Ted, >I agree that in a single array configuration it does not have the gain >realizable by a directive antenna, no omni-directional antenna will. >But in those cases where a rotatable antenna is not feasible nor permitted >(as on some public structures housing EOCs)
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
