SteveShannon

So I sent a link to a couple friends of mine in Washington state. One of them is really into EMCOMMs. Here’s what he said: “Anyway, I was wrong in my initial assessment of this. It's SO EASY to use on VHF/UHF and probably HF (if noise is low) that it's a must have.”

I suggest trying another microphone. What happens if you speak into the mike?

Sorry, you’re right.

It’s simply not possible to answer your question without knowing a lot more. What’s the terrain like? What buildings surround you? What cable are you using? If you’re surrounded by buildings, hills, or leafy trees, your signals may be attenuated such that you just can’t get through.

Yes, higher gain means that the signal is more concentrated in some directions and weaker in others. For an omnidirectional antenna that typically means thinner vertically, which may make it easier to miss repeaters. Like a pancake compared to a donut. If the antenna is mounted too low the narrower signal might angle more upward, in a kind of shallow cone, angling over the repeaters you’re trying to hit. I would stay with the GP-6.

If you’re mounting the GP-9 in the same place as the GP-6 was, I would suspect that the flatter propagation pattern of the higher gain GP-9 simply misses the repeater. I assume that the GP-9 is tuned correctly etc.

So, your CERT Net was going on and while it was going on when someone checked in you could occasionally hear someone else on the receive frequency. In other words, when your receiver broke squelch because the repeater transmitted a tone, you could hear the folks in the background who were trying to talk on the simplex receive frequency, is that right? Could anyone else on the CERT Net hear them, or were they local to you only? Before you started the Net, did anyone listen with squelch off to hear if the channel was in use? When you did hear them, did you transmit on 462.675 MHz and announce, politely, that the frequency was in use? They could have been on GMRS or FRS. Except during an emergency, they have as much right to be on the channel as your CERT Net. We share the repeater receive frequencies with simplex users of both GMRS and FRS radios and while it would be ideal for each of us to listen with squelch turned off to hear if a frequency is in use before transmitting, there is no GMRS training that covers that. It sounds like folks were just using their radios and it happened at the same time as the Net. If they were using a different tone from you they might not have even heard you. As far as it being “a violation”, no, it wasn’t, at least in my opinion. No more than the Net operators were in violation for transmitting on a channel that was in use already by a couple of folks with their radios. And since you liked seeing the actual regulation regarding emergency use, here’s the one that requires shared use: § 95.359 Sharing of channels. Unless otherwise provided in the subparts governing the individual services, all channels designated for use in the Personal Radio Services are available for use on a shared basis, and are not assigned by the FCC for the exclusive use of any person or station. Operators of Personal Radio Service stations must cooperate in the selection and use of channels in order to avoid interference and make efficient use of these shared channels.

Or were the parties on simplex simply using their radios, oblivious to the presence of a net taking place.

Was there an emergency? If there was, 95.1731(a) says: (a) Emergency communications. Any GMRS channel may be used for emergency communications or for traveler assistance. Operators of GMRS stations must, at all times and on all channels, give priority to emergency communications.

That’s correct, with a patch panel you run coax to each antenna and then switch at the radio end like an old fashioned switchboard. That allows you to use multiple antennas with multiple radios simultaneously. I think I understand better now what you’re talking about. You’re trying to use multiple antennas with a single piece of feedline, using a remote coax switch near the antennas. Is that right? Are you then switching that single coax to multiple radios at the bottom also?

A patch panel is cheaper and more flexible than two coax switches connected common to common, if that’s what you’re thinking about doing.

Power output is much less important than antenna and antenna placement. I easily get 20 miles to a repeater with a 5 watt handheld and rubber ducky because the repeater and antenna are on a mountain. I use the same antenna and mount as you on my vehicle. Are you in a vehicle or using this hardware in a house? You and your buddy should find a couple hills and see if things get better.

What antenna? And what is your buddy using?

It depends on the city and your antenna as well as your buddy’s radio and antenna. Also, are you really getting 50 watts out? The firmware in many radios will reduce your power to remain in compliance with FCC regs.

This kind of crap doesn’t belong here.

What map are you looking at? Here’s what it looks like on mygmrs.com:

Post the zip file.

I think the classified section is only available to Premium members.

Garmin Rhino handhelds are made in Taiwan. I think most other part 95 radios are all manufactured in China.

I don’t think anyone would argue that it’s the best, with all the other devices that are available, but the fact that it doesn’t rely on special hardware or cables makes it potentially valuable in the absence of those devices.

It’s covered (poorly) on page 25 and 26 of the manual - menu 10-13: https://baofeng.s3.amazonaws.com/BAOFENG_UV-9G_GMRS_User_Manual_20210806.pdf

@Blaise, So, I finally installed Rattlegram. Everything you said is exactly what they represent. I don’t understand how the speakers and microphones in smartphones can transduce ultrasound, much less the speakers and microphone in a two way radio. I also don’t understand how the radios modulate signals in the ultrasonic range. I’m intrigued.

Yeah, but I’ve kinda been wanting to pick up an Android tablet for ham radio anyway.

Fascinating. I haven’t loaded the app yet. My iPad says it’s too old and I don’t load test apps on my iPhone usually. I probably need to pick up a couple inexpensive Android tablets to play radio.

I’m not questioning you, please don’t take it as a personal attack. We see too much of that. Here’s why I’m questioning what really happened. Because we use FM the frequency of the RF signal varies with the frequency of the audio which modulates it. But the government (and courtesy) stipulate how much bandwidth we’re allowed. For FM stereo broadcast transmitters are allowed a wide bandwidth so they can broadcast a wider audio spectrum. But two way radios is only expected to reproduce speech. In fact I would expect our radios to have a filter between the microphone and the modulator to avoid creating too wide of a bandwidth. I would also expect that neither the speakers nor microphones on the inexpensive radios to be able to reproduce ultrasound. I thought I read in their PDFs, that Ribbit attempts to send digital data by converting data into audio tones that are in the center of the spoken voice audio spectrum, between 500 Hz and 2500 Hz. Their centerpoint is 1500 Hz and they go 1000 Hz either side. 20,100 Hz is way above that, but 2100 Hz is right in there. If you were able to transmit at 20100 Hz, I would be interested in what an RF spectrum analyzer would measure. But, I always say you can’t argue with empirical evidence, so I’m trying to understand what really happened.