Saturday, February 03, 2007

Motorla GP68 Radio Motorla GP68 Radio

Working at Keystone ski area, we use two-way radios heavily. They are 4/5 watt UHF radios, and there are some 35 or so sets of UHF frequencies in this county tied up by or used by the two Vail resorts. (I say sets, because most of them are duplexed, meaning different transmit frequencies, with the transmit frequency 5 mhz above the receive to work with repeaters).

Our lives on the slopes are controlled by our radios. That is how you know what is happening, and thus, where you should be and what you should be doing. My problem, and that of much of Mountain Watch, is that our radios are the dregs, most at least a decade old. They have been heavily used and are quite heavy. Another problem is that we get and drop off our radios at the top of the Peru lift. This means that the first ride up and last run down are w/o radios - and the later is when you run into a lot of accidents.

So, I decided to get my own radio, since you can pick them up on ebay for under $100. My first shot, a Motorola P110 is nice, but I am still having troubles getting it programmed. But there are so many of those on ebay that when I get it figured out, I may go into the radio business selling to the other experienced Mountain Watch.

Then, I started seeing ebay auctions for Motorola GP68 radios. They looked great. Fully programmable from the front. Powerful, light, and with great volume.

The problem is that they are "gray" goods, shipped in from Hong Kong. Motorola never distributed the radios in this country, but apparently did extensively throught Asia and Europe. My guess is that the reason that the radios are "gray" is that they can scan the entire frequency range they are designed for (in my case, 430-470 mhz). And this means that they may be usable on some public safety frequencies.

And, indeed, Motorola seems to have used different battery configurations for just this reason - these charge from the bottom instead of the rear like all the other two way Motorola portable radios I have seen. Still 7.5 volt batteries - just different form factors and charging points.

So, the battery charger that they come with is 220 Volt, and does not work on American current. Indeed, the charger is the first one from Motorola that is a one piece unit - all the rest have a transformer plug that plugs into the actual charging unit (and, of course, I have one of those transformer plugs).

The answer to that problem is purchasing a 110/220 volt converter for about $10 aimed at just this sort of thing. They are aimed at running European and Asian appliances, etc. on American power.

The next problem was programming. The "manual" that came with the radio is an obvious copyright infringement. Some pages from some manuals have been photocopied and stuck together in a .pdf file on an OEM mini-CD.

I was despairing until I ran into documentation through Google for the AP73 that was considered functionally equivalent to the GP68. And, after reading the AP73 User's manual, programming the GP68 was a snap. The first channel took maybe five minutes to figure out. By the third or so, it was taking me about a minute or two per channel to program in a transmit and receive frequency and a PL/DPL signalling frequency and then assign it to a channel. Then, I turned off scan for all except two channels, and I was done.

The only complaint I have so far is that the channel scan isn't a priority scan, and if you aren't careful, you can find yourself transmitting on the wrong channel. I want to be able to scan channels 1 and 3, giving preference to 3, and then transmit on 3. I just have to be careful when in scan mode. We operate on 3, and the patrol on 1. But then we move to 1 when our dispatch shuts down at about 4 p.m., at which time I turn of scanning. Oh, and if you are going to be operating in the mountains, you need to slap on a longer antenna.


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