CB Radio Amplifiers

[Tiretool]

Anyone know (in detail) how to make one of these? Got a list of parts I can hit up Radio Shack for? Got a web site explaining how to assmeble?

[Tiretool]

Come on Toaster, I know you have some skills in the electronics dept.

[jessho]

http://ctrlcom.com/maycom/amp.html

I don't know if this will help, but good luck.

[Toaster]

Define "CB amplifier" do you mean a "linear" type aplifier or a simple audio amplifier?
Big difference, one is easy and the other is a bit tricky.


The Linear version amplifies the outgoing signal.
The audio version is simply to increase speaker power.

[Tiretool]

A linear amp... maybe a 150 or 200 Watt unit...

[Toaster]

A liear amp is not something one should attempt unless one is very familiar with high frequency curcuits. Linear amps are VERY tricky to tune and build and parts are a problem as well. The parts MUST be close tolerance parts because the curcuit MUST be very stable and clean. I`ll look through my "projects" of yore, it`s been a while since I dabbled in communications type curcuits. I do see these at "hock" shops on occaision but not in the wattage you wish.

[Tiretool]

What wattage do you see them in? From what I understand, they are outlawed by the FCC for use on CB radios, so why would they be freely for sale at hock shops?

[lukedamac]

I had one of those "squash boxes" named so beacause while using it you drown out everyone in a 30 mile radious. It was 80 watts. I never took a screwdriver to it though. I had one hell of a rig, radio shack cb4000xt 40chan had the plug in crystals w/ tuners, omni and directional tennas about 60 feet up. If I didnt like you id point my arrowheads at you and blast yah with 80watts of squeeling haha. Wish i hadnt sold all that stuff, it was pretty fun, before computers were practicle. they are illegal, heard stories of fcc tracking you down.

Luke DaMac

[Toaster]

Most Linear amps were designed for ham use and adapted for CB use. Thats why the end up in hock shops.
I believe that the FCC limited CB to 5 watts total radiated power. (I may be wrong here)
The "squash box" you refer to is a converted ham linear amp and what you suggest in the way it performs is very typical.
They tend to "trash" everything in a 20mi. radius, including broadcast TV and radio. This is why the FCC comes around and confinscates equipment.
Better built linears for CB`s dont have these charictoristics and are less likely to arouse the FCC`s need to "get difficult".
The amps I see are in the 25-100 watt range of "typical" manufacture.

[Tiretool]

If anyone on these forums has or knows where they can get one of these, I'd be willing to make a deal!

[Toaster]

Hey there tool,
Like I said, I see them in hock shops. Give me your price range and wattage and I`ll keep you informed.

[Tiretool]

I never see them in the local pawn shops here...

I'd be willing to pay up to $100 for a 85-100W model.
Thanks!

[bailey]

I do hope that every one here is well aware that it is illeagle to own or build one of these devices in the United States, they are in violation of the FCC rules and regulations, and heavy fines and penilites are enforced in there use, and I would file a complaint to the FCC of anyone I know of that is useing one. I feel as strongly about this as I do about drunk drivers.
so be forewarned.

[Tiretool]

Well, be aware... they don't cause wrecks and kill innocent people, and I don't live near you and wouldn't be worried about your "complaint" if I did... The chances of the FCC tracking down and punishing a person running one of these "squash boxes" seems nil to me. I've heard several people who run them locally on the radio for years... and they're still running them and have never had run-ins with the law about them to my knowledge.

So there!

:P

[bailey]

don't misunderstand me, I don't complaine untill it interferes with me, most operation with illigal cb stations are on the amature 10 meter band, causing a lot of anger with the amature's and they will track down the problem for the FCC and insure the final outcome. likewise I dont complaine with drunk drivers till they interfere with me.

amature's do police there own frequencys in a very effective way

its still breaking the law no matter how you look at it

[Tiretool]

In all sincerity, if you're using one with malicious intent, then you deserve to be blasted by the FCC... I understand that they are illegal. But, if you're wanting to get out a little further on your transmit signal, there's really no other way to do it, other than a base station with a high antenna, and if you're not being a pest and "walking" on other people, I see no problem with it.

Anyways... no offense Bailey.

[bailey]

I tend to agree with you, but the biggest part of the problem is in the design of the amp, first most are setup for at least 100 watts od drive to function properly, people try to drive them with much less power and in doing so causes improper biaseing which creates sperious signals that is amplified with the signal resulting in a output that is on more frequencys that intended, resulting in the interferance, to use one of these with a cb radio, you must first insure that the driving signal is clean and not more than the 100 pecrent modulation, and has no spurious sideband signals, this can only be detected with a spectrum anaylizer, which most people don't have,
there they go ahead and hook them up, drive them with all they got, then add a power mic to get all the audio punch they can, which causes overmodulation, which then caused the interfereing signals in the output to the antenna. and I know that every cb'er out there knows what this can do to chanel two on there own tv at home.

when done properly, it will work fine, but 99 percent of them don't.
it realy don't take a very strong signal to cause great havic in radio reception, something as simple as slite leakage from a cable tv system can distroy reception of the 2 meter ham band. any leakage is also illeagle and delt with very quickly, upon recept of a complaint of catv leakage they are contacted by the FCC and given 10 days to correct the problem.
sorry for the long response, but this hits on a subject that I love to cure, any type of radio interferance. I have spent 40 years traceing down this type of problem, I realy enjoy it.

bob bailey wb7dmx

[Tiretool]

Is that your ham radio handle?

[bailey]

handel? hams don't have a handel, we have call letters that are issued by the FCC upon passing a testing and profincey test.
yes I am proud to say that is my call letters

[bailey]

tiretool:

in answere to your first question, yes I can instruct you step by step in how to build one, do you want it to be tube type or solid state?

[Tiretool]

Since learning that they are so readily available, I think I'll just consider finding one already built. Any recommendations as to which brand to steer clear of or which ones to go to?

[bailey]

no, sience I personaly am not into that kind of stuff, I cant recomemend anything, but my son can, he is at work right now, but I will have him post a reply here for you tomarrow, with a sorce and everything, I hope I did not come on too strongly here but I got on my soap box and got carried away, I do that sometimes, so please don't take me too serious. bob


ps I had a kenwood ts940at, 200 watts out and would transmit and recive on all frequencys from 30kc to 30 mhz
in all modes, am, fm, ssb, cw, fax, rtty, ect, best radio I ever had.

[Edited by bailey on 11-17-2000 at 09:48 PM]

[Toaster]

It is NOT illeagal to have a Linear amplifier but it is illeagal to use one on CB frequencies. I believe that the FCC limited these radios to have a maximum radiated output of 5watts. Maybe bailey could correct me if i`m wrong.
Most Linear amps were designed soley for HAM usage and NOT CB usage. They were simply modified. True, they tend to be VERY poor in signal quality due to improper usages.
Most HAM radio folks I know are on the 2M band and perfer tube amps over transistorized amps.

[bailey]

solid state for under 100 watts, and yes the limit is 5 watte pep for cb radios on am .

[bailey]

toaster- I belive that the law reads this way, it is illigal to have one that is capable of operation on 11 meters. weather you use it or not, if it can be used on 11 meters it is a no no, all ham amplifers are designed to not operate on or near 11 meters or even the 10 meter ham band today and for the past 10 years, most ham radios have a normal output power of 100-300 watts, so having a ampilfier of that wattage would make no sence except for illigal operation on 11 meters, when a ham builds or buys a amp,it will most likely be in the range of 1500-2000 watte pep.
2000 watts is the maxium that we are licensed for.