From Dick, PA0SE
The band 135.7 - 137.8 kHz was made available to Dutch amateurs in June 1998.
Maximum allowed transmitter output is 400 W; only CW (A1A).
My station is located at Leiderdorp, a town adjacent to the university town of
Leyden. The QTH is 40 km SW of Amsterdam and 12 km from the North Sea coast.
Transmitter output is about 100 W, of which 45 milliwatt is radiated, as
determined by measuring the field strength at 1 km distance from the station.
I have worked DJ5DI, DK9DX, DJ5BV, DF0WD, G3LDO, G3GRO, G3YXM, G3KAU, G3WSC,
GB4RS, G4XTZ, G4GVC, G4HYM, G3KEV, G4WMZ, G3XDV, G3OLB, GW4ALG, GM3YXM/P,
ON4ZK, ON7YD, ON6ND, PA0LQ, PA0CWF, PA0MLC, PA0SSB, PA0DSW, PA0CC, PA2NJN.
My urban location is a bit noisy, mainly local QRM and a bit of LORAN. But I just
finished contruction of a 4-pole audio filter, centre frequency 1000 Hz and with only 35
Hz bandwidth. It is a phase linear design which means that it does not ring. Maximum CW
speed that can be passed seems to be about 24 wpm; more than the operator can handle! The
filter was designed by Harry Grimbergen, PA0LQ, using a combination of info from
"Reference Data for Radio Engineers" and computer simulation.
I hope the filer will help in copying weak signals in teh noise.
The same result, or maybe an even better one, could have been achieved by an
external DSP unit between receiver and headphones or software in the computer.
But these solutions must be bought and I like to make it myself.
I am available for skeds (hand-keyed morse only) almost any day and time.
Evening hours are to be avoided because man made noise is then unreasonably
strong.
73 from Dick
D.W. Rollema, PA0SE
V.d. Marckstraat 5
2352 RA Leiderdorp
The Netherlands
Tel. +31 71 589 27 34
E-mail: [email protected]
(I applied for [email protected] but AMSAT advises that implementation may take
some time.)
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