[ICOM] 60 meters

[Adam Farson]

Steve, Herman,

The LPF issue in the 756Pro and 756Pro2 is discussed here. The 756Pro3 is
not affected.

http://www.ab4oj.com/icom/ic756pro2/po.html 

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 N4ch at aol.com
Sent: 25-Jan-11 18:06
To: icom at mailman.qth.net
Subject: Re: [ICOM] 60 meters

Hello Steve,
 
A good place to look for modifying virtually ANY  "general-coverage receive"
transceiver to also transmit over the entire 1.8-30  MHz range (including 60
meters) is:
 
_www.mods.dk_ (http://www.mods.dk) 
 
There are quite a few entries including Icom, Kenwood,  Yaesu, and pretty 
much everything else that's out there.   In most  cases, the required 
modification involves careful removal of a small SMT diode  or resistor
chip, 
and/or "bridging" a set of solder pads that were originally  left open.
I've 
never had a problem with any of the changes I've  made using information
from 
this site, including the IC-706/MK2/G series of  transceivers.   I don't own

a 756/Pro/II/III, but I HAVE heard that at  least one or two versions of
these rigs may not be the best candidate for such a  change, because once
modified for general-coverage transmit, the PA output is  routed thru a low
pass filter section that has the "corner" too low in frequency  when 5 MHz 
transmit is desired.   I've heard (but cannot confirm) that  the low pass
filter 
section that's normally selected for 80/75 meters is the one  that's still
in-circuit when 60 meters transmit is selected, and this often cuts  into
the PA's output by at least a couple dB, resulting in lower power output,
and excessive dissipation within the PA as a result.......not a good
situation. 
  I've never heard of this being a problem on any other  Icom radio; I've
used info from this site to modify quite a few  other Icom radios (besides
the IC-706 variants), including the IC-707, 718,  725,6,8,9, 736,7,8, 745, 
746, 751, 765, etc.   No problems (including  the IC-756 LPF power loss
issue 
mentioned above) were ever evident in any of  these radios.
 
Good luck and 73, Herman, N4CH.
 
----
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