View Full Version : Mobile HF: Mounting HF antenna on the 4x4lab Jerrycan carrier
11-04-2010, 11:18 AM
It looks to me that mounting the HF antenna on the Jerrycan carrier can provide substantial mounting point.
Either welding a tab or with attaching a tab with U bolts to the top ring.
That would start the base of the antenna about half way. The coil can be then mounted behind the truck with only the whip sticking above the roof line.
Obviously the connection will have to be cleared from powder coating for good grounding. Do they make conductive paint I can use to protect from rust?
There are two issues I can see:
1. Trees - branches chopping off the setup
2. Off-Road extreme vibration
For me the screwdriver multi freq antenna type are out.
So I am looking at HF radio with automatic antenna tuner inside the vehicle, a permanent mount and coil, and manually attaching different whips depending on the bandwidth.
For start may only do 10M or 20M. and see how it goes.
Looking for any comment, suggestions, DOs and DONTs. regarding Mobile HF.
Specifically doing HF in Moab type environment (open desert type expedition) would also be very helpful.
11-04-2010, 01:18 PM
that you've taken this step. I hope to hear you on the air soon mobile HF.
It is an awesome feeling to make those types of contacts. When I was riding shotgun on the "Ladies in 80's" run, I was able to make a 5-9 contact with a station operating a contest on the big island of Hawaii while I was at the top of (IIRC) Kingston Peak at about 12000' ASL.
I personally believe that this website is the most comprehensive mobile HF website around. It can be somewhat technical sometimes, but nevertheless, it is full of great knowledge that will, if followed, drastically improve your mobile station's ability and safety.
Check it out. If it somehow needs clarification, ask here.
My answer to the removal of the paint and rust issue was to make my mount out of stainless steel and weld it before paint. The other option I would suggest is to bare the metal and use dielectric grease like Butter Its Not (http://www.bencher.com/ham/index.php?main_page=product_info&products_id=28).
You need to read the section of the website entitled "Bonding" and follow it closely. The "antennas, commercial" article will also give you a head up on what not to buy.
There are actually antennas sold which are nothing more than a 50 Ω resistor with a radiating element (?) attached to one end. Obviously, they rate an F. One of these is the Maxx-Com. At $400 it is as costly as some screwdriver antennas.
The Comet HA-750BL is similar, but uses a very lossy, 6:1 impedance transformer, It is even worse than a dummy load if that's possible. It appears Comet has come to their senses, as the antenna is no longer listed on their web site.
Comet's UHF 6, shown at right, isn't any better. At less than five feet overall (72 inches with 80 meter coil), coils wound with #26 wire, it is the epitome of a dummy load on a stick.
The Diamond HV7A isn't a dummy load per sé, but it might as well be. Besides UHF and VHF, it covers 6 and 10 meters, plus one other HF band (40 and above). Its overall length is just 50 inches, and the coils are not just small, they're miniscule. The optional 40 meter coil is wound with what appears to be size #26 wire.
The Opek®, shown at left, shouldn't be called an antenna. With just 100 watts of power, the coil gets very warm after just a minute or two of operation.
If you buy one of these F rated antennas, you're throwing your money away.
11-04-2010, 03:06 PM
Thank you. Reading http://www.k0bg.com/
Also there is an exam given on the 11/13/10 and none I can see after that.
So I will be studying full time till then and hopefully will passed the extra and be done with it.
Dave, believe it or not, but I almost understand what you say...... give me two more weeks.
11-04-2010, 03:39 PM
You guys are making me want to get my General and Extra..... I guess I could talk to the Denver area from the desert in Utah huh? Man, that'd be handy.
11-05-2010, 08:44 AM
Welcome to HF. No matter which way you go, mobile or base station, most all of your resources (money, effort, etc) should go into your antenna. A rule of thumb is the best antenna is the one with the most aluminum in the sky and as high as you can get it. To help choose a commercial antenna, go to www.eham.net. In the reviews section, you will get comments from other hams regarding the pros and cons of just about any ham gear you can imagine. Also, I would stay clear of 10 meters. Openings on 10 meters are few and far between due to our current sunspot numbers. 10 meters is a fun band (when it's open) and 10 meter antennas are small and easy to pack. Currently, the workhorse band is 20 meters (17 meters is a close second). But the physical size of 20 meter antennas make them a pain (20 meters = 66 feet!) in the rear. A good mobile antenna brand is HI-Q but at $500 and up they are out of reach for many. You get what you pay for and like I mentioned earlier, most of your system's cost should be in the antenna. Have you considered homebrew? When you build your own antennas you learn quickly what works and what doesn't. I like Dave's idea of not operating while driving but rather set up your temporary station when you get to a good spot. In Moab that might be a high spot on the trail. Good luck.
11-05-2010, 01:53 PM
The General is doable as it extension of the technician into HF.
The Extra is a B#tch. High School/College all over again and I did not study physics.
It is interesting and challenging but not sure if it is useful.
Groaning moaning and whining in NY.
11-05-2010, 02:08 PM
Dave and Bruce,
Are you recommending to forget about the antenna tuner such as the LDG 200Pro?
I understand of all the infinite possibilities. But I like to start with something concrete, learn about it and then if I want to venture into other territories I will.
Currently my interest is focused on mobile communications with all its limitations and constrains. I am OK with picking up a band such as 20M and just work it up until I am ready to learn new stuff.
What Marco mentioned up a thread, being in remote location and communicating to event base such as BFE is appealing to me.
Looks like I am dreaming about the Kenwood TS-480HX (200W) with the LDG 200Pro and a 20M setup. A local guy has the TS-480SAT and he helped another guy setup in base station the TS-480HX with the LDG200Pro. I have not met him yet, but he sounds logical over the 2M repeater.
I am ok with stopping to operate if this is what required, but I would like to be it like a cell phone. Once stopped, operate not configurate.
11-06-2010, 08:13 AM
I think the best place to go for mobile operation help and advice is, like Nathaniel mentioned earlier in this post, www.k0bg.com.
Are you currently on HF now? If so, I think 14.185kHz is one spot the mobile guys hang out on. You may want to listen in on that frequency (I don't think you can transmit there as a novice or a general), copy some call signs, then email the guys who are into mobile operations and ask for help. Some mobile ops have great signals. How they do it I don't know. I'm into base station operations. Playing radio in the car doesn't appeal to me.
11-06-2010, 08:25 AM
I should have said playing radio in the car doesn't appeal to me, but setting up an HF operation in the middle of nowhere and talking to the world is very appealing.
I think it would be really cool to setup a portable station on some high, rocky point around Moab and talk to somebody on the other side of the world. But the high spots we wheel around in Moab are no place to string a dipole. My bet would be on some sort of vertical antenna (either truck mounted or disassembled and tied to the roof rack for assembly later) with a bunch of radials strung along the ground.
11-06-2010, 08:50 AM
I dont have HF equipment yet
the best way to describe what I am after is that I want my "shack" to be my car, not the house. And I'll take all the limitations that come with it.
To that extend, I can design the shack for "in motion" or "static"
In addition, I am coming into the activity late with terrific equipment available.
So for practical decision point I am only interested in what is available today, not was not available 10 years a go
you guys are tremendous help, many thanks.
11-07-2010, 11:38 AM
The antenna Sean uses for his 60 has 10-80 meter cababilitys, forgot the name of it. His setup is a more stationary when talking. But we were able to make contacts to Washinton St, Alaska and Tasmania. Tried to get W0IIN on the air but he wasnt in the 80 at the time:blah:
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