[ARC5] HP 23 for ARC5

[Mark K3MSB]

Hi Russ.

Lot's of good info being provided to you.    I would encourage you to keep
it simple for your first time using an AN/ARC-5  transmitter.   A variac on
your HP power supply to give you 550V and 3 resistors (20K 5W,  15K 10W,
and 100K 1W) will give you the 3 voltages you need.  The voltage divider is
what you'd find in the BC-456 modulator and I assume the MD-7 as well;
it's how the system was originally designed and it's worked well for 85
years.....

I've attached two documents from Dave AB5S which are great for someone
starting out with AN/ARC-5 or SCR-274N radios.   You'll find the design for
the voltage divider in one of the documents.   Dirt simple and it works.

The transformer in the HP-23 looks to be stout enough so you should not see
much sag on key down.   If you do, and the resulting chirp is too bad,
then regulation for the oscillator and screen may be necessary.

73 Mark K3MSB











On Mon, Feb 24, 2025 at 12:20 PM Russ Tine via ARC5 <arc5 at mailman.qth.net>
wrote:

> Hi Folks,
>
> I'm new to the list, and I am looking for some advice about using an HP 23
> power supply for my T-22.
>
> I still use the power supply for my HW 101, so I do not want to make any
> mods to the PS itself, I would rather add a voltage divider external to the
> PS that I could plug in for the T-22 and remove for the HP 23.
>
> Thanks in advance and 73,
>
> Russ Tine K1RWT
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