Re: UHF and FRS/GMRS Compatibility
 

Hey Guys,

After reading the following thread (UHF RAdio Users - Compatibility Information), I still don't completely understand the radio compatibility criteria.

I have an opportunity to get a used Yaesu 60R and I was wondering if it works on the FRS/GMRS frequencies. I understand that FRS/GMRS operates around 460-470 MHz, but is this transmitting or recieving? The 60R seems to be able to receive on that frequency, but does not transmit. Will this be a problem? Or have I misunderstood something?

Thanks.

Frequency Coverage:
Receive:
108-137 MHz (Air Band)
137-520 MHz (AM / FM)
(Cellular phone Blocked)
700-999 MHz (FM)
(Cellular phone Blocked)
Transmit:
144-148 MHz
430-450 MHz
Transmit Output Power:
High 5 W (@ 7.2 V FNB-83)
Mid 2 W (@ 7.2 V FNB-83)
Low 0.5 W (@ 7.2 V FNB-83)
Modes of Operation:
F2 (data packet 1200 baud), FM

No, you're correct. By default, most UHF radios will NOT transmit on the FRS/GMRS frequencies. This is by design, since most dual-band or tri-band transievers will transmit at 5-6 watts, where FRS/GMRS are limited to 0.5 to 2 watts. Therefore, transmitting on those bands at 5 watts is technically illegal, although its extremely unlikely that anyone would ever notice or complain.

Fortunately, there are simple modifications that can be performed on most transievers (including the 60R) that open up these frequencies for transmitting. The modification typically consits of unsoldering a specific diode on the mainboard. Detailed instructions are available via Google.

Incidentally, if you have available VHF frequencies, and your teammates can use them, they're FAR superior in range and clarity to the FRS/GMRS frequencies. The only reason those frequencies have been designated "public" is because they're basically useless for anything other than short range communications and nobody in their right mind would pay for them...

Thanks for the info MadMorbius!

I was wondering if you could direct me to some instructions on how to do this. A quick search lead me to the following website: http://www.ham.dmz.ro/yaesu/ft-60r-m...d-transmit.php
Is this the correct guide? And are there better ones out there?

The guide says to "Remove R1164" in the photo below. Does this mean to literally unsolder and remove? Or can I just heat up the diode by placing the iron on it for 1-2 sec, rendering it inactive?

Thanks for your help.

http://www.ham.dmz.ro/pictures/yaesu/ft-60_mars-7.jpg

To be honest, I didn't do the work myself. I'm a bonehead with the actual electronics so I had someone do it for me. From what I recall however, that's correct.

I've asked for confirmation from the fellow who did the work on mine; I'll post as soon as he replies.

Thanks!

Yeah the 60R is nice if you want dual band, but doesn't cover GMRS/FRS bands. It was one of the radios I was considering when I was shopping for one.

You can find a copy of the manual here if you want more details on how it operates.

If you're looking for a radio (UHF) with similar specs and capabilities, check out the PuXing PX777 or 777+

Drake - I have the 60R modded and it talks on GMRS/FRS and receives MARS. I can talk to airplanes on it if I choose to, which makes it usefull if you're a pilot and need a backup radio.

If you don't mind modding the radios, they're a great buy.

Yeah, I found instructions on how to do it, back when I was looking... but reading through it I didn't quite feel it was something I was up to do doing. Seemed likely I'd just end up with a nifty looking paper weight.

VHF wasn't really a requirement for me, and the PX777 was about half the price, hence my suggestion to Blade if he isn't keen on modding either.

Hey Drake thanks for the suggestion - and I found out that I suck at soldering today. I tried to desolder an old circuit board I had lying around and it was an ugly sight! Now give me a person and I'd be able to sew an artery together, but engineering is completely new to me.

I'll probably stick with the FT-60R though, b/c I like the functionality of the radio and I've read many great reviews for it. Hopefully I won't have to modify it myself! :rolleyes:

I would recommend the Yaesu VX-7R. Its about $400 from Radioworld in Toronto, however, the big plus is you can buy a USB cable and download the free Commander software for it on the internet and not only program the entire radio through a Windows GUI, but you can also perform the appropriate transmit enable modification through software. This would avoid the need to open the radio up and make the modification, although on that model I did it myself as its dead easy. Frankly Yaseu is catering to the illegal mod market with this particular model.

I had mine programmed with every freq I needed including the CB bands (receive only unfortunately) inside of 10 minutes, versus spending literally HOURS on the keypad of my old Kenwood (trusty as it is).

The Yaseu VX-7R is what a radio *should* be and was long overdue.

• Yaesu's official page with specifications, brochure and manual.
• VX-7R Modifications & Information
• VX-7r Commander software for programming the VX-7R.
• VX-7R mods from www.mods.dk.
• eHam.net Reviews of the VX-7R
• Review by N0UQZ.

Yeah actually Scarecrow brings up a good point: whichever radio you end up getting, spend the extra $20 and get the programming cable for it. It makes setting the radio up much simpler/faster (setting Labels for 20 channels, for example, is tedious at best using the keypad) and often gives access to features which can only be accessed via the computer interface.

The 60R (and the PX-777 and many other radios for that matter) have cables available.

Hey J. Thanks for the info, I didn't know you could program the frequencies into the 7R through the computer. Long story short, I borrowed both my friend's 60R and 7R for a couple of days - neither of which have been modded for the FRS/GMRS. I don't really want to physically alter the 60R, so that leaves the 7R mod.

I've downloaded the VX-7 Commander software, but I'm not sure how to enable FRS/GMRS frequencies; perhaps you could explain? [Note: My friend also gave me the 'Advanced Data Management System for the Yaesu VX-7' (ADMS-1G), which connects to my computer's serial port - is this the correct cable?]

Thanks again!

I got the 7R working on FRS/GMRS last night - a fairly easy process; but the transmission is quite bad though. My voice doesn't come through as clearly as my $40 GMRS radios - my voice sounds all raspy with a little static in the background. Is this normal for the 7R (i.e. bad microphone)? Do I need to get an external mic? Or is there something I can adjust on the 7R, itself?

If you are transmitting on 5 watts to a regular GMRS/FRS handset, you are likely overloading the GMRS/FRS handset.

Get a buddy to transmit from the 7R from at least 100M away.


FYI - To remove the diode on the 60R, you just heat up the iron and touch it for about 2 seconds on the diode, it will melt enough to stick to the iron and pull right off.

Thanks Blackthorne, I did notice that the reception was clearer when transmitting at 0.5 Watts... and now I have a good explanation as to why.

And yes, I thought as much with the diode, although I don't want to permanently alter my friend's radio. The 7R is pretty sweet, but the 60R is quite excellent for the price.

You won't render a diode inactive by holding a soldering iron on it for a couple seconds. Just remove it flat out, if things don't work then solder a piece of wire in there to shunt it. Diodes aren't very sensitive things, at least as far as heat goes. They can withstand numerous heat cycles (one heat cycle is prety much equal to one second), and during manufacturing go through at least a couple cycles alone. Best to just either remove it or shunt it, depending on the nature of the diode itself within the circuit.

And here I am thinking they were extremely sensitive to heat! Goes to show how much I know - I should probably learn more from that 'How It's Made' show I watch so often.

Question:
It's weird, I have 2 Cobra GMRS/FRS radios and when I use the 7R and transmit, one Cobra receives the voice clearly and the other receives a garbled/static voice (hardly discernible). I have a theory on the cause, but I was hoping to get other opinions. Any guesses?

As Blackthorne says - part of it is transmit power can overwhelm a regular FRS/GMRS radio, but there is one other issue - and sorry, I should have mentioned this earlier - the one downside to VX-7R is one thing that makes the radio compelling - it is truely submersible in water. The downside is the mic has a waterproof membrane over it that can obsure the voice. I definitely recommend a separate Mic/PTT for this unit unless you want to mod the radio to remove the membrane. Once I got an inexpensive Mic/PTT for the unit, that problem was insta-resolved. I hate using radio's built in mikes and prefer hand and headsets, so it didn't immediately occur to me to mention this anyways - and in airsoft most everyone uses a boom mike, a PPT or an earpiece/mic combination. There are some HK ones I was selling but they are commonly available on eBay on the cheap - so much so I usually buy several because I tend to lose or destroy them.

That WILL solve your mic problem.

Yep, I am planning to get a headset for the new radio. I had an Iasus Sniper Pro throat mic for my Cobra, but I had some problems with it. And I am definitely not planning to remove the waterproof membrane if I do get the 7R - that would probably defeat the whole purpose of IPX7 compliance.

My guess as to why one Cobra sucks is that it has been fielded several times (battle damage?); while the other one is still virgin. I hope the 7R is more rugged. :D