Batboard

Anyone ever use a PO mount in a vehicle roof?

What size hole is needed?

Do they include a weather seal?

Problems?

I have a Comet SB-15 on a lip mount now on my van. For curiosity sake i took that antenna and put it on a mag mount and put it in the middle of the roof, seems to be a bit more omni directional on the roof so i would like to put it there if possible but not with a stinkin mag mount.

According to Comet their antennas are optimized for lip mounts off to one corner or another of the vehicle, but it seems to me the old addage of being in the middle still applies to them after testing it for the heck of it.

You may as well put an "S" at the end of "PO". I had one on my old car. It didn't leak or cause rust, but the electrical connection I found was less than ideal. I had a perfect SWR across the VHF ham band. After 6 months or so, that SWR went up to around 2:1. I changed antennas, changed coax, even changed radio. No luck. But, when I took the mount out I noticed that over time the sleeve that the centre conductor goes into had widened, assumably from wind load flexing. Personally, I would advise against using a PO mount, if at all possible.

I've never had any trouble with them. And all my antennas are PL-259 now, hence why i need a PO mount.

I might just leave it on the lip mount. I would hate to put another hole in the van if i didnt need to.

The biggest problem i had was with NMO, but not the mounts. It was that damn tab in the antenna base that contacts the center of the mount. Take the antenna off for anything and put it back on without first bending the tab back out and it wouldn't work again.

I would also vote that the PO is a POS.

Yes, it is a personal preference, but I've had many problems with them just like bellersley.

How is it you guys are having problems with these? Once tight they make a lot better connection than the center tab on these NMO antennas.

I had one on my car in Japan, because that's all that was available (no NMO mounts)...

It was okay for a 1/4 VHF, but others that were using the longer Comet style antennas started having problems. As stated above, the weight of the antenna would rock around and "spread out" the center conductor. After a while, the center of the antenna would not make contact with the center of the mount. They would get sporadic connections/performance and an ever changing SWR.

I HATE those antennas and lothed every minute of having to put one on my car, but I had no choice. This was before internet was so wide-spread, so we were all out of luck.

There is an adapter made to convert a NMO mount to a SO239, that is available from RF Parts
http://www.rfparts.com/nmouhf.html

techie wrote:There is an adapter made to convert a NMO mount to a SO239, that is available from RF Parts
http://www.rfparts.com/nmouhf.html

That adaptor also came as a standard mount, but nothing internal to the mount, plus you needed the screw-in spring contact that 'replaced' the center contact of the PL-259 on the antenna, and with the varying lengths/depths of these, there were several spring contacts made, and they again, took the place of the center contact on the antenna base.

I used to have a whole drawer filled with these, and over the years and after non-use, I gave them away or just tossed them.

Besides the obvious, the PL-259 is NOT a 50 ohm interface for anything above low VHF, and I wouldn't even consider it for use with any 33CM gear.

Comtelco and Antenex have used spring loaded 'plungers' on their mobile antenna line for years, but I doubt you'll ever see this arrangement on any 1/4 wave El-Cheapo spike anytime soon.

But as my feelings for Comet and Diamond go...they can keep them.

I despise having any spring loaded anything in the radiating path of my antenna 'system' as they will and do, introduce loss and impedance bumps, and not to mention corrosion in the housing after XX number of months or years in an environment that has any sort of salty rains, or heavy salt use during winter months...even the spray from passing cars gets into the antenna and reeks havoc....No thank you!