LF: 500kHz simple 5W TX/RX transverter

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Dear All,

My WSPR tx up-converter has now been modified to a full TX/RX tranverter suitable for WSPR, QRSS and CW  in a very simple way, making use of the FT817 split facility
which allows you to RX on 500kHz and TX on 28MHz. By adding a series LC
between the TX PA and the FT817 input/output RF connection (with
back-to-back diodes at the L and C junction, this allows "pass through"
from the 500kHz ATU to the FT817 on RX (tuned to 500kHz). On TX, the
diodes conduct and the C part is in parallel with the first cap in the
TX low pass filter. This scheme is now working really well with good RX
sensitivity and no change in TX power out.

Schematic of the transverter is on my blog at http://g3xbm-qrp.blogspot.com/ . My attempt to add it as an attachment to an email here earlier failed.

This more or less concludes my 500kHz experimenting, apart from getting a few more CW QSOs in the log. It's been great fun all the way with lots of support from folks here. I was going to try 136kHz, but think I will now give this a miss for now.

73s
Roger G3XBM
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http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
G3XBM    GQRP 1678      ISWL G11088