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Author Topic: Everything you wanted to know about my antenna farm, but were afraid to ask  (Read 3958 times)

Offline relaxing

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Very nice! Wish I had the free space. Those sky wires are fantastic.

Here we have a double loop on 40m phased, switches to a single FW on 75/80m. Vertically hung, horizontally polarized mostly, apex bottom delta.

About to string up a 160m dipole, it will have a 130ft flattop with a 90degree turn at both ends and about 60 more feet vertical off each end, so it will hopefully not have any FW phase cancellation on 80 meter and work good there also. I am so surrounded by trees so alot of the RF gets absorbed/blocked.

Offline ChrisSmolinski

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Very nice! Wish I had the free space. Those sky wires are fantastic.

Here we have a double loop on 40m phased, switches to a single FW on 75/80m. Vertically hung, horizontally polarized mostly, apex bottom delta.

About to string up a 160m dipole, it will have a 130ft flattop with a 90degree turn at both ends and about 60 more feet vertical off each end, so it will hopefully not have any FW phase cancellation on 80 meter and work good there also. I am so surrounded by trees so alot of the RF gets absorbed/blocked.

Very nice. I have been considering a 160m dipole, or actually something a tiny bit longer, resonant on the expanded MW band, where the pirates also hang out.

I am also surrounded by trees, and wonder how much of an impact they have at HF. It is noticeable at VHF and UHF, I get more distant / better reception of stations there with the discone in the winter vs the summer.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline ChrisSmolinski

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Time for an update on the antennas... I have added three new ones:

1. A 75m dipole. My initial goal was to help pull in the western USA desert pirate beacons on 4 MHz (4096 and the neighborhood). I can't say it has helped too much there, I still just hear Windy and sometimes ZN. But... it works fairly well on other bands, it is not too bad on 43m (I thought it would be, due to being about a wavelength long) as well as 19m. Go figure? Always nice to have another antenna in the arsenal, anyway.

2. A 350 ft LoG (Loop on Ground) antenna. These are advertised as being low noise antennas. And guess what - they are. They are also low signal, but the signal to noise ratio can be pretty good. This has become the de-facto antenna on the KiwiSDR now. It used to share the sky loop with the netSDR, but the KiwiSDR overloads at night with the sky loop. Not an issue with the LoG. I do sometimes switch that out and connect it to the 43m dipole when pirates are on and others are using the KiwiSDR to listen to them.  This LoG works very well on MW.

3. A 50 ft LoG, which works better on the higher bands (25m and up).

I have to say, if you live in a neighborhood with HOA trolls, and cannot have a visible antenna, the LoG may be ideal for you. Even if you can have antennas, you may want to try one. This is what I am using to feed the LoG, home made matching transformers that are potted in epoxy resin, so they are waterproof (vs trying to mess with sealing plastic enclosures). I am planning on making and selling these, 4:1 and 9:1 impedance ratios (4:1.5 and 9:1.5 for the 75 ohm F connector versions). I think they could be handy for other antenna designs as well:

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Josh

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Considering the distance from you to the typical midwest and eastcoast pirate activity, I'd go vertical. Hoist 50ft of wire up a tree and run some radials and enjoy. Or if you've the space, a mini bev or full sized aligned so a lobe covers say Pittsburgh.
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Offline pjxii

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Chris, I have the land to set up a 1240' true square sky loop and have a couple of questions.
Do you notice any directionality at all with regard to the balun placement, or does it seem truly omnidirectional?
Also, I have your Squid, what impedence would you expect this sky loop to be seeing?  With so many configurations of the wires on the Squid I know I can experiment but what would you recommend as a starting point?

Offline ChrisSmolinski

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Chris, I have the land to set up a 1240' true square sky loop and have a couple of questions.
Do you notice any directionality at all with regard to the balun placement, or does it seem truly omnidirectional?

Based on observations of what stations (mostly) pirates consistently come in well, or poorly, I believe the antenna has lots of peaks and nulls in various directions depending on the frequency, since it is multiple wavelengths on HF. Where those are directed... I have no idea.

/quote]
Also, I have your Squid, what impedence would you expect this sky loop to be seeing?  With so many configurations of the wires on the Squid I know I can experiment but what would you recommend as a starting point?
[/quote]

I'd start with the 253 ohm taps, and then move up or down from there. There's probably no one ideal match over the entire spectrum, as the impedance is going to vary, so maybe pick the band of most interest to you and optimize there?
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline jmlx

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Concerning your sky loop: gain continues to increase with increase in freq I.e. multiples of wavelengths over fumdamental. Also, as freq increases angle of reception becomes lower and lower off the  sides. Could be it recieves at too low an angle for your needs above 19meters.. At the fundamental freq it picks up mostly at 90 degrees or overhead. Also, as freq increases feedline losses become more of an issue especially with a feedline impedance mismatch. That's the downside to feeding it with lossy feedline like coax. Overall the big horizontal loop is a very effective antenna for general coverage recieve.  I wish I had one!
Nashville, TN.
Icom R75. Tuned magnetic loop.
Kenwood TS-850S. Kenwood TS 2000. 40 meter inverted v.

Offline ChrisSmolinski

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Some more updates:

A few weeks ago I rebuilt the 20 meter dipole. It's up pretty high, maybe 60 ft or more? I actually suspect it may be up too high for an optimum low angle pattern, which would be about half a wavelength or 35 ft, reference: https://www.qsl.net/aa3rl/ant2.html

It is oriented east-west and has maximum pickup to the north and south, it does do well with stations from Latin America.

Then about a week ago I put up another 20m dipole. This one is oriented roughly NE to SW with a maximum lobe to the NW, for a good pattern towards AA7AS in MT (we work 20m SSTV fairly often) as well as continuing to Oceania. This one is at the optimum half wavelength or 35 ft height, and works very well indeed.

I also use the 58 ft T2FD for 20m SSTV (reception only, not transmitting) and it works rather well overall, especially towards Europe.

I am considering  reconfiguring the high 20m dipole as a 43m dipole. In theory with the height and orientation it should be very good for signals from Latin America.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Dude111

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Thank you for sharing what you have on your farm Chris,looks quite nice buddy!!!
« Last Edit: January 05, 2020, 1927 UTC by Dude111 »

Offline Josh

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To see the patterns you can try eznec
https://www.eznec.com/demoinfo.htm
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Offline Pigmeat

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Chris, seeing that we both live in forested, mostly hardwood terrain, what I've noticed is all reception starts to get crappy when the trees bud out and doesn't improve much until the leaves fall, no matter what the antenna. I've always thought it was sap related w/ the hardwoods? Pines can be a problem, but I think it has something to do with the soils they prefer?

Offline ChrisSmolinski

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Chris, seeing that we both live in forested, mostly hardwood terrain, what I've noticed is all reception starts to get crappy when the trees bud out and doesn't improve much until the leaves fall, no matter what the antenna. I've always thought it was sap related w/ the hardwoods? Pines can be a problem, but I think it has something to do with the soils they prefer?

I'll have to pay closer attention and see if I notice any degradation in HF signals once the trees leaf out this Spring. I certainly notice a decrease in VHF/UHF distance once that happens.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline ChrisSmolinski

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Minor update...

I realized I had a spare rope going over a tree since I relocated the discone to another tree. So I used it to about double the height of the 10/11 meter folded dipole with minimal effort. The other end of the dipole is tied off to a fence, the horizontal distance of that rope is long enough that the antenna itself is not sloped too much, perhaps 30 degrees or so from horizontal? When I get the chance I may get that rope at least up into a low tree to make it slightly closer to true horizontal, although I have to say I am pretty happy with the current performance. It gets much better reception from some of the weaker local guys, and still does great on DX.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree