From: "Clemens Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <94719482.20170623130346@gmail.com>
In-Reply-To: <94719482.20170623130346@gmail.com>
Date: Sat, 24 Jun 2017 12:34:18 +0200
Message-ID: <EFA843B116824E4B89B87C3BAAE2DB33@Clemens0811>
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Subject: LF: RE: Transformer questions.
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Hi Chris, 

>Can I wind the isolating
>transformer as a 1 : 1 and do impedance matching (which changes with
>weather / foliage growth) indoors using a tapped combiner auto
>transformer? 

This would be possible but more or less lossy.
What is the impedance as seen by your AIM when you measure on the secondary side of the 1:1 isolation transformer
with antenna and feeder connected to the primary winding?
How long is the coax between the isolation- and the auto-transformer?
With these data it is easy to predict the losses quite accurately.

73
Clemens
DL4RAJ 


>-----Original Message-----
>From: owner-rsgb_lf_group@blacksheep.org 
>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Chris Wilson
>Sent: Friday, June 23, 2017 2:04 PM
>To: rsgb_lf_group@blacksheep.org
>Subject: LF: Transformer questions.
>
>Hello LF'ers,
>
>Two 500 watt Class D amps combined. The output transformer of the
>combiner is now an auto transformer. This feeds, via RG-213 to
>outdoors, where an isolating transformer, that is a conventional
>primary / secondary transformer with taps for impedance matching then
>feeds my loading coil and then the antenna. Can I wind the isolating
>transformer as a 1 : 1 and do impedance matching (which changes with
>weather / foliage growth) indoors using a tapped combiner auto
>transformer? I want to change the impedance matching / isolating
>transformer anyway as it runs a bit hot on long TX sequences. I tried
>an auto trans former as the impedance matching one outside, but had
>serious RF into the mains causing various issues, a conventional
>isolating / impedance transformer fixed all that, so I assume it needs
>to stay, even as a 1 :1 ? Thanks.
>
>  
>
>-- 
>Best regards,
> Chris                          mailto:dead.fets@gmail.com
>
>
>
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