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Author Topic: DXing in the longwave basement one fine August afternoon  (Read 4500 times)

Offline ChrisSmolinski

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DXing in the longwave basement one fine August afternoon
« on: August 23, 2019, 1854 UTC »
AFE822x and the Crossed Parallel Loop antenna, rotated 3 directions to show directivity.

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline refmo

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Re: DXing in the longwave basement one fine August afternoon
« Reply #1 on: August 23, 2019, 2311 UTC »
That is quite an impressive demonstration of the Crossed Parallel Loop antenna, Chris.
For comparison, I made a similar screenshot using the Wellbrook Loop, model ALA-1530LNP, also using an AFEDRI AFE822X.
I would say the Wellbrook is somewhat less directional, at least down here in the longwave basement.

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Radios: Afedri AFE822x, Airspy HF+, RX-888, RSPdx, Tecsun PL880
Antennas: 700' Loop Skywire, Wellbrook ALA1530LN Loop, 400' Beverage, 34' Vertical, low dipoles on upper bands.

Offline jFarley

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Re: DXing in the longwave basement one fine August afternoon
« Reply #2 on: August 24, 2019, 0023 UTC »
Very inspiring, both.  So much so that I actually tuned down there, which is something I rarely do since all I have ever seen down there is a monstrous miasmic mess of man made slop presumably from switching supplies et al which obliterates everything up to about 185 kHz.  Not today, as I was able to pretty much see a waterfall similar to refmo's, which is thrilling to no end. 

Thanks, guys!

This was with a 96" amplified whip, base about 9 ft AGL.
Joe Farley, Near Chicago
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QSLS appreciated to:    jfarley44@att.net

Offline ChrisSmolinski

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Re: DXing in the longwave basement one fine August afternoon
« Reply #3 on: August 24, 2019, 1134 UTC »
I was also surprised at the relative lack of RFI down there.  I posted a video in Equipment of WWVB, also showing the directivity of the Crossed Parallel Loop. Turns out it works perfectly fine without a preamp, with the correct receiver, and a good matching transformer. I am using a variant of my Jellyfish transformer, with the turns set up for lower input impedances than normal, which works well.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline NJQA

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Re: DXing in the longwave basement one fine August afternoon
« Reply #4 on: August 26, 2019, 0926 UTC »
Can you provide a few more details on how you have the loops and transformer connected?  Why did you decide to remove the preamp?  Are you using RG6 feedline?

Offline ChrisSmolinski

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Re: DXing in the longwave basement one fine August afternoon
« Reply #5 on: August 26, 2019, 1225 UTC »
Can you provide a few more details on how you have the loops and transformer connected?  Why did you decide to remove the preamp?  Are you using RG6 feedline?

I'd have to pull the transformer to measure the turns ratio I am using. It's a special version of the Jellyfish transformer I make: https://www.blackcatsystems.com/rf-products/potted_matching-transformer-unun-balun-beverage-longwire-k9ay-flag-ewe-dipole-antenna-shortwave-ham-radio.html

LZ1AQ has some good info on the crossed parallel loop wiring here http://www.lz1aq.signacor.com/docs/wsml/wideband-active-sm-loop-antenna.htm

You end up with two connection points to the four loops.

The loops are connected to the transformer, the output of which is an F connector, then a run of RG6, most of which is underground, probably 100 or 120 ft total length?

I removed the preamp because it died from water getting in.  Looks like I don't need it anyway.  I'm a fan of passive antennas anyway, less to go wrong or cause mischief.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree