Re: [Amps] ACOM 2000A and Two Transmitter In-Band Operation

[Val <val@vip.bg>]

Andy,

The ARC fault means a sparking connection or a relay contact.

Did you make sure that the amp is operating normally on the run without 
switching to the mult radio? Rule out an internal amp issue first.
Though you say it trips off at different stages in the process, the 
culprit most likely is one. Do a few tests that would narrow it.
1. Switch both radios in test mode and simulate a contest operation 
without RF. If the amp keeps on faulting, it is the switching circuit. 
Could be a sparking pedal contact. R+C across the contact should help.
2. If the amp does not fault without RF, leave one radio in test mode 
and make the other to transmit RF. Next swap the test and RF radios.
73, Val LZ1VB



На 19-11-21 в 01:10, Andy Cook via Amps написа:
> Like many multi-op contest stations, at M6T we have the ability to operate
> two interlocked stations on the same band, and for the mult station to
> interrupt the transmission of the run station to call a needed QSO / mult on
> the same band, grabbing the same amplifier and antenna.
>
>   
>
> This is the sequence
>
> 1.      Run radio is transmitting
> 2.      Mult radio sends PTT line low,
> 3.      the run radio is immediately inhibited from transmitting (TX-INH
> line on K3)
> 4.      a relay switches the amplifier input to the Tx output of the second
> radio
> 5.      after a software configured delay (and I've tried delays of several
> hundred ms as a test) - the second radio starts generating RF
> 6.      the second radio drops its PTT line
> 7.      TX-INH on the run radio stays asserted for another few hundred
> milliseconds
> 8.      Run radio starts transmitting again.
>
>   
>
> All this time, the PTT line to the amplifier is held low.
>
>   
>
> My problem is that, when doing this, quite frequently the ACOM2000A
> amplifier will trip off with an arc fault - and at differing stages in the
> process. Drive level is not excessive, and reducing the drive power on with
> radio appears to have no significant effect. Both radios are K3s which are
> normally well controlled from a power transient persective.
>
>   
>
> I just wondered if anyone had a solid method for keeping an ACOM2000A
> on-line in this scenario - other than swapping it for a less fussy
> amplifier! A reasonably well protected Alpha 99 doesn't fault in this
> scenario.
>
>   
>
> 73,
>
>   
>
> Andy, G4PIQ
>
>   
>
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