[ICOM] ALC interconnect

[Adam Farson]

Hi Dave,

The Icom HF transceivers require a negative-going ALC voltage in the range 0
to -4V. There is no ALC threshold control on the radio; this adjustment is
normally on the amplifier.

If the ALC output on the NCL-2000 is compatible (typically 0 to -10V), the
ALC line can be directly connected. It may be necessary to add an ALC
potentiometer and possibly also a phase inverter, if the ALC output is
positive-going.

An auxiliary keying relay or buffer may also be needed. Your friend should
measure the ALC voltage, the open-circuit keying-line voltage and the
keying-line current on the NCL-2000 before starting. If the keying line
exceeds the 16V/0.5A limit, a keying buffer will be required.

http://www.qsl.net/icom/auxrelay.html

There is information on the Web on re-tubing the NCL-2000 with 4CX250B's or
4CX350A's, which are much more readily available than the 8122's used in the
stock amplifier.

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: 14 August 2005 11:54
To: ICOM Reflector
Subject: [ICOM] ALC interconnect

A friend of mine asked me how he could hook up an old amplifier to his IC756
(non PRO version) as he knew I had ICOM radios.

He is using a National NCL-2000 tabletop amp, and there is a RCA jack
providing ALC voltage.  He has the ICOM manual but not the manual for the
amplifier.

I will go and measure the voltage and polarity but I would assume it is
about 0 to 3 volts negative.

How does he hook up the units up?  Is ALC "self-adjusing" or is there a
proceedure needed to adjust the threshold?

Thanks -

73

David N1EA 



Scanned by WinProxy
http://www.Ositis.com/