What Would You Choose For Car To Car Simplex Communications?

[alcahuete]

Interesting that you post that. Has anybody done that particular comparison? If so, I would love to watch a You Tube video of it. While it would seem like 5 watts, analog UHF would be better than 1 watt, digital 900 MHz, would to see real world experience on this.

I have read that folks have compared on cruise ships and found Motorola DTR outperformed GMRS on ships, but they have far more metal than a typical car.

Now an even more interesting experiment might be UHF radios, be it with licensed hams or what have you, comparing whichever flavors of digital, using 4 or 5 watts, to DTR radios. I doubt that which mode of digital would matter, but it could be fun to compare MOTO TRBO (DMR), to APCO P25, to NXDN, Yaesu System Fusion and, yes, even the Death Star mode.

Funny you should ask. Though I don't have a Youtube of it, I have run dozens of comparison tests with DTRs and whatever else, just because the radios are so damn good. I love putting them through their paces, and I'm never disappointed. I live on some property out in the Mojave Desert, and aside from some houses here and there, there's a lot of open space, with really no major obstacles.

With one DTR radio up on my balcony at probably 15', I went out driving with another DTR inside the car. I was able to reach 20+ miles and actually ran out of road before I ran out of signal. I don't remember the exact distance. I do have the GPS plots on Google Maps somewhere. I'll have to look for them. There was a time or two here and there where I had to stick the radio out the window or sunroof, but generally speaking, it was in the car the whole time. Of course in urban areas, that is going to be drastically different.

I was not able to replicate those results with any other handheld radios at 4w (UHF) or 5w (VHF), or any other mode (DMR, P25, NXDN). I don't have any of the hammy modes available, so those were not tested. The closest I was able to get along the same route was DMR on my XPR7550e. I'm guessing part of that is due to the ultra-hot receivers on those radios.

The DTRs also outperformed the XPR7580 (2.5w) on DMR, I'm guessing largely due to the FHSS. The FHSS seems to make a pretty big difference on ships too.

Where I was also surprised once was a situation where we were boating out at Lake Mojave. Boat was onshore and we went hiking into the mountains probably 2-2.5 miles deep. The marine radios, even with the boat radio at 25W, were unusable. DTRs had no problem. It was a time where VHF should probably theoretically outperform anything else, and it didn't. I didn't have UHF for comparison, but the the DTRs worked, the VHF didn't.

Some other extreme examples I have are basically full ship coverage on any ship you can think of, I was able to have full terminal coverage and even terminal-to-terminal coverage at the DFW airport (I specifically use that airport because it is so massive), and pretty much full hotel coverage at several of Las Vegas' largest hotels.

I should also note that I only own DTR650s and a 550 or two. I do not own any of the newer DTR radios. Performance should be identical, but I just wanted to note that.

 

[APX8000]

I'd use GMRS in P25 strapped with AES. Too soon ?

 

[WRVB]

We did well with our FRS radios traveling with another RV as long as we didn't get too far away. But the batteries discharged rather fast when driving for hours and the build quality is not as good. My Motorola units kept having the transmit key stick. I think it was the thick rubber covers for making them water resistant. I had the only CB, a nice small President Bill. It would have worked well if we all had them. But we migrated to the GMRS. So far we both have KG-935G's and programming is easy. I also have a mobile Midland MXT575. I like having both so I can have one inside the RV or the extra power in the truck. We will give them a good workout soon. I also like having both the CB and GMRS in the cab. CB mostly for when there is a problem on the road, it is most often talked about on the CB. Other than that it is quite or trash talk around cities. I have been talking on the GMRS about 5 miles away and it is clear as a bell until a hill gets in the way. I am very happy with all three. If I had to pick just one like you asked, it would be GMRS.

 

[mmckenna]

If I had to pick just one like you asked, it would be GMRS.

A good GMRS mobile radio connected to a good permanent mount antenna outside the vehicle will give you a lot of reliable range. Topology comes into play with these higher frequencies, however. I once did about 17 miles between vehicles, but that was in a long valley with little between them.

GMRS was, for a long time, overlooked by many. It took Midland coming out with their GMRS mobiles to really make it popular. Up until a few years ago, it was only the hardcore users that really used it to its full extent. It's a great resource for your kind of usage.