[ICOM] SWR tuning issue with IC-706MkIIG

[Gary Fiber]

Mike,
The power out control uses the built in SWR meter even if the display 
meter is enabled or not. If the SWR circuit is not providing some sort 
of feedback to the CPU it will not likely provide any output power.
Even though the display is a 1 to 1 SWR for all anyone knows the CPU 
could be seeing something a lot higher and folding back the output power.
The 706 power out meters not measured by the 760MKIIG but a software 
indication unlike the SWR is.

You are with in between the band edge beeps? If you are outside of those 
beeps the rig will not transmit and no SWR will be displayed. This 
happens too when you are in split mode and accidentally try to transmit 
out of band.

You mentioned something in your first email that you observed the SWR 
moving about, did you see the meter doing that or assuming that would be 
happening as the antenna was moved by the Turbo Tuner? I don't have 
access to your first email on this computer.

The rig is mobile or base operated, I am asking to be sure the power 
source can handle the transmit current requirements of the 706MKIIG, 
even something like loose or dirty connections can cause issues.

So have you connected an external power meter to see if you have power out?

Have you checked the SWR with an external meter to be sure the radio is 
incorrect, though while an antenna tunes I would think it should show 
something.

Do you have or access to a dummy load to take the antenna system out of 
the picture?

Have a friend who also owns an IC-706MKIIG to you could swap in your rig 
and or parts of  your rig like the RF Deck or control head to see if the 
trouble travels to his station?

A reset should have restored basic factory settings and basic transmit 
capability. For what ever reason determined by the factory the CW 
transmit is defaulted to off from the factory so you finding that 
condition after a reset is normal.

The SWR circuit is much like the moni match SWR meter the ARRL handbook 
had for years in it.

Hope some of this helps.

Gary K8IZ



On 1/8/2011 1:24 PM, Michael G. Carper wrote:
> Okay... found the CW break-in and turned it on (no idea why that would be
> defaulted to OFF, but whatever).
>
> Problem remains - no SWR reading (yes, I'm absolutely certain that the meter
> is set to SWR.  I've heard folks say there's some kind of diode issue that
> comes up.  The radio is probably 10 years old now.  I may send it in for a
> look (but would rather not, if I could find a simple cause).
>
> Mike, WA9PIE
>
> -----Original Message-----
> From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
> Behalf Of Tom Bates
> Sent: Saturday, January 08, 2011 12:20 PM
> To: ICOM Reflector
> Subject: Re: [ICOM] SWR tuning issue with IC-706MkIIG
>
>    
>>> Update.
>>>        
> (After doing a CPU reset) Now the rig won't key the transmitter in CW mode
> (though I can hear the sidetone).  Still no display of SWR.
>
>
>
> Did you turn CW break-in back on after the reset?  I think the default is
> "off",  and if not set properly the rig will not give output in CW mode even
> tho you can hear the sidetone.
>
> Tom  -  AA1NZ
>
>
>
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>    


-- 
Gary Fiber K8IZ
Washington State Resident