I was able to measure a difference or period of time between the external
keying line going low and the RF output of the transceiver. The RF appeared
before the keying line went low. I don't recall the amount but I do recall
it clipped the first dit or so. Thus the need to engage the keying loop and
it's 15 ms delay. As I don't work QSK on VHF or UHF the delay is of no
concern. I have longer delays elsewhere in the system.
As to RF sensed amps, I suppose they work quite well on SSB. However, for
CW the delay seems would be reason or cause for concern.
In my application, the mast mounted preamp has to be switched out of the
line and terminated, the power amp input & output has to be switched into
transmit configuration, the transverter has to be switched from RX to TX,
the Omni VII has to switch from RX to TX and all of these sequences have to
be verified by a logic system before any RF is produced from the Omni VII.
Or in the earlier case the Omni VI Plus. Failure of any circuit to properly
switch can and has caused failure of one or more systems. A couple of KW of
stray RF at 432 MHz makes a real mess.
73
Bob, K4TAX
----- Original Message -----
From: "Paul Christensen" <w9ac@arrl.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Monday, April 14, 2008 5:25 PM
Subject: Re: [TenTec] Alpha 89
>> Specifically, in the Omni VII, the radio outputs RF before the N.O.
>> actually
>> relay for control of external items closes and settles. I had to deal
>> with
>> this when using it to control my sequencer for the VHF and UHF station
>> where
>> there are lots of things to switch an settle before producing RF from the
>> transceiver. It is only a millisecond or so, but the RF is there. This
>> could spell "bad" for a PIN switched amp.
>
> Perhaps with an older Omni VII F/W version? I believe the amp key line
> from the Omni VII comes from a HV transistor. What relay needs settling?
>
> I am using an Alpha 86 with an Omni VII (no keying loop) and the two
> sequence perfectly at speeds better than 80 WPM. My Alpha 70V is actually
> more sensitive to timing issues and there's no hot-switching with either
> amp
> when using the Omni VII.
>
> Paul, W9AC
>
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