On Tue, 5 Jan 1999 07:13:01 -0800 Rich Measures <measures@vc.net> writes:
>
>>
>>YO3CTK says
>>
>>>Ten amps is the PEAK
>>
>>Whoops! Sorry, Mike is correct. 10amps pk is 7 amps rms so the losses
>are 87
>>watts. Still substantial.
>>
>>I'm seriously considering silver soldering the taps on the tank coil
>-
>>that's with solder melting at redheat, not the lower melting point
>stuff for
>>ordinary soldering irons.
>>
>? If one is using a pressurized chassis, by drilling a grid of small
>holes in the chassis underneath L1, an updraft is created which cools
>the
>coil. Thus, one can use 6% Ag, 94% Sn solder (eutectic 221 degrees
>C).
>This material is approx. 4 times stronger than Ag/Pb solder, and is
>more
>conductive too. // Apparently, Heath had things figured out pretty
>well
>by putting cooling air on the SB-220 tank and bandswitch.
The SB-220 is a poor example to use for efficiency but it speaks volumes
if this discussion wants to get into total network design, component
selection and not just the tank coil.
At 2KW input the average SB-220 will crank out a massive 900-1000W on 10M
for 45-50% efficiency. OTOH, with all that HF stuff removed and rebuilt
strictly for 6M the power out will be 60-65% efficient with good tubes.
So where does the missing 15-20% of the power go on 10M ?
73 Carl KM1H
>
>
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
>
>
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>
>
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