dosw

Usually the repeater published range is just a number as a radius from the antenna. In real world RF propagation it's not that simple. I can pretty easily hit a repeater 22 miles away from me with a 40 mile published range. There is another repeater five miles away that I usually cannot hit from home, and it has a published range of 20 miles. The difference, really, is that I have almost perfect line of sight to the repeater 40 miles away. The one 20 miles away has a mountain between us. It doesn't matter if you're only five miles apart if there's several miles of dirt and rock between. In your case, you may be hearing a repeater over 45 miles away because the conditions are such that you can pick it up. Those favorable conditions may include one or more of the following: Most importantly, line of sight. After that, a good receiving antenna and good receiver. And of course factors such as minimal interference on the frequency, a good transmitter and good transmission antenna.

Midland's GTX1000 handhelds are sold this way: 50 channels. Of those 50, 22 are frequencies corresponding with GMRS 1 through 22. And then 23 through 50 are those same frequencies preprogrammed with either CTCSS or DCS codes. Those codes are squelch codes. This means that they are codes someone must transmit for your receiver to open squelch and listen to the transmission. Or that your transmitter must send so that receivers programmed with the same codes will open their squelch and listen. Any receiver that is not programmed to require a squelch code to open squelch will default to receiving all transmissions on a given frequency. And those transmissions are in no way encrypted (GMRS doesn't allow for scrambling). So conversations held between transceivers operating with squelch codes are openly available to transceivers or scanners that are not set to limit by squelch code. There is no privacy. At any rate, channel 50 in a Midland radio, for example, is going to be one of the 22 GMRS frequencies, and one of the conventional CTCSS or DCS codes. If you transmit on channel 50 at the same time someone is transmitting on the equivalent standard GMRS channel, you'll be stomping on each other, because they're analog transmissions on the same frequency. There are only 22 real channels. Everything else is just a preset code on top of one of those 22.

Again, it seems like the call feature is a noisemaker, and essentially intended for entertainment. I don't know why the FCC allows manufacturers to include the feature. We'd be better off without it.

I read the entire Part 95 section yesterday, and one thing that stood out to me is this: § 95.1733 Prohibited GMRS uses. (a) In addition to the prohibited uses outlined in § 95.333 of this chapter, GMRS stations must not communicate: .... (4) Music, whistling, sound effects or material to amuse or entertain; Every blister-pack GMRS radio I see has a "call" button. This button causes the radio to transmit either: Music, whistling, or sound effects. The rule above prohibits music, whistling, and sound effects OR material to amuse or entertain. Every GMRS sold in a blister pack will, with its call button, transmit a sound effect, so breaks the left-hand side of that OR clause. The purpose of the call button could arguably be "to amuse or entertain" as well, though I understand manufacturers will claim it is not intended to amuse or entertain (not even the duck calls... definitely those are neither amusing nor entertaining). Again, to violate 95.1733a4, the transmission is either music, or whistling, or a sound effect, OR material to amuse or entertain. I would love to see that feature excluded from radios, or at least harder for kids to discover.