[ICOM] Amp Keying Question Again

[David J. Ring, Jr.]

How about sequencing, Adam?  When keying from ACC(2) pin 3 of the ICOM 
exciter, does that pin switch at xx milliseconds before r.f. is generated?

In otherwords, can I hook up my amplifier relay to ACC(2) pin 3 have the 
relay be energized and then the ICOM exciter generates r.f.?

I've seen some elegant solutions to hot switching - including a bucket 
brigade delay which divided the voice signal (which activated the VOX) into 
two components - the first activated the amplifier relay.  The second was 
time delayed by 20 ms by the bucket brigade digital delay and then fed to 
the microphone input of the exciter.

Thus no hot switching - and no missed first sylables caused by VOX clipping 
because the VOX was turned on by the "real-time" speech, but that speech was 
delayed digitally and fed to the exciter - so it never got chopped off.  No 
need to say "ahhhhh".

The problem with some of the digital modes, and CW QSK is that the r.f. is 
hot switched.  I've seen amplifiers that show this damage - it often causes 
the relays to arc over and burn up - especially with high power commercial 
installations.

I haven't investigated this with the ICOM radios, I wonder if anyone has.

73

David N1EA

----- Original Message ----- 
From: "Adam Farson" <farson at shaw.ca>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Tuesday, June 21, 2005 11:13 PM
Subject: RE: [ICOM] Amp Keying Question Again


Hi Dave,

Actually, when keying an amplifier from ACC(2) Pin 3 of an Icom exciter,
there is no need to disable the reed relay. For example, the Icom IC-PW1 is
keyed from ACC(2), and the exciter's reed relay has no function.

Cheers for now, 73,
Adam VA7OJ/AB4OJ

-----Original Message-----
From: icom-bounces at mailman.qth.net
[mailto:icom-bounces at mailman.qth.net]On Behalf Of David J. Ring, Jr.
Sent: Tuesday, June 21, 2005 15:33
To: ICOM Reflector
Subject: Re: [ICOM] Amp Keying Question Again


There are some ideas for QSK and speeding up transceiver switching (namely
eliminating the relays) for some transceivers.

http://www.somis.org/QSK922.html

I am not the author of the page, but the author is held in high regard by
many.

73

David N1EA

----- Original Message -----
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Monday, June 20, 2005 1:56 PM
Subject: RE: [ICOM] Amp Keying Question Again


Hi Joe,

The amplifier keying relay in an Icom transceiver cannot be disabled, but
you may be able to connect ACC(2) Pin 3 (SEND) to the AmpKeyer input. The
SEND line is bi-directional; it goes low on transmit, and grounding it
externally keys the transceiver. The relay will still operate, but keying
from the SEND line eliminates the relay's 1 mS latency.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
Icom Users Net: Sundays, 1700Z, 14.316 MHz
Icom FAQ: http://www.qsl.net/icom/


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Icom FAQ: http://www.qsl.net/icom/


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