[ICOM] SWR problem on 706Mk2G

[Gary Fiber]

Good, that will be a good test. Sounds like neither have traps. How high was the SWR? Still might be a power amp issue.

Gary P. Fiber K8IZ



> On Dec 25, 2015, at 8:18 PM, John Geiger <af5cc2 at gmail.com> wrote:
> 
> Hi Gary,
> 
> On 15m it was using a monoband 15m Moxon, and on 6m a 3 element monoband
> yagi. I had a different 706MKIIG a few weeks ago and don't remember these
> problems. Just picked up another 706MKIIG so will try it out when I get
> home and see if I get the same results.
> 
> 73 John AF5CC
> 
>> On Fri, Dec 25, 2015 at 3:18 PM, Gary Fiber <gfiber at comcast.net> wrote:
>> 
>> 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
>>