I'd like to pass along a practice we feel we need to follow for our informal 2m digital ragchew net, the "257 Net" here in South Carolina. We currently use PSK63 but are probably going to switch to DominoEX shortly, as multipath interference appears to be less damaging to Domino than to PSK31 or PSK63. The decision will be made on the overall impression as to which mode has less errors for most people over eight net gatherings, because multipath is not a problem for everyone. It depends upon the locations of the stations and reflective surfaces in the path. So far, Domino appears to be better than PSK63 at handling multipath. PSK31 does not do nearly as well as PSK63.
I have departed from my own recommended approach in the DigiPan Help of specifying the actual RF frequency, because many hams still do not understand how to set the transceiver for the actual RF frequency, and we want our net to be easy to locate for everyone - including newcomers, and FM HT operators (they have to use a multimode or SSB transceiver, of course). Instead, I say we are on 144.257 Mhz, USB, around a tone frequency of 1000 Hz on the waterfall. So, even though we call ourselves the "257 Net", we are actually operating on or near an RF frequency of 144.258 MHz. I say "on or near", because we have found much variation between transceivers at this high frequency, so we accomodate that by suggesting that everyone use USB only, set the transceiver dial to 144.257 (for the "257 Net") and then just click on the signal on the waterfall, which should hopefully be around somewhere! Generally, the Net signals will be within +/- 100 or 200 Hz of the 1000 Hz tone frequency, but everybody will be on the SAME RF frequency, once they click on a signal. Since this is a 2m net, there are seldom any other signals on the waterfall to confuse the issue. It is not practical to tune around looking for a signal, since often stations are near the noise level, so knowing where to start is important to being found. I still find it uncomfortable to depart from the accepted "correct" way to specify the frequency as the true transmitted RF frequency, but in our case we feel an exception is necessary. To say to just set the transceiver dial to 144.257 and use USB, is the simplest way to explain where we are, since seeing the trace on the waterfall does the rest. 144.260 MHz is widely used to coordinate microwave communications, but the convention is to use USB on VHF, so working between 144.258 and 144.260 true RF frequencies is not going to interfere with USB users starting at 144.260 and they are not going to interfere with our digital activity on their lower sideband, unless someone is accidentally operating below 144.260 with his suppressed carrier, and since we are at 144.258 MHz, a moderate degree of mistuning by either of us is not going to interfere with the other. Skip KH6TY
