LZ3NY написа: ↑28 май 2018, 20:38
Браво на дружината.
73!
п.п. Следващия път повече снимки да нащракаш
Първо трябва да оптимизираме станцията и после снимки
. Имахме проблеми с шум от второто радио, който леко ни забавяше. Ето това писа Денис на юнаците от YCCC:
At HQ9X, we had some interstation interference this past weekend. While we
did operate through it, we found that it did hurt our efficiency on the
interfered band, so we would like to see if we can eliminate it.
As transmitters, we used a K3 and a 7610. The interference was band
related, and it was independent of which radio was used as the
transmitter. Our particular interference concerns were 40M into 20M, 80M
into 40M, and 20M into 10M. I realize that in all 3 cases the interference
cited are the second harmonics of the main signal. The actual
interference sounds like what I think of as "phase noise", as it covers the
entire band in a raspy sounding interference. There are frequencies where
the interference is not as bad, and some frequencies where the problem is
worse. We don't expect to be able to operated with 10KHz of the 2nd
harmonic, but we would like to be able to reduce the interference across
the band.
The linears in use are Alpha 99s, which don't have a tuned input. When
transmitting on 80M, the signal is passed through a high power BPF, on 40M
the signal goes through a hih power BPF, and on 20M the signal goes through
a high power BPF and then a high power Triplexer. Still, the problem
exists.
The antennas in use are 1/4 wave verticals for 40 and 80M, situated about
250ft apart. The 40M vertical is also located about 300ft from the beam
antenna in use for 20M.
We have considered several possible solutions:
1. Some kind of BPFs between the radios and the amplifier, to reduce the
broadband noise presented to the amplifier.
2. Stubs somewhere in the RF chain.
3. Some kind of tuned input between the radios and the amplifier, again to
reduce the broadband noise presented to the amplifier.
We don't expect to solve this problem in a day, but would like some insight
on the most effective method of reducing the interference. Its manageable
by choosing frequencies and beam directions, or by reducing power, but we
would like to make it even better!