In a message dated 2/20/04 9:44:39 PM Eastern Standard Time,
jimlux@earthlink.net writes:
>>Inexpensive
run of the mill steppers (with decent temperature ranges, etc.) are probably
around $50, brand new, in big quantities. Shielded steppers with the fancy
connectors are more like $500 or $1000. Fluidmotion would have a hard time
selling $10,000 antennas, and I suspect that folks would balk at spending
dollars/foot for high performance shielded control cables as well.<<
You don't need $500 to put shield over the leads coming from the motor and to
use shielded cables. We have been doing it for $5 with ignition noises in
mobile installations where thousands of volts and real sparks are involved. Dog
food can and piece of braid can do miracles.
Also instead of square wave hard pulses, something closer to a perfect keying
waveform (or sine wave) might do to minimize the harmonics generation and
noise way up in the HF frequencies.
Nothing is impossible. I managed to reduce my 28 MHz second harmonics from
the 14 MHz exciter after going through 2 kW linear, into tribander by 20 dB.
The
same helped 10m QRM to Channel 2 TV. Some PI-L filtering, stubs and link
coupled network can do "miracles".
It would be interesting to see what steps were taken by SteppIR to reduce the
noise problem. Is ANY filtering/suppression used? Again, I do not have their
antennas, just saw the pictures and judging by the comments.
73 Yuri, K3BU.us
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