[ICOM] SWR problem on 706Mk2G

[Gary Fiber]

What kind of antenna is it? If not a dipole and have the room, build one up and see if that changes the outcome the the affected bands. Antennas with a lot of tuning traps can be problematic. 

Have or can you borrow an antenna analyzer to see if the antenna exhibits either inducting or capacitive reactance on the bands the 706 does not like ? 

You may have to make some antenna adjustments to neutralize the reactance as much as possible. Though as many will say that component will never generally reduce to nothing, but you may make the antenna useable with the 706. 

Have a ham friend near by to test the 706 on his antenna system?

In my 11 years at Icom, there were times SWR issues were from a final amp being  
Spurious. Generally it was due to the amp oscillating for some reason. Possibly as another suggested a faulty low pass filter if within the radio. Also an oscillating final many times presents no output power control. Also ran into weird issues with some antennas so testing into a non reactive load was in order.

Did you get a chance to try the 706 into a dummy load? 

Sorry I do not have a better answer.

Gary P. Fiber K8IZ



> On Dec 24, 2015, at 9:38 PM, John Geiger <af5cc2 at gmail.com> wrote:
> 
> Hi Gary,
> 
> If it is a reactive component that the 706MKIIG doesn't like, what is the
> best way to handle that?
> 
> 73 John AF5CC
> 
>> On Sat, Dec 19, 2015 at 5:26 PM, Gary Fiber <gfiber at comcast.net> wrote:
>> 
>> Does the SWR straighten out when you transmit into a dummy load? I always
>> question use of an antenna as a standard test jig even if "Ok" with other
>> rigs. Maybe the PA is spurious on 15 and 6 meters. Maybe some reactive
>> component in the antenna the 706MK II does not like. Icom's were pretty
>> tight for correct SWR specs, some other rigs like Kenwoods don't care and
>> will be happy into almost a 3:1 mismatch, Icoms like 1:5:1 maybe 2:1 at the
>> most.
>> 
>> Gary P. Fiber K8IZ
>> 
>> 
>> 
>>> On Dec 19, 2015, at 12:33 PM, John Geiger <af5cc2 at gmail.com> wrote:
>>> 
>>> I recently purchased a used ICOM 706MK2G and it seems to have swr meter
>>> issues on a couple of bands.  This occurs on 15 and 6 meters where the
>> swr
>>> is reading higher than what it should.  Has anyone seen this before, or
>>> knows how to fix it?
>>> I tried tightening the circuit board screws and that didn't fix it.
>>> 
>>> 73
>>> John AF5CC
>>> ----
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>> ----
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> ----
> 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/
> To support QSL/QTH.net: http://www.qsl.net/donate.html