Running Moblie

[ctvanover]

I have a Magnum S9 that I am planning on using in a Peterbilt Daycab truck. I've used the Wislon 1000 and the 5000 trucker mirror mount antennas before. This time around I want to use an 102" whip and from what I can understand is that I'll probably have to use a spring or some kind of an extension at the bottom to make it 108" whip. I am going to mount it behind the cab of the truck on the deck plate right above the frame. My question is.....does the length of the coax matter because it's going to take more than 18' of coax to get to the radio?

 

[tba02]

does the length of the coax matter because it's going to take more than 18' of coax to get to the radio?

Short Answer - No (but maybe)
The type of coax matters as there is loss associated with length. If you use RG8x any loss due to the extra length you are probably talking about is negligible.
Even with RG58, the difference between 18 and 25 feet is about 0.14 db loss.

 

[ctvanover]

OK so what would be the best size coax for the job? and also if I were to use an extender at the bottom of the antenna instead of a spring say like a Wilson Antennas Replacement 5 0r 10" Stainless Steel Shaft would that make a difference....would it help it or hurt it?

 

[RatsoW8]

The type or length of coax in a run this short isn't going to matter at CB frequencies. Just run the length you need to connect the radio to the antenna.

Your problem is going to be the way your mounting the stainless whip. It's going to react with the truck cab and you may never get a good match between the antenna and radio. The antenna needs to be mounted as high as possible and in the clear. If yo can't do that then go with what you have.

 

[ctvanover]

I was thinking about using a rubber fuel line or a garden hose to help keep it away from the cab or even a rubber ball. Also the is a grab handle about half way up the back of the cab just below the back window. I thought about mounting it there also. I would then have to run a ground cable down to the frame but that's no big deal either.

 

[The DB]

Short Answer - No (but maybe)

Let me correct this...

Short Answer - No (period, no ifs, ands, ors, or buts).


The DB

 

[RatsoW8]

The rubber hose may protect your paint job but that's about it. You can't mount an antenna parallel and in close proximity to metal objects and expect it to work. The base of the antenna should be above the cab. I realize you may not be able to do that so you may want to re-think they type of antenna you are going to use.

 

[ctvanover]

OK what about maybe using a Predator antenna

 

[tba02]

Let me correct this...

Short Answer - No (period, no ifs, ands, ors, or buts).


The DB

Well, yeah.
- length impact would only relate to increased loss if he was running, oh say, 100 feet of coax around the cab!

 

[222DBFL]

The new sirio 5000 comes in a center load that would work well I would think. Check out DNJ radio. Also when mounting the s9 make sure to use good power and ground wire (#8awg) or larger, and also give some soace for the rear of the radio to stay cool. As far as coax goes everyone has their opinion, I like lmr240, it's high quality coax that is made to take the elements. And it's double shielded. Times microwave or Andrew lmr240 or lmr24uf, the UF stands for ultra flex. Use enough coax to go from point a to point b and that's it. That 18ft of coax crap is a myth, unless the antenna requires that specific length and then the coax is part of the antenna. Use good connectors as well. Amphenol pl259 connectors work well. I only say use these parts as from my own experience. The lmr240 I have has been in use for about 2 years now and it isn't faded or giving me any issues and I use my mobile daily to talk DX around the world. Spend the money once and get some quality stuff and it will be cheaper in the end IMO. Good luck and God bless.

 

[ctvanover]

You can't mount an antenna parallel and in close proximity to metal objects and expect it to work. The base of the antenna should be above the cab.

Hmmmm I don't know about that because I have used a 102" whip mounted to the t-bar in front of the radiator on an '97 Mack RD-800 and ran them for years like that with no problems before. This is what I drive during work and all I have is a Uniden Pro 510 mounted on the dash and using a 102" whip mounted out on the front with no problems.