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GMRS mobiles?
- Thread starter fasteddy
- Start date
Have you tried these? Is it comparable to 70 cm? I have been looking for something my wife and I can use for local comms, because she has no interest in becoming a ham, or even having a "huge" antenna on her car.
Hi C.T.,
The FRS/GMRS frequencies are right next to the 70cm ham band. And will behave pretty much the same. Flat terrain tends to offer better range than lumpy terrain.
If you have used 70cm radios in your "foothills" neighborhood, you already know what to expect. The higher the base antenna, the fewer shadows you'll have when you're behind higher terrain. And the shadowed areas will be smaller, too.
A good gain antenna on each end is a good idea. The shorter you can make the base-antenna coax the better. Losses are a lot higher at 460-some MHz. Good coax will lose only half your power (each way) per hundred feet. Lower-performance "CB" coax may lose 90 percent of the signal over a 100 foot run. First UHF radio I ever used on a local FM repeater was a tube-type GE "Progress Line" radio, only delivered about 6 or 7 Watts. The only coax handy was some old stuff marked "RG-8 'type coax. The word "type" meant that it only had about 25% shield coverage. This stuff was really cheap.
Anyway, it would hardly get into or out of the repeater, with a ground plane on the roof. Carried the wattmeter up to the roof and hooked it between the long coax and the antenna. My 6 Watts was only about a quarter of a Watt by the time it got through the junky coax. Explained why I couldn't hear much, either.
A commercial radio base on that band would use Heliax. In the old days, a UHF base would often get put in a closet on the top floor of a building, and remote speaker/mike/squelch installed at the front desk, or wherever the dispatcher worked. The indoor wire used for the remote was a lot cheaper than the equivalent length of Heliax.
I suppose there must be some limit on how high you can put your base antenna? That, most of all will limit your range, base-to-mobile, pretty much.
Besides, it should be a legal use for GMRS, too.
73
The FRS/GMRS frequencies are right next to the 70cm ham band. And will behave pretty much the same. Flat terrain tends to offer better range than lumpy terrain.
If you have used 70cm radios in your "foothills" neighborhood, you already know what to expect. The higher the base antenna, the fewer shadows you'll have when you're behind higher terrain. And the shadowed areas will be smaller, too.
A good gain antenna on each end is a good idea. The shorter you can make the base-antenna coax the better. Losses are a lot higher at 460-some MHz. Good coax will lose only half your power (each way) per hundred feet. Lower-performance "CB" coax may lose 90 percent of the signal over a 100 foot run. First UHF radio I ever used on a local FM repeater was a tube-type GE "Progress Line" radio, only delivered about 6 or 7 Watts. The only coax handy was some old stuff marked "RG-8 'type coax. The word "type" meant that it only had about 25% shield coverage. This stuff was really cheap.
Anyway, it would hardly get into or out of the repeater, with a ground plane on the roof. Carried the wattmeter up to the roof and hooked it between the long coax and the antenna. My 6 Watts was only about a quarter of a Watt by the time it got through the junky coax. Explained why I couldn't hear much, either.
A commercial radio base on that band would use Heliax. In the old days, a UHF base would often get put in a closet on the top floor of a building, and remote speaker/mike/squelch installed at the front desk, or wherever the dispatcher worked. The indoor wire used for the remote was a lot cheaper than the equivalent length of Heliax.
I suppose there must be some limit on how high you can put your base antenna? That, most of all will limit your range, base-to-mobile, pretty much.
Besides, it should be a legal use for GMRS, too.
73
I'd guess that I could go read it somewhere, but is it legal to modify a ham radio 70cm to transmit on gmrs frequencies? As long as you are within the power limits or whatever?
hey there..
is it legal to redo a 70cm radio to work within the frs/gmrs frequencys...
in a word "NO"
did i mode my 706MKIIG to gain me access to FRS-GMRS-MURS
you bet...
however such radios usally exibit a great loss of power when out of band..
but since i rarly use those frequencys...then that is fine by me..
Later
is it legal to redo a 70cm radio to work within the frs/gmrs frequencys...
in a word "NO"
did i mode my 706MKIIG to gain me access to FRS-GMRS-MURS
you bet...
however such radios usally exibit a great loss of power when out of band..
but since i rarly use those frequencys...then that is fine by me..
Later
They won't lose much, if any power on the FRS/GMRS freqs....they're so close to the 70cm band. It's not legal, but....
...Seriously though, someone needs to rethink the rules on type acceptance for vhf/uhf radios. IMO, if you have a valid Amateur license and are using a FCC certified radio, you ought to be able to use it at the appropriate power levels on MURS, FRS, GMRS. I mean seriously, how many radios do they think one guy can carry around?
...Seriously though, someone needs to rethink the rules on type acceptance for vhf/uhf radios. IMO, if you have a valid Amateur license and are using a FCC certified radio, you ought to be able to use it at the appropriate power levels on MURS, FRS, GMRS. I mean seriously, how many radios do they think one guy can carry around?
kenwood tk805
the kenwood tk805 is an older commercial radio usally avialable for 50 to 100 dollars on e-bay, 25 watts user programable and I can tell you this thing is durable as hell with loud audio. THe cheapest most bullet proof frs-gmrs radio. much better than an ametuer radio because the reciever is tuned to work in that range. I've used modded ametuer radios and the reciever sensitivity was crap, plus the audio was weak, the commercial rigs are the way to fly and cheaper too!!!! Steve44
the kenwood tk805 is an older commercial radio usally avialable for 50 to 100 dollars on e-bay, 25 watts user programable and I can tell you this thing is durable as hell with loud audio. THe cheapest most bullet proof frs-gmrs radio. much better than an ametuer radio because the reciever is tuned to work in that range. I've used modded ametuer radios and the reciever sensitivity was crap, plus the audio was weak, the commercial rigs are the way to fly and cheaper too!!!! Steve44
I use LMR radios made by Midland, Maxon, Kenwood, Vertex & Johnson.
I have programming capabilities for all these radios, but the Kenwood TK-805D can be programmed from the front panel by moving a jumper inside the radio.
One important note...
many if these radios were made to cover a specific frequency range while having the same model number, with a freq designator added, such as the TK805D-1,2,3 or Midland 70-1530A,B,C,D where the last number or letter indicated the freq range, such as 420-450, or 450-470, 470-490, etc.
Be sure of the freq range if you go for one of these radios.
These types of radios are great for GMRS mobile use, real heavy duty and come in 25w and 45w versions. Power output is often user programmable via software.
Like Steve said, these radios are often very inexpensive on ebay, depending on the availability to program them.
If you need programming services, you can e-mail me.
Using amateur gear does not work too well because the the radio will lose a lot of sensativity and power output trying to tune so far out of band (462/467mhz versus 420/440mhz).
Also, your amateur dual band antenna will typically not be broadbanded enough to cover this range without serious degradation to your match.
I have programming capabilities for all these radios, but the Kenwood TK-805D can be programmed from the front panel by moving a jumper inside the radio.
One important note...
many if these radios were made to cover a specific frequency range while having the same model number, with a freq designator added, such as the TK805D-1,2,3 or Midland 70-1530A,B,C,D where the last number or letter indicated the freq range, such as 420-450, or 450-470, 470-490, etc.
Be sure of the freq range if you go for one of these radios.
These types of radios are great for GMRS mobile use, real heavy duty and come in 25w and 45w versions. Power output is often user programmable via software.
Like Steve said, these radios are often very inexpensive on ebay, depending on the availability to program them.
If you need programming services, you can e-mail me.
Using amateur gear does not work too well because the the radio will lose a lot of sensativity and power output trying to tune so far out of band (462/467mhz versus 420/440mhz).
Also, your amateur dual band antenna will typically not be broadbanded enough to cover this range without serious degradation to your match.
I use a KENWOOD TK-880 on the local GMRS freq's never a problem at all many diff rptrs to choose from here in northern il and southern wi. Loud audio from the radio no freq drift to speak of I also use a TK-780 for the murs freq's I also loaded it full of fire frequencies police ect. Both radios also have a scan function ctcss ect.
I use my Icom 706 MKIIG (moded ofcourse)..
Although that is over kill for GMRS..
One might want to look to Motoola
they make a couple of mobil radios with 50 watts out..
they work well..
Later
Although that is over kill for GMRS..
One might want to look to Motoola
they make a couple of mobil radios with 50 watts out..
they work well..
Later
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