2 kinds of loops
 

On 03/01/2011 12:35 AM, wrote:
On Feb 28, 9:12 am, wrote:

My large horizontal loop requires no aiming nor tuning. It is for SWL
and amateur receiving only. Set it and forget it. QRM was the main
problem. It is 95% solved. I never (never) hear light switches (which
cause huge explosions on my ham radio) or the oscillators in my analog
TV; and like that there.- Hide quoted text -

- Show quoted text -

Horiz. sweep circuits in the CRT based units are extremely rich in
harmonics . You must have built an extremely successful product . Any
details/schematic available ?

Length feet = 1005/frequency of interest

Make area inside the loop as large as possible. Get it up in the air
(although under the eaves will work if you don't have a lot of metal
flashing.) It seems to be deaf to most QRM generated in the "near
field", so I have it 3' above my roof, generally in the same shape as
the house, parallel to the ground. I cut the loop and put an MFJ-913 4:1
current BalUn, 'cause that's what I had lying around. For receive you
can get away with a reversed CATV BalUn.

It wants to be balanced. Use ladder line, twinlead, or a BalUn with coax.

This article is only about half bull****:

http://n1su.com/loop.html

2 kinds of loops
 

On Mar 1, 5:58*am, dave wrote:
On 03/01/2011 12:35 AM, wrote:

On Feb 28, 9:12 am, *wrote:
My large horizontal loop requires no aiming nor tuning. It is for SWL
and amateur receiving only. Set it and forget it. QRM was the main
problem. It is 95% solved. I never (never) hear light switches (which
cause huge explosions on my ham radio) or the oscillators in my analog
TV; and like that there.- Hide quoted text -

- Show quoted text -

Horiz. sweep circuits in the CRT based units are extremely rich in
harmonics . You must have built an extremely successful product . Any
details/schematic available ?

Length feet = 1005/frequency of interest

Make area inside the loop as large as possible. Get it up in the air
(although under the eaves will work if you don't have a lot of metal
flashing.) It seems to be deaf to most QRM generated in the "near
field", so I have it 3' above my roof, generally in the same shape as
the house, parallel to the ground. I cut the loop and put an MFJ-913 4:1
current BalUn, 'cause that's what I had lying around. For receive you
can get away with a reversed CATV BalUn.

It wants to be balanced. Use ladder line, twinlead, or a BalUn with coax.

This article is only about half bull****:

http://n1su.com/loop.html

SkyWires · SkyWire Loop Antennas
http://groups.yahoo.com/group/SkyWires/

2 kinds of loops
 

On Mar 1, 2:45*pm, bpnjensen wrote:
On Mar 1, 2:20*pm, RHF wrote:

Getting the Wire Up 40 Feet in the Air at all 4
Corners would be a challenge for most SWLs.

~ RHF
*.- Hide quoted text -

- Show quoted text -

Be pretty hard on a typical suburban lot, that's for sure.

Especially with a Square 160M Loop Antenna
that is 136 Feet per side. ;;-}} ~ RHF

2 kinds of loops
 

On 03/01/2011 03:49 PM, RHF wrote:

.
The "Skywire" Loop Antenna
http://srgproperties.inetusanow.net/.../9467_2192.pdf
.

That article is way obsolete. Ladder line or a BalUn is mandatory.
Antenna must be balanced.

Two SWL "Sky-Wire" Loop Antennas
 

On Mar 2, 5:16*am, dave wrote:
On 03/01/2011 02:20 PM, RHF wrote:



On Mar 1, 5:58 am, *wrote:

This article is only about half bull****:

http://n1su.com/loop.html

Don't know seems about right to me
http://n1su.com/loop.png
Notice that he does not feed the Loop :
At a Corner or in the
Middle of the Side :
Sort of Off-Set... like a Windom

- - Getting the Wire Up 40 Feet in the Air at all 4
- - Corners would be a challenge for most SWLs.

- There's your "bull****" part right there.

Dave more than just "N1SU" cite using a 160 Meter
Band Full Wave Loop Antenna of 574 Feet Rigged
at a Height of 40 Feet.

1005 / 1.750 = 574 Feet
1/4th Wave Length = 144 Feet High
1/8th Wave Length = 72 Feet High
-and- 1/10th Wave Length = 57 Feet
-so- 40 Feet High would be 1/10th WL for NVIS Operation