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Author Topic: Tips on broomstick receiving antenna  (Read 7632 times)

Offline Antennae

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Tips on broomstick receiving antenna
« on: April 30, 2014, 0434 UTC »
I wound 147' of 20 gauge insulated wire around a pvc pipe with outer diameter of 1 5/8".  It doesn't work that well. 
Do I need a smaller diameter form? 
Do I need the capacitive hat on the top (an aluminum disc)? 
Does it work better with a tuner?
Thanks
California Coast
RCVRs: Radio Shack DX-398 portable / SDR: Elad FDM S2
Antenna: usually a random wire with tuner

Offline Pigmeat

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Re: Tips on broomstick receiving antenna
« Reply #1 on: April 30, 2014, 0643 UTC »
I've fooled around with homemade helical antenna's for listening for years. A simple random wire tuner makes all the difference in the world the things. The hat isn't necessary unless you plan on transmitting with the thing, IMO.


Offline Swan270

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Re: Tips on broomstick receiving antenna
« Reply #2 on: May 02, 2014, 0233 UTC »
Try winding about half that on the PVC. I think that your coils are too tight and there is a lot of coupling going on between the windings, which would increase the inductance and not be a good match for shortwave frequencies. . You didn't say how long the PVC was. Last time I did a helical vertical like that, I used a 20 foot long bamboo pole and wound plastic coated speaker wire on it and spaced the coils about 2" apart. Worked really well in the 49 meter international broadcast band.

Just a thought

73

Offline Antennae

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Re: Tips on broomstick receiving antenna
« Reply #3 on: May 02, 2014, 0359 UTC »
Thanks Pigmeat.  This is just for receiving. 

Swan270 thanks for the tip. Part of the intrigue with this is the compact size.  By the way, 20' is pretty long, was your bamboo the thick 4" diameter kind?
I made the windings touch. My pvc is only 4.5' long. And the windings only cover about 2' of the pvc. 

When I get my hands on a tuner I'll let you know how it goes.
California Coast
RCVRs: Radio Shack DX-398 portable / SDR: Elad FDM S2
Antenna: usually a random wire with tuner

Offline Chickin Little

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Re: Tips on broomstick receiving antenna
« Reply #4 on: May 02, 2014, 1546 UTC »
I bought a "Magic Stick" antenna from Ebay for $15, about a year ago for camping trips.  It works suprisingly well, and supposedly has some extra circuitry inside besides the wound up wire on a stick.  Never opened it up to see inside, though.   
Tecsun PL880 w/9:1 balun/45' wire @25'.

Offline Antennae

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Re: Tips on broomstick receiving antenna
« Reply #5 on: June 07, 2014, 1554 UTC »
I got a tuner. And it did make a difference on the strong 15.000mHz Universal Time station.  But nothing too fancy.
I was going to make a longer antenna with half the wire but when I took off my wire it was all curly and turned into some ungodly knots like out of a cartoon.  I threw the wire away.

$15 for something that works sounds worth the money!
California Coast
RCVRs: Radio Shack DX-398 portable / SDR: Elad FDM S2
Antenna: usually a random wire with tuner

Offline Chickin Little

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Tecsun PL880 w/9:1 balun/45' wire @25'.

Offline Dr. Strangelove

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Re: Tips on broomstick receiving antenna
« Reply #7 on: June 13, 2014, 0116 UTC »
I have to agree I got one of those Magic Stik antennas to use while traveling and it works pretty good.  Easy to use and store, I just leave it in the trunk of the car.
R-390a, WJ-8718, Collins HF-2050, Hagenuk RX-1001M, NC-183D, 51j-4, Cubic R2411, Racal RA6830JD, tons of glow in the dark radios.  I might have a problem, Lol!  Please QSL to morrisgarage770@msn.com   Northwest AL

Offline Tom S

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Re: Tips on broomstick receiving antenna
« Reply #8 on: June 13, 2014, 2033 UTC »
I've found that if you wind your coils too tightly, the capacitive reactance will work against the inductance and basically what you have is a trap.  When I was experimenting with a vertical antenna for SWL'ing years ago, I wrapped some copper-clad steel antenna wire around a short length of PVC pipe in the middle of two sections of pipe, making a center-loaded vertical.  The problem was that it was blocking all signals on the AM BCB.  I think it blocked everything 2 MHZ and below.  I took a lot of wire off the coil and spread out the turns a bit, and it worked fine.

The problem with a broomstick antenna is that you have so much wire in close proximity to each other, and unless you have a strong signal it's not going to hear very well.  It certainly won't hear signals as well as if you took all that wire coiled up on the broomstick and straightened it out.  Think of how well you hear signals on a rolled up wire.  It just doesn't work that well unless you space out the coils.  Something like a stretched-out slinky would work much better.
Happiness is a good antenna system.