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So the antenna I'm thinking about doing might be* way too large for my property.

Is there another simple, cheap, DIY antenna I could try on my receiver? I know I'm going to want to hook it up and have a listen before the last solder joint has cooled. Ideally it would cover 160 m to 10 m reasonably well.

The most complicated antenna I've built was a Gray Hoverman for UHF reception. It would be nice if it weren't much more complex, but if it's inexpensive and good enough I'm willing to do a bit of work for an antenna I'll use a long time.

I'm not interested in aiming right now, so an omnidirectional antenna would be best. I do have a 25' attic I can use if needed.

*Is almost certainly...

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6 Answers 6

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Receive antennas are the easiest thing ever. You just need two things:

  1. something that conducts electricity
  2. another thing that conducts electricity

Attach one to the center contact on a BNC connector. Connect another to the shield. Boom, done. If you can't find two things, then one can be the Earth.

Alternately, you can use two ends of one thing that encircles something that permits magnetic fields (like, air).

Until you are approaching a significant fraction of a wavelength (like, 1/4 wavelength), then making either thing bigger will get you more signal. However, once you have enough signal that you are well above your receiver's noise floor, more signal won't make you receive any better: it will just give you louder noise. I'd say, however much space you have, make it that big.

Don't worry about tuning, or impedance matching. This also will increase the fraction of the energy received by your antenna coupled to the receiver, but again, once you have enough to overcome the receiver's noise, more is of absolutely no help. See What is the relationship between SWR and receive performance?

Don't worry about polarization. At HF most of your signals will arrive via the ionosphere which is constantly swirling and changing the polarization of received signals. Whatever polarization you pick, it will be the wrong one in 30 seconds, so don't worry about it.

If you really must worry about something, worry about getting your antenna away from noise sources. Your house, being full of all varieties of noisy digital electronics, is very noisy. If you can get an antenna away from these things, that's good. You must also take care to avoid making the feedline part of the antenna. See Using a balun with a resonant dipole Although that question asks about resonant dipoles, the answers apply to any type of antenna.

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There is nothing simpler than a random length wire. It doesn't have to be strung up or even straight, though, obviously, those would improve it's performance. Of course the ironic thing about a random length wire antenna is that the most effective lengths aren't actually random. They work best when the antenna is at least a quarter wavelength at the lowest operating frequency, 65' for 80m, for instance.

To maximize the effectiveness, and have something useful down the line, you could build a small tuner. An L-network random wire tuner is probably the simplest matching network in existence, designs about on the net. Like this one: How to Build a Cheap Antenna Tuner or this one: SWL Receiving Antenna Experiments.

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    $\begingroup$ Your 2nd reference advises against tuning a receive antenna: "When you tune a receive antenna you increase received noise and desired signals proportionally and therefore do not improve the signal to noise ratio in a meaningful way. Sometimes until you perform some experimentation, you don't really believe even good advice." $\endgroup$
    – Phil Frost - W8II
    Commented Dec 16, 2013 at 8:10
  • $\begingroup$ Yeah, I saw that line and scratched my head. While it's true, you aren't matching an antenna for best SNR... The stronger the signal starts, the more room you have for filtering to improve the desired signal, so I don't get his point unless it's pure SWL where you aren't doing anything to the received signals and since hams always tinker... $\endgroup$
    – WPrecht
    Commented Dec 16, 2013 at 11:33
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    $\begingroup$ I think you miss the point. You can make all the "room" you need with an amplifier. Any ordinary modern receiver already has a pretty good, low noise receive amplifier that does this. $\endgroup$
    – Phil Frost - W8II
    Commented Dec 19, 2013 at 13:29
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Not real thrilled about the attic; if you can go outdoors, I'd recommend a random length horizontal loop, as described at http://www.k4qky.com/the-station/the-antenna and http://www.smeter.net/antennas/large-transmitting-loop.php for its design simplicity.

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    $\begingroup$ Why a loop? Why horizontal? What's wrong with the attic? $\endgroup$
    – Phil Frost - W8II
    Commented Dec 15, 2013 at 21:22
  • $\begingroup$ The attic often is close to all sorts of electronic noise - house wiring, perhaps an HVAC system, the structure itself will attenuate incoming signals to some extent. If it's your only option due to HOA restrictions, that's one thing (although there are lots of clever ways to hide antennas - especially receiving antennas). However, it's not often seen as a first choice given the above factors. $\endgroup$
    – RQDQ
    Commented Dec 17, 2013 at 16:39
  • $\begingroup$ Why horizontal? As you noted previously, "Don't worry about polarization. At HF most of your signals will arrive via the ionosphere which is constantly swirling and changing the polarization of received signals. Whatever polarization you pick, it will be the wrong one in 30 seconds, so don't worry about it." $\endgroup$
    – K7AAY
    Commented Dec 17, 2013 at 16:56
  • $\begingroup$ Right, so why specifically recommend a horizontal antenna? With no explanation for why you are making these recommendations, I don't think this is a very good answer. $\endgroup$
    – Phil Frost - W8II
    Commented Jan 16, 2014 at 21:40
  • $\begingroup$ A horizontal loop would be omnidirectional in azimuth, no? So not needing to point it is one less thing to worry about? Fits the OP's "simple" criteria. $\endgroup$
    – bcattle
    Commented Sep 16, 2016 at 8:05
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For receiving horizontal antennas pick up a lot less manmade noise than vertical ones. So if I were you I'd try to put up a horizontal one.

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  • $\begingroup$ yes but tuning is pretty hard if you only have a receiver. With a transmitter and an automatic antenna tuner you mostly only need to push a button. $\endgroup$
    – ON5MF Jurgen
    Commented May 3, 2017 at 18:42
  • $\begingroup$ I forget the audience here. (They say half the world's population is now under 30 years old) We didn't have any of that when I learned radio. You can tune an antenna by listening to the noise. But your point is still good about horizontal being better. Besides, for casual listening it makes more sense to string a wire than to set up a proper vertical. $\endgroup$
    – SDsolar
    Commented May 4, 2017 at 1:11
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I'd say, if you plan on putting it in the attic /loft, then figure out where your wiring is, and in what orientations, and let that dictate the size and orientation of your antenna. Smaller might be better if it means you avoid closer interactions with noisy wiring.

Most of my wiring runs horizontally EW along the loft and vertically down the house, and my lowest noise loft antenna was NS along the inside of the roof (actually at a diagonal) therfore at eight angles to most of the closest wiring.

I put a horizontal wire in the garden and it picks up more local noise, probably due to orientation relative wiring in to the houses around...and the huge number of dishwashers and washing machines generating the noise.

My property is small. All my antennas are tuned or loaded. The best receive I eve had though is on a small tuned loop. You can null out a particular source of noise, and it's pretty narrow bandwidth. You can make one out of cheap stuff if you're not planning to transmit.

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The "LoG" or "Loop on Ground" is a simple antenna to get you going. http://www.kk5jy.net/LoG/?fbclid=IwAR0dDk21M6XqZg7IwQ5NE7ggmS5Ux6Ivc_-_gtSZpE9Qbeu4EB9h5T4NGyU

Like you, I have limited space in my yard, so the LoG works out nicely at a perimeter of 60 feet.

You don't have to build the transformer yourself, as Black Cat Systems makes one for receiving already: https://www.blackcatsystems.com/rf-products/cyclops_rf_ham_shortwave_radio_matching_transformer.html. Chris at Black Cat is a Jedi Master of HF receiving antennas and can get you squared away.

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