QRP contesting at 160 mtrs!
Normally I take part in each QRP contest that will exist. But I special like 160mtrs. Some 160mtr stations have very good receiving antennas. Good will say....a good signal to noise ratio....They will pick up 5 watts QRP signals without any problem. Sometimes I ask, "can you copy my 1 Watt signal"? Sometimes I go even further down to 100mW (yes at 160 mtrs). It is possible to bridge a distance of 800 - 1000Km with 100mW at 160 mtrs (in CW) if the other station has a seriously low noise receiving antenna.At the same time, some other stations can not, or hardly copy me at 160 mtrs, even not if I make 250 Watts in the same antenna.
It happened many times that I heard a station with S9 + 30dB or
even louder. On my S-meter 50dB above the noise. Imagine the station
should lower his power to one (1) Watt, I could still copy it with S9
and a signal to noise ratio of 20dB. But while I was making 10 Watts,
and called him several times, the other station could not copy me, it
was completely deaf.
At 160 mtrs, the noise level at the receiving side is most important.
Of course you can also make QSO's with a tuned random wire and a
1KW amplifier, a high receive noise level, and working the other KW
stations. Many amateurs do not like this band, but 160 Mtrs contesting
is for real professionals. At 160 mtrs, the noise level at the receiving side is most important.
There are situations when it is possible to make 160m SSB qso's over a distance of 150-300Km (first skip). Very loud signals with not more than 10Watts PEP. Best time is during the day when the QRM levels are low.
Once I tuned an old car radio for use at 160mtrs. Just AM, but this gives an easy and low cost receiver. It is not difficult to make an AM transmitter for this band, it could be built into the housing of another AM car radio. You can buy old radio's at flea markets for just a few Euro.
I like using 160 mtrs and do all kind of experiments.
K2/K3 are very usefull transceivers to perform 160mtrs experiments due to their high dynamic range and the second RX antenna input.
I build an amplifier with low cost switching power fets. Input 10 Watt, output 800Watts, power supply 80V @ 20A. Can be used for 80/160m. This is fun but no qrp.
See the amplifier below at the footer picture. right corner, build into old PC housing.
VHF contesting 50MHz (6mtrs)
I have a Rhombick antenna (unusual shape) which I use for 30 to 6 mtrs. Best performance (highest gain) is in the North-South direction. I did not mount the resister so I have radiation in two directions. Simulations did prove that the gain at 10mtrs is 16 dB with a low radiation angle to the horizon. At 6mtrs the gain is even higher but I did not simulate this yet.See the pictures for some 6mtrs ES openings in June and July 2010.