Rising Sun Member Forums  

Go Back   Rising Sun Member Forums > Other Hobbies > Ham & CB Radio Corner

Reply
 
Thread Tools
  #11  
Old 02-11-2009, 01:07 PM
MDH33's Avatar
MDH33 MDH33 is offline
Rising Sun Member
 
Join Date: Mar 2006
Location: Land of Corn
Posts: 5,787
Default

Quote:
Originally Posted by Bruce Miller View Post
Coil the extra coax into about an 8" diameter loop then zip tie the loop in its center to form a figure 8 in the coil. Doing this will prevent your introducing problems into your antenna system (read: high SWR) from a circular coil causing unwanted inductance in your antenna feed line. Make sense?
I have been having trouble transmitting in my 40. I have a Cobra 19DXIV and a 3' Firestik antenna. I have about 10 feet of extra coax that I have coiled and zip tied as Bruce suggested. I also grounded my antenna directly to my frame and have no continuity between the center pin of the coax and the outer threaded portion. I wired the CB direct to the battery. I hooked up the SWR and I get a nice low reading. However, no one can hear me on runs and when they do, they tell me it is very garbled and noisy...

Any ideas? I would really like to finally get this thing working... before I put the new HAM in and start having trouble with that too.
__________________
--Martin

'85 FJ60
Reply With Quote
  #12  
Old 02-11-2009, 01:19 PM
Groucho's Avatar
Groucho Groucho is offline
Rising Sun Ham Guru
 
Join Date: Aug 2005
Location: Arvada, Colorado
Posts: 1,650
Default

Quote:
Originally Posted by MDH33 View Post
I have been having trouble transmitting in my 40. I have a Cobra 19DXIV and a 3' Firestik antenna. I have about 10 feet of extra coax that I have coiled and zip tied as Bruce suggested. I also grounded my antenna directly to my frame and have no continuity between the center pin of the coax and the outer threaded portion. I wired the CB direct to the battery. I hooked up the SWR and I get a nice low reading. However, no one can hear me on runs and when they do, they tell me it is very garbled and noisy...

Any ideas? I would really like to finally get this thing working... before I put the new HAM in and start having trouble with that too.

Can you drive it to the HAM class monday night? I'd like to see for myself what is happening...
__________________
--Choose Wisely--
Reply With Quote
  #13  
Old 02-11-2009, 01:28 PM
Uncle Ben's Avatar
Uncle Ben Uncle Ben is offline
Rising Sun Member
 
Join Date: Aug 2005
Location: Louisville, Colorado
Posts: 13,149
Send a message via AIM to Uncle Ben
Default

Quote:
Originally Posted by MDH33 View Post
I have been having trouble transmitting in my 40. I have a Cobra 19DXIV and a 3' Firestik antenna. I have about 10 feet of extra coax that I have coiled and zip tied as Bruce suggested. I also grounded my antenna directly to my frame and have no continuity between the center pin of the coax and the outer threaded portion. I wired the CB direct to the battery. I hooked up the SWR and I get a nice low reading. However, no one can hear me on runs and when they do, they tell me it is very garbled and noisy...

Any ideas? I would really like to finally get this thing working... before I put the new HAM in and start having trouble with that too.
Borrow someones Mic and try it!
__________________
KUBN
Kevin
TLCA #3007
Northside!

Colorado Trail Patrol
Stay on the Trail!
I'm the God-fearing, gun-toting, American flag-waving, conservative you were warned about!
Quote:
Originally Posted by AxleIke View Post
I need an FJ40....
Quote:
Originally Posted by Red_Chili View Post
Cruisers are superior
Reply With Quote
  #14  
Old 02-11-2009, 03:14 PM
MDH33's Avatar
MDH33 MDH33 is offline
Rising Sun Member
 
Join Date: Mar 2006
Location: Land of Corn
Posts: 5,787
Default

Quote:
Originally Posted by Groucho View Post
Can you drive it to the HAM class monday night? I'd like to see for myself what is happening...
Will Do.

Quote:
Originally Posted by Uncle Ben View Post
Borrow someones Mic and try it!
That's what Randy suggested too and we swapped out the mic on the last snow run and no change.
__________________
--Martin

'85 FJ60
Reply With Quote
  #15  
Old 02-11-2009, 03:48 PM
DaveInDenver's Avatar
DaveInDenver DaveInDenver is offline
Hard Core 4+
 
Join Date: Jun 2006
Location: Larimer County
Posts: 6,552
Default

Quote:
Originally Posted by Bruce Miller View Post
Did you mean tune the antenna to the transceiver for $30? Because if you're paying somebody any amount of money to "tune" your CB radio, you're getting ripped off. You cannot "tune" your CB radio to have better transmission. You can tune your antenna to your radio, though. Is that what you meant to say?
You are 100% right that you cannot legally 'tune-up' a radio to transmit more power than is legal for a CB (4W carrier power), but there is nothing wrong with having a tech refurbish a radio to bring it up to spec.

It's an RF device like any other. CBs are usually very old designs (if not just simply old in age) and are usually full of discrete parts. Caps in particular age and drift out of tolerance, which can degrade performance badly. The guys at Radio Service Center when they do a 'tune-up' give the radio a once over, R&R bad parts and bring the radio up to legal limits, which is a perfectly legitimate thing to have done.
__________________
'91 Toyota Pickup
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29

"They say the test of literary power is whether a man can write an inscription. I say, 'Can he name a kitten?'" -- Samuel Butler
Reply With Quote
  #16  
Old 02-11-2009, 04:16 PM
LARGEONE's Avatar
LARGEONE LARGEONE is offline
Rising Sun Member
 
Join Date: Jun 2007
Location: Broomfield, CO
Posts: 683
Default

Thank you, Bruce. I knew there would be a trick!

Is it also important to not run the COAX parallel to other electrical (12V) lines? I know with speaker wire in my surround sound at home, I had to make sure to try to cross 110v power at 90* and not run it parallel.

Thanks for your help.
__________________
_______________________________
Paul
Horribly Painted '95 FZJ80 Has Some - Still Needs More!
"Just because California does it, doesn't make it a good idea, or the right way to do it! If you like California so much, please move there. Don't make the rest of us live in the same HORROR!!!"
Reply With Quote
  #17  
Old 02-11-2009, 11:14 PM
farnhamstj's Avatar
farnhamstj farnhamstj is online now
Hard Core 4+
 
Join Date: Aug 2005
Location: vail co
Posts: 2,581
Default

I recomend drilling a hole in the flat horizontal part of the ARB bumper. The light tab holes are too big and your antenea will work it's way loose. I have a 48" firestick with a quick release at the base. I think it was $20. I also have a Uniden CB about a $45 model that's small. coax cable was like $15. They come in certain sizes I asume they need to be certain lengths to function properly. Be sure you get a coax cable that you can unthread one end in order to pass it through the firewall. Don't forget the Mount. connects the co to the antenea. fits into 5/8 hole that you drill into the arb. About $5. I never tuned mine and it has a couple-three mile range sounds pretty good. Give yourself more time than you think to install it well and try it a few times before CM. It sucks running around last minute on something so easy to do before hand. www.gijoesradioelectronics.com/
I agree do not pay for a "tune the radio" before it is shiped to you. The antenea is tuneable with some help from your friends.
__________________
98 uzj100. Factory rear-ARB front locked 4.88's. ARB Bull, Warn 9000, Irbis rear bumper, Slee sliders and belly pan. OME t-bars w/863 rears, HID, XM
KD0GWO

Last edited by farnhamstj; 02-11-2009 at 11:27 PM. Reason: more info
Reply With Quote
  #18  
Old 02-12-2009, 06:43 AM
Groucho's Avatar
Groucho Groucho is offline
Rising Sun Ham Guru
 
Join Date: Aug 2005
Location: Arvada, Colorado
Posts: 1,650
Default

Quote:
Originally Posted by DaveInDenver View Post
You are 100% right that you cannot legally 'tune-up' a radio to transmit more power than is legal for a CB (4W carrier power), but there is nothing wrong with having a tech refurbish a radio to bring it up to spec.

It's an RF device like any other. CBs are usually very old designs (if not just simply old in age) and are usually full of discrete parts. Caps in particular age and drift out of tolerance, which can degrade performance badly. The guys at Radio Service Center when they do a 'tune-up' give the radio a once over, R&R bad parts and bring the radio up to legal limits, which is a perfectly legitimate thing to have done.
Absolutely. If someone owns a CB that has been a very stable workhorse for years, the FCC regs prohibiting internal modifications state that certain exemptions are allowed, primarily repair or servicing of a CB transmitter to include changing plug-ins that were certified as part of that CB transmitter's design. It is like getting new belts on the cruiser. Parts that are, by design, going to wear out can be replaced, that way the maximum efficiency can be maintained.

Of course the argument then is, a new CB radio is only $10-$20 more than repairing the unit at $30 (which may or may not include replacement parts), so how much do you love your grandfather's CB? (I myself have and sometimes use my grandfather's CB. It is a Realistic, if that gives any indication to how old it is. But it works.)
__________________
--Choose Wisely--
Reply With Quote
  #19  
Old 02-12-2009, 07:01 AM
Groucho's Avatar
Groucho Groucho is offline
Rising Sun Ham Guru
 
Join Date: Aug 2005
Location: Arvada, Colorado
Posts: 1,650
Default

Quote:
Originally Posted by LARGEONE View Post
Thank you, Bruce. I knew there would be a trick!

Is it also important to not run the COAX parallel to other electrical (12V) lines? I know with speaker wire in my surround sound at home, I had to make sure to try to cross 110v power at 90* and not run it parallel.

Thanks for your help.
It is not as consequential to keep 12V lines away from coax as it is to, say, keep from squeezing the coax (for example when we run a mag-mount antenna's coax through the door and squash it when the door closes).

Most vehicles today have wiring running down both sides of the vehicle, so staying away from the 12V lines may be more difficult than practical. Ideally the coax should be on its own, yes. Realistically, being able to do this may be more trouble than its worth. The principal idea behind mobile installations is to minimize as much interference as possible, because it will never go away entirely.
__________________
--Choose Wisely--
Reply With Quote
  #20  
Old 02-12-2009, 11:52 AM
DaveInDenver's Avatar
DaveInDenver DaveInDenver is offline
Hard Core 4+
 
Join Date: Jun 2006
Location: Larimer County
Posts: 6,552
Default

A couple of points to add to Groucho's comments.

1. Regarding CB and repairs. I should have mentioned that repairs have to be done by FCC licensed techs, this is not something that you can legally do yourself. That is very much unlike ham, where you are not only allowed but expected to tinker with your radios!

2. As far as repairing an old radio vs. buying a new one, that's a valid point that it might not necessarily be all that much savings. Although $20 saved is $20 more you have, not to mention it's a lot better than tossing an old radio into the trash, right? Plus, even a new radio isn't necessarily perfectly tuned, it's been handled a lot coming from China, experienced temp changes, humidity changes, things burn-in during the first few hours of use. It possible that even a year old radio is already under performing quite a bit. Just like a brand new engine breaks in, etc., so do electronics. In fact everything that is launched into space is already used for hundreds of hours to make sure everything has drifted, burned-in, failed if it's going to, etc. And these are $5 resistors, thousands of dollar ICs and ASICs and the like with known history and ultra careful handling. Still ESD will occasionally get a part, natural fall out will kill a part, etc.

3. In car installations it's not 12VDC that is the problem, but switching. The problem with running a coax next to a static 12VDC wire is more that you might induce noise into the car system more than the radio (i.e. make dash lights flicker, screw up your clock, weirdness like that). But if you run a coax next to say some of the wires that run to or from the ECU, then 12V switching is more than enough to introduce noise into the radio coax. It's safest to consider every wire potentially switching and do your orthogonality checks and keep separation. But that's also not really practical all the time, so sometimes you have to make due. This is also a function of the quality of your coax, workmanship on connectors, etc. Good coax can shield the signal better than cheap coax, so it's less likely to leak or be susceptible to induced noise.
__________________
'91 Toyota Pickup
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29

"They say the test of literary power is whether a man can write an inscription. I say, 'Can he name a kitten?'" -- Samuel Butler
Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -6. The time now is 08:00 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.