Topband: Shared Apex Loop Array

[Tom W8JI]

I have used 4 bi-direction 760 foot Beverages for 5 years or so here in 
Michigan.
I put up the AS SAL-30 a month ago and my experience with the has been very 
favorable.
I can't do a direct A to B with the Beverages right now so I must reserve 
making any bold statements about the comparative performance as yet, but it 
definitely beats a full size 4-Square on 80M.

Modeling indicates that if single band (160M only) performance is desired - 
it can be optimized even further from the broadband 'tuning' I am using at 
present.>>>>

QEX has an article on this antenna, and it is republished on the Antenna 
Specialties website.

Is is a two element crossfire vertically polarized array made from loops.

Personally, if I were going to build one, I would spread the loops apart. I 
would make the loop centers as far apart as possible, not to exceed 1/4 
wavelength on the highest band.

The directivity should be very similar to a properly designed and 
functioning four square, although near field coupling in congested 
installations could make a larger element four square, or a larger array, 
more noisy.

When I was fighting LORAIN on 160 and wanted to work Japan (for Asia), I 
built an open wire line coupled array of eight loops like this. The loops 
were 70 ft on centers. This, and a good noise pulse blanker, allowed me to 
work JA1HKP and JA7AO on 160 through 100 kW.

My long array loop design was a offshoot of looking at an advertisement for 
a loop array sold by some commercial company for the military. If they could 
do it I could figure out how I could do it.

My noise pulse blanker was a offshoot of a LORAIN blanker concept of a W6 
published in the 1950's (I guess). I just used a different circuitry of my 
own style, and added a delay line so the blanking pulses appeared on the 
switch tube (I originally used a 6BE6, and later changes to those new 
devices called semiconductor diodes).

The log-loop array allowed me to hear only one or two LORAIN signals, so 
blanking time when signals were blanked decreased.

I probably spent 400 hours so I could work two JA stations.

73 Tom