T1 Remote Tuning and Power Supply

Posted by GeorgeP1111 on Nov 16, 2010; 5:25pm
URL: http://elecraft.85.s1.nabble.com/T1-Remote-Tuning-and-Power-Supply-tp5744646.html

I am in the process of slowly reconfiguring my station for the inevitable future move to a condo or antenna restricted area where I will have to play the "Stealth" antenna game.  My station comprises of a Yaesu FT-817ND, W1 PWR/SWR Indicator, 3ft diameter remotely tuned home built 20m-10m Magnetic Loop antenna, and a 80/40 meter Trapped Dipole using the T1 Tuner for fine tuning.  I figure I can always wrap plastic flowers around the Mag Loop and pass it off as a Christmas Wreath, but I will still want some sort of outdoor wire using the T1 tuner for the lower bands.

I want to use the T1 at the antenna end vs the radio end as I am now.  I know that the T1 has the ability to be remotely tuned via the port on the side, but I want to kick it up a notch.  I'm running DC up the coax to control the capacitor motor in my Mag Loop using the standard inductor/capacitor configuration, and I want to follow the same plan for the T1.  The idea is to use a push button to supply the 9v (I'll probably use a higher voltage and reduce it at the tuner to compensate for line loss) via the coax to the T1 (vs using the internal battery) and a LM556 Dual Timer at the T1.  Key Up, Push and hold the button, the T1 turns on and boots up and at the same time the LM556 starts timing.  After a preset amount of time (1 second?) the LM556 would pull the Tune line low via a Optical Isolator for say 1 second starting the Tune function.  Watch the SWR on the FT-817 or the W1 and when it stabilizes low, release the button and unkey.

Granted, I could leave the internal battery installed and just use the 9v to pull the Optical Isolator low but by adding the LM556 I can eliminate the battery as well.

I know the power via coax will work, and the LM556 (or even a PIC) will work, so I guess I'm asking if there is a problem with turning On/Off the power to the T1 and is 1 second enough time to stabilize prior to initiating Tune?

tnx

de George
WD0AKZ