What Would You Choose For Car To Car Simplex Communications?

[K6GBW]

Given the restriction of a hand held with a ducky antenna then GMRS would be best. The MURS radio is VHF and the wave length is over six feet. The cars metal roof and floor pan will attenuate the signal. The 900 MHz radios will only be one watt. The GMRS radio can be 5 watts and the signal will get out of the cars windows better.

 

[Mophead]

For me the biggest bang for the buck would be a couple of Nextel phones on Direct Talk. Works similar to DTR, but much cheaper. I’ve used them all over the Orlando ham fest grounds, & never ran out of range. No license needed. When I’m with hams we use XPR6380’s, & 6580’s. Much lighter than an APX, or XTS.

I thought the nextels were shut down ? We had to surrender them in work about 10 or so years ago.

 

[JASII]

[QUOTE="Mophead, post: 3762968, member: 617959"I thought the Nextels were shut down? We had to surrender them in work about 10 or so years ago.[/QUOTE]

Yes, they were, but this is where attention to detail pays off. Nextel Direct Talk is simplex. Simplex does not need a network, so it will continue to work despite their iDEN network vanishing.

 

[JASII]

Given the restriction of a hand held with a ducky antenna then GMRS would be best. The MURS radio is VHF and the wave length is over six feet. The cars metal roof and floor pan will attenuate the signal. The 900 MHz radios will only be one watt. The GMRS radio can be 5 watts and the signal will get out of the cars windows better.

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.

 

[amcferrin90]

Southern Link remained well after Nextel shut down. Nextel was not the only iDen carrier.

 

[KC3ECJ]

I've gotten something like 7 miles car to car on 5 watt GMRS handhelds with the antennas on the radios inside the car.

But it varies with terrain, so maybe something like 2 miles maybe more typical.

 

[JASII]

Great point. I edited it to say "their" iDEN network vanishing, which is more accurate.

 

[JASII]

I've gotten something like 7 miles car to car on 5 watt GMRS handhelds with the antennas on the radios inside the car.

But it varies with terrain, so maybe something like 2 miles maybe more typical.

I agree that something like 2 miles may be more typical.

When I had DTR radios, I would leave one home and I would drive in my pickup truck and press the push-to-talk switch. With those, one type of beep indicated it is being received and another sound indicates out of range. I would get about .7 of a mile, consistently. With digital, you seem to have it or not, unlike analog.

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.

 

[WPXN]

GMRS

 

[SmitHans]

Handheld, I think I'd use GMRS. Other services are less efficient with a rubber duck antenna.

Mobile, I'd use AM CB. Especially if there are multiple mobiles I want to keep in touch with. And use SSB to extend range.

 

[Firemandakota87]

dose anyone use frs and would it work for a anytone mobile radio like the 779uv and the 778uv

 

[mmckenna]

dose anyone use frs and would it work for a anytone mobile radio like the 779uv and the 778uv

No. FRS is limited to no more than 2 watts or 1/2 watt, depending on the channel, and non-removable antenna.
And the radios you have are not FCC type accepted for FRS.

As we keep saying, the ONLY legal place to use these radios is on the amateur radio bands.

Do yourself a favor, get your ham license. You purchased radios without doing your research, and now your only legal option to talk to your friends is to get your ham licenses. There is no amount of gyrations or reasoning that is going to make anything else legal.

 

[KK6HRW]

In defense of the humble FRS, I have experienced clear communication between vehicles in a tight convoy of ten over flat terrain with these radios in use.

 

[Project25_MASTR]

I agree that something like 2 miles may be more typical.

When I had DTR radios, I would leave one home and I would drive in my pickup truck and press the push-to-talk switch. With those, one type of beep indicated it is being received and another sound indicates out of range. I would get about .7 of a mile, consistently. With digital, you seem to have it or not, unlike analog.

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.

It's really going to depend in the vehicle. A lot of more modern vehicles are moving to the Low-E glass/tint which essentially turns the inside of the vehicle into a faraday cage. While it's not as drastic as the Low-E glass being used in new construction commercial buildings, it will affect things much more greatly.

As for comparing digital modes, it really does matter. Best weak mode format is NXDN Narrow due to having the highest power density and provides roughly 3-6 dB more usable link budget compared to other commercial modes (for all intents and purposes D-Star and YSF can't really be compared as we have no way of getting baseline measurements due to the fact there is not a diagnostic mode available nor function generator to create a test pattern to test receive sensitivity outside of Yaesu and Icom facilities) but even then there are differences between radios such as the NX-3000 being a SoC design where the NX-5000 is a super-het design. P25 these days is about 98% on par with straight analog 20 years ago when looking at the system as whole. Most modern radios are also optimized for digital though and it's not uncommon to see a digital radio test with 5-6 dB more sensitivity when operating in a digital mode versus analog.

 

[Project25_MASTR]

Given the restriction of a hand held with a ducky antenna then GMRS would be best. The MURS radio is VHF and the wave length is over six feet. The cars metal roof and floor pan will attenuate the signal. The 900 MHz radios will only be one watt. The GMRS radio can be 5 watts and the signal will get out of the cars windows better.

By that logic with 900 MHz having nearly half the wavelength of 462 MHz it would be much more efficient at getting out of the vehicle on a much broader range of vehicles in comparison. Also, 900 MHz portable antennas being much more efficient...better power transfer meaning more usable signal radiated. So with 900 MHz you might have an ERP close to 2W where GMRS on a 5W hand held you might have an ERP closer to 3.5 or 4W...at that point the primary differences are going to be the what you consider a usable signal on analog (personally I can't stand noise and much rather listen to bit error so any analog signal that isn't full quieting I don't classify as usable).

 

[Giddyuptd]

Gmrs or dtr650s. Unless you need repeaters even then gmrs pairs would suffice if you have a mobile repeater setup in your group.

 

[K6GBW]

I can speak from actual experience. My agency used VHF up until 1997. We had very poor communication using hand held inside detective cars. When following people on the freeway we found it hard to copy beyond about 300 yards! In 1998 we switched to an 800 mhz trunked system. The 800 mhz hand held ran only three watts and worked pretty poorly from inside a car. We typically got only a few blocks with them. That’s why we obtained UHF Motorola XTS3000’s for use in surveillance situations. Four watts UHF actually worked pretty well. We ran both analog and P25 digital and found about a 15-20 percent range improvement with digital. The only bad thing about digital was that if two people talked at the same time the signals were corrupted and we just didn’t hear anything, unlike analog FM where we could make out the stronger signal. Also, when digital hit its range limit the R2D2 sound was annoying as hell. If we were using antennas outside a car I would thing the VHF would be better, but from handhelds I’d go UHF every time.

 

[Project25_MASTR]

I can speak from actual experience. My agency used VHF up until 1997. We had very poor communication using hand held inside detective cars. When following people on the freeway we found it hard to copy beyond about 300 yards! In 1998 we switched to an 800 mhz trunked system. The 800 mhz hand held ran only three watts and worked pretty poorly from inside a car. We typically got only a few blocks with them. That’s why we obtained UHF Motorola XTS3000’s for use in surveillance situations. Four watts UHF actually worked pretty well. We ran both analog and P25 digital and found about a 15-20 percent range improvement with digital. The only bad thing about digital was that if two people talked at the same time the signals were corrupted and we just didn’t hear anything, unlike analog FM where we could make out the stronger signal. Also, when digital hit its range limit the R2D2 sound was annoying as hell. If we were using antennas outside a car I would thing the VHF would be better, but from handhelds I’d go UHF every time.

The only problem with that experience is vehicles have drastically changed in the last 20 years. See my comment about the Low-E glass and tints being used today just as an example. I actually had a customer who had to install AVA's three years ago for their new detective's vehicles simply because enough changes had been made in the newer generation of detective vehicles that they simply couldn't rely on using their APX6000's in the vehicle anymore and needed an external antenna.

 

[Peter_SD911]

What if were driving a Tesla or EV?
AM is out!
We use a dixie cup and some 8lb test fishing line.

Too much strange rf and ev noises in the Tesla.

 

[Firemandakota87]

Dose anyone know what the pl1,2 and the ph1,2 means on the anytone779uv if anyone can direct me the right way