I think it would work well enough. When I get a round tuit, I hope to
make a gadget that will insert a 10 dB pad between the exciter and
the amplifier if the ALC voltage exceeds the setpoint. It would have
to be manually reset to resume full drive after tripping and would be
totally independent of the PC.
A simple PTT switch should do OK, with very little "hot switching"
risk to the amp.
If you build it, they will come ;-)
Jerry W4UK
At 12:21 PM 10/14/2008, Lee A Crocker wrote:
My guess is a PTT feedback scheme would be too slow to save your
bacon unless it somehow anticipates the fault.
----- Original Message ----
From: Neal Campbell K3NC <[EMAIL PROTECTED]>
To: Bob McGwier <[EMAIL PROTECTED]>
Cc: Steve Nance <[EMAIL PROTECTED]>; Lee A Crocker
<[EMAIL PROTECTED]>; Flexradio <FlexRadio@flex-radio.biz>
Sent: Tuesday, October 14, 2008 12:06:56 PM
Subject: Re: [Flexradio] What would you like to see in an accessory box?
I think we have come to the same conclusion so there would be a PTT
line pass-thru and we will defeat it if the calibrated voltage is
exceeded (is exceeded t he right word for going too negative!)
Neal Campbell
www.abrohamnealsoftware.com
AIM:nealk3nc
On Oct 14, 2008, at 12:03 PM, Bob McGwier wrote:
> VERY sound advice.
>
> Bob
>
>
> ARRL SDR Working Group Chair
> Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
> NJQRP, QRP ARCI, QCWA, FRC.
> "Trample the slow .... Hurdle the dead"
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Lux, James P
> Sent: Tuesday, October 14, 2008 9:04 AM
> To: Lee A Crocker; Flexradio
> Subject: Re: [Flexradio] What would you like to see in an accessory
> box?
>
>
>
>
> On 10/14/08 12:21 AM, "Lee A Crocker" <[EMAIL PROTECTED]> wrote:
>
>> I do like the idea of being able to plug the flex wire into the box
>> for
> PSDR
>> connectivity independent of ddutil. I have at some times had
>> stability
> issues
>> with ddutil and would like another path into the box. Also I would
>> like
> to
>> see an output that would be compatable with previous X2 interfaces
>>
>> Do you really think this will be fast enough to do ALC? If you are
>> going
> to
>> use this to "protect" your amp it has to be virtually failsafe.
>
>
> Trust not protection to a software implementation on a PC. If you're
> really
> worried about overdriving an amplifier, then you need a hardware input
> limiter of some sort. There's just too many things that can go
> wrong in the
> PC environment (oops, it just hung, my protection loop froze..).
> Remember
> that the dttsp core has to get an input from the ALC signal, and
> then go in
> and adjust the gain, which then changes the levels of the signals
> emerging
> from the DAC.
>
> Software is ok for this kind of thing, but you want it running in a
> dedicated processor (e.g. That PIC).
>
>
>
>
>
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