Coax for NGP mobile antenna?

OkieBoyKJ5JFG

Member
Joined
May 16, 2022
Messages
43
I want to put a 2m/70cm radio in my 2009 Ram 1500 short bed, single cab truck. The problem is getting a decent ground plane. I did some experimenting with a mag mount antenna and the only places I could get SWR below 2.0 were on top of the cab and smack in the middle of the hood. The truck is modestly lifted and I don't want to put an antenna on top if I can help it because I won't be able to go through bank or restaurant drive-thrus. I bought a Nagoya NMO-HDA which supposedly doesn't require a ground plane but I get SWRs from 2.5 - 4+ no matter where I place it. Behind the cab, on the rail halfway down the bed, at the end of the bed...no improvement. Today I read that NGP antennas require a different type of coaxial cable than regular antennas, but I couldn't find anything to tell me what that coax is. First, is that correct? Second, if it's correct, what coax do I need? Thanks!
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
25,726
Location
United States
Seriously, many, many of us run full size trucks. I've got an F-350 at work that is running on larger than stock tires. I run up and down some access roads that are overgrown and my antennas hitting low branches is about as common as hitting bugs with my windshield.

Do yourself a long term favor, skip the Chinese antennas and compromise mounts. Do it right once and you'll never regret it. Pop a name brand NMO mount dead center of your cab roof. Install one of these on your roof and you'll never have to play games with antennas again.

It's hard doing your first one. Yes, it'll probably hit a tree branch, your antenna/truck will be just fine. Trust me, my antennas have probably hit more tree branches than your truck has hit potholes.
 

RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
7,555
First, is that correct? Second, if it's correct, what coax do I need? Thanks!
Only for those crappy FireStik NGP 27 MHz CB antennas. The "ground plane" aka counterpoise, is the coax and your results will likely vary. Like playing the slots..
 

RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
7,555
I want to put a 2m/70cm radio in my 2009 Ram 1500 short bed, single cab truck. The problem is getting a decent ground plane. I did some experimenting with a mag mount antenna and the only places I could get SWR below 2.0 were on top of the cab and smack in the middle of the hood. The truck is modestly lifted and I don't want to put an antenna on top if I can help it because I won't be able to go through bank or restaurant drive-thrus. I bought a Nagoya NMO-HDA which supposedly doesn't require a ground plane but I get SWRs from 2.5 - 4+ no matter where I place it. Behind the cab, on the rail halfway down the bed, at the end of the bed...no improvement. Today I read that NGP antennas require a different type of coaxial cable than regular antennas, but I couldn't find anything to tell me what that coax is. First, is that correct? Second, if it's correct, what coax do I need? Thanks!
You can put two NMO antennas VHF and UHF unity gain on the roof of your truck. The VHF will be about 18.5 inches and the UHF about 6 inches. You will need a diplexer like a Comet to split the V and U bands assuming your hammy radio has one lone coax connector. It will work so much better and require no tuning. Return the Nagoy antenna and you will pay for the diplexer.
 

DeoVindice

P25 Underground
Joined
Sep 27, 2019
Messages
544
Location
Gadsden Purchase
You can put two NMO antennas VHF and UHF unity gain on the roof of your truck. The VHF will be about 18.5 inches and the UHF about 6 inches. You will need a diplexer like a Comet to split the V and U bands assuming your hammy radio has one lone coax connector. It will work so much better and require no tuning. Return the Nagoy antenna and you will pay for the diplexer.
This is the way. Quarterwave for each.
 
Top