[CW] CW Digest, Vol 111, Issue 18

Tue Jul 30 19:14:59 EDT 2013

During years I have tried to eliminate the ITV in the channel 2 TV
when I transmit in 6 mtrs and it is impossible.
Low pass filters that solves the problem doesn't exist.

I wish you good luck.

Strong hug 73
Eduardo CO8LY

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Subject: CW Digest, Vol 111, Issue 18

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Today's Topics:

   1. My low pass filter works (Hans Brakob)
   2. Re: My low pass filter works (D.J.J. Ring, Jr.)

----------------------------------------------------------------------

Message: 1
Date: Mon, 29 Jul 2013 21:41:21 -0700 (PDT)
From: "Hans Brakob" <kzerohb at gmail.com>
To: "CW Reflector" <cw at mailman.qth.net>
Subject: [CW] My low pass filter works
Message-ID: <1375159280557.87f1c2aa at Nodemailer>
Content-Type: text/plain; charset="utf-8"

Did you ever have one of those days that you thought maybe you ought to 
check to see if your Novice license was still valid?

Couple years ago K0CKB gifted me a modern Yaesu FTdx-5000 radio which 
includes all those new WARC bands, and even 6 meters.

Well I finally got curious to see what lay behind that "50" band-button, and 
having no antenna, I cut and bent and soldered up a bunch of copper water 
pipe into a reasonable facsimile of a 6-meter J-Pole last week.

Put it up in the air, ran some fresh coax to the shack, and hooked it to a 
vacant connector on my antenna switch box.

Mashed in the "50" button on the rig, tuned around, and the band seemed 
empty.??Checked the SWR at 50.010 --- infinity.??Checked SWR at the top of 
the band and spots between --- infinity at all those spots too!??Checked all 
my construction dimensions, ohmed out the new coax, tried several 
adjustments to the J-pole feed point looking for a match.??NOTHING.

So this evening I borrowed an antenna analyzer from N0AT.

Unhooked the coax from the switch box, attached the analyzer, fired it up, 
and found a nice 1:1 match at 52.873 mHz, and under 2.5:1 across the band.

WTF!?!?

Hooked the coax back to the switch box and checked the SWR at the 
radio.??Infinite mismatch across the band.

WTF!?!?

Clambering around under the desk looking for a bad patch cord (or 
something), I came face to face with......

.....the low pass filter (50 mHz cutoff) that I installed way-back-when to 
protect TV channel 2 in the neighborhood.??On the input line to my antenna 
switch box!

Sunnuvagun!??See the subject line.

de Hans, K(n)0HB
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Message: 2
Date: Tue, 30 Jul 2013 01:08:26 -0400
From: "D.J.J. Ring, Jr." <n1ea at arrl.net>
To: CW Reflector <cw at mailman.qth.net>
Subject: Re: [CW] My low pass filter works
Message-ID:
<CADO5RbigiMy9JmrrcfSGCmdSj4pa01eR8J1wth9Dm1ntOVWSKQ at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

My low pass is a 54 MHz cutoff.  You could have purchased the 34 MHz
version as 50 MHz cutoff does nothing for you.

When you took it out did it work?

David
On Jul 30, 2013 12:41 AM, "Hans Brakob" <kzerohb at gmail.com> wrote:

> Did you ever have one of those days that you thought maybe you ought to
> check to see if your Novice license was still valid?
>
>
>
>
> Couple years ago K0CKB gifted me a modern Yaesu FTdx-5000 radio which
> includes all those new WARC bands, and even 6 meters.
>
>
>
>
> Well I finally got curious to see what lay behind that "50" band-button,
> and having no antenna, I cut and bent and soldered up a bunch of copper
> water pipe into a reasonable facsimile of a 6-meter J-Pole last week.
>
>
>
>
> Put it up in the air, ran some fresh coax to the shack, and hooked it to a
> vacant connector on my antenna switch box.
>
>
>
>
> Mashed in the "50" button on the rig, tuned around, and the band seemed
> empty.  Checked the SWR at 50.010 --- infinity.  Checked SWR at the top
> of the band and spots between --- infinity at all those spots too! 
> Checked
> all my construction dimensions, ohmed out the new coax, tried several
> adjustments to the J-pole feed point looking for a match.  NOTHING.
>
>
>
>
> So this evening I borrowed an antenna analyzer from N0AT.
>
>
>
>
> Unhooked the coax from the switch box, attached the analyzer, fired it up,
> and found a nice 1:1 match at 52.873 mHz, and under 2.5:1 across the band.
>
>
>
>
> WTF!?!?
>
>
>
>
> Hooked the coax back to the switch box and checked the SWR at the radio. 
> Infinite
> mismatch across the band.
>
>
>
>
> WTF!?!?
>
>
>
>
> Clambering around under the desk looking for a bad patch cord (or
> something), I came face to face with......
>
>
>
>
> .....the low pass filter (50 mHz cutoff) that I installed way-back-when to
> protect TV channel 2 in the neighborhood.  On the input line to my
> antenna switch box!
>
>
>
>
> Sunnuvagun!  See the subject line.
>
>
>
>
> de Hans, K(n)0HB
>
> ______________________________________________________________
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> =30=
>
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End of CW Digest, Vol 111, Issue 18
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