[CVARC] Re: CW VT practice net starts Monday night

  • From: Ed Hutchinson <ehutch@xxxxxxxxx>
  • To: cvarc@xxxxxxxxxxxxx
  • Date: Sun, 24 Apr 2016 21:51:27 -0400

I just need to get my 500' loop back up in the air, but I have had too much going on for a while. The 160 meter dipole is the only thing left in the air and it is far from optimal but does load on 160 and several other bands but not 80.

I tried loading up one leg of the 160 m dipole (center or braid only, it didn't seem to make any difference) with the open wire feed of the tuner (shorting strap in place to ground). Using a decent ground as a couter-poise, but got so much rf in the shack that I couldn't handle the mic. The ground is OK but the shack is on a second floor and everything else is also grounded to the same line. I think the distance to earth was dropping too much RF voltage.

On 04/24/2016 08:38 PM, Catherine James wrote:

That's a good idea, but it's best if the antenna isn't exactly full wave.  
Don't use the formula.  For example, my multiband antenna for 80/40/30/20/17/15 
is 150 feet long, with ladder line all the way to the shack.  Making it 130 - 
135 feet would make it harder to tune on 80 without giving me any benefit.

73,
Cathy
N5WVR

--------------------------------------------
On Sun, 4/24/16, KA1LHZ <sboard.ka1lhz@xxxxxxxxx> wrote:

  Subject: [CVARC] Re: CW VT practice net starts Monday night
  To: cvarc@xxxxxxxxxxxxx
  Date: Sunday, April 24, 2016, 9:21 AM
Or you could feed it with ladder line right to the tuner. I do that
      as do several others on the 1930 kc Toad Harbor Net. My antenna
      loads up on 20 through 160. I've worked Australia on 20 with it.
73
DE KA1LHZ
On 04/10/2016 08:41 PM,
  Catherine James
        wrote:
No
  surprise
                      that a 160 dipole doesn't want to
  load on 80. Center
                      fed dipoles don't like even
  harmonics, but will work
                      on odd harmonics. But most amateur HF
  bands are even
                      harmonics of each other, so except for
  40/15 that
                      doesn't help.
                That's why my
                      40 meter dipole is off-center fed. If
  you feed at
                      about one-third of the way from one end
  toward the
                      other, you'll get a consistent
  impedance on the
                      fundamental and even harmonics. So I use
  it on 40,
                      20, and 10, and all are
  SWR
  less than 2. (Typically
                      around 1.7 or better)
                The
  catch is
                      that the feedpoint impedance is about
  150-200 ohms,
                      so you need a 4:1 balun transformer at
  the
                      feedpoint.
                I'm not
                      suggesting you modify your 160 dipole to
  off-center
                      feed, but it's a useful trick to
  know.
                73,
Cathy
N5WVR
                Sent
                        from Yahoo Mail on
  Android
From:"Alan Zaur"
                          <alanlzaur@xxxxxxxxx>
Date:Sun, Apr 10, 2016 at 7:55 PM
Subject:[CVARC] Re: CW VT practice
  net starts
                          Monday night
Hi Ed,
I am also going to be putting up
  some new wire
                          this year.  Maybe we should get the
  F.A.R.T.
                          together.  I have a pneumatic
  launcher, etc.  Be
                          thinking of you tomorrow.
Alan
Sent from my iPhone
> On Apr 10, 2016, at 7:29 PM,
  Ed
                            Hutchinson <ehutch@xxxxxxxxx>
                            wrote:
>
> Hi Cathy,
> Thanks for the notice about
  the CW
                            practice net.
> I think I will "listen
  only" at least the
                            first week or perhaps two.  The
  only antenna I
                            have up right now is a 160m
  dipole. I just
                            tried to load it in several places
  in the 80m
                            band and I can't get better
  than 6:1 with a
                            tuner anywhere.  It seems to work
  tolerably on
                            40m, 20m, 15m, and 10m (not 1:1
  but usable),
                            but nothing doing on 80.
>
> We have our annual Green
  Mountain Chorus
                            concert this week and I will be
  traveling up
                            to Winooski or Essex Jct several
  times this
                            week (tomorrow, and Tues, and
  Friday, and
                            Saturday). Who would have thought
  singing
                            would have such a big carbon
  footprint.
>
> There is little chance that I
  will hang
                            up an 80m dipole tomorrow (but I
  should be
                            home by 7:00 or soon after to
  listen, if I can
                            find the group). The GMC tech crew
  is meeting
                            at EJHS at 2:00 (for an hour or
  two - if one
                            believes that).  I know I have
  several
                            multiband antennas and I think at
  least one
                            80m 1/2wave wire cut with coax
  attached.  But
                            they are out in the barn
  somewhere, and I will
                            need to figure out where to hang
  one.
>
> Ed, n1fmp
>





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