Hi,
I am considering buying one of these. Concerned my input
amp, mechanical relay is being "hot switched", at least at
key-up. Have searched diligently for info, but all Ameritron
has posted is about the PC card version of this gadget, not
the stand alone version in which I am interested.
However, as I gather, the keyer plugs into the QSK-5 unit,
and the gadget is also connected to your transceiver and
the amplifier in such a way that the amp T/R input relay is
turned on before the transceiver RF is allowed out; and the amp
input T/R relay is turned off only well after the RF from the
transceiver has stopped. This should all be done just by
sequence timing of the amp relay T/R signal from the transceiver.
The transceiver, an Omni VI+, uses a mechanical relay
to signal the amp's T/R switching relays. Figure at least 10 ms
for this relay to operate. Then RF output appears less than
5 ms after the contact closure since per the ARRL lab tests,
my Omni keying has about a 15msec delay between key down
and RF output, and 17 msec delay between key up and the
RF stopping.
5 to 7 milliseconds is less time than the amp Guardian input relay
needs to operate. Therefore when the input relay contact opens, it
is carrying RF current, and so it will arc as it opens. Every time.
My only concern is the input T/R relay; I believe the output
vacuum relay in my amp is fast enough as I do not use "full
QSK" timing, that is switch the relays between every dit.
My output relay is a Jennings R2B, SPDT, 26 vdc unit.
The Guardian input relay is not as fast, so my concern.
I have already had to replace it once.
Can I use the QSK-5 to only control this input, or must it
be set up to switch both amp input and output ports. My
concern about the unit also being in series with the output
is that, in a couple of places (but not in the Ameritron info
I have found on the web) it is said that you must fan cool
the QSK-5 if you are going to use amateur legal output
powers!
73, Jim KH7M
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