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Author Topic: High inverted V or low loop for SWL  (Read 1389 times)

Offline bandarr3000

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High inverted V or low loop for SWL
« on: August 06, 2018, 0105 UTC »
Hi, everyone.  With my particular setup I could put up an inverted v dipole with an angle around 100 degrees, at height of about 30 feet (I have a good sized maple in the middle of my small backyard).  Or, I could stick with my horizontal loop, which is about 10 to 18 feet off the ground.  The loop has been great for the noise in my urban environment, but I think I could do better if I got above the noise, even with a dipole.  I can't get a loop any higher. What's your opinion?  Thanks.

Yaesu FTDX3000D
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W6LVP loop antenna
EFHW 40-10 as inverted L
Grand Rapids, MI

eQSL please to bandarr@gmail.com

Offline bandarr3000

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Re: High inverted V or low loop for SWL
« Reply #1 on: August 06, 2018, 0106 UTC »
I should add that the loop is on The Squid, cut for 6925 khz.
Yaesu FTDX3000D
SDRPlay RSP1A
W6LVP loop antenna
EFHW 40-10 as inverted L
Grand Rapids, MI

eQSL please to bandarr@gmail.com

Offline Pigmeat

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Re: High inverted V or low loop for SWL
« Reply #2 on: August 06, 2018, 0221 UTC »
The inverted "v" is going to give you some vertical polarity for low angle signals. However, the size of the loop is going to give you more gain. The "v" might help if your noise problems are from the excess gain of the loop increasing the level of local noise sources. Sometimes bigger isn't always better. Vee's are dead easy to build. You can crank one out in a couple of hours. Build one,  give it a try, and go with the one you like best.

BTW, it's cool that you've still got maples. A blight has wiped them out by the thousands here. I miss them.

Offline Josh

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Re: High inverted V or low loop for SWL
« Reply #3 on: August 06, 2018, 0504 UTC »
Mebbe try a vertical wire up the trunk as far as you dare? Then some radials and see how it plays. Verticals are great for opening and closing bands.
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Offline ChrisSmolinski

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Re: High inverted V or low loop for SWL
« Reply #4 on: August 06, 2018, 1248 UTC »
Why not have both antennas? Keep the loop, and put up the inverted vee as well. I'd strongly consider building the inverted vee with 300 ohm ladder line, fed with a 4:1 balun into 75 ohm (RG-6) coax. It will be lower noise and wider bandwidth vs using regular wire.

I've never had good luck with vertical antennas, always very noisy.
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Offline bandarr3000

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Re: High inverted V or low loop for SWL
« Reply #5 on: August 07, 2018, 1943 UTC »
Chris, do you mean ladder line for the "radiators" or as a matching segment?  Thanks.
Yaesu FTDX3000D
SDRPlay RSP1A
W6LVP loop antenna
EFHW 40-10 as inverted L
Grand Rapids, MI

eQSL please to bandarr@gmail.com

Offline ChrisSmolinski

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Re: High inverted V or low loop for SWL
« Reply #6 on: August 07, 2018, 2006 UTC »
Chris, do you mean ladder line for the "radiators" or as a matching segment?  Thanks.

For the radiating wires. Find a page that describes a folded dipole made with 300 ohm ladder line. You can use 300 ohm TV twin lead, but it will not survive the first winter. Ask me how I know.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline Pigmeat

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Re: High inverted V or low loop for SWL
« Reply #7 on: August 08, 2018, 2340 UTC »
Chris, do you mean ladder line for the "radiators" or as a matching segment?  Thanks.

For the radiating wires. Find a page that describes a folded dipole made with 300 ohm ladder line. You can use 300 ohm TV twin lead, but it will not survive the first winter. Ask me how I know.

LOL! I find the better quality stuff with the foam insulation works well as feedline, but that brown light stuff is strictly for feedline for a season of pack in pirating, as that's about as long as it's good for. It's cheap, but that's about it.

Offline bandarr3000

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Re: High inverted V or low loop for SWL
« Reply #8 on: August 11, 2018, 0234 UTC »
Thanks for the advice, everyone.  Until I can get the money together for all the pieces-parts of the inverted V ladder line antenna, I've managed to get a good chunk of my loop higher into the tree, at around 25 to 30 feet, and it has helped considerably. 
Yaesu FTDX3000D
SDRPlay RSP1A
W6LVP loop antenna
EFHW 40-10 as inverted L
Grand Rapids, MI

eQSL please to bandarr@gmail.com

Offline n3umw

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Re: High inverted V or low loop for SWL
« Reply #9 on: October 25, 2018, 1404 UTC »
Try adding a loop on the ground (LoG) to help with the noise. This will also improve your DX reception. If you are only interested in 6925, use 20 feet of wire (5 foot sides). If you also listen to 80m and MW, use the 15 foot sides.

Plans and data for LoG
http://www.kk5jy.net/LoG/

LoG experiments
https://forums.radioreference.com/receive-antennas-below-30mhz/370110-160-20m-log-loop-ground.html
RX: Afedri SDR-net, WJ-8711, Lowe HF-150, RSPduo, AirSpy HF+
TX: Icom IC-718
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Offline mysticstar

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Re: High inverted V or low loop for SWL
« Reply #10 on: October 27, 2018, 0120 UTC »
        Hey All,
          I'm kind of new here so here goes. I take it when you said small back yard, you meant that you really don't either have the room or you have a home owners association? I personally use a Alpha Delta Sloper which has 2 resonating coils. I have it at about a 45 to 60 degrees. The reception has always been great, taking into account our solar cycle. Low noise and "big ears". You've got a tall tree to take advantage of it. Sometimes you just have to explore other routes. Hope this helps a little.
RCVR: AIRSPY HF+
XMTR: Kenwood TH-K2 Handheld
ANT: Alpha Delta DX-SWL Sloper
KD8OPV   KDE3BG :)

Offline Josh

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Re: High inverted V or low loop for SWL
« Reply #11 on: October 28, 2018, 1700 UTC »
Chris, do you mean ladder line for the "radiators" or as a matching segment?  Thanks.

For the radiating wires. Find a page that describes a folded dipole made with 300 ohm ladder line. You can use 300 ohm TV twin lead, but it will not survive the first winter. Ask me how I know.

LOL! I find the better quality stuff with the foam insulation works well as feedline, but that brown light stuff is strictly for feedline for a season of pack in pirating, as that's about as long as it's good for. It's cheap, but that's about it.

The light brown twinlead can be made a bit hardier by putting a few twists per foot in the line, then make sure to double up on the soldered ends as these will be stress points that will work harden the copper over time. The twinlead with foam does have lower loss but twinlead's low loss to begin with.
Conveniently located near Vincennes Indiana.

Offline Pigmeat

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Re: High inverted V or low loop for SWL
« Reply #12 on: October 30, 2018, 0853 UTC »
Try adding a loop on the ground (LoG) to help with the noise. This will also improve your DX reception. If you are only interested in 6925, use 20 feet of wire (5 foot sides). If you also listen to 80m and MW, use the 15 foot sides.

Plans and data for LoG
http://www.kk5jy.net/LoG/

LoG experiments
https://forums.radioreference.com/receive-antennas-below-30mhz/370110-160-20m-log-loop-ground.html

I carry a 100 ft. roll of wire with me when I travel for my mighty LoG/BoG and have for years. It works great with a portable. I've never had one overload a portable like that much wire in the air will do to most of them.

Offline Josh

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Re: High inverted V or low loop for SWL
« Reply #13 on: October 30, 2018, 1949 UTC »
Try adding a loop on the ground (LoG) to help with the noise. This will also improve your DX reception. If you are only interested in 6925, use 20 feet of wire (5 foot sides). If you also listen to 80m and MW, use the 15 foot sides.

Plans and data for LoG
http://www.kk5jy.net/LoG/

LoG experiments
https://forums.radioreference.com/receive-antennas-below-30mhz/370110-160-20m-log-loop-ground.html

I carry a 100 ft. roll of wire with me when I travel for my mighty LoG/BoG and have for years. It works great with a portable. I've never had one overload a portable like that much wire in the air will do to most of them.

That's a salient point, the bogs and logs (loop on ground) will have reduced signal powers but reduced noise pickup as well. This is great for those of us who run sdrs and portables limited in dynamic range. You can only handle so much signal with 8 or 12 bits.
Conveniently located near Vincennes Indiana.