Hello All,
With the current craze of hot-rodding Ultralight radios by
transplanting super antennas into the tiny wonders, some ultra-exciting
results have been
obtained. However, unless the following precautions are observed, your
results are unlikely to thrill you.
1) Choose your antenna recipient carefully. The SRF39FP, SRF-59 and the
DT-200VX are good candidates for transplant experiments because of their high
resistance to spurs, images and selectivity meltdowns. The DT-210V would be an
acceptable choice also, despite its image reception issue. If your ULR
already has serious selectivity or spurious problems, a huge increase in
sensitivity will aggravate these issues immensely.
2) Choose your antenna carefully. If you transplant a short loopstick
into a ULR, you may be doing a lot of work for very little gain in
sensitivity.
Size really does matter (both ferrite length, and diameter). For best
results, use the biggest monster you can find!
3) Follow the stock loopstick's coil proportions and circuitry connections
EXACTLY. When you prepare the transplant loopstick, carefully observe the
mathematical proportion between larger, shorter and/or piggyback coils.
Duplicate these proportions exactly in the larger transplant, and attempt to
create
a larger proportion "copy" of the stock loopstick (but reduce the number of
coil turns to compensate for the increased inductance of the longer ferrite
bar).
4) Wind your coils on a cardboard form, that can easily slide along the
new, longer ferrite bar. This is extremely important for alignment purposes.
5) Alignment is always the final step of the transplant. You will know if
your super-antenna is working by whether or not you can peak a 600 kHz
signal, by sliding the new coils along the ferrite bar.
6) Super sensitivity is extremely exciting, but may bring minor side
effects. Your radio's selectivity will be assaulted by huge signal strengths.
Any
spurs or images will be enhanced. You may lose sleep, wondering if the
sunrise TP period is near. And finally, you may wonder exactly how you came
to
the point where creating these tiny little Frankensteins has become so
fascinating, and how thrilled you are when they hear weak TP heterodynes that
your
"classic" receivers have no trace of.
After four of these transplants (the first of which is fully described
on dxer.ca, under "Super Prison Radio"), I feel that everyone deserves fair
warning before subjecting themselves to this transplant-induced
ultra-excitement. DXing will become incredibly thrilling. Consider yourself
fully
warned!!!
73, Gary DeBock.
**************Ideas to please picky eaters. Watch video on AOL Living.
(http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/
2050827?NCID=aolcmp00300000002598)
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