Re: NEC-LIST: horizontal quad loop - matching problem

Radiation efficiency is 40% at 7 MHz and over 50% above that. It has
some gain on 20 meters and above although the lobes might not point
right where you want them. Looks good to me.

The 16:1 balun will need to be homebrewed but should not be too
difficult to build.

   Dave Cuthbert

-----Original Message-----
From: nec-list-admin_at_gweep.ca [mailto:nec-list-admin_at_gweep.ca] On Behalf
Of drcuthbert
Sent: Wednesday, July 07, 2004 12:32 PM
To: nec-list_at_gweep.ca
Subject: Re: NEC-LIST: horizontal quad loop - matching problem

Chris,

I modeled this as a horizontal loop 43 meters on a side and 10 meters
above average GND. It is fed at one corner. When terminated at the
opposite corner with 800 ohms, and fed with a 16:1 balun, it presents a
VSWR of under 1.6:1 from 2-30 MHz. When terminated into 450 ohms the
VSWR peaks at 3.6:1. Somewhat directive towards the termination. A sort
of Rhombic, I suspect.

    Dave Cuthbert WX7G
    Micron Technology

-----Original Message-----
From: nec-list-admin_at_gweep.ca [mailto:nec-list-admin_at_gweep.ca] On Behalf
Of chris Turner
Sent: Wednesday, July 07, 2004 12:13 PM
To: nec-list_at_gweep.ca
Subject: NEC-LIST: horizontal quad loop - matching problem

(long lines)

The following appeared on a technical news group and I too would like an
answer to this problem.
Can anyone help?

Yesterday I erected a horizontal quad loop for 160 between 4 wooden
poles 10m up.
It works OK on 160 and 80 TX and RX on all HF bands. No problem with a
ATU on the higher bands.
I used this very same antenna many years ago in ZS3 (now V51) with great
success, BUT, it
worked on ALL HF bands with low SWR (we then called it a German Quad).
I cannot recall what I did differently then and lost the original 73
Magazine article with all the specs, etc.
Current setup: feeding it with 50ohm coax to a 1:1 balun (yes I know the
match is not
perfect but this is the very same balun I used way back).
I vaguely remember something of a step ladder at the opposite end of the
cubica. Ideally I would
like to use a 2:1 or 3:1 balun. I don't want to use an ATU.

Any help, ideas and advice?

Chris Turner IEng MIIE
G4HKP
Tel: +44 1844 238502
Mob: +44 7812 174133

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