Re: Digitally Controllable Heathkit Vacuum Tube Radio
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Gordon Gibby
¿ªÔÆÌåÓý?Created a fairly straightforward pcb to provide RFI / EMP protection for a Raduino driving a Heathkit.? ?The real advantage of vacuum tube gear is its inherent EMP hardening (verfied by published QST tests).? ?Much military gear is already hardened, and
some groups of which I'm a part are working to harden some of their systems now that NK is so capable.
Two lines have to come out of the Raduino enclosure:? power and signal.
For my heathkit, signal is a 5MHz VFO signal, so I put a 10 MHz LPF (from a kit), and a diode back-to-back array designed to clamp at +1.8 and -1.8 volts; similar to what is used in some T/R circuity.? Also a gas discharge tube at the outside-world end.?
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Power gets filtered with two capacitors, and protected with another gas discharge tube, a TVS diode, and a series diode to prevent those "oops" moments.? ?
This is to go into a hardened system for our local Emergency Operations Center, then I need to build one for myself as well.? ?
From: [email protected] <[email protected]> on behalf of John P <j.m.price@...>
Sent: Monday, January 8, 2018 3:15 PM To: [email protected] Subject: Re: [BITX20] Digitally Controllable Heathkit Vacuum Tube Radio ?
On Mon, Jan 8, 2018 at 11:59 am, Jack Purdum wrote:
If you're going to use the Si5351, take a look at QRP-Labs Si5351A synthesizer kit.I ordered a couple of the Adafruit boards. Basically the?same thing already assembled except for the header pins. ? -- John - WA2FZW |
