[Icom] IC756 SWR meter compared with FC902 or DAIWA CN101

Sat, 22 Mar 2003 13:30:23 -0800

Yes, you have warned me of this before.  I am a little more educated and 
donot use the internal tuner at all, just the display.  And after the tes 
of max output giving a high SWR I did that once.  So always low SWR to the 
rig meter.  The external meter gives a good indication but no always dips 
when the internal dips.  So go by the internal.

Again thank you Adam.

Chris opr VE7HCB

At 12:25 PM 2003-03-22 -0800, you wrote:
>Hi Chris,
>
>Just a note of caution - you should always disengage the internal autotuner
>when attempting to match the load with an external tuner.
>
>Tuning for maximum output is not the correct procedure; when using an
>external tuner, it is essential to tune for minimum SWR as indicated on the
>radio's SWR scale. The reason for this is that a tuning point which presents
>a complex load to the transmitter will cause the internal reflectometer to
>fold back the drive, so as to protect the PA. The maximum-output reading is
>deceptive, as the meter reading cannot be trusted if the load presented to
>the transmitter is anything other than 50 ohms. The complex load impedance
>in your experiment caused high SWR readings on both meters.
>
>In general, if your antennas are within a 2.5:1 SWR range on all bands, you
>are best off using the internal autotuner and not even connecting an
>external tuner. This minimises the possibility of mistakes.
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>
>
>-----Original Message-----
>From: [email protected] [mailto:[email protected]]On
>Behalf Of Chris BONDE
>Sent: Saturday, March 22, 2003 11:06
>To: [email protected]
>Subject: Re: [Icom] IC756 SWR meter compared with FC902 or DAIWA CN101
>
>
>My rig, IC756P  (old now) has a digital (bar) and analogue (needle meter),
>both internal meters read very close to the same.  I use the bar as it is
>easier to read from about 1 metre.  I have an external tuner with meter,
>analogue.   The external meter is usually a little higher than the
>internal.  But as one person said, "If the rig is happy, that is the way to
>go".
>
>Some one said to tune to max output.  I tried that and became
>frightened.  I used both the rig output to max and the external tuner
>output to max, then checked the SWR.  The SWR was higher than 3:1 on both
>the internal and external meters.  So what is going on?
>
>Chris opr VE7HCB
>
>
>
> >Hi Juan,
> >
> >I would put my trust on the the CN101 (I own one and I'm very happy
> >with it), the scaling on a good SWR meter will give you a better
> >reading than the rig build in rig meter, especially if the rig uses a
> >LCD bar display (my 706MKIIG uses one of these).
> >
> >73
> >Demetre - SV1ENS
>
>
>----
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>Icom Users Net: Sundays, 1700Z, 14.315 MHz
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>
>----
>Your Moderator: Dick Flanagan W6OLD, [email protected]
>Icom Users Net: Sundays, 1700Z, 14.315 MHz
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