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dave · July 17th 14, 04:20 PM posted to rec.radio.shortwave

On 07/16/2014 12:19 PM, wrote:
On Wednesday, July 16, 2014 12:22:24 PM UTC-4, dave wrote:
On 07/15/2014 10:23 AM, wrote:

On Tuesday, July 15, 2014 11:18:17 AM UTC-4, dave wrote:

On 07/14/2014 04:40 PM, outsider wrote:

I got my Pixel loop about 2 months ago. I have it mounted in my back

yard about 10 feet up to the bottom of the loop on an inexpensive

rotor. There was an initial problem. The power supply was generating a

birdie in the middle of 40 meters. Pixel immediately sent me a new

power supply as soon as I phoned them. They sent me a prepaid label to

return the bad supply.

I installed an A-B switch for my receiver to make instant comparisons

between my full size 75 meter horizontal loop and the Pixel Loop.

Now to the performance. Be aware throughout this little missive that I

am comparing the Pixel Loop to a 75 meter full size horizontal loop

about 35 feet off the ground. I live in a small town about 3 blocks from

city centre. I have had serious noise problem when using a dipole. The

full size loop did a whole lot to lessen my noise from nearby

residential homes and small businesses. My full size loop crosses my

metal roof with about 5 feet to spare on the two ends of my home. I am

on a 100 X 120 lot.

First I will note that using the Pixel loop to null noise from a storm

works pretty well. My full size loop will work better on 75 meters in

almost all conditions than the Pixel Loop. The only exception is at

night when the storm noise is coming from just one direction and I can

null it with the Pixel Loop. So it kinda makes sense from a simply gut

feeling that a full size loop fed with open wire line is going to work

better than the Pixel Loop. I find this gut feeling to be true in fact.

Now, I have no antenna for transmitting on 160 meters so I will not say

much except that the Pixel loop will receive better than my 75 meter

loop. When working on 40 meters and reception conditions are marginal,

I find myself switching to the Pixel. The signal strength is down but I

can just hear the other station better. These situations involve

stations that are not even moving my S meter. I cannot give measured

S/N ration readings. I am just going by what I can hear. This is also

true on 20 and 17 meters.

On 15 and 10 there is a very different story. Switching to the Pixel

will show an increase in my S meter reading and a significant increase

in S/N ratio. An average example on 10 meters where this antenna works

best for me would be hearing a station showing an S 1 signal strength on

my 75 meter loop. Switching the Pixel would bring up the strength to S3

or even 4. This is also with less noise.

It took me some time to test and get a feel for this antenna. My initial

feeling after hooking up this antenna was disappointment. I expected my

75 meter loop to out perform the Pixel on 75, but I did not expect the S

meter reading to drop several points on 40 meters. I thought I had

wasted my money. However, after operating with this antenna for a couple

of months, I kept finding myself switching to the Pixel when reception

started getting dicey. This is true on 40, 20, an 17. On 15 and 10, it

is obviously showing stronger S meter readings and much better S/N. I no

longer have a dipole to compare performance. I suspect however, that

this Pixel would run rings around a dipole when operated in an urban

environment. I believe that for those who live in a city with a lot of

QRN around them, that this antenna mated with a dipole or loop makes a

very good antenna system. For most who only have room for a dipole and

are at the mercy of surrounding plasma tvs, I would think that they

would find this antenna to be a very welcome relief from the noise. I

also use a DSP audio ADAPTIVE noise reduction module. I have become very

spoiled now. I expect that most of my QSOs will sound like FM.

Again, I think that this is a pretty good investment for those who live

in an urban environment. You could spend thousands more on a Cadillac

transceiver and still be plagued by a noisy received signal.

W8EZI

I make full wave loops out of scraps of 12g stranded from the pile at

Home Depot and MJF Guanella baluns. I receive on the loops and transmit

from a 43' vertical or (for 10) My M400 Starduster. I also SWL on a full

wave 80m loop and there is no QRN. I am in a neighborhood full of cheap

dimmers, cheap SMPSs, RV chargers, plasma TVs, etc. and I never hear a

lick of it. Full wave loops have common mode rejection of local noise

and once that is not a factor you'll get more realistic S-meter

readings. S:N is what is important, not total S-meter deflection. YMMV

73 de dave kd6il

I had good results from MLB by RF Systems. Very low noise- rejection of the usual cable tv, florescent lights and even the power line hum.

I won't spend more than $30 for a receive antenna because I don't have

to. When I was with SWLP there was a monitor in a high rise who dropped

a 60' wire off the balcony at night; some form of mag loop would have

worked way better.

In general high rise buildings are steel structures. Lots of it . Therefore in that case he had not much of a choice . Also many buildings don't give permission to hang wires on the roof. I think the slinky type antenna was a partial solution.

No cancellation, no directionality, no chance. A small shielded loop for
the band of interest, rotatable in all directions (up,down,azimuth) on
the balcony (remote controlled) or in front of a glass wall, would have
the best chance at DX. Interesting idea for a project as tailor mades
cost a fortune.

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