[Milsurplus] [ARC5] Considering GO-9 Transmitter Power Options.

[David Stinson]

On 9/2/2019 12:21 PM, howard holden wrote:
 >
 > ... a commercial regulated supply which puts out 350VDC...
 >I opted to try keying the center tap of the 837 filament trans
 >through its 1000 ohm resistor, which happens to work
 >just fine. I know keying the VFO is a supposed “no-no”,
 >but chirp is almost non-existent, and stability is exceptional
 >for an 80 year old transmitter...

Good tips.  I've also found that one key to stability and chirp-less 
keying is good, hard regulation of the supply to the MO, assuming it 
can  source the needed current.  Regulating any voltage up to thousands 
is childs-play now with MOSFET regulators and just a few parts.  FETs 
that  can regulate 3000V for you are like $15 and those for typical MO 
supplies can be had NOS for a couple of bucks.  One can build and 
incorporate the circuit in a couple of hours.   The Australian AT5/AR8 
is powered by a ham rig 12V mobile supply.  It "sang like a bird" until 
I tacked-together a FET regulator for the Osc. supply.  Now the keying 
(and stability) are nearly as good as the $10,000 plastic "Barbie and 
Ken" radios one can buy today.
P.S. Attached diagram:  "Stack to unregulated voltage" means the 
unregulated voltage under the intended load.  I use 5W zeners, just 
because they're cheap and look cool ;-)

GL OM ES 73 DE Dave AB5S




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