unfortunately, this radio (the FT-757GX1) has only slow or fast AGC from the front panel. I have yet to find the control that will turn it off.

At the moment, I also have a repair issue with the radio (it lost output power yesterday on a known good antenna with low SWR). Of course, its probably due to the age of the radio (parts will break over time). I just hope I can find someone who can repair it without charging me an arm and a leg (or signing away the rights to my first born).

DE N7zzt Eric Oyen
On Oct 17, 2013, at 6:21 AM, Gary Lee wrote:

> good tutorial.  I would only add one step.
> 
> first, turn off AGC if possible.
> 
> And, tentec makes a similar device as a kit.
> 
> ----- Original Message ----- 
> From: "eric oyen" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, October 16, 2013 3:19 PM
> Subject: tuning an antenna tuner using a noise bridge.
> 
> 
>> ok,
>> I have one of these devices (an antenna noise tuner). its called a =
>> Palomar tuner-tuner (no longer made from what I hear).
>> this device sits between your antenna tuner and the radio.=20
>> 
>> The basics: you use the noise bridge to tune the antenna tuner to =
>> minimum noise (the quieter, the closer to resonance you are).
>> 
>> How I do it:
>> 1. tune to the desired frequency in AM mode
>> 2. turn on attenuator or reduce RF gain to 50%
>> 3. turn on the noise device
>> 4. adjust inductor for closest band (setting a or b for 10 meters, etc.)
>> 5. adjust input capacitor for lowest noise
>> 6. adjust antenna capacitor for lowest noise.
>> 7. repeat steps 5 and 6 until noise is reduced to almost nil (or as lo =
>> as you can get it)
>> 8. turn off device, turn up RF gain and set desired mode.
>> 
>> 
>> 
>> I use the palomar tuner-tuner to retune my antenna for optimal =
>> efficiency on any band. I also record the settings so that I can get =
>> close the next time (reduces tuning time).
>> 
>> Unfortunately, the tuner-tuner unit is no longer manufactured. I wish =
>> that MFJ would make something similar.=20
>> 
>> This is the cheap alternative to an expensive auto-tuner for your HF =
>> radio. It also has the advantage of allowing you to tune the antenna =
>> without having to key the transmitter (thus causing unintended =
>> interference) and saving wear and tear on the finals of your radio.
>> The reason I use AM to listen is that it gives the best noise figure, =
>> thus making it easier to find the resonance dip.
>> 
>> anyway, there is my tutorial for using a noise bridge to tune an antenna =
>> with a tuner.
>> 
>> DE N7zzt - eric.=