I have been using a 253 for years now to feed a 40m inverted V dipole with
400w of RF, via 20 feet of coax to a Centaur balun followed by 50-60 feet of
ladderline. I work all bands 80-10m with this setup. I do not pretend it is
ideal, but then our home is on a 30 foot by 150 foot lot, only 3 miles from
the centre of a major UK city. An antenna farm is impractical.
I can only admire the ingenuity of others in finding ways to use the 253 that
TT never thought of ... My approach seems downright trivial. The line-up is
Omni-v.9, Hercules II and the 253, interconnected with the regular TT cable.
The Omni is also controlled from a PC, so complete band/mode/ATU switching
can be done from the keyboard.
I use an old Heathkit antenna switch connected by three short coax cables to
the 253 (plus one coax jumper to my K2.) The 253 "Antenna 1" stores the
current (or last) CW setting on non-WARC bands. "Antenna 2" likewise stores
the SSB setting on non-WARC bands. "Antenna 3" stores a setting for each of
the WARC bands. It would be nice to have more settings for different parts of
the band(s) but thats not necessarily helpful, because using ladderline, the
settings vary with the weather ... sometimes a great deal.
One wrong setting per band segment is more useful than a basket full of them
to be re-adjusted every time it rains, yes ?? This setup has helped me hit
the top of the DXCC Honor Roll (mixed), so I guess that avoiding too many
complications is not a bad idea.
Final point. The X2404 chip seems to be readily available here only as the
cmos version X24C04, but it works just fine. I got a bag of them from the UK
parent of Newark. Incidentally the same chip is used in the Omni-V but is
NOT socketed. If you have memory problems on a much-used Omni-V then swap the
chip, but after cutting the old one out and cleaning the holes, fit a socket !
Note that pins 2 and 7 are also soldered to a jumper trace on top of the
board, and a turned pin socket has room to re-solder these connections
without melting the socket - if you are very careful.. Otherwise put an
insulated jumper on the underside. Just as good and less difficult to do.
John G3JAG
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