18-2008, 12:42 PM
You can buy the extended wire for the faceplate from the guy on eBay -- it's in one of these threads. It comes with a wire to extend to your remote speaker.

You don't need a new speaker if you're going to use one of the speakers in the dash -- they put out plenty of volume. I used the one next to the glovebox.

You should take a look at what Convert used to mount his faceplate up high. It is really slick.

nakman
07-18-2008, 02:15 PM
Mike let me know if you need any more mic clips.


and FWIW, I've become disappointed with where I mounted my antenna. I have the same Comet (S BB5?) dual bander that several of the other guys have, and the lip mount on the side of my hood, and I have experienced noticably worse performance than the guys running similar setups, but with the antennas on the rear hatch. While my setup is more than adequate for trails runs and hitting the local repeaters around town, it's not as good as it will be when I move the antenna from the side of the hood to the top of the rear hatch, as I've now proven with several examples some of which are:

Ex1: I couldn't hear Matt who was on the other side of Lake Tahoe, but Dave could, all due to his superiour ground plane.

Ex2: I couldn't hear Romer & Uncle Ben as well as they could hear me on I-80, when we were 30-40 miles apart.

Ex3: I couldn't hear Romer talk to Matt when he was up on I-80 near Reno and we were down closer to Hwy 50, closer to Carson City. I could hear Matt's side of the conversation, but not Ken's (but Matt was right in front of me).

so bottom line if you want better performance than CB you could probably stick the antenna anywhere, but based on my experience and what I've observed from others the "best" practical antenna location for an 80 is...,

#1 right in the center of your roof. Second best is on the top of the rear hatch, I'd rank side of the hood at 3rd, and on top of the front ARB bumper probably 4th. Back bumper is probably in contention for the 3rd or 4th slot, depending on how well grounded you are and how high it is. Rest of you 80 hammers agree/disagree?

Hulk
07-18-2008, 02:58 PM
Yep. I mounted mine pretty high up on the back hatch. Also, I run a dedicated 2-meter antenna, not a dual-band. It's a Diamond, IIRC. There are always compromises in a dual-band antenna, and a dedicated 2-meter seems to perform a bit better and is also cheaper. :)

Groucho
07-21-2008, 05:39 PM
I agree with Tim. Mine are always mounted high (on my roofrack, which incidentally acts as an awesome groundplane) except for my HF antenna that I have to mount a littlelower (like on my swingout tire carrier) so I can keep the top of the whip under 13'6" (to avoid hitting overpasses).

nakman
07-21-2008, 06:11 PM
60 more examples yesterday- I couldn't hear Terry nearly as well as others as he was driving away from us, even though I was closer. I couldn't hear Convert on the way home, even though Groucho could, etc. etc.

I'm also considering getting a 2m-only antenna, and dropping the dual bander for the truck. Or maybe keep it in the back somewhere for that blue moon where I need 70cm?

wesintl
07-21-2008, 06:15 PM
I have mine on the bar out front. Seems to me I was getting good reception and transmissions from talking to bruce from the other side of handcock and over waunita. I did start out booming 50w the whole time but then found how to use the power button but I think i'll use that mostly and adopt bruces' saying "life if too short for qrp" unless I know i'm only in communication with the group and were all close. I use a straight 2m radio and 2m antenna.

When have you guys with 70 cm used it yet?

Bruce Miller
07-22-2008, 09:48 AM
QRO = Increase power.

treerootCO
07-22-2008, 09:59 AM
Can someone confirm that the mic is RJ-11 and the radio uses cat5e? I haven't purchased the radio and need to know what wires need to be run.

nakman
07-22-2008, 12:22 PM
When have you guys with 70 cm used it yet?

Only once, and that was to access a repeater to listen in on an expedition portal net. Oh, and one time trying to learn how to cross-band repeat. that's it..

Mike I am not sure what the faceplate wire is, it sure looks like CAT5 but I don't think the connectors are that wide. I think Shark Bait has an extra cable, or you're welcome to come up and stare at mine if you want.

Rock Dog
08-01-2008, 06:25 PM
what about a quad band antenna vs a dual band ? is there even more of a compromise ?
What about the quad band and radio vs the Dual band radio? it is abut $45 more which is like 25 bucks a band....

Groucho
08-01-2008, 09:31 PM
Each time you spit the antenna up with a trap or coil you lose some of its radiating efficiency. That is not to say that it won't radiate effectively, it will just be less than optimal for any one band. Kinda think of it like this, in a sense you are tricking the antenna into thinking it is longer than it actually is for some bands, and not for others. Like silly putty you are asking it to take different shapes on.

In our discussion over the CB antennas, the 102" whip will far out-do the firestik (or similar) antenna, simply because you are putting more metal into the air.

The home brew 5/8λ 2M antenna will out perform a dual band antenna for 2M and 70CM. The difference might be unoticable for your purpose. Same thing goes for single band vs multi band yagis. A single band yagi will have maximized forward power and gain for the band for which it was designed. A tri-bander will have forward power and gain maximized to work for all three bands, not just one.

So to put it this way, if you use all four bands regularly, it will be more beneficial to you to get the 4 band antenna. If you think you will play mostly on 2M and for fun do 70 CM once in a while, stay with a dual bander. If you don't think anything other than 2M will be of use to you, get a mono-bander. Remember, too, that the quad band radios are usually for 10M FM, 6M FM, 2M FM and 70CM FM. 6M is said to be the magic band right now, with awesome opnings frequently allowing 1000 mile plus transmissions, 10M FM is not that busy.

Do what you like and what interests you. Go for it all. Play with it;), its what makes the hobby fun!:thumb:

Rock Dog
08-02-2008, 01:21 AM
Thanks Nathaniel,
that really helps calrify it for me and explains why Nakman believed the "2 meter only" antenna reached out better, because it probably does. But at the cost on not being to do 70 CM.
for the extra 45 bucks i believe i will go with the FT-8900 and start with a dual band antenna mounted on the rear hatch.

It is all new and interesting at the moment. It may be i want to carry a 2M dual band and quad band antenna at some point just to have options, but baby steps for now.....

Jacket
11-11-2008, 05:11 PM
The antenna thing still baffles me. So many choices, so many mounts, so many different opinions. Since many of you have now had your setups for a couple years or more, can you sum up some of your experiences (good and bad).

I have at least a couple of options for the Tacoma:

- When I had my rear bumper built, I had Jed include an antenna tab on the drivers side for future use. I could mount something there.

- Front drivers side fender/hood mount. I currently have my radio antenna on the drivers side, and my CB antenna on the front ARB on the passenger side.

For reasons that others have concluded, a roof top mount would introduce some height issues. In the rear, my truck has a part-time can back, and a composite bed, so I don't have anything resembling a ground plane back there. So in my situation, is the driver front fender the best spot?

Jacket
11-11-2008, 05:23 PM
The other thing that I'm having a hard time with is selection. Brands like Diamond, Comet, Larsen with similar and different models, and all kinds of options that I don't really understand. I could just pick a dual band NMO that has worked for someone else with a similar setup, but I'd like to understand it a bit more than I do. What is important in antenna selection? Height? Wavelength? Single vs Dual Band?

BTW - I'm leaning toward the Yaesu 7800.

nakman
11-12-2008, 10:39 AM
Matt, my solution has been two antennas: both of mine are Comets, for no other reason than everyone else seemed to be buying them. I've got a longer SBB5 that is great for highway travel, on the way to runs, etc., and Moab. Then I've got the shorter SBB1 for wheeling in trees. Since my mount is up at the top of the hatch now, even the little one (think it's 18"?) gets bent over by trees, but it works very well for trail communication, and can still hit the repeaters.

But the longer one is better, no doubt about it.. proven several times this past summer on the Ghost Town & Ouray runs, as well as many monday nights talking to guys on the repeaters and on simplex. If you get a 7800 and a SBB5 antenna I'd be able to talk to you from your house to mine, but if one of us had a shorter antenna that would be more difficult, and impossible if we both had a short one. Not that ability to talk to me at my house should be any decision criteria for antenna purchase, just sayin... :rolleyes:

Also I went to HRO and asked for a 2m only antenna, but they said you can't really get one, pretty much everything off the shelf is dual band these days.

60wag
11-12-2008, 11:22 AM
I have an SBB1 mounted on the rear hatch. It works well and won't snag branches. I have been looking for a higher gain antenna for non wheeling use. The SBB5 is with a 2m gain of 3.0 is good but my likely next purchase will be a Comet CA2X4SR which is also a 40" antenna but touts a gain of 3.8 on 2m.

Hulk
11-12-2008, 12:35 PM
Also I went to HRO and asked for a 2m only antenna, but they said you can't really get one, pretty much everything off the shelf is dual band these days.

I went through a similar process almost 2 years ago. Details here (http://www.risingsun4x4club.org/forum2/showthread.php?t=3584).

Long story short: I ended up with a 2m only antenna, the Larsen NMO 150-B. The good news is that it's inexpensive. The even better news is that it works great!

I have the Yaesu 7800 as well, but I only use the 2m. I mainly wanted the separation functionality so I could mount the faceplace in a tight space up front and the rest of the radio in the back. Otherwise, I would have bought the Yaesu 2800, which is a great radio that is 2m only.

I did a quick Google search. The Larsen is still available. Here's one place (http://www.hol4g.com/ac/product.aspx?number=LAR-NMO-150-B&p=160478&sc=0) that has it for $30.

HRO sells the Larsen NMO-150CHW, a 2M half wave antenna, for $36.50. This is similar to the 150B in a shorter length (1/2 wave vs. 5/8). My antenna is at the top of page 4.

Here's a link to the Larsen catalog section with their 2M antennas (http://www.larsen-antennas.com/docfiles/ASB9/Mobile/VHF136to174MHz.pdf).

Hamcity.com sells a Comet with the fold-over for $40: link (http://www.hamcity.com/SearchResult.aspx?CategoryID=2210).

Hulk
11-12-2008, 12:44 PM
Here's the link to Larsen's multiband antennas (http://www.larsen-antennas.com/docfiles/ASB9/Mobile/MultibandVHFUHF.pdf), if you want to go with a dual-band antenna.

Jacket
11-12-2008, 01:18 PM
Thanks for the insights. A few things I'm pulling out of your suggestions:

- Two antennas is a good idea. A "stubby" for the trails, and a tall (1/2 wave) antenna for traveling and local stuff. I assume you have quick disconnects to make it easy to jump back and forth?

- A single band, 2M antenna performs better than a dual-band? I'm mainly interested in the 7800 for the separation feature as well (as opposed to the dual-band), but at the same time it seems counter-intuitive to limit yourself to 2M use only when you could have both.

- No advantage to hood mount over rear bumper mount? I don't know enough about ground planes to know if the hood could act as a ground plane (to some degree) even though the antenna is out on a fender.

Since I'm talking about opposite ends of the rig, trial and error becomes less attractive since I'd have to rerun all the cable. But maybe I'm just splitting hairs here ...

Hulk
11-12-2008, 01:57 PM
If you mount it on the rear bumper, will most of the length of the antenna have a parallel metal surface nearby (the back of the truck)? If so, this is not your best location. It will work better mounted on your fender where the fender/hood will act as a ground plane.

As for 2 meter vs. dual band, I'll quote Seldom Seen:

Not to muddy things up too much, but here is a 3rd option. If the shorty performs well on 2 & 70, skip the longer dual band all together and get an ant optimized for 2meter for backcountry use. Something like a 5/8 wave Larson MNO150. Dual band antennas are always going to be a compromise so having a dedicated 2meter for out in the bush, where you may need to reach way out and touch some one, might come in handy.

nuclearlemon
11-12-2008, 03:37 PM
I assume you have quick disconnects to make it easy to jump back and forth?

-...

i run nmo mounts on mine. it's screw mount, but a wide thread so it unthreads/threads on real quick. i swap my antenna and radio rig to rig. i just have coax/ant mount and wiring harness for the radio that are permanent on the rigs.

nakman
11-12-2008, 04:32 PM
I'd also point out that after having my antenna mounted on the edge of the hood for 1.5 years, the bend in the coax was so tight that it ultimately crimped the cable and stopped working. It turns out on an 80 (that is what this thread's about, right? :)) there can be a much gentler curve to the coax when mounted in the rear hatch. So be mindful of your routing, and what kind of stresses the really skinny portion of the coax is going to see over time.

Jacket
11-13-2008, 09:36 AM
If you mount it on the rear bumper, will most of the length of the antenna have a parallel metal surface nearby (the back of the truck)? If so, this is not your best location. It will work better mounted on your fender where the fender/hood will act as a ground plane.



I wondered about this too. Since its a pickup, I've got a lower profile than a wagon, but it's still probably 18-24" or so up from the bumper to the top of the bed. So for a 36"+ antenna, maybe I'd be fine, but a stubby would probably have some issues. Maybe I wouldn't need a stubby...

By the by - KDFQQ as of last week :cool:

Hulk
11-13-2008, 10:25 AM
By the by - KDFQQ as of last week :cool:

Congratulations!

:cheers:

Uncle Ben
11-13-2008, 10:36 AM
Congratulations!

:cheers:


Very Cool Matt! If you want to play with my VX-7 for a while your welcome to it! I'm not using it very often.

Jacket
11-14-2008, 10:54 AM
Does anyone know what Bruce is talking about here:


I hate to see any antenna mounted to the swing out tire thing or the rear bumper where the antenna is behind the truck. That's like transmitting inside a tunnel.


But in the attachment, I see a rear bumper mount. :confused:

Hulk
11-14-2008, 11:04 AM
He has a lot of the antenna above the truck. If I were you, I'd mount your ham antenna on the front fender. You can easily unscrew it and put a plastic cap (sealed with an inner o-ring) on the NMO mount when you're not using it. I keep both my CB antenna and my Ham antenna mounts capped until I need them, that way I'm not dealing with the antennas hitting the top of my garage.

Hulk
11-17-2008, 01:15 AM
Here are some pictures of the mounts on my 80. Both of these are NMO mounts. I use one for my CB antenna and the other for my Ham antenna.

First, the front fender mount:
http://rustybrain.com/cruisers/ham/nmo-1.jpg

http://rustybrain.com/cruisers/ham/nmo-2.jpg

http://rustybrain.com/cruisers/ham/nmo-3.jpg

I usually keep it capped, unless I am on a road trip or 4WD trip. The caps are available at HRO or a CB shop, and have an o-ring on the inside to keep moisture away.

----

Here is the back mount on my 80. This keeps the majority of the antenna above the vehicle. I do have a shorty antenna that I could keep on here all the time (that would clear my garage), but most of the time I just keep it capped.
http://rustybrain.com/cruisers/ham/nmo-4.jpg

Jacket
11-17-2008, 08:57 AM
Thanks Matt. I made the drive down to HRO on Saturday and talked to the guys behind the desk there, plus a couple of shoppers who just couldn't help themselves and jumped in to the conversation.

Not surprisingly, their recommendations were right in line with you guys. Roof top or trunk lid is best, but given the choice between hood mount and rear bumper mount, consensus was hood. So I came home with a lip mount similar to picture 1 above, a Larson NMO 2/70, and some cable. I installed it pretty high on the fender toward the cab, so it's mostly out of sight without being too close to the A-pillar.

They were out of stock on FT7800's, so I ordered one. Should be here by the end of the week, then the real fun starts.....

corsair23
06-04-2009, 02:15 PM
General antenna question...not just for 80s anymore :)

I went ahead and bought a M285SNMO (http://www.rfparts.com/diamond/pdfdocs/M285S-M285SNMO.pdf) (Diamond 144-174MHz NMO mount antenna) to use on the 80 with the FT-8800. After spending a week on the road with Hulk for the Rubithon trip and experiencing the performance of his setup, I was pretty much convinced that having a 2m only antenna offered pretty good performance gains over the combo antennas. I still have my combo antenna should I need it but so far 100% of the time I've only been using 2m so this should work well.

My question is that the antenna comes with a cutting chart to "tune" the antenna. Length on the left if mm and Frequency along the bottom. Length goes from 1200mm down to 895mm to match up with the Frequency going from 144MHz up to 174MHz.

According to the specs the whip is 50" long to start and should be cut to length from there. The link above has the instructions but I am wondering how many people have, or would, even bother to do that? Or would you just mount it and run with it as is out of the package?

Based on the chart, my desired length would be anywhere from 47.25" (144MHz) down to about 45.25" (147MHz). 146.460MHz shows a length of just under 46" is optimal. I'm wondering if I should just trim the whip to 47.25" and call it good, or just leave it as is, or....

corsair23
06-04-2009, 05:39 PM
Maybe that is why it was relatively cheap :)

So would I "dial it in" for something in the middle of my planned use (like 146.460) or for the lowest freq like (like 144.000) ?

Bruce Miller
06-04-2009, 06:35 PM
Jeff, the first thing you have to do is find someone with an antenna analyzer and find out what frequency your antenna is resonant on right now. You have to do this before cutting (or adding) to the antenna's current length. I would shoot for a frequency that you usually use, say, the RS club's 146.46. When your antenna is resonant on 146.46, you should have a very low SWR on that frequency. Your SWR will climb as you change frequencies, up and down. Again, the antenna analyzer will tell you how far from your resonant frequency you may comfortably operate (before your SWR becomes unacceptably high). When you match your resonant frequency with the frequency you wish to operate on, your rig will be putting as much of its rated power into the antenna (transmitted signal) with little waste. (A high SWR can be damaging to your rig, too.) With an antenna that is matched to your desired frequency, your signal will get through where a poorly tuned antenna may not.

You know somebody with an antenna analyzer.

Hulk
06-04-2009, 07:29 PM
I bought a shorter "garage friendly" version of the Larsen a few weeks ago, and tuned it to 146. I figured that I might as well optimize for our normal simplex freq., since that's what I use 90% of the time anyway. I used some diagonal cutting pliers (http://www.craftsman.com/shc/s/p_10155_12602_00945077000P?vName=Tools+%26+Equipment&cName=Hand+Tools&keyword=diagonal+cutting) to snip the whip.

corsair23
06-05-2009, 03:59 PM
Jeff, the first thing you have to do is find someone with an antenna analyzer and find out what frequency your antenna is resonant on right now.

Thanks Bruce...Antenna analyzer = SWR meter? If so, I have a SWR meter which was what I was planning to use. If they are not one and the same then no I don't have one nor do I know anyone that does.


In other words, it should deviate to no more than 1.5:1 over a range of +/- 4MHz from the center frequency. So at 146.460, which is pretty close to the middle of where you'd be operating, you should expect around 1.3:1 as a max SWR at the corners if you're at 1.1:1 on 146.460.

Thanks Dave :) - My guess was to cut/tune for 146.460 and call it good but I like to hear my thinking is sound from a PE :thumb:


I used some diagonal cutting pliers (http://www.craftsman.com/shc/s/p_10155_12602_00945077000P?vName=Tools+%26+Equipment&cName=Hand+Tools&keyword=diagonal+cutting) to snip the whip.

Thanks Matt...I was going to ask what I should use to cut the whip...I call those wire snips...Never knew they had a fancy name...So did you just cut yours based on length or did you "analyze" it first?

Bruce Miller
06-05-2009, 06:43 PM
The two instruments are not the same. An antenna analyzer will connect to the PL-259 connector at the end of your coax. Like Dave said, the transceiver isn't used for this test. Using the antenna analyzer, you dial the meter to show a dip. This dip is your resonant frequency which is shown as a digital readout on the analyzer's meter. You can dial away from your resonant frequency, both higher and lower in frequency, to show the frequency range that you should feel comfortable operating in because the SWR is still at a reasonable level. If the dip matches a frequency far from your desired frequency, then it's time to "trim" the antenna, either by shortening it or lengthening it. I think that is a question on the ham exam, something about the relationship between shortening or lengthening the antenna to increase or decrease the frequency.

Bruce Miller
06-05-2009, 08:03 PM
Jeff, I doubt you will have to adjust the length of your store bought antenna but going through the exercise with the antenna analyzer would make for an interesting project. A quick project, too, as it only takes a minute.

corsair23
06-06-2009, 10:56 PM
Thanks guys :thumb: - Interesting stuff

rhyary
08-11-2010, 08:06 AM
I can't see this link. My user id is not authorized to see this one:
http://www.risingsun4x4club.org/foru...ghlight=setups

Can one of the moderators help?

Rami

corsair23
08-11-2010, 10:04 AM
I can't see this link. My user id is not authorized to see this one:
http://www.risingsun4x4club.org/foru...ghlight=setups

Can one of the moderators help?

Rami

Rami,

That link takes folks to the Members Only section of the forum which unfortunately you don't have access to...You could join the club :D

I looked through the thread and there isn't much there that isn't here in this thread and other threads in the HAM section...I bet if you looked at Romer's ROTW posts on MUD you'd probably see most, if not all, of what is in the thread.

rhyary
08-11-2010, 11:00 AM
Tnx, Jeff.
My 350R stopped transmitting. I can hear very well
When I do radio check with a local repeater, people on the net say that someone is trying to transmit but they can not tell who it is.

So my conclusion for now is that the antenna got whacked somehow. The mag comes with the think coax and it is possible the door got it kinked.

So I went a head the ordered the Diamond setup for the trunk gate.
It comes with the thin coax and it folds as well.
Here is my antenna order in case you guys see something fishy (I got the tri band antenna):
K400C - mounting setup with thin coax
CR-320A - triband 2m, 440, 220
SBB-1 - short dual band for our NE trees.

Rami
Counting the days to Moab 2011.

wesintl
08-11-2010, 11:51 AM
me thinks its a setting on the 350. I have the same radio and I was able to talk to nathaniel on the CC on the way to moab but coming back I was having issues. I haven't looked into it much but I need to get it working. I think with mine though no one was saying they were hearing a transmit but no voice.

corsair23
08-11-2010, 12:02 PM
Tone offset or whatever it is got changed? Sorry, still a HAM noob but I know when I first got my HT and started using it I spaced out the fact that although you can hear folks on the repeater, if you don't have the tone or what not set up right no one can hear you. Although maybe the fact that others were hearing the "break" means that this isn't the case.

nakman
08-11-2010, 12:10 PM
Although maybe the fact that others were hearing the "break" means that this isn't the case.
;)

corsair23
08-11-2010, 12:12 PM
So I went a head the ordered the Diamond setup for the trunk gate.
It comes with the thin coax and it folds as well.
Here is my antenna order in case you guys see something fishy (I got the tri band antenna):
K400C - mounting setup with thin coax
CR-320A - triband 2m, 440, 220
SBB-1 - short dual band for our NE trees.

Ahhh...

You were probably looking for the parts "list". Here is the pertinent info from the thread:

FT-7800R -- Yaesu FT-7800R 2M/70CM Dual Band FM Transceiver. Wide Receive of 108-520MHz and 700-999MHz (Cell Blocked). NOAA Weather Alert. Illuminated keypad & microphone.
K400CNMO -- NMO Deluxe mount. w/6.5' RG-316 Teflon coax & PL259.
SBB-5NMO -- Comet 2M/70cm Mobile Antenna (Black), 3.0/5.5 Gain, 38" Length, NMO Connector

My setup is similar but the FT-8800, K400CNMO mount, and a Diamond antenna similar to the Comet (the Comet was on back order when I was buying).

I've been real happy with the mount aside from finding a reliable way to attach the thin coax to the upper gate to keep it in place and safe from getting pinched. The little doodads/clips that I've been using that have sticky tape fall off in short order when the tape gets hot, wet, etc.

rhyary
08-11-2010, 12:30 PM
I switched the order to NMO type. Changed the short antenna to a diamond antenna to stay with one brand.

Most of the repeaters in my area are open. No need for tone. But the mic has an option (button) to change the tone, so I may have pressed something in inadvertently.

Damn, it was working so well when first installed. But anyway, the mag was only temp anyway.

The only think that could have change by mistake is pressing something on the mic. The 350R comes with multi function mic that has many buttons.

rhyary
08-11-2010, 01:47 PM
Did system reset. Still no worky.
I really hope that the cable got pinched and somehow the new antenna will fix everything. If nothing else but to prove DaveInDenver wrong :-)

But I talked to Yasue tech support and he sort of echoed Dave's opinion. The TX got toast somehow.

I don't have a good confirmation from the guys on the repeater but if they did hear something than that means I am transmitting but not very good. That may point out to the antenna.

rhyary
08-11-2010, 02:53 PM
The 350R has a mic in the faceplate and I tried that.

I have a repeater near by that when transmitting it, it just repeat back its signature. No one else involved. That is not working and it used to work when I got the radio.

In addition I am running APRS on one side and I can no longer see myself here:

http://aprs.fi/?call=KC2YRF-9&mt=m&z=11&timerange=3600

That was working fine.

rhyary
08-11-2010, 03:13 PM
Now that I think about it, something similar happened on my CB during CM2010.
I can hear everyone fine and clear, but when I was transmitting everyone was complaining about noise and squealing. It turns out that the ring of the PL connector was not screwed all the way. Once I tightened it, TX was fine.
Point is, and my hope is, that it can be the antenna/cable even if I can hear clear.

Doing simplex test at 5pm with a co-worker. Having the cars at close proximity should tell us something.

rhyary
08-11-2010, 04:23 PM
Good news.
Simplex worked up to about 1 mile. After that I heard great but co-worker started to loose clearness. By 2 miles I heard him loud and clear and he could not hear me. I guess.

So I would guess antenna or antenna wire. Will be replaced when the new setup is here.

Should be good to go for CM2011 :-)

Rami

rhyary
08-17-2010, 11:03 AM
Well, I installed the new antenna and same thing.
I also did a SWR test on it and no power is coming out of the 350R.
Yesterday it went to Yaesu for warranty repair.
Not Happy!

And yes, turns out DaveInDenver was right after all. :-)

rover67
08-17-2010, 11:05 AM
Wow, bummer to hear that the radio is not working. Good to hear that you figured out what was up though. now at least you know all the in's and out's of the setup you have!

rhyary
08-17-2010, 12:32 PM
Nothing like troubles to get you familiar with your equipment.
I had run the 350R in the back seat for awhile and when I figured out all is good, I perma mounted it in the pass rear quarter. It worked for a while and some point it quit. I was listening for the repeaters around Albany but not transmitting. So I don't really know when it quit. Since I have the APRS, I can track myself and do a radio check that way on regular basis.

Monday I had a day off and worked on getting the 350R out of the back. I also took the time to run the extension properly in the pass side channel all the way to the front. Figure out a way to mount the the face plate. I am pretty happy with the location. I hope it is steady enough.

Back to Antenna topics. I got the 320NMO tri band for experiment on three freq. I also wanted a longer one for the tail. So I was about to get the Diamond 7900. I called Diamond tech support to see what they have to say. Well, they don't want the 7900 off road. The say that because the coils are loaded up high it will swing to much. So I got the 770 instead for the trail. It is open coil design 1/2 wave for 2M and 5/8 for 70cm. That should cover Moab and other expedition type trails, I hope. For the NE trees I have a short NR-72BNMO.

I mounted the KC400NMO on the trunk on the driver side per Diamond instruction. crossed-over and used the 10' extension to get to the radio. Since I only needed about 2 feet extension, most of the 10' is sort of coiled in the quarter panel. I have to see the implications of that when I get the radio back and measure the SWR.

I will load some pictures soon.

rhyary
08-17-2010, 12:52 PM
I am not happy with how the antenna cable enter the trunk. If you guys can make suggestion to make it better it will be great.

rhyary
08-17-2010, 12:57 PM
I took the console apart and stuck the windshield mounting bracket (just the rubber end into a hole I made in the metal mash. Because the plunger type bracket is pretty big, it is held by the plastic grid that is before the metal mash. That give me a strong mounting. the unit still rotated few mm when I push the buttons, so I stuck a small piece of rubber on both ends of the plate to give it support in the corner. time will tell if this is good. I am afraid passengers will bump it or with use pushing buttons the mounting will loosen up. Will see..

nakman
08-17-2010, 01:58 PM
I am not happy with how the antenna cable enter the trunk. If you guys can make suggestion to make it better it will be great.

Mine runs underneath the light brown plastic, all the way up to the headliner. That would bury that connection you show behind the panel, and would look a little cleaner?

And are you using the lip of the cupholder as your mic holder? :eek:

Jacket
08-17-2010, 02:08 PM
Same here. Mine runs all the way down the pillar behind that light brown plastic, and then behind the darker brown plastic to my radio. The rest of the cabling runs up along the door sill to the front.

Will that connector fit behind the plastic, or is it too big?

rover67
08-17-2010, 02:50 PM
you need some of these :)

http://www.gamiviti.com/html/products_micholders.html

rhyary
08-17-2010, 02:56 PM
Don't have blanks left for gamiviti!

I see what I can do to burry the cable. But I am more concern about the entry to the trunk.

wesintl
08-17-2010, 03:02 PM
Don't have blanks left for gamiviti!

I see what I can do to burry the cable. But I am more concern about the entry to the trunk.

cupholder bezel
http://www.gamiviti.com/html/products_bezels.html

corsair23
08-17-2010, 03:29 PM
Since I only needed about 2 feet extension, most of the 10' is sort of coiled in the quarter panel. I have to see the implications of that when I get the radio back and measure the SWR.

Don't "loop" the extra length but rather make it into a figure 8 shape with a twist tie/zip tie in the middle...Per the experts IIRC :D

Don't have blanks left for gamiviti!

I see what I can do to burry the cable. But I am more concern about the entry to the trunk.

What's next to your rear heat switch? I relocated my antenna button down there (never use it anyway) and that opens up a spot. I have the uber cool Gamiviti bezel with mic holder and battery monitor though :)


As for routing the cable...I mounted my base on the PS of the lift gate (I must have missed the recommendation by Diamond to mount it on the DS or I just ignored it :hill:) and then I wrapped the snot out of the cable with electrical tape for protection where it tends to get pinched. I routed my cable to the underside of the mount and then up to the headliner area and behind the molding. You can buy cable "stays" or clips that the cable will clip into but I haven't found any that will stick for more than a few months :( - I'm thinking of ripping off the sticky tape/foam stuff from the clips and trying some strong adhesive instead because with the clips in place the cable stays nice and safe.

Corbet
08-17-2010, 03:58 PM
I am not happy with how the antenna cable enter the trunk. If you guys can make suggestion to make it better it will be great.

I ordered one of the grommets that is used for the wiper fluid hose. I plan to drill a hole into the D pillar by my antenna mount and run it though threre. But I have not taken the time to make sure everything will work yet. I will post up results when done. Just another one of my countless projects waiting for the time.

rhyary
08-17-2010, 04:03 PM
Next to the rear heater is the only blank I have left.
I moved the alarm down.
I use the antenna switch after I disconnect the power since the automatic raising the antenna needs to be reset to extend it all the way manually.

That blank bother me too. I have to find something for it :-)

rhyary
08-17-2010, 04:04 PM
Corbet,
I like your solution, but I will let you drill first!

Would you mind posting a picture where you think you will be drilling? Next to the extising fluid hose?

nakman
08-17-2010, 04:12 PM
What about left of your steering column, any more blanks over there? Pretty easy to extend the wires for hazard or something, then free up another one on the dash.. that is, presuming you want to maintain the cupholder, which could create two more ;)

Hey if you didn't have an LX you'd have 4 more blanks in the center console.. :)

Groucho
08-18-2010, 07:46 AM
Don't "loop" the extra length but rather make it into a figure 8 shape with a twist tie/zip tie in the middle...Per the experts IIRC :D



What's next to your rear heat switch? I relocated my antenna button down there (never use it anyway) and that opens up a spot. I have the uber cool Gamiviti bezel with mic holder and battery monitor though :)

You're getting wise, young grasshopper, but you are not a HAM master, yet!:lmao::thumb:

Ditch that lousy factory Toyota cupholder and get the uber cool Gamiviti dash blank panel (http://www.tallowpot.com/bezels_mikeholders_paypal.html). Then upgrade your cupholder situation with an equally uber cool cup holder(s) setup from these guys TallowPot Products (http://www.tallowpot.com/tranny_hump_cup_holders.html). They reportedly will withstand severe angles during runs or precarious positions and not spill if there is weight in them. Plus they fit nicely in the glove box when the passenger wants to really lounge out. :D

But seriously. You will only find out the best place for everything through trial and error and input from others. I ran all of my cables behind all of the side panels until it was time to go to the center, then I pulled up my center console and went under carpet as much as possible. My antenna coax came in through the bathroom window. Wait, no, it came in through the grommet for the rear window drain. Beatles?

Corbet
08-18-2010, 07:49 AM
Corbet,
I like your solution, but I will let you drill first!

Would you mind posting a picture where you think you will be drilling? Next to the extising fluid hose?

I'm thinking on the D pilliar inside the rear hatch jam. about 6" from the top.

rhyary
08-18-2010, 08:50 AM
Corbat,
I guess I don't know what a D pillar is.

Marco,
Blanks on the left, ARE YOU KIDDING ME?
The antenna switch is actually the winch control via Slee's setup.
ordered gamiviti stuff.

nakman
08-18-2010, 09:20 AM
Man nice work on filling up the switches, you may have to just upgrade to a Land Cruiser center console after all, trade that little speaker in on 4 more.. :D


ordered gamiviti stuff.

:beer: :beer: are on me & Groucho next Moab :bowdown:

Corbet
08-18-2010, 08:59 PM
Corbat,
I guess I don't know what a D pillar is.



D-pillar

rhyary
09-01-2010, 01:13 PM
Quick update, Yaesu is sending me a new radio. should get it this week. That will allow me to test with the new antenna mount mentioned above.

rhyary
09-02-2010, 07:59 AM
Yes. They say water damage. But I pressed on the issue since water damage is not covered under warranty that that gets them off the hook.

They asked for installation location pictures which I provided. Also, I drove a whole day in the rain after I send them the radio and checked the installation location that there was no water there.

There is the possibility that water slided thru the mag antenna wire which came thru the passenger door and was the thick kind. But I am not really sure.

The tech manager was not very clear on what they found. He said the board is not working and it has traces of water. He said they had to replace the whole board $400 plus installation like $80. Basically at that point it was the price of a new radio.

rhyary
09-02-2010, 10:30 AM
Honestly a mobile radio that can't stand condensation is a problem!
It has been a while since my car fit in my garage. I blame MUD for it.
I have the radio installed were many have installed it. In the passenger side, D panel.

wesintl
09-02-2010, 10:56 AM
in that case you might reconsider that location. I put mine under the driver seat

rhyary
09-02-2010, 01:53 PM
I have no proof that the location is bad.

wesintl
09-02-2010, 02:08 PM
well, you think yaesu will give you another if it isn't? not a gamble i would take with that thing in the fender

corsair23
09-02-2010, 02:46 PM
I have no proof that the location is bad.

My DS rear slider or vent or something in that area leaks based on what I found when I pulled out my bottle jack last year to do some work back there. I can't find any evidence of the PS leaking but considered that when I mounted my FT-8800 back there.

We don't get near the rain here that you do so I don't worry about it. That said, Dave brings up a good point with the humidity and temp changes in your area as well that probably creates a good deal of condensation.

Maybe consider making a more waterproof, but not airtight, enclosure for the radio? Of, do like Hulk did and mount it in the "pocket" back there so it is more protected by the plastic surrounding it.

rhyary
09-03-2010, 09:46 AM
The pocket is a good location for me, so I may have to settle on that.
I don't know how to make a container that is waterproof and well ventilated.
After reviewing some of Mark's Alaska trip pictures on MUD I may want to put the radio up in the pocket anyway for any kind of water crossings even if I forget about rain and condensation. Those pictures gave me the creeps.

Rami

Groucho
09-03-2010, 11:42 AM
So it is susceptible to moisture failure depending on conditions. It is not an "all weather radio".

The FT-2900R (along with its predecessor the FT-2800M) IS made to MIL STD 810, and Yaesu's FTM-10R is made to IP57 which means it is dust protected and can sustain submersion to 1M.

The first radio is not able to have the faceplate removed for remote placement, the second is.

It sounds like the purpose for the FTR-350 was supposed to be an "All weather Radio". My advice would be to do the best job possible to protect it from the elements. Keep it cleans. Don't do water crossings that would allow water above the floor of the vehicle. Otherwise, the FTM-10R is a better choice.

corsair23
09-03-2010, 01:53 PM
I don't know how to make a container that is waterproof and well ventilated.

Not waterproof, just more waterproof than sitting in a big open area :)

The pocket won't be waterproof, and with the cover on not all that well ventilated but I don't recall Hulk ever saying he's had an issue. His radio survived the Rubicon trip with some pretty deep water crossings so....

As for a waterproof enclosure, I was thinking of a box with vent holes/slots in the bottom and sides but not the top. Big enough that there is plenty of air around the radio for the fan to circulate and hopefully any water/condensation will go out of the bottom instead of onto/into the radio. That said, the most impressive thing I've build was a sub enclosure years ago for 2 10" subs so I don't have much experience/knowledge in this are.

rhyary
09-03-2010, 01:57 PM
Just got a call from Yaesu with a tracking number. should be receiving it today, Friday. Which is a good thing as I am planning to go on the trails Saturday and to my property on Monday. When I am on my property (big) by myself, the radio becomes important should anything happen. I have a local repeater near by. One of the reason for the FT350 is that I plan on getting, eventually a protable. I can configure the portable to talk to the 350 and the 350 to relay out with 50W. Typically I will be chainsawing trails a way from my car so a portable on me in case some sugar maple or big pine tree falls on me I should be able to radio for help. I think the FT350 is going into the rear passenger pocket giving the above discussion.

corsair23
09-03-2010, 02:09 PM
You could get real fancy and design a box (nearly waterproof) with inlet and outlet fans to keep the radio cool :)

Groucho
09-03-2010, 03:13 PM
It sounds like the purpose for the FTR-350 was supposed to be an "All weather Radio". My advice would be to do the best job possible to protect it from the elements. Keep it cleans. Don't do water crossings that would allow water above the floor of the vehicle. Otherwise, the FTM-10R is a better choice.

Dave, I was implying that rhyary might have intended his choice of radio to be an "all weather radio". That idea I was suggesting was a poor one, and suggested the FTM10R as a suitable replacement. Even though it is FM, the 10 W power should be adequate with the right antenna for the intended use.

Don't you agree?

rhyary
09-08-2010, 09:40 AM
Not waterproof, just more waterproof than sitting in a big open area :)

The pocket won't be waterproof, and with the cover on not all that well ventilated but I don't recall Hulk ever saying he's had an issue. His radio survived the Rubicon trip with some pretty deep water crossings so....
experience/knowledge in this are.

The radio went into the pocket. It is a bit cramp there, but I think the radio has some thermal protection and I will take that over water damage.

Overall I am very happy with the setup. I was able to hit a repeater 33 miles away with the diamond (770) 1/2 antenna. Sporadically I was able to get 50 miles to a repeater but only when I was on high grounds.

The location of the face plate is great and convenient to use. I saw on another web site that a mounting bracket from the FTM-10 will fit the 350. I wish I knew that because it would have been a better to use that bracket than using what came with the 350. The main difference is that the FTM-10 bracket has two mounting bolts and the 350 has one. So in order for faceplate not to twist, I had to tighten it more than I want to. I can upload pictures if anyone interested.

corsair23
09-08-2010, 01:00 PM
I can upload pictures if anyone interested.

We ALWAYS want to see the pictures :hill:

I've decided that I am going to have to do something different with my antenna coax routing. It creates enough of a gap in the weatherstripping that I get water in the rear of the LX going through a car wash. Of course the water that gets in there is NOTHING compared to the literal flood I get during a car wash from the sunroof area :(

rhyary
09-21-2010, 09:02 AM
My last blank position has been used for the 3 way selector. Gamiviti did not work for me because at the end I did not want to loose the JDM cap holder. So I installed the digital display in the ashtray. I can close the ashtray at night if the light bothers me.



I needed a 3 way rotary switch for the digital display since I am monitoring the two batteries and the digital filterminder yet to be installed.

All the wiring is done. I really enjoy seeing the voltage information. I can see how my ham radio affect voltage when transmitting, I can see how it drops when I start the car. I can see how the alternator pump 14.3V and then quites down to 13.8.

I really like all this information, but I am weired, I like to watch the progress bar when installing applications on computers. God help me......

Rami

60wag
09-21-2010, 10:18 AM
I moved the alarm indicator over to the left side of the steering wheel where there are more blanks. The wire behind the dash was long enough so that no rewiring was needed.

rhyary
09-21-2010, 10:35 AM
I moved the alarm indicator over to the left side of the steering wheel where there are more blanks. The wire behind the dash was long enough so that no rewiring was needed.

More blanks? Marco already said that joke... :-)
http://www.risingsun4x4club.org/forum2/showpost.php?p=159335&postcount=97

60wag
09-21-2010, 04:00 PM
Hmmm.. well you still have options: toss the alarm indicator inside the dash somewhere because you don't really need to see it, or get out the jigsaw and start carving rectangular holes in the dash :)

rhyary
09-22-2010, 05:25 AM
I thought about it, but on the LX450 there is a sensor located next to the blinking red.
I think it is for inside temp for the auto climate control.
I didnt want to mess with it further. it has been already moved from up row to low row with unknown consequences. It may be the cause for 12mpg?
Just kidding.

60wag
09-22-2010, 06:42 AM
I think the sensor is the glass breakage sensor to trigger the alarm.

corsair23
09-22-2010, 11:15 AM
I think the sensor is the glass breakage sensor to trigger the alarm.

Yep, that be what it is and whether it even works?

Rami, the sensor for the HVAC that you are probably thinking about I believe hides somewhere behind the little "vents" below the fan off button. IIRC there is a white tube stuck to the back of the vents that goes off somewhere...

rhyary
09-22-2010, 02:03 PM
Rami, the sensor for the HVAC that you are probably thinking about I believe hides somewhere behind the little "vents" below the fan off button. IIRC there is a white tube stuck to the back of the vents that goes off somewhere...

Oh yea, I think you are right. I porgot bout that one.

Inukshuk
03-26-2011, 06:59 PM
Revival -

Current Antenna: Larsen NMO 150 5/8 wave ground plane antenna for trail and a shorty kept handy in the rig.

An Elmer member to be suggested a "no ground plane antenna". Maybe, but:

Will the expanded metal floor of a roofrack function as an effective groundplane? If not, and if I wish to avoid drilling the roof for a mount, which BTW would then cause the antenna to be sitting low relative to the rack, would a metal disk, probably stainless sheet, make sense to do? Could the disk be effective if it was on the underside of the expanded metal or must it be on top? What size? My reading suggests 18" diameter.

Also, the expanded metal is heavily powdercoated. Does the mount need to have clean metal contact to the expanded metal - which would perhaps be another reason to just locate a disk up there.

OR, should I just clamp it to a crossbar and call it good.

I also plan to move the CB antenna up there.

Will metal fuel cans interfere?

I assume non-metallic loads will not (ie, firewood, plastic gear boxes, etc.)

Thanks!

Inukshuk
03-27-2011, 01:49 PM
An antenna in the middle of that expanded metal floor would be about as perfect a mobile VHF or UHF as you're likely to find!

Dave, you rock.

....Radio waves will find anything conductive for their return path.... It's your job to give the energy an efficient way to get home to the radio

Doesn't the coaxial provide the return path to the radio?

Just need to remove powdercoat enough to make contact at one spot.... If it was electrically isolated at the feedpoint, that would be a problem....

What is a "feedpoint"

The contact at the one point, is it for the antenna bracket, which then provides the ground plane connection to the antenna?

CB: Same principles apply, although the size of the ground plane grows from 18" to about 8 feet. Everyone runs a compromised ground for CB (and HF ham for that matter). Our best hope is that the whole car acts reasonably like a ground plane. The mount for the CB antenna needs to conduct to the rack and it would be best if the rack itself was also conductive to the truck body. See the thread on 'bonding' that KD2KDK started when doing his HF radio installation.

Would the same ground wires used for the lights work for the CB ground, or must I run the lights on a ground wire back to the battery and separately ground the rack to the roof?

Thanks!

Seldom Seen
03-28-2011, 05:15 PM
OR, should I just clamp it to a crossbar and call it good.


Yep, get a roof rack mount and make sure you have a good electrical connection, then switch the NMO 150 for a 1/2 wave (something like a MNO 2/70) and call it good. You have plenty of metal under the antenna to dissipate any common mode current (is that the correct term, Dave?) keeping it off the feed line.

Don't get hung up on "ground planes" unless your running a ground plane antenna ie: 1/4 wave whip. A half wave is a "no ground plane antenna" but reality it's a ground "lessdependent" antenna, no ground plane required you just need to keep the feed line from radiating.

For the Chicken Band antenna, use a couple of ground STRAPS not wire. They'll be good for RF and DC.

Inukshuk
03-29-2011, 12:55 AM
Yep, get a roof rack mount and make sure you have a good electrical connection, then switch the NMO 150 for a 1/2 wave (something like a MNO 2/70) and call it good. You have plenty of metal under the antenna to dissipate any common mode current (is that the correct term, Dave?) keeping it off the feed line.

Don't get hung up on "ground planes" unless your running a ground plane antenna ie: 1/4 wave whip. A half wave is a "no ground plane antenna" but reality it's a ground "lessdependent" antenna, no ground plane required you just need to keep the feed line from radiating.

For the Chicken Band antenna, use a couple of ground STRAPS not wire. They'll be good for RF and DC.

Sean is also advocating the "no ground plane" antenna. Either way it looks like I'll want a rack to body ground strap.

Inukshuk
03-29-2011, 11:45 AM
Being ground plane independent is a misnomer, an end fed 1/2λ antenna still needs a return path. Being 1/2λ just means the antenna is self resonant and does not need the counterpoise to radiate RF.

The feedpoint impedance will be VERY high and can develop a pretty sizable voltage (at 50W it can be 250 to 500V pretty easily, the theoretical feedpoint impedance is infinite and practically ends up >1800 ohms). This is a particular problem if you don't give the antenna a balanced feed, i.e. when you use coax and mount it with zero ground plane. It is critical that the antenna mount be grounded. This is why Larsen recommends an NMO mounted in the roof of your car or artificial ground radials. Trust me, you can get a pretty good tickle from outside of an uninsulated floating 1/2λ feedpoint...

BTW, this is not common mode current per say, but a byproduct of the actual differential counterpoise currents (consider it the 3rd path on the outside of the shield, you will have current on the center conductor and the inside of the outside conductor). So choking the shield is a band-aid for antenna inefficiency. OTOH, without a choke the coax will be radiating, which is never good.

This is the problem with unbalanced feedlines, resonant antenna currents are always differential and there has to be a conversion somewhere if you feed with unbalanced cable (coax). If you don't provide it, RF will figure it out for you (it finds the assumed capacitively coupled return) but it might not be ideal. Antenna manufacturers know this limitation and build in LC tanks to couple the feedpoint (transform impedances) to the unbalanced feedline, but that circuit is assumed to be referenced to RF ground. It should be mentioned that it's almost impossible to have a 100% balanced system, so chokes are absolutely acceptable to minimize common mode currents on coax. Just key to understand that choked currents are lost to heat and are not doing any work for you.

Thus, this is why people drill NMO holes or bolt directly to the body of the truck. IOW, if you are mounting the antenna electrical isolated from your RF ground the advice to use braid to ground the outer ring of the mount is very good indeed.

Great advice. I just don't have the brainpower to understand it.....