Re: T1 Remote tuning

[dw-4]

Hi George,
If your interested in sharing, I would be interested in your config for
your tuner.
I built a form of the remote "balanced-balanced" tuner for a 135'
doublet a few years before remote tuners came out on the market.
It didn't not have the ability to tune up/dwn within each band.
Only the ability to switch to one pre-set set-point for each band.
I controlled it with a PIC inside the house activating an old stepper
switch.
It was primarily a split coil ( one series coil on each side of the
ladder line ) and a cap between the two, with tapped points for coil and
separate caps for each band.

Later on I found out that a simple L-network would work just as well and
I've been using that config ever since.  With that doublets
characteristics, I found that 10uh was all I needed for the "L" and
2000pf was the max I needed for the "C".

I'm CW only, so in the upper bands the bandwidth was sufficient.
But on 40, 80 and 160, "C" adjustment would be needed for the full
spectrum of the CW portion @ low swr.

I'm in the process of acquiring parts for an updated unit that handle a
kw.
So I'm curious on how anyone is building remote tuners these days :)
Thanks
Duane
N1BBR
--
 [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[GeorgeP1111]

dw-4 wrote

Hi George,
If your interested in sharing, I would be interested in your config for
your tuner.
I'm in the process of acquiring parts for an updated unit that handle a
kw.
So I'm curious on how anyone is building remote tuners these days :)

Hi Duane...

I think you may have misunderstood my post.  I'm not building a remote tuner, I'm building a interface to use the T1 tuner's remote control tuning option so I can mount the T1 outside at the antenna sight.

That being said, basically what I'm doing is sending my 13.8vdc bench supply out the coax to the remote interface where is dropped to 9v to power ON the T1 and 5v to start a PIC counting 2 seconds (to allow the T1 to boot up and stabilize) then pulling the tune line low for 1 second to initiate the T1's TUNE function.  After the T1 tunes up, the 13.8v is turned OFF until next tune-up is needed.  Actually, the way I'm probably going to configure it is to use a NC push button from the my 13.8v bench supply to keep power applied to the T1 when the station is running because I think I'm going to put a DPDT relay out there also (in the interface) to ground the antenna when the station is not in use.  Momentary pushing the button would restart the T1 & PIC activating the TUNE.

73's

de George
WD0AKZ