If I recall correctly earlier K3's failed the "AMTOR" -like mode turn
around time from rx to tx and back.
I believe that is about 15 ms. This was apparently fixed. The 10ms
delay between PTT and RF helps it meet this.
So if it is too slow, some group complains. If it is too fast others
complain. The need is apparently more than user dependent. It can be
mode dependent.
There is an xmit inhibit pin (aux i/o 7) that (at least in the
transverter mode) can inhibit RF until it is set high. Those of you
into serious VHF/UHF/Microwaves probably already have some kind of
sequencer. Using this pin with your sequencer can solve the "slow
waveguide" relay problem. See Page 19 of manual.
Has anybody tried to use this pin yet? Maybe it can also be used for HF
applications with some menu setting.
On the FT-1000MP many HF'ers used it's inhibit pin to avoid hot
switching of their amps. Same idea here.
73 de Brian/K3KO
AD6XY - Mike wrote:
This is a mots worrying post. I think it demonstrates considerable ignorance
of the many and varied applications of the K3. There is so much more to life
than HF.
How do you suggest we speed up a waveguide relay to 10mS?
Fern Rivard wrote:
Hi Ian and the group:
I would suggest that you fix/modernize your old amplier and leave the
K3 as is! The problem is NOT with the K3 but rather your amplifier.
Upgrade the darn linear with more modern faster switching relays and
vacuum relays are not that expensive if you shop around for some good used
ones.
73 from Fern VE7GZ with a fine K3 transceiver
----- Original Message -----
From: "Ian White GM3SEK" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, March 20, 2008 11:31 AM
Subject: Re: [Elecraft] K3 and linear amp
Roger Marrotte wrote:
I guess as of now I'm out of luck if I want to use my amp with a K3. I
just checked the manual for my AL-811H and "The open frame relay in the
AL-811H takes approximately 15ms to switch states". My K3 is on order.
I hope there's a K3 firmware change made before I get my K3, that will
allow me to adjust the change over timing. I'm far from an expert with
amps. I have no idea what an average switch over time is for amps in
general. Ameritron sells a high speed switching option, the QSK-5,
that reduces the switching time to 1ms. It costs around $300.00. A K3
firmware change would sure be less expensive.
That firmware change is surely needed, but there is another inexpensive
way which often works - speed up that open-frame relay.
The circuit shown in the link below uses the existing relay supply rail,
and it will shorten the switching time of most relays by about one-half.
The same circuit will also convert many older amplifiers to a modern
standards +12V, low-current switch interface.
http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#speedup
--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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