PugetSounder

I have the same GM-15 radios. The Radioddity software I used is GM30 v1.05 from their website. Works perfectly on my radios. I've added police and fire on DIY channels w/no issues. I bought the BTECH cable with the FTDI chip and Windows 10 recognized it without having to load any additional drivers. Some users have reported issues after using the GM30 firmware update on the GM-15 Pro so I took their advice and didn't use it. BTW. Get the GM 30 manual while you're there. It's well written and fully compatible with your GM-15.

Thanks for that excellent reply. I'm just a humble hobbyist and trying to get my head wrapped around all this.

Clipped from an ARES 2m Net instruction page: The repeater is linked into the (Name Removed ) network of repeaters during the net, so remember to pause for a full second or two before talking when transmitting to allow for all of the repeaters in the network to sync up. Given the nature of many GMRS users, I would expect a total mess so be careful of what you wish for. Also, network of repeaters seems to be the appropriate term in this context. Glad the FCC doesn't allow it. (My bold)

People need to think about the delay that exists in linking repeaters. The more repeaters, the bigger the delay. This is not a problem with trained hams that meet and discuss operational procedures. They are trained on what to expect. Now get a bunch of newbies with a fresh GMRS license and a $25 radio and you will hear a ton of partial transmissions, people stepping on each other and requests to try again. I spent 8 years in NATO (Germany and Italy) and just making a simple phone call across the Atlantic was an issue because of the delay. Even though we knew that there was a delay, it was still difficult to time your words without stepping on each other.

I don't know either, but I was just speculating that the radio briskly polling between the two would result in a bit larger draw as opposed to just monitoring a single channel.

That makes sense. So I've been dual watching (scanning) two different channels on the same frequency and it's just burning battery faster without any appreciable benefit.

I should also add that I can hear the repeater with my Cobra FRS radios for short periods. TSQL is also heard. Not routinely though. I'm assuming because of changes in propagation.

Thank you Steve. You got me thinking... Maybe I should listen for the TSQL to be sure. Sure enough, I'm hearing TSQL on both channels (018 and 026). But the arrow will change at times. This led me to believe that the radio was able to distinguish between simplex and duplex. Now I'm not confident. Does anybody have an explanation for this or am I missing something?

"Would lowering the squelch on the HT and the Repeater help with this issue at all, even if only in a small way?" Absolutely. Lower the squelch until you get constant static. Then move the setting up a bit until it quiets. If you get occasional noise without readable traffic, move it up another notch. You're looking for the lowest squelch setting without annoying noise. Having squelch at lower settings helps to receive weaker signals that higher squelch settings will ignore. Do one at a time though. I would start with my HTs on simplex.

That last sentence probably didn't make much sense. So let's try again. Male voice is WWV Ft. Collins, Colorado Female voice is WWVH Kauai, Hawaii. Different calls signs. But still a good propagation day if I can get them both.

I used 198.309.441 per the guidance in Sshannon's link. There's a solid pilot there that is easy to zero. Tech tip #1 - Calibrating your SDR / Finding a suitable frequency source <snip> When calibrating a unit, use as high a frequency as you can. The higher the frequency, the more accurate the unit will be over the entire reception range. Errors will multiply as the frequency multiplies. Conversely, errors will divide as the frequency is divided. A 4 Hz error at 200 MHz will be 8 Hz at 400 and 16 Hz at 800 MHz. but if you calibrate to within 4Hz at 800 MHz, that will translate to a 2 Hz error at 400 MHz and 1 Hz error at 200 MHz. A GPS Disiplined Oscillator is the preferred common source. If you do not have access to one, an ATSC DTV transmitter pilot carrier is a good over-the-air alternative. These can be found at 309.440559 kHz above the lower channel edge. For example, if the DTV station transmits on Channel 11 (198-204 MHz) this pilot can be found at 198.309440559 MHz. Obviously the Airspy will not resolve to MilliHertz, so use 198.309441 MHz. That will still be accurate within 1 Hz. But I do like to use WWV @ 5, 10, 15 etc to find open bands. On a good day I can hear both the male and female voices indicating a strong signal from both Hawaii and Colorado.

And here's my apology to NOAA (if you are out there)

Turns out that my setting is -2. Mystery solved!

Man that is a great find! And this a helpful group. Thank you all.

Thank you! This seems to be what I've been missing. -Easy enough too.

I have two SDRs based on different chip-sets and they both center at +257Hz. Same software though, so that might be a factor.

Great idea. I'm going to check this out. I think I read somewhere that transmitting without an antenna would damage your radio? Is that untrue? Also, could you tell me how you got your screenshot? I fiddled with it for a bit and finally gave up and used a camera.

Thanks! And I appreciate your input. I'm somewhat new at this. Just brainstorming and hoping to understand function and theory a bit better. -So many variables... I spent a few years monitoring HF LSB/USB and I would just turn the VFO and tune in that way. A few Hz +- to find center becomes easy after doing it for awhile. Now, with a couple of HTs, and considering a mobile (which are type accepted) that's not an option. So I thought I'd look into what is being transmitted and what I'm receiving. It looks to me that the output tolerances are larger than I expected. As an example, NOAA ch3 is 162.475.00 in my area. It's loud and clear from my station but looking at the waterfall, center frequency is actually 162.475.257. Moving up to the latter frequency gives me better fidelity on my laptop. The voice becomes closer to a real human if that makes sense. Now I would think that NOAA is using the best transmitters in the world, but they still seem to be off frequency by a bit. Idn, maybe they re-calibrate on some schedule or maybe they consider that they are within tolerance and leave it be. I don't know the answer...

Thanks for the correction. And the info. For the record, I can hear the difference on my PC w/a discone, but obviously not on my cheap HT with a small speaker and whip. Do you think it might impact rx for people out in fringe areas? At 25 kHz, there appears to be some (perhaps minor) modulation cutoff on the upper side.

I’ve been monitoring the OlyCom3 (Tiger Mt E) repeater with my RTL-SDR. I have 2 SDRs V-3 and V4. Both are reading the same. The repeater output looks to be 1MHz off center as shown in the 1st pic. Moving the freq up to 626 (pic 2) shows the signal at center of the modulation. You can clearly see it by the station ID in CW (pic 3). As an experiment, I tuned my SDR to a strong commercial FM station. My reasoning is these stations broadcast in Wide FM as well. So for instance 97.7 KIRO FM booms in the Puget Sound area The signal is center frequency. At 97.6 I still read the station OK but fidelity suffers. Same with 97.8. I'm still learning so I thought I would ask more experienced people here. Has the Repeater drifted off frequency or is this normal due to the positive offset setting? I'm unsure.

My radios show the active channel by way of an arrow? Don't they all when in Dual Watch?

You may already know this but here goes: A cheap SDR will give you the ability to see what's out there on HF, VHF, UHF, slow scan TV, track satellites, listen to the space station etc. Additionally, you can listen to international shortwave broadcasts, pirate and spy stations. Listening to active NETS is super easy. -There is a lot more but it's TLDR. You can program in all of the active frequencies within your antennas reach and use a scanner plug-in to monitor traffic. People get into the radio hobby for different reasons. I personally like to listen mostly. I humbly advise that if you want to be a HAM, check the radio bands chart and then use the cheap SDR to monitor the allowed bands that you are shooting for. This will give you a realistic idea of what is going on out there and help you decide if you would like to spend time and $$ to get in on it.

Yes. The repeater is 50+ miles from here. However I have heard someone walking their dog in Yelm and coming in clearly with their HT. Also someone in Tenino was booming with a handheld. Tenino is 15 miles further south, but they have some hilly areas vs Yelm which is fairly flat prairie land. I have a large 10x30 metal RV carport near my shack. It's around 12' tall. I was thinking about putting a mag mount GMRS antenna on it and see what happens. That will = 4 antennas. Glad I'm not in an HOA. I should mention that I have dual watch set to channel 18 and 26 so I can see if I'm picking up simplex or repeater. On occasion, I can even hear the repeaters CW on one of my Cobra FRS radios.

Thanks for that. I don't want to throw money at it just to be disappointed. The Abbrees did have good reviews. I used the line of site website and there are no terrain issues between me and the repeater. I wonder if my mic is the issue. I read somewhere where people gently drilled out the mic hole to open it up a bit? I looked at some Comet analyzers and was wondering which one you have?