Lots of interesting things. I completely accept that VHF SSB (which can also mean digital) communication is really the only practical longer distance VHF mode that works without infrastructure. But will we have a turn around in the number of operators who actually use these modes? There is no question that an increasing number of hams have the equipment now. But very few are using them for 6 and 2 meter SSB. Fewer hams are operating weak signal SSB, which has caused a significant drop in interest considering that there are several times as many hams today than when this was much more popular.
A local weak signal ham (50 miles north) said to me recently that years ago (decade or more) there used to be many midwest U.S. stations on 2 meter SSB, both fixed and mobile. But that is no longer true. And there does not seem to be any improvement as of late. Maybe other areas are seeing some increase? But the unaswered question is, how much different would the path gain be between horizontal and vertical polarization? And that might depend on the distance since it seems that the farther out you go, perhaps the horizontal polarization gives a slight edge. But really how much of an edge? Isn't it really the gain of the antenna over the polarization of the antenna? Just because weak signal operators use horizontal does not mean that emergency and local SSB operators need to do this. We have many stations (most stations) that have gain on vertical and nothing available on horizontal and never will have anything on horizontal. Even hams who buy a multimode/multiband rig and now might want to try SSB or digital are rarely buying a new beam just for 2 meter SSB. Partly because of cost, partly because they can not due to local restrictions, and partly because they often have upgraded and also want to put energy into HF. The other factor that seems to be in play, is that there does not seem to be much correlation between hams who do weak signal and also do public service, compared with the ham who is primarily involved in public service and might add an new dimension to their operation if asked to provide this needed service providing that they could use their existing antenna or at least not have to have two separate antennas. Consider the number of FM hams who have beams on vertical polarization including fairly high gain antennas such as the double 13 element Cushcrafts. Using vertical polarization, they can often use FM to access repeaters from one side of our state to the other but unlike SSB they can drop below the threshold at times as there can be QSB on these kinds of signals. SSB would give them at least 6 dB or more margin and digital should give quite a bit more. Your comment about PSK63 only working 50% of the time when you have marginal phone communication makes me wonder if the digital modes are able to work as deeply into the noise as claimed. Shouldn't there be solid copy in PSK modes, even PSK250 or at least PSK125 at a few dB below zero dB S/N? Phone communication, even SSB would need a bit over zero dB wouldn't it? 73, Rick, KV9U kh6ty wrote: > > This illustrates the core of the problem of not having enough total path > gain to communicate with the EOC if the repeaters are down. > > Either the portable station in the disaster area, or the EOC 100 miles away, > will have to have at least a 10-element beam in order for the portable > station to be heard at all. > > I have a 13 element beam with 14 dBi of gain and several times, I have > worked WO4DX on 2m mobile on SSB phone to his stacked loops and 100 watts. > He periodically travels on business from the coastal town where I live (near > Charleston, SC), to his home QTH in Dawsonville, GA, and I can consistently > work him for 100 miles, going NW up I-26, until he turns and starts heading > to Augusta, GA on I-20 and then I start losing him. I also periodically work > rover NK4Q, also with 100 watts and stacked loops on his truck, up to 120 > miles away, along I-20 as he heads east to the Outer Banks for the VHF > contest, but to copy these stations, I must use my 13-element beam. If I > switch to my skeleton-slot antenna, which I use for the local PSK63 net (6 > dB down from the beam), I cannot copy either of them. If NK4Q switches from > stacked square loops to the skeleton-slot antenna I made for him, picking up > 6 dB more gain, I can again copy him until he gets over 120 miles away. When > he arrives at the Outer Banks, I again cannot copy him unless I switch to > the 13-element beam, and copy is still marginal on phone. However, if we > switch to PSK63, print is over 50%. If NK4Q then switches to a 10-element > beam, picking up another 3 dB, print improves to 100%. This is a distance of > 300 miles, with both stations at sea level. > > So, if the EOC is not able to either have extra height, or to use a > higher-gain antenna, or if I cannot set up a beam outside the hurricane > shelter, I will simply be unable to reach the state EOC in Columbia from a > hurricane shelter in Charleston, 100 miles away, if the repeaters are down > locally, and we will have no commumications except hopefully on 80m or 40m > using NVIS antennas, which takes more real estate to set up, and is more > susceptible to QRN. > > I do realize it is going to take time for a substantial number of stations > to discover 2m VHF SSB phone and digital for both emcomm and casual > operating, but in the end, 2m VHF SSB digital, with sufficient antenna gain, > is the most practical and reliable emcomm alternative to using repeaters, > which may not be operational when we need them. > > If anybody reading this is within 200 miles of Charleston, SC, and would > like to try 2m PSK63, you are invited to beam toward Charleston and check in > to our informal ragchew net on 144.144 MHz, USB, around1500 Hz tone > frequency, at 8 PM on Wednesday nights and 9 PM on Sunday nights. > > 73, Skip KH6TY > > > > >
