TheRadioBoard

Just completed a broomstick antenna made with 3/4 in. pvc, 1 meter in length. It is wrapped with 100' of no. 18 speaker wire. I added a varicap to aid in fine tuneing. It works great with my O1A tube regenny SW coil radio. Note: I joined Photobucket, but damned if I can figure out how to paste the images on this post.

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What would our world be like, if Tesla was alive in our time?

Thanks Dave for the help in putting a picture up. I will let the bride help me with this computer stuff! I guess that's why my Mother always told me to let a woman figure it all out, then you take the credit

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What would our world be like, if Tesla was alive in our time?

Hi,

Looks great and it works too. Nice and compact. Wonder if you made the top disc out of aluminum, would the bandwidth be broader.

Thank's for the picture, Helmut

helmut

You mean make the top disc a capacity hat?
What is is made of now?

Helmut the top capacitor hat is made of alumunum roofing material. This antenna really is worth making. I can use it indoors on bad weather days and get off the outside wire for safety. If you buy a roll of 18 guage speaker wire and just wind it as it comes off the spool, and your pvc pipe is 1 meter long, it will work like intended. Start by tapping onto the top cap and wind to the bottom. Run a bolt through pvc at bottom and just clip onto the antenna for some DX
This can also be used for transmitt up to 100 watts.

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What would our world be like, if Tesla was alive in our time?

I know this is an old post, but I want to build one of these this weekend. Everything I read says to use speaker wire, speaker wire has 2 wires to it maybe I'm being thick headed, but wouldn't you only use a single wire

Thanks,
Dan

Arnie Coro, who's probably forgotten more about antennas than I'll ever know, has this version of the broomstick, which uses single conductor wire:

http://www.hard-core-dx.com/nordicdx/antenna/special/bromstik.html

The idea is to confine the length of the wire by wrapping it around a support. The type of wire is not important if you're not transmitting. In some transmitting situations the voltage between turns, especially near the top, might be high enough to arc through the insulation.

73,

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http://kr1s.kearman.com/
http://qrp.kearman.com/

I'm not sure about Dan ... but ... if one is using a 2-conductor wire, is only 1 of the conductors used as the "antenna?"

Or, is one end shorted to the other, effectively doubling the length of the antenna?

Or, are both ends shorted?

Or what?

Thanks KR1S ! I think that is a link I was already referencing, but I will double check it.

Dosco, These are the very same questions I was wondering ?

Thanks,
Dan

Dan:
I figured as much, and I share your curiousity. It is not entirely clear to me as to how to build the antenna.

-Dave

Is the top cap the same size as the bottom stand? In the picture the top appears larger. This looks like a fun project and a good receive antenna! Very nice looking also!

SWsenior

The base is only to keep it from tipping over. Its size otherwise doesn't matter. The top plate provides additional capacitance to ground, to partially offset the shortness (in wavelengths) of the antenna. You need an impedance-matching network (AKA 'tuner') with an antenna like this.

73,

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http://kr1s.kearman.com/
http://qrp.kearman.com/

Thanks much for the info, I believe I will try it and see how it works!

SWsenior

Hmmmm--

interesting---since there is a possibility that i will again become a 'cliff dweller'

its time i looked into this one--had hoped to avoid that situation again for the remainder of my life

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TB
In GOD we trust,
all others we monitor!

I feel your pain! An antenna like this has a narrow bandwidth, meaning you have to adjust the matching network frequently as you tune across a band. There's a potential benefit, though, all other things being equal, as it gives you some added selectivity. But any antenna in close proximity to house wiring is bound to pick up noise, and a vertically polarized antenna is especially susceptible. If you want to transmit, you might consider a "Texas Bug Catcher" antenna, with a big, fat loading coil and a fairly long radiator on top. I had one, with a CB whip on top, strapped on the back of my Subaru hatchback in the 90s. Had to get out and change the taps to change bands, but driving from Connecticut to Florida was a lot more fun. As a mobile, I couldn't have a ground plane other than the car body. Backed her down onto a beach once (4WD) and laid out some radials into the Gulf, to give out an IOTA island (Boca Grande). That worked really well. You lose some radiation in the coil, but even a base-loaded CB whip will put out a decent signal down to 40 M if conditions are right.

73,

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http://kr1s.kearman.com/
http://qrp.kearman.com/