>
>Does anyone know what the spes are for the
>wire used with the SB-200 Parasitic Suppressors?
>Type, diameter, and how many turns required
>on the 47 ohm Carbon Composition Resistors!
>I broke one and need to make repairs.
>
The SB-200 was not unconditionslly VHF-stable with the original VHF
suppressors. The most common damage from this problem was arcing the
open contacts on the 80m Tune-C padder switch - which switches in the
100pF padder on the 80m band. Oscillation is especially a problem with
newer production 572Bs because they exhibit more VHF gain than the tubes
originally used. Thus, it might be a good idea to improve the suppressor
by decreasing its VHF Q and Rp in order to decrease VHF amplification.
This means using more Lsupp and more Rsupp. Using resistance-wire
instead of copper-wire also helps to decrease VHF Q. The trade-off is
that resistance-wire requires an acid flux and Silver-Tin solder to make
satisfactorily connections.
- Murphy was right: "Nothing is as easy at looks."
>
cheers, Vince
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
end
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