AdmiralCochrane

I had the same experience with a fairly expensive radio with pretty good filtering. I was only 200 - 300 feet from a local dispatch repeater. Apparently first harmonic of their UHF frequency was right in GMRS.

I didn't know there were waterproof mobiles. Handy for open vehicles like Jeeps I guess

I have not had 2 way UHF transmissions via ducting, but have had 2 way ducting VHF transmissions between Long Island and central Maryland

I have successfully used this type of antenna mounting. I am using it on a small van every day on 70cm and 2m. In the past I used it on a new tall full sized van with tall ladder racks and always received complements on my signal strength in fringe areas. Greatest simplex contact was 11 miles. If I understand your picture that the antenna is on the passenger's side rail, your best propagation will be to the driver's side, but you may never actually notice the difference. Don't change a thing.

I missed the part about repeater coordination and who gets dibs on 2 channels in each locale

I can hit more than a dozen repeaters from my house. Might be able to do 8 or 9 with an HT.

The old saying "A man with a watch knows what time it is, a man with 2 isn't certain."

Once you propose how to prevent hogging all repeater channels I will sign. Without the hogging limitation, this just solves one thing and presents a new problem in its place. Ursula K. Le Guin's Lathe of Heaven

Dang, how can I get on your Christmas list? Wait, nothing I own has chrome on it

If both devices are 100% accurate, the difference can be explained by the different load presented on both the coax and the antenna, more likely the coax. You haven't told us the type of coax or the length or the transmitting power. What you are seeing is likely cable loss - some power not getting to the antenna (being absorbed on the way up) and some power not reaching the SWR meter on reflection (some power being absorbed on the way back down). The skew of the readings agrees with this. (WOW, I got to use "skew" in a sentence!) Moving the SWR meter to the other end of the coax may or may not confirm this. Also possibly changing the transmit power. A way to help most people understand this is a dummy load on the end of the coax. The SWR of a dummy load (in ideal conditions) is exactly 1:1 because all of the energy is consumed at the dummy load end; NONE is reflected back. Some time back someone posted that they measured 1:1 SWR with a dummy load. As a joke, I posted "I hope so." Only a few people got it.

I think the critique was mostly regarding off-road rough trail driving. Mall crawling is a lot easier on antenna mounting.

In practice those readings are so close I would not have given it a second thought.

I'm less worried about my pole falling over than I am about the wind breaking my antenna. I may devise some scheme to lower it so I could put it back up after a storm.

That's not just frequencies, that's different assigned bands. Fine for SHTF operation, but completely contrary to regs before then. 156.5750 is in the marine band. FCC and USCG definitely monitor marine band and hunt down land based violators. Another exception is, a fairly narrow slice of spectrum like this is easily monitored by a very fast scanner that would hear it all.

SSTV is still a thing. There is a club near me that is big into it.

dosw nailed it. That's how radio works. /end thread

Yeah I was looking at that radio when it came out

Unless you drive a Jeep

Marc, I am going to get an FM CB sometime in the next year or two, but haven't decided how or where to mount it in my Jeep. Pretty sure we are only an hour or so apart (depending on traffic). We can probably both hit some of the same repeaters that are between us. I actually haven't tried them in a while

Don't confound government agency opinion with its actual regulations.

Uncle Charlie definitely frowns on people trying to own entire bands. Again, the actions of a few spoiling something that could benefit many.

What is the frequency Kenneth?

A 90-341 type relay is a 2 pole double throw relay with a 120v coil with each contact rated for 15 amps. If you use both poles you are 15x2 amps. It is the second most common relay in HVAC/R work ... the most common being the 90-340, same relay with 24v coil

I read in the first post he is using a 50w GMRS radio.

Reuters seems to know more about this than Massad