Roger asked:
- When using the M2 egg beaters how important is it to install a masthead
preamplifier?
OK, here is my opinion. Eggbeaters - or any other omni type antenna are only slightly above worthless. Uplink is not really a problem as you can always add power to make up for a poor antenna, but downlink IS a problem because once signal is lost, you can't make it back up. So yes, unless you have an extremely short coax run, I highly recommend a pre-amp at the antenna.
As has been commented many times on the BB, the vast majority of amateur satellite operation is weak signal. Too often new operators try to treat the FM satellites just like a repeater. That's fine if your repeater is 2,000 miles away and only transmitting a quarter watt. It's NOT! It is a weak signal. For people operating terrestrial weak signal, NO ONE would consider using a quarter wave ground plane antenna, but for some reason, so many people try to do essentially just that for satellite. It does not work well.
- Again with egg beater will 30 watts be enough to get back to the bird?
For the LEO satellites, that is plenty (or more than plenty in many cases).
I am using about 80 feet of RG213 to connect the antenna.
As someone else already pointed out, that is not overly good coax, so that makes a good low noise pre-amp AT the antenna even more important.
Disclaimer: Essentially all of my satellite operation has been voice - either FM or preferably SSB on the linear birds. I have no experience with some of the newer "weak signal" digital modes that can dig signals out that are at or below the noise floor. I have operated as a telemetry downlink station for the first USNA satellite which was using one of several omni designs, and worked like crap. For the record, I also operated some SSTV and Hellschreiber (Feld Hell) via AO-40 during it's short life :( At home I ran an AO-10 class antenna system: http://members.dslextreme.com/users/k6ccc/Photo/Pics/SatAnt1.html http://members.dslextreme.com/users/k6ccc/Photo/Pics/S-band1.html
Even mobile (special event) I ran yagis and El/Az rotors in my truck: http://members.dslextreme.com/users/k6ccc/Photo/Pics/MobileSat2.html
73 ----- Jim Walls - K6CCC jim@k6ccc.org