[SOC] Matching G5RV
Dennis
[email protected]
Mon, 18 Aug 2003 16:09:45 -0400
me too... with a grinding sort of pronounciation..??
----- Original Message -----
From: "Hank Kohl K8DD" <[email protected]>
To: <[email protected]>
Sent: Monday, August 18, 2003 3:57 PM
Subject: Re: [SOC] Matching G5RV
>
> naw .... i was really SOC'ing it .....
>
> condoms with a Brit pronounciation!
>
>
>
>
>
> At 8/18/2003 02:58 PM -0400, you wrote:
>
>
> ur thinking of
> carborundum....
>
>
>
>
> ----- Original Message -----
>
> From: {quot}Hank Kohl K8DD{quot} <[email protected]>
> To: <[email protected]>; <[email protected]>;
> {quot}Paul Bartlett{quot}
> <[email protected]>
> Sent: Monday, August 18, 2003 2:12 PM
>
> Subject: Re: [SOC] Matching G5RV
>
>
>
>
> >
> > At 8/18/2003 05:51 PM +0100, Paul Bartlett wrote:
> >
> >
> > Hi All,
> >
> >
> > I have a conundrum to solve.
> >
> > Hmmm.... Trojan or Ramses?
> >
> >
> >
> >
> > I have a K2, a full size G5RV
> > (104') and an ex-miltary ATU (Redifon type
> >
> > A.C.U.9) kindly loaned to me by Paul MW3PWA.
> >
> >
> > The ladder-line phasing section of the G5RV terminates in a
> 50R
>
> > co-ax
> >
> > connector and is immediately followed by a 10 turn co-ax
> 'choke
>
> > balun'
> >
> > (about 6{quot} in diameter). There's then a 30' run of co-ax to
> the
>
> > shack.
> >
> > Personally .... I don't see a need for the choke balun, but tis
> my
>
> > personal
> >
> > opinion ..... and opinions are like noses ..... everyone has one
> ....
>
> > some smell
> >
> > ..... some don't.
> >
> >
> >
> >
> > The ATU takes an RF input via a BNC
> > connector which runs to the K2.
> >
> > Disassembling the ATU I see that the hot input passes to a bank
> of
>
> >
> > switchable capacitors down to ground and thence to variable
> series
>
> > inductor
> >
> > (rather nicely made).
> >
> >
> > There are three output terminals: Earth; the other end of the
> inductor;
>
> > and
> >
> > a third terminal connected to the second via a high-voltage cap
> which
>
> > value
> >
> > I can't determine.
> >
> > If I understand the description ....
> >
> >
> > input
> >
> ----------|--------|--------|--------UUUUUUUUUUUUU--------|--------
>
> > output
> >
> >
> > |
> > |
> > |
> > |
> >
> >
> > --- ---
> > ---
> > ---
> >
> >
> > --- ---
> > ---
> > ---
> >
> >
> > |
> > |
> > |
> > |
> >
> >
> > |
> >
> -------|--------|---------------------------------------------|---------
>
> > earth ground
> >
> >
> > |
> >
> > Ground
> >
> >
> > Looks like a pi network .... The input caps are switchable in or out
> ....
>
> > the output cap is switchable in or out
> >
> > Looks like a pi network .... If the only {quot}tuning
> that
>
> > can be done is the switchable input capacitors, I'd think it may
> be
>
> > usable. If one of the input caps and the output cap are
> variable,
>
> > I'd think it would be real usable.
> >
> >
> >
> >
> >
> > Questions:
> >
> >
> > Is the ATU sensibly usable at all with my mix of antenna and feed?
> If
>
> > so,
> >
> > how?
> >
> > Here's what I would do ....
> >
> > Get a cup of tea.
> >
> > Hook the input up to the K2.
> > Hook the output to the coax feeding the G5RV.
> > Sit back, drink some tea, look at the set up and confirm that it
> is
>
> > correct.
> >
> > Listen on, let's say, 20M .... CW of course!
> >
> > Vary the inductor until you get maximum noise or signal.
> >
> > Switch the capacitors in and out until you get maximum noise.
> >
> > Vary the inductor some more for maximum noise or signal.
> >
> > Write down, while sipping on tea, which capacitors are switched in,
> where
>
> > the setting on the inductor is, and if the output capacitor is in
> or
>
> > out. And the S meter reading.
> > At a watt or two, touch the tune button, or key the K2 with a
> straight
>
> > key and check the SWR.
> >
> > If it's not below 1.5 or so, vary the inductor to see if it goes up
> or
>
> > down .... adjust accordingly.
> >
> > Get another tea.
> >
> > Check if switching around with the input caps lowers the SWR.
> >
> >
> > I think you see where this is going .....
> >
> >
> >
> >
> > Do I need a further balun after the
> > ATU to match the unbalanced feed?
> >
> > No .... but then I'm not a fan of baluns.
> >
> >
> > Should I ground the ATU via it's
> > EARTH terminal?
> >
> > Absolutely, unless it works better without a ground!
> >
> >
> > 73 hank k8dd
> > soc #69
> >
> >
> > Any and all suggestions
> > welcomed.
> >
> >
> > Best,
> >
> >
> > Paul M3CRQ :-)
> >
> >
> >
> >
> > _______________________________________________
> >
> > SOC mailing list
> >
> > [email protected]
> >
> >
> http://mailman.qth.net/mailman/listinfo/soc
>
> >
> > */ Hank Kohl
> > K8DD [email protected]
> > */ ARRL
> > TS
> >
> http://www.qsl.net/k8dd
>
> >
> > */ MI-QRP - Vice Pres. QRP-ARCI
> -
>
> > Director
> >
> > */
> >
> > If God intended you to be on single sideband, he would have given
> you
>
> > only one nostril.
> >
> > - Steve, K2PTS (SK)
> >
> >
> >
> >
> >
> >
> >
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> >
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> >
>
>
> _______________________________________________
>
> SOC mailing list
>
> [email protected]
>
> http://mailman.qth.net/mailman/listinfo/soc
>
> */ Hank Kohl
> K8DD [email protected]
> */ ARRL
> TS
> http://www.qsl.net/k8dd
>
> */ MI-QRP - Vice Pres. QRP-ARCI -
> Director
>
> */
>
> If God intended you to be on single sideband, he would have given you
> only one nostril.
>
> - Steve, K2PTS (SK)
>
>
>
>
>
>
>
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