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Re: [Amps] ACOM 1500 and transmit delay

To: Amps Reflector <>
Subject: Re: [Amps] ACOM 1500 and transmit delay
From: "Bob Wilson, N6TV" <>
Date: Tue, 4 Dec 2018 20:39:35 -0800
List-post: <>
On Tue, Dec 4, 2018 at 5:19 AM <> wrote:

> I recently had to place my 2.5 year old ACOM 1500 into an envelope (large)
> and ship it off to
> be repaired due to the 1ATR4B error which was the indication that the
> Transmit Receive
> relay had died.

Did you use full break-in (QSK mode a lot)?  QSK mode will wear out an amp.
relay much faster than semi-breakin.  Did you use the default IC-7610 MENU:
SET > CONNECTORS > Send Relay Type MOS-FET ?  This should be faster (and
quieter) than type "Reed".

My question....I was driving the amp with the ICOM 7610 which had its
> transmit delay set to
> 10ms.  Could that had caused the trouble.

Probably not.  If it works like the 2000A, the amp. should display an error
message such as "Hot switching" if it senses RF before relay closure while
in operate mode.  The 1ATR4B error indicates a problem with the output T/R

I am now running the 7610 with the transmit  delay set to 20ms.  Or does
> the transmit delay even matter for an amp with the t/r relay being
> a vacumn relay?

It matters, but 10 ms should be enough.  Best to write directly to ACOM to
ask them what that amp. requires.   The manual says nothing useful about a
required TX Delay.  I was told 10 ms is fine for an ACOM 2000A.  Of course,
one cannot always rely on what the transceiver claims for TX delay.  For
example, an Elecraft K3S (or K3 with KSYN3A upgrade) with CONFIG:TX DLY set
to the default, NOR 008, does *not* actually provide 8 ms of TX delay as
claimed, but only about 6 ms.  You need to set TX DLY to about 12 to get a
10 ms TX DLY, and on CW you need 10 ms of external keying compensation,
otherwise the first CW element (or every element in QSK mode) will be
shortened too much.

Bob, N6TV
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