[Amps] Amplifier for 630 meter band

[Chris Wilson]

Hello Catherine,

I run several W1VD design Class D MOSFET amps on LF (136kHz) and they
perform really well. Most expensive item to source here in the UK is
the LPF toroids, mainly di=ue to carriage from the USA. Heatsink
requirements are extremely modest, and an HP 50V server SMPS runs one
a treat, and those too are dirt cheap used, over in the US. I get into
East coast nUSA on LF using WSPR and we are only allowed 1W ERP...

I too fancy making a GS35B tube LF amp, but sourcing the caps would be
a costly PITA over here I feel.I do have the HV and filament supplies
for one though, should I feel like having a go at one. Good luck!
2E0ILY

Here's the link to his designs:

http://www.w1vd.com/137-500-KWTX.html




On Friday, November 10, 2017,  you wrote:

> "U may well have a tough time  stuffing parts into a SB-200
> chassis.  This is where a simple, bigger box would help out. 
> Something like a  single  3-400Z /  3-500Z would do the trick, dead
> simple.  Then u could also stuff a 4-400 A / B /C in there as well."

> Yes, it may make sense to pull some of the larger tuning and LP
> filtering components into a separate case, outside the SB-200 case. 
> One nice thing about VLF is that tolerances are very loose for
> things like lead lengths.  Just be sure that wires carrying high voltages are very well insulated.

> I'm certainly open to having a second case with the additional
> filtering components. That second case won't have a power supply or
> tubes needing cooling, which simplifies things greatly.

> I'm not dead set on starting with an SB-200 by any means. If a junk
> 3-500Z or 4-400 amp drops into my lap, I could just as readily run
> with that. I will check out NEARFEST on the spring and see what turns up.

> If anyone in New England reads this and thinks they may have a
> suitable amp for sale (no tubes is fine, burned bandswitch is fine,
> power supply must be good, price must reflect condition; looking for
> a low-priced junker amp for extensive modifications), please reach out to me directly.

> 73,
> Cathy
> N5WVR
> <n5wvr at arrl.net>
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-- 
Best regards,
 Chris                            mailto:chris at chriswilson.tv