the reason I said take everything right out of line is then there is no head 
scratching or mistakes made by accidentally leaving the tuner on or 
something and having the swr meter give odd readings.
also, eliminates patch cables that might be bad or connecters that might be 
malfunctioning.
unless of course the wire is going right from the external tuner, in which 
case, obviously you need it lol.
73
Colin, V A6BKX
----- Original Message ----- 
From: "tom behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, July 27, 2010 4:48 PM
Subject: Re: Question About TW 1 and readings


>    Hey, Colin:
>
> I have a quick question here, just for the record.
>
> I agree totally on disabling the radio's internal tuner when tuning an
> antenna.  However, instead of also having to totally dis-connect the 
> manual
> tuner to get an accurate SWR reading, couldn't you simply put the manual
> tuner in bypass mode if the tuner has such a feature as does my Tentec 
> 238A?
>
> Not trying to argue here or question what you have said, but just trying 
> to
> consider one other possibility that might be easier as a means to get the
> antenna's true SWR.
>
> 73 from Tom Behler:  KB8TYJ
>
> ----- Original Message ----- 
> From: "Colin McDonald" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, July 27, 2010 5:14 PM
> Subject: Re: Question About TW 1 and readings
>
>
> not a head scratcher at all.
> the meter is expecting a 50 ohm load on the radio side.  the internal 
> tuner
> is altering that load to compensate for the impedance of the antenna 
> system
> and is therefore no longer 50ohms when it is activated.
> so, the meter is seeing something other than 50ohms on the radio side and
> gives inaccurate readings because of it.
> That's why everyone keeps telling you to turn both the internal tuner, and
> the other tuner off, take the external one right out of line actually, 
> then
> tune the antenna with the meter.
> in fact, to be safe, disable the internal antenna tuner in the radio's 
> menus
> so you don't accidentally turn it on at some point.
> Physically disconnect the external tuner from everything.
> Then, make sure you have a counter poise of some kind for the antenna.
> After that, you can start trimming or adding wire to your quarter wave
> length radiator until you achieve a 1 to 1 match.
> You won't hurt the radio if you use 5W to check the swr, no matter how 
> high
> the swr is.
> You could key down all day long with no antenna connected at all with 5 w
> and the radio wouldn't be hurt.
> Remember, tune in CW mode.
> Not AM or FM as the modulation will cause the power to fluctuate and could
> alter your readings for SWR before you reach a 1 to 1, or close match.
> As long as the antenna is 3 to 1 or below you will be fine...the internal
> tuner will take care of anything from a 3 to 1 match down and make the 
> radio
> efficient.
> 73
> Colin, V A6BKX
>
> ----- Original Message ----- 
> From: "mark Torgerson" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, July 27, 2010 2:26 PM
> Subject: Re: Question About TW 1 and readings
>
>
>> Hi
>>     The internal antenna tuner is simply to protect the radio. I want =
>> to=20
>> have the SWR meter reading the true value of the antenna system =
>> including as=20
>> much of the feed line as possible. Interestingly though, when I take the 
>> =
>>
>> internal tuner off line the SWR tends to jump about two units on the=20
>> external meter. Now, there is a head scratcher.
>>
>> God bless,
>> Mark Torgerson
>> =20