[hpsdr] Hermes question -- amplifier keying

[Mike Collins]

Hi John and Jeff,

I bought Jeffs 418 amp from him and have been using it quite a bit.

I built a 5W driver amp (RD16) for boosting up the Hermes level for the 
TenTec 418.  I initially used the
Hermes amp key output to drive both the driver and 418 keying inputs.  
The 5W driver I built was very quick
to turn on so had some faults (no damage) detected by the 418 circuits.  
Using the Hermes to drive the 418 keying
input; and using the 418 output (delayed as you noted) to drive the 5W 
driver amp did fix the faults.   This works great other than if
I only want to use the 5W driver (for remote antenna tuner) becuz the 
418 doesn't pass the keyline thru when turned
off.   The final solution for me was to add a small RC time constant on 
the 5W driver keying circuit and go back to the Hermes
driving both amp keying circuits...  now I can run 5W or the full 75W 
from the TenTec 418 (no need for the 418 keying output).

Also reverse engineered the serial control interface on the 418 and 
wrote a small patch to the firmware that lets me use
the Hermes Apollo connector to auto band switch the 418 amp.  This all 
works really good and can go anywhere with the
amp auto switching as I change bands in PowerSDR.

If you or anyone wants/needs the 5W driver schem or RC delay 
circuit.....or the firmware patch to control a TenTec 418; just drop me
a email.

73,  Mike Collins   KF4BQ

On 5/26/2013 9:52 PM, Jeff Kelly wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> I used 2 and 25 on the breakout cable from Hermes and it worked fine
> keying the 418.  (make sure you have the corrected pin #'s)
>
> Jeff
> K2SDR
>
>
>
> -----Original Message----- From: John Ackermann
> Sent: Sunday, May 26, 2013 9:35 AM
> To: HPSDR List
> Subject: [hpsdr] Hermes question -- amplifier keying
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> I'm probably going to be bother the list a few times over the next week
> or so as I try to get my portable Hermes station ready for a trip to
> northern Michigan.  I'll post these questions separately to keep any
> threads organized.
>
> I'm using a TAPR-built Hermes with the Apache Labs 10W amp and
> enclosure, so it looks like an ANAN-10 to PowerSDR.
>
> The 10W output is driving a Ten-Tec 418 amp (5-10W in, 100W out). The
> 418 has both a key-in and a key-out line.  If I read the documentation
> correctly, the key out has a 4ms delay on keying to avoid hot switching.
>
> Question -- should I simply use the Hermes key-out line to drive the 418
> and count on the Hermes TX sequencing, or is it worthwhile to send PTT
> to the 418 key-in and let the 418 key-out drive Hermes?
>
> Thanks,
>
> John


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