[Icom] WTB: IC-781 Accessory

Tue, 01 Jul 2003 09:40:48 -0700

Hi Jim,

The IC-781 is factory-fitted with a CR-228 precision OCXO, rated at +/-0.25
ppm (-30?C ~ +60?C). That equates to +/- 3.5 Hz at 14 MHz, after a 15 min.
warm-up time. Icom never offered an upgrade part. The CR-228 already
complies with the NATO spec under which the IC-781 was designed.

If the drift is significantly more than this, the OCXO may be defective and
require replacement. I owned an IC-781 for five years; calibrated the master
oscillator when I installed the radio, and never touched it again.

You can help the IC-781 to run cooler either by installing the Sherwood fan
kit, by using an external fan to blow air across the rear heatsink, or by
reducing the mains voltage to around 105V.

Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/
Icom FAQ site:
http://www.qsl.net/icom/

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of [email protected]
Sent: Tuesday, July 01, 2003 09:24
To: [email protected]
Subject: Re: [Icom] WTB: IC-781 Accessory

I saw one advertised not too long ago. My 781 drifts a tad before warm up -
45min.
I should add a fan on the rear like some do.

  Thanks for the reply,  Jim   w9ud
----
Your Moderator: Dick Flanagan W6OLD, [email protected]
Icom Users Net: Sundays, 1700Z, 14.315 MHz
Icom FAQ: http://www.qsl.net/icom/