Hi,
I thought I'd better introduce myself to the group now that I am on the air.
I am operational on 181kHz and have had resonable results considering I'm a
beginner at LF! In just one evening I was copied by numerous stations with
RST 569 from ZL4OL at a distance of about 1000km. I was running about 250W.
I have a lot of improvements to make, (I'm sure everyone on LF thinks the
same!), but I'm pleased to have made such a good start. I'm currently
running a beacon on 181.400kHz with 1W output, and it has been confirmed on
Argo by ZL2CA at about 450km range.
My station consists of:
Exciter - ZL1BPU LF Exciter, DDS, with new firmware including 'Castle' Mode
and JASON, 1W output to 250kHz, TCXO reference.
Transmitter - One drawer of a Southern Avionics (USA) SC1000 USCG DGPS
transmitter, 1kW capable. I have the whole system, ex-Navy surplus!
Antenna - Marconi Tee with 70m top wire and sloping 20m upwire. Highest
point 8m. Tuner is original Southern Avionics coil with a 'bucket of wire'
inductively coupled in the top for 1.95mH total. Coil grounded and tapped to
transmitter. Four short radials and ground stake.
RX Antenna - homebrew active whip, J310 cascode design, with 500kHz LP
filter, mounted 10m from house and 7m up in the air. Isolated feed to
receiver and battery supply. Goes well from 10kHz upwards. Nice quiet
operating site.
Receivers - Harris RF-505A with frequency referenced to HP 5065A Rubidium
Standard
- Icom IC-R71
The transmitter is VERY interesting. Only a few years old, it is a broadband
design, and uses a Class D H-bridge FET transmitter, each 500W module with
its own Class S modulator / power supply adjustable 0 - 130V at 7A. The
modulator has 0 - 4kHz bandwidth, so is AM capable. Anyone for Kahn EER? I
key the drive and the modulator with the LF Exciter. Transmitter efficiency
is > 95%. More info on the transmitter on my web site.
73,
Murray ZL1BPU
www.qsl.net/zl1bpu
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