Re: [IRCA] 9 Foot Longwave Box Loop (and other projects)

[D1028Gary@xxxxxxx]

Hello Again Rick,
 
After adding three more turns of #18 wire to the 9' LW box loop, I now have 
 567 feet of wire in 22 coil turns, and a tuning range from 142 to 350 kHz. 
 This should be OK for DX testing, so I'll probably wrap it up this way. 
It's  amazing how much wire you need to add to get the tuning range a little  
lower, on LW.
 
The coil turn spacing on the loop is actually wider than .25 inches,  
because although that was the width of the wooden spacers used with the circular  
saw to cut the wire slots, I forgot to account for the kerf width of the  
circular saw blade. The actual coil turn spacing is about .4 inches.
 
The variable cap used in this project (and all the PVC loops) was a  
compact, 8:1 vernier drive single-section unit from the eBay seller  
"crystalradiosupply." This split-stator cap fits neatly inside of a section of  1.5" 
diameter PVC pipe, for waterproofing the loop tuning system.
 
This LW box loop project was essentially an afterthought, after the  
construction of ten MW PVC-frame box loops of various sizes. The mail goal of  the 
project was to design and test lightweight, structurally strong PVC frames  
for extremely large loop sizes-- a goal which was entirely successful.  
Refinements to some of the larger loops can probably be made for  optimum 
performance, and I'm happy that Steve R. has expressed interest in  making one of 
these LW box loops according to my design, for testing  against his 1600' 
long wire. Living on a residential lot of .33 acre, I don't  quite have the 
experimental freedom that he has, in deploying sizable LW  antennas.
 
73, Gary  
 
 
 
 
In a message dated 5/4/2009 12:08:52 P.M. Pacific Daylight Time,  
k9ao@xxxxxxxxxxx writes:

D1028Gary@xxxxxxx wrote:
> The design was a basic one-loop coil  system in a traditional box loop  
> (non-spiral) design, wound on  a PVC support frame, tuned by a 4-400 pf 
capacitor 
>  connected  directly at the coil ends.

Is that a split-stator of a single-section  cap?

> The coil windings are spaced by slots 
> cut  in  short sections of PVC pipe, which are offset from the main PVC 
> frame  by  90 degree PVC "elbow" fittings. The spacing slots are 
separated by  
> .25", and are  all symmetrically cut into the PVC by a circular  saw with 
> multiple wooden  spacers of identical .25" width. The  19 coil windings 
(of #18 
> wire) are  then pulled tightly to  ensure optimal loop symmetry, in a 
system 
> which  apparently  provides excellent nulling capability. The 490 feet 
loop coil 
> of  #18  stranded wire tunes from 167 kHz to 444 kHz in the current 
setup,  
> but I plan to  add a few more turns to drop the coverage down to  150 
kHz. 
> Photos of the  loop and support structure are available  upon request.

I'd love to see anything you might have, but can wait for  your article 
too.I know you must be busy.

The split-stator cap and  center-tapped loop primary winding improves 
loop symmetry and  balance.

As to the spreading of the windings, the spreaders that splay  every 
other turn up and down in two (maybe more) sections help a lot in  
increasing the range of tuning. Let me know if photos of that might help  
exp[lain what it looks like. I used wide tongue depressors, but small  
round PVC pipe sections would probably work better in that big  loop.

Rick  Kunath
_______________________________________________
IRCA mailing  list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions  expressed in messages on this mailing list are those of the 
original  contributors and do not necessarily reflect the opinion of the IRCA, 
its  editors, publishing staff, or officers

For more information:  http://www.ircaonline.org

To Post a message:  irca@xxxxxxxxxxxxxxxx



**************2009 3 Free CREDIT SCORES: See Your 3 Credit Scores from All 
3 Bureaus FREE! 
(http://pr.atwola.com/promoclk/100126575x1221797372x1201397989/aol?redir=https:%2F%2Fwww.freescore.com%2FOffers%2FStart%2FFreeCreditRepor
tAndScore.aspx%3FID%3D91831F371F138345B53A153F49D4D872%26siteid%3De927580bf7
)
_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx