Re: LF: remote antenna tuning

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

Check  on Garys  g4wgt  web site , the  voltage  divider  was  changed  for   high  power  500  work

 

G,

From: Dave G3WCB.

Sent: Friday, November 08, 2013 8:08 PM

To: rsgb_lf_group@blacksheep.org

Subject: RE: LF: remote antenna tuning

Hi, Rik.

 

I have built Jim's phasemeter and used it on 137 kHz. It seems to work fine on 475 kHz also, although it seems more sensitive on 475kHz. You could take the DC output from the phasemeter and feed it back up the coax to the shack for a remote indication. Or you could use the output of the phasemeter to control the motor directly. I think that Marcus has some arrangement like this.

 

73, Dave G3WCB IO91RM 

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Rik Strobbe
Sent: 08 November 2013 19:45
To: rsgb_lf_group@blacksheep.org
Subject: RE: LF: remote antenna tuning

I had a look at the M0BMU LF tuning meter and will built it.

Does anyone used it on 475/500 kHz? Maybe the transformers need to be adapted but that should be no real problem.

 

73, Rik  ON7YD - OR7T

 

---

Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Stefan Schäfer [Stefan.Schaefer@iup.uni-heidelberg.de]
Verzonden: vrijdag 8 november 2013 19:53
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: remote antenna tuning

Oh yes, or, a phase meter (M0BMU) and a battery operated variometer motor. Without an additional cable to the shack. Then the SWR meter in the shack confirms that everything is fine.

73, Stefan

Am 08.11.2013 19:40, schrieb pat:

Hi All,

A suggestion: battery operated tuning device at antenna end and "wireless" link back to shack. Wireless can operate at a non-interfering frequncy (HF/VHF/UHF/Optical).

73






On 08/11/13 16:09, Stefan Schäfer wrote:

Hi Rik,

Am 08.11.2013 16:06, schrieb Rik Strobbe:

Hi Stefan,

 

remote tuning of the loading should be done by optimizing SWR (at the TX), not for maximum RF current.

If one keeps that in mind there is no problem.

...which is in agreement with what i said.
But once you have matched your antenna to 50 Ohm on resonance and you can only vary the reactive part of the antennas impedance (after doing QSY), then you will get the maximum antenna current at best SWR (assuming that Rrad+Rloss is constant which is not to far from reality).

I am not sure if I will keep the remote variometer tuning. It needs some extra wires to the loading coil and I am not sure how long the small DC motor will function properly with all the rain and frost coming up.

Here it holds since more than 2 years for LF now..

73, Stefan

-- 
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK