I certainly like the idea of a double balanced Pi better than a balanced T.
You at least get some harmonic attenuation.
It doesn't have as much rejection to common mode current as the link coupled
does, but buying a link coupled tuner (new) is impossible and used is
difficult; building one is nearly impossible if you want it to cover all
bands.
BTW, the HAMWARE remote tuners are double-balanced-Pi tuners; very nice but
cost an arm and a leg.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Stuart
Rohre
Sent: Monday, July 18, 2016 10:08 PM
To: tentec@contesting.com
Subject: Re: [TenTec] OT: Question to the group -tuner and dipoles
There is at least one internet project with photos of a double PI net
balanced tuner, which should work quite well. It uses copper tubing for two
large inductors and transmitting sized variable capacitors.
The 135 foot wire or a close to that length dipole will work close to the
ground for NVIS. Feed it with 450 ohm or 600 ohm open wire line for all
band use.
Working at 1/8 wave above soil, brings as signal to noise gain, in that
"skip static" from Summer thunderstorms is greatly attenuated or not picked
up at all.
NVIS brought back 80m to usefulness for Field Days due to the reduced noise
floor when the antenna was 5 to 6 feet off ground with a reflector at grass
top level. (after mowing).
-Stuart Rohre
K5KVH
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|