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Newbie CB Radio Questions

seyit

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Tokat , Turkey
Top of the mount: Gasket, then insulator
Bottom: Grounding plate (get a good ground to the mount), gasket then insulator

Make sure that you have a good ground between the grounding plate and mount, mount and adapter, and adapter to the body. The grounding clamp from the grounding plate should be tightened around the PL259 connector.
Thank you,Matt.
Considering the paint on the bottom side of the mounting bracket where the grounding plate will contact,body sheet metal,the back face of the mount to the body etc(though some sanding prior to installation perhaps) do you suggest extra ground strap/wire to somewhere else?
 

seyit

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Tokat , Turkey
Sorry all for my questions,but ; I come accross with " Baluns " and " Tuners" while I'm going through this issue.
1.How necessary is a balun while adopting a military antenna(MS-116,117,118) and base (AB-15) to a CB?
2. So far as I understand some tuners are used only to adjust the SWR and then put aside while some others are installed handy in the system to apply to the changing conditions,right?
So I am thinking to dissmiss my present VHF CB and buy a HF/VHF/UHF one.
In that case do I have to install (or had better)one of them in the system ?
3.Will I be able to use some military type baluns and tuners such as VHF Automatic Antenna Tuning Unit " TUAAM ", "ARFAT" RF Antenna Tuning Box,Clansman Initiate Box,Center Junction Dipole Balun,Clansman PRC-319 Dipole Balun,Clansman PRC-320 Dipole Balun etc?
Are these for some specific military radio models or for general use? If specific ,do I have to go for some civillian models? ( If all necessary of course)
 

tennmogger

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Hi Seyit,

You are asking questions that everyone ponders when they get involved with radio. Even though I am no expert I have been a licensed ham since 1965 and I'm still learning but will throw in my 2c worth anyway.

What is an antenna? It's a means to couple radio waves into the atmosphere. Some forms of antennas work better than others for some jobs, like a 1/4 wave vertical radiator above a ground plane works great when you have a moving mass of metal to use as a ground reference, like a truck. Or consider a dipole which is a half wave fed in the middle and not requiring a ground (even though the real ground highly effects it). Now add umpteen other shapes and forms of antennas to the list, all having unique characteristics. It gets complicated. Let's stay simple here.

Since most interest here is antennas on vehicles, and a ground plane antenna lends itself to vehicle mount, lets start there.

Your AB-15 mount and length of elements is a good example. The goal is to provide best coupling into the antenna at the frequency (or narrow frequency range) of interest.

The difference between operating on one frequency, and desiring to operate on multiple frequencies becomes the complication. The antenna can be resonant on one frequency (and odd multiples) but it cannot be resonant on all frequencies. The result is deviation from a usable feed point impedance.

For operation on one frequency (or narrow band like CB) the 1/4 wave antenna can simply be tuned for resonance. We want to have the radio "see" about 50 Ohm's resistance (non-reactive) at the frequency we operate. Why 50 Ohms? Check this out: http://www.belden.com/blog/broadcastav/50-ohms-the-forgotten-impedance.cfm

So our radio is mounted to the truck (mechanically grounded to it, but does not have to be), we run a piece of coax to the base of the AB-15 and its whip, hook it up and apply RF power. We don't ground the antenna end of the coax shield. What radiates and what does not? The part of the antenna 'system' that radiates the most to the atmosphere is the part above the metal surface of the truck. But there's also radiation from the coax outer conductor inside the truck.

By grounding the far end of the coax shield we allow the coax to do it's job by defining "where the antenna begins" with that ground. Everything before that grounded point is now forced to be non-radiating 50 Ohm transmission line. That's why a complete AB-15, or any other antenna base (with exceptions, later) has to have a ground. Any CB whip antenna will also be grounded at the fender, unless thwarted by heavy paint.

With the correct ground at the antenna, the antenna performance can be tuned. But, the meter we use has to be installed at the base of the antenna for best results! Why? because the Forward power and reflected power, SWR, (standing wave ratio), or Return Loss, whatever we measure, will vary all along the length of the coax, and the length of the coax is critical to what the radio sees. I'll just call the measurements the SWR.

So, how do we handle that coax stuff? Most of us just cut whatever length we need, install the antenna, install the radio, and cut the antenna so the radio likes what it sees. An SWR meter installed at the output of the radio will tell us that. We have tuned not only the antenna but the coax, too. We might have tuned the coax to operate at a different impedance and losses might have gone up, but we really do not care. The radio will work and nothing will smoke.

Ideally we would cut the coax to a length such that there is an odd multiple of half waves at the frequency of interest, inside the coax. That's a mouthful. Couple of important words there: The "frequency", and "inside". Most of you have heard the term 'velocity factor'. That's the fudge factor we have to multiply by to calculate the actual length of a wavelength of a specific frequency, inside the coax. That number varies from around .5 to about .8. Specifications on the coax will tell us a number that's usually close enough if we want to trim our coax length for perfection.

Ever wonder why a standard CB antenna usually came with about 17 ft of coax? At least they used to come that way before "economy" of coax overtook engineering. 17 ft is roughly the length of a multiple 1/4 wave at about 27 MHz (trust me, or ask me LOL). The manufacturers wanted you to see the SWR at the radio that is presented at the antenna.

That sort of covers the "one operating frequency" scenario. What if we want to operate across a whole band, or even many different bands? First, the whip cannot be tuned to multiple frequencies at the same time, the impedance at the base of the antenna will not be 50 Ohms, and there is no resonance of the antenna.

This is where a coupler comes in. Call it a coupler, antenna tuner, antenna matcher, whatever the name, the purpose is to transform the impedance seen at the base of the non-resonant antenna into something close to the radio's 50 Ohms. With such a miracle device we can theoretically operate that whip antenna on multiple frequencies.

Seyit, you mentioned TUAAM, and other names for antenna matchers. That term is common with the British Clansman radios and means 'Tuning unit automatic antenna matching'. We might know of the more common matcher in the base of many USA VHF radio antennas like the AS-1729, AS-3900, and others. Note that "automatic" in most cases does not mean the tuner actually does anything on it's own. It has to be pre-tuned by a human then the suitable band is switched by the radio. Some, like the AS-3900 are fixed tuned and do not switch. They work like ^%$# too.

Earlier I said that an antenna base does not have to be grounded and may not be at 50 Ohms. Some radio installations do not force the radio to output 50 Ohms, or for the antenna to present a 50 Ohm load. A good example would be an old RF-302 antenna coupler that connects directly to the base of a whip antenna and actually does a good job of matching it across a wide range of frequencies. No '50 Ohms" applies in this case, and the feedpoint of the antenna is not grounded.

To specifically answer your questions, by number:
1) To use an AB-15 and it's whip on CB you do not need a balun. The antenna system is unbalanced end to end and no conversion to 'balanced' is needed. If you want to put a dipole on your CB, as in camp, where ever, then a balun at the feedpoint of the dipole is a great idea.

2) That is correct. If you want to operate an antenna as a non-resonant antenna on multiple frequencies, then the tuner can allow you to move around in frequency and still have a reasonable match to the antenna.

3) Great question. In most of those cases of antenna paraphernalia, you can use those on any antenna system, military, ham, or commercial. Just analyze what the military device does and use it instead of the commercial/ham counterpart. You will find, though, that many military devices have unique mounts, unique shapes, or require specific connection types. Weight and cost are not insignificant either. Military parts can get expensive when they are in short supply.

Bob WB4ETT


Sorry all for my questions,but ; I come accross with " Baluns " and " Tuners" while I'm going through this issue.
1.How necessary is a balun while adopting a military antenna(MS-116,117,118 and base (AB-15) to a CB?
2. So far as I understand some tuners are used only to adjust the SWR and then put aside while some others are installed handy in the system to apply to the changing conditions,right?
So I am thinking to dissmiss my present VHF CB and buy a HF/VHF/UHF one.
In that case do I have to install (or had better)one of them in the system ?
3.Will I be able to use some military type baluns and tuners such as VHF Automatic Antenna Tuning Unit " TUAAM ", "ARFAT" RF Antenna Tuning Box,Clansman Initiate Box,Center Junction Dipole Balun,Clansman PRC-319 Dipole Balun,Clansman PRC-320 Dipole Balun etc?
Are these for some specific military radio models or for general use? If specific ,do I have to go for some civillian models? ( If all necessary of course)
 
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seyit

New member
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Location
Tokat , Turkey
Thank you very much for the valuable information and also sparing time for my questions,Bob WB4ETT.
I am completely green on the radios,CBs etc.I have to spend quite a lot of time in the country,mostly in remote areas and every now and then am having various problems.I got someone install a CB in my jeep.Sometime I get contact hundreds of miles away while I am unable to get in touch with some body only 3 miles away.Then I found out it is because of the single frequency ( UHF) of the CB.At this point I made some search and only recently have learned about VHF,UHF more than what these letters stand for. To overcome the problem I thought that I had to shift to multiple bands where one falls short.Possibly a HF or FM will be better.I don't know indeed.But as more as possible.Meanwhile I just want to go with the classical appearance of my jeep.That is why I am talking on military antennas.Now every thing is so new in a short period of time that I am having difficulty to tell A from B.
As for those British clansman radio/antenna accessories; I have met them on the net while studying the tuners and baluns if they are necessary or not.
I want to read what you write above a couple more times.What I understand at first glance is that a tuner in the system for multi bands is good,but does not automatically tunes and I have to play with sort of knobs to tune when I switch the band.And no need to go after military accessories,but a reliable commercial one sounds better.
I have to ground the antenna,but not the base.
I want to read what you write about the coax a couple more times.
Well,thank you very much again.Being a foreigner I can't use much technical terms.Sorry for that,too.
 

wilfreeman

Active member
1,082
7
38
Location
Richburg, SC
Thank you,Matt.
Considering the paint on the bottom side of the mounting bracket where the grounding plate will contact,body sheet metal,the back face of the mount to the body etc(though some sanding prior to installation perhaps) do you suggest extra ground strap/wire to somewhere else?
The grounding plate has small "tits" stamped into it. Install the plate with them facing the mounting bracket. Give it a little twist before you tighten it up all the way, so that the tits can dig into the metal on the mounting plate giving you a good ground. The other fasteners connecting the mount to the adapter and the adapter to the body should have star washers on both sides. They are designed to bite into the metal giving you a good ground. You can add an extra ground wire under the ground clamp and run it to a known good ground on the body if you can't achieve ground using the correct fasteners and washers.

Sorry all for my questions,but ; I come accross with " Baluns " and " Tuners" while I'm going through this issue.
1.How necessary is a balun while adopting a military antenna(MS-116,117,118) and base (AB-15) to a CB?
2. So far as I understand some tuners are used only to adjust the SWR and then put aside while some others are installed handy in the system to apply to the changing conditions,right?
So I am thinking to dissmiss my present VHF CB and buy a HF/VHF/UHF one.
In that case do I have to install (or had better)one of them in the system ?
3.Will I be able to use some military type baluns and tuners such as VHF Automatic Antenna Tuning Unit " TUAAM ", "ARFAT" RF Antenna Tuning Box,Clansman Initiate Box,Center Junction Dipole Balun,Clansman PRC-319 Dipole Balun,Clansman PRC-320 Dipole Balun etc?
Are these for some specific military radio models or for general use? If specific ,do I have to go for some civillian models? ( If all necessary of course)
Getting above my head on these questions. Someone into ham radio will have to answer these. All I can tell you is that you shouldn't need to adjust this setup unless you plan on taking it apart or using a different cb with the antenna.
 

M813A1

Member
867
3
18
Location
OKC, Oklahoma
The AB-15 antenna. Mount is the way to as long as you keep the antenna whip between 106 and 110 inches your set will be in . Using the AB-15 antenna base with the MS-116 , MS-117 and MS-118 antenna section will be the best setup to use with a CB. If you have to tune the antenna just trim the top of the MS-118 antenna section. You will be Happy with that antenna.
 

seyit

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Location
Tokat , Turkey
Thanks again Matt and M813A1.I have not installed the AB-15 on the jeep yet.I have it at home and just dismantelled it to see what is in there.The mast sections I had were ANT-129 ( 8 pieces/circa 2.60 meters) but I found out that the thread at the bottom end does not fit in the AB-15 and that I had to use MS-116,117,118 along with AB-15.So I ordered a set of them.The bracket I have from an M 151 Mutt with that 2" hole anyway.I don't want to set up the antenna after receiving the antenna sections,because I want to buy a multi band CB and do all that setting up with the new CB so as not to do it again and again.
I will pay special attention to what you say on the grounding issue.
 

seyit

New member
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0
Location
Tokat , Turkey
What do you mean by "Multi-band" CB? Upper and lower side band?
Well,at the very beginning I told that I am completely green on these radio things.While I was making some search I read in the listings that some are dual band (VHF and UHF) still some others are triple band ( HF,VHF and UHF) Sellers also typed the term " Multi band " so I thought this is a term among the radio people to indicate those models.
However; To my horror I have found out today that I without having a radio licence can only buy and use AM/FM ones ,and those with HF/VHF/UHF require licence.At least here in Turkey.
Now I am back to my present CB-obviously FM or something.
 

tennmogger

Well-known member
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Will you be able to use HF CB if you get a license? What is required to get that license? To us here in the USA, when CB is mentioned, we think HF, 11 meters. That causes confusion when talking to Europeans with VHF CB. The AB-15 and MS-type antenna sections apply for the HF situation.

Seyit, you have mentioned British Clansman radios. The Clansman antenna sections also fit the AB-15. Is it easier for you to get Clansman radio parts?

Number 5985-99-630-8455 is the bottom section and may be stacked, that is, multiple pieces may be used for long antennas.
Number 5985-99-630-8456 is the middle, tapered section. One is used.
Number 5985-99-649-8140 is the top section.

If you use one section of each, the total length is 112 inches, and you still have to add the length of the active section of the AB-15 spring. The total is much too long to use on HF CB without cutting.

Bob
 
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seyit

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Location
Tokat , Turkey
Thank you Bob.
The story is a bit complicated.My famil has a ranch in a remote valley.Even within the borders of the ranch communication with some other members have always been problem.Moreover I go hunting , fishing and I like trail ridings in the back country.The mobil phones were not available and I was in need of sort of communication means.Prior to 1980s any kind of wireless systems were banned in Turkey.We lived through the years that anybody who dared to talk about a wireless was accused to be a Soviet spy. LOL ! Then in 1980s government freed people to use CBs.Then the system spread.I had no idea about FM/HF/VHF etc.I purchased a CB and got someone install it in my jeep.İt is there eversince.For me it was a wireless,and a wireless was a wireless anyway.Though the mobil phones in the following years replaced CB use to great extends personally I need it quite often.I was young and when I tangled somewheres walking for miles even in deep snow or during bilizards was not so important.Now I am aging and looking for some short cuts.And this CB thing steps forward at this point.With the one in my jeep I have been able to reach hundreds of miles away someday while failing to reach only three miles beyond a rocky hill. When I had a look at the listings of some sellers I spotted these things .Some were FM.There were others saying HF,VHF,UHF etc.I thought that if I bought one with more than one feature then I could solve the problem of falling short every now and then.Only within these very recent couple of days I find out that we are allowed FM without a licence,but for having a HF,VHF,UHF and I think more than 5 Watts a licence is required.To have a licence one has to become a radio man with a diploma from related government office.Now this a long way for me.
So I should say a farewell to HF/VHF etc and stick to my FM CB.
Meanwhile,my jeep is actually a 1962 Kaiser CJ5,but practically she is a hybrid of Kaiser CJ5 and M38A1.She looks more military than civillian. I have always disliked that chrome CB antenna on her.I don't remember when and where I got,but for years I have had a military antenna base(only recently I've found out that its AB-15/GR )and two antenna masts( again very recently I've found out that one is BC 1000 SCR 300 while the other ( 8 sections) is ANT-129)
I just wondered if I can replace the chrome antenna with that base and long mast.Here I learned that I need MS 116,117,118 and ordered them as a set etc.Thus I want to get rid of that civillian antenna and put the one with military look.This is jeep and Eugene the jeep gave her the name,so I think I have tangled myself in a ridiculus situation and should find a way out,lol.
As for the British Clansman radio parts and accessories,they are not available in Turkey-at least commercially,but unless the radio itself,I think I can easilly buy them on eBay etc.,and import.Same for the American ones.So going for Clansmans is not necessary.
Now with what we are allowed( FM) and AB-15 along with MS-116,117,118 that I have already ordered,do you suggest that I can connect the present CB?
I can't upload pictures here ,but my CB is Maxcom(with chrome knobs.There is another model with black knobs)İt is kinda vintage now.
BTW; I talked to a couple of guys about that licence.They are talking about a test that government gives once or twice a year.But I don't know what test.What should I study before taking it.If I can find a text or something I want to have a look at it.If I dare to study and take such a test I want to give a try to it,too.( Eugene the jeep is around again,lol)
Regards,Bob
 

SCSG-G4

PSVB 3003
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Seyit,

In USA there is the ARRL who have books and a study guide for the examinations. There are even practice examinations using the same questions that will be asked on the real test. Only problem is there are over 1000 practice questions and only about 100 used on the test. For you the problem in using these test questions to study is that in Turkey, the frequencies that are available to Amateur Radio Operators will not be the same as in USA, and the regulations will be in a different part of the legal code. And, it is all in English. Your test should not be in English. Hope this helps!
 

seyit

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Tokat , Turkey
Thank you MikeKK4AIF.
I contacted someone who has some documents consisting of the subjects here in Turkey.They are in Turkish,and possibly -with your words the regulations will be the legal code.
I think it will be boring to start studying again at the age of 63,but I want to have a look before deciding to go on or quit.
 
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