On my amp, the circuit locks out, lights a LED, and requires a manual
reset. When I get some time I'll sketch out a circuit.
73 Tom W0IVJ
Jerry Flanders wrote:
Sounds like a good workaround. Does it lockout somehow, or just buzz
until you manually shut it down?
A circuit diagram
Of Tom Thompson
Sent: Wednesday, July 18, 2007 4:15 PM
To: Jerry Flanders
Cc: Flex Radio; Robert McGwier; FireBrick
Subject: Re: [Flexradio] [SPAM] Re: thank you SDr
On my SDR-1000, I am using one of the open collector outputs to key the
amp. If you AND a good ALC signal with that open collector
Read the ALC voltage fed to the SDR backside in real-time with a cheap A/D
that feeds the hardware controller (possibly even an A/D on the hardware
controller, if there is one), then report the real-time measurement back
to PowerSDR for action.
73,
Dan KB5MY/6
Agreed that the circuit is
FireBrick wrote:
Maybe I don't understand but...
In the Quadra, ALC is also used to cut back ft1000mp power in case of
wrong antenna selection.
The high swr, would cause the Quadra ALC to shut down exciter power to
protect the Quadra finals.
Especially in dxing or contesting, it's so easy
I think it is this kind of situation where flex will eventually shine. At some
point you should be able to write a script that would ensure the correct
antenna was connected to the correct amp which had the correct drive for a
given band. It should virtually eliminate the wrong antenna or too
In the homebrew , 600 watt amplifier that I built, I placed the SWR
bridge before the filters so the amplifier will fault if the antenna is
wrong or the bandswitch is wrong. The fault mode just does not allow
the amplifier to be in line. If it is a high SWR that causes the fault,
then the
Hi Tom
How does your exciter know to cut back the drive? In most
exciters, the hardware ALC does this, and the amp can use that to
command a cutback. But if the exciter has no hardware ALC (like
Flex-radio products), then what?
Incidentally, all the non-Flex exciters that I am personally
Jerry,
The exciter does not cut back the drive in my set up. What happens is
the amplifier refuses to key under a fault condition, so it is bypassed
and the exciter sees the antenna instead of the amp input.
In thinking about this, it might be pretty easy to detect the ALC out of
the amp
Agreed that the circuit is trivial, but the interface between that
circuit and PowerSDR or SDR-1000 is not.
Only thing I have been able to think of is an independent attenuator
pad between exciter and amp that would be switched in under ALC
panic control voltage level. If anyone has a better
Tom Thompson wrote:
It really should be the amplifier that handles
these conditions, so that the amplifier can be used with a variety of
exciters.
That said, having hardware TX inhibit is pretty important
sometimes. Transverters ain't cheap.
Yaesu did a nice thing in that regard. On the
At 03:19 PM 7/18/2007, you wrote:
Agreed that the circuit is trivial, but the interface between that
circuit and PowerSDR or SDR-1000 is not.
Only thing I have been able to think of is an independent attenuator
pad between exciter and amp that would be switched in under ALC
panic control voltage
Sounds like a good workaround. Does it lockout somehow, or just
buzz until you manually shut it down?
A circuit diagram would be helpful. Maybe it could be placed in the
knowledge base for reference.
Jerry W4UK
At 07:15 PM 7/18/2007, Tom Thompson wrote:
On my SDR-1000, I am using one of the
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