OkieBoyKJ5JFG
Member
- Joined
- May 16, 2022
- Messages
- 208
- Reaction score
- 181
I've decided to play around with the 1.25 meter band, and to that end, I've been looking for an antenna for my truck. The problem is that the only place on the entire vehicle with a decent ground plane is on the roof which for a variety of reasons isn't practical for me.
After some reading and some recommendations from people on here (Thanks, guys!), I ordered the Comet SBB224, and it arrived today. It isn't a NGP antenna, but some anecdotal reports were promising. On the back of my truck, I have identical NMO mounts in the stake beds, each attached to 15' of RG8X which runs along the bed rail, over the front rail, down the front of the bed, and up through holes in the floor of the cab. On the driver side, I had a Diamond SG7900 which IS a NGP antenna and is quite happy on either side. With the Diamond, I get SWRs well below 2.0:1 on 2m, 70cm, and GMRS. On MURS, it crosses 2.0:1 at 154.6 MHz. I stuck the new Comet on the passenger side mount and this is what I got:
I was not encouraged.
However, I swapped it over to the driver side and checked it again. This time, it was better. A lot better.
Identical mounts, identical coax, dramatically different results. Just to be sure, I swapped it back and forth several times and always got the same readings. It just prefers to be on the driver side. There's no real ground plane on either side.
Just out of curiosity, I stuck the 224 on the top of my car where it has a good ground plane, and (unsurprisingly) it looked good.
So now, the Diamond lives on the passenger side where it's quite happy and the Comet resides on the driver side. Why is it great on the driver side and crap on the passenger side? No idea. I'm not going to argue with success, but RF energy definitely does funny stuff.
After some reading and some recommendations from people on here (Thanks, guys!), I ordered the Comet SBB224, and it arrived today. It isn't a NGP antenna, but some anecdotal reports were promising. On the back of my truck, I have identical NMO mounts in the stake beds, each attached to 15' of RG8X which runs along the bed rail, over the front rail, down the front of the bed, and up through holes in the floor of the cab. On the driver side, I had a Diamond SG7900 which IS a NGP antenna and is quite happy on either side. With the Diamond, I get SWRs well below 2.0:1 on 2m, 70cm, and GMRS. On MURS, it crosses 2.0:1 at 154.6 MHz. I stuck the new Comet on the passenger side mount and this is what I got:
I was not encouraged.
However, I swapped it over to the driver side and checked it again. This time, it was better. A lot better.
Identical mounts, identical coax, dramatically different results. Just to be sure, I swapped it back and forth several times and always got the same readings. It just prefers to be on the driver side. There's no real ground plane on either side.
Just out of curiosity, I stuck the 224 on the top of my car where it has a good ground plane, and (unsurprisingly) it looked good.
So now, the Diamond lives on the passenger side where it's quite happy and the Comet resides on the driver side. Why is it great on the driver side and crap on the passenger side? No idea. I'm not going to argue with success, but RF energy definitely does funny stuff.
