[A ham friend of mine recently asked me for the details of how I use my rain gutter and downspout as an antenna. I originally did a write-up on it in 1994. That article found its way into several ham radio publications and newsletters. Most of the original article is still relevant but I have made some changes in the way I feed the “antenna.” So, here’s an updated description of my Downspout Antenna. – WB3GCK]
After years of trying to come up with a good way to get on the HF bands from my little townhouse (without attracting a lot of attention from my neighbors), I started experimenting with using my aluminum rain gutter and downspout for an antenna. The results have been surprisingly good. In fact, it has turned out to be the ultimate low-profile antenna!
The downspout has a vertical run of about 16 feet, connecting the horizontal rain gutter which is about 16 feet long across the front of the house. Including the feed wire into the shack, the total length is in the neighborhood of 42 feet; over a quarter wavelength for 40 meters and almost a half-wave for 30 meters. The house is made of brick, so the entire system is isolated from ground.
I use my downspout like a random wire antenna, using a commercial autotuner (or internal tuner, in the case of my KX3). I feed the antenna through a homebrew 1:1 unun. I use a short run of coax between the unun and the autotuner on my operating table. A length of #22 stranded hookup wire is used to connect the output of the unun to the downspout outside.
To connect the wire to the downspout, I first sanded the downspout and connected the wire using three sheet metal screws. I used multiple screws to help ensure a low resistance connection. After making the connections to the downspout, I sealed them up using an adhesive/sealant called Goop. Goop is available at most hardware stores.
With the downspout behaving essentially like an end-fed wire, it really helps to work this type of antenna against a good ground. Fortunately, my basement operating position is only a few feet away from where the water supply pipe enters the house. I used a piece of 1/2-inch copper pipe as a ground bus between my operating position and the incoming water pipe. A tinned copper braid strap and a couple of ordinary automotive hose clamps were used to connect the bus to the water pipe. A short braid strap connects the ground stud on the unun to the copper ground bus.
For good measure, I attached counterpoise wires to the ground stud of the unun; one each for 40, 30, 20, and 15 meters. The counterpoise wires are made from garden variety stranded hookup wire cut to a quarter-wavelength. I just run these wires around the shack, hiding them under the rug. Operation on the 80 meter band has been successful using just the ground bus.
How well does it work? During the first few months of operation, I worked 49 states; all with 5 watts or less. I’ve also worked a bunch of DX stations (though I’m more of a casual rag chewer than a DX-chaser). The length of the “antenna” is somewhat short for 80 meters, but performance on that band has been a big surprise. Signal reports on 30 and 40 meters, my primary bands, have been consistently good. In fact, the downspout has been my main antenna at home for more than 20 years.
While this arrangement has served me well, it is not without an issue or two. I find that it helps to clean up and re-do the connections at the downspout periodically. Typically, I do this maintenance every other year or so. Also, I have noticed that my local noise levels on 80 and 40 meters have steadily increased over the years. I attribute this to the proliferation of electronic gadgets both in my house as well as my neighbors’ houses. Those bands are still usable, though.
Some words of caution are in order, however, if you plan to use your rainspout as an antenna:
- Make sure your gutter and downspout are isolated from ground.
- Make sure there is solid electrical continuity between the various sections of your downspout and gutter. Mine are fastened with pop rivets (not the greatest for RF work, but they appear to be doing the job.)
- Watch your power. I wouldn’t recommend running a kilowatt into your rainspout. Ham radio is fun, but not worth burning down your house.
- Make sure people and pets won’t come in contact with the “antenna” while you’re transmitting. This isn’t too much of a problem at QRP power levels, but be careful.
So, if you find your HF antenna options are limited by either space or legal restrictions, take a look at the outside of your house. There just might be a free multi-band antenna hanging out there!
72, Craig WB3GCK
WB3GCK QRP Amateur Radio 
Hi There,
It was a good idea for guys who are restricted and no space in the ground or so. Thanks for the idea !
Hope this will be a hit for some !
Kindest Regards! 73!
Leonard Fernando.
4S7LF
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Craig :
I finally got around to trying this idea of using downspouts/rain-gutters as an antenna at home.
I have a two story house that is about 25 feet across the back and about 50 feet long and my gutters form a horizontal U shape, with two downspouts at the back. So, assuming good electrical connections (hard to tell) I have something that looks like a T-antenna with the flat-top folded forward into a U and an extra vertical bit. I followed your advice of feeding it with a short length of coax to a 1:1 Unun and I am using 3 x 50 foot radials plus a ground rod and a connection to a cold water pipe (house plumbing is all copper). In a couple of hours of very casual operating in the ARRL 160m contest I worked 25 stations, most on the first call, with me running 5W! I don’t have space for a “real” 160m antenna so this gets me on that band. FWIW, I find it quite noisy on RX on the lower bands so I am using a Loop on the Ground as an RX-only antenna and the combo seems to be working pretty well for me on 160m QRP.
For not a lot of effort, I am very pleased with the results. I can get a good match from 10m through 160m so now I have a backup antenna, in case my other antennas fall prey to ice storms over the winter (if the rain-gutters fall off the house I have bigger problems than antennas ;-o )
Cheers
Michael VE3WMB (Polar Bear #19) Grrrrr…
P.S. I modeled this in EZNEC (purely speculative assuming all the aluminum is well bonded) and it shows that most of the current on 160m would be in the vertical downspout I am feeding, as well as the 25 foot horizontal run across the back of the house, making a 45 foot inverted-L. The two 50 foot horizontal runs along the side of the house seem to be acting mostly as loading on this band.
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Glad to hear your gutter antenna worked out for you. One of the major downsides for me is that it’s close to the house. As a result, I also have noise issues on the lower bands, with 40M being the worst. Good luck with your new “antenna.”
72 & GRRR, Craig WB3GCK
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Craig :
I too find it noisy on the low-bands, especially. I am using a TS-590SG at home and it has a separate RX antenna port that takes care of RX/TX antenna switching inside the rig. I laid down a LoG (Loop on the Ground) RX-only antenna in the backyard about a month ago and now don’t know how I ever lived without it.
http://kk5jy.net/LoG/
Our local club has an 80m SSB net on Sunday mornings and for the first time I am able to hear everyone checking in. On my 80m inverted-L, background noise tends to run from about S5 to S9+. The LoG gives me about a 5+ S-unit improvement in S/N, which makes a huge difference on 160m through 40m RX.
Cheers
Michael VE3WMB
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Hi Craig – Thirty-odd years ago I used a two story aluminum downspout at an antenna-hostile site. I don’t know if it was connected to the gutter. I drove a 4 foot steel mast section into the ground under the downspout so it would stay damp. It loaded up just fine on 20M with an L-network but was difficult on other bands, so I laid in three radials, as long as possible (actually not very long), and connected them to the ground stake. There was no appreciable change. Judging by its performance on 20M (I’m guessing it was close to a quarter wave), the ground stake was probably sufficient, but another tuner configuration may have tuned the other bands. Then it was time to move…
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BTW – Your feedpoint maintenance issue is likely due to aluminum in contact with copper in the presence of water. That invites galvanic corrosion.
Cut your feedpoint maintenance by using a stainless steel screw, four stainless nuts, and four stainless internal toothed lock washers.
Put a lock washer on the screw, then feed it from the inside of the drain pipe out through a hole.
Put another lockwasher over the protruding screw, then securely tighten a nut on it. (Lock washers give a good low-resistance “bite” through anodizing, oxide, or finish on both sides of the metal.)
Then put a second nut on it, snug it slightly, then back it off two or three turns. Put another lockwasher on the screw, then the lug, then a fourth lockwasher, and then the fourth nut.
Position the lug so the wire exits upward. That reduces water infiltrating the wire strands.
While holding the third nut with a wrench or pliers, tighten the third and fourth nuts against each other, squeezing the lug. Don’t tighten the second and third nuts against each other. Leave a gap wide enough between the lugs and the downspout that can’t be bridged when they’re wet.
Don’t try to seal the joint, as that traps moisture in it to do its “dirty work.” Let the joint dry out.
It’s expensive, but there are very good reasons for using stainless steel hardware outdoors!
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Thanks for the tips, Ken. Where I feed the downspout, I can’t get inside to insert a bolt. I’ve been using stainless steel sheet metal screws and external toothed star washers, and the connection has been holding up well for quite a while now 73, Craig WB3GCK
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