Short Portable 8-Band Doublet Antenna - Just 25ft Long

Here is a demonstration of how a short Doublet Antenna can be made to cover frequency bands much lower than you might expect. Here, Peter G3OJC, shows the results he got from this very compact design erected at only 4m above the ground.
www.hamradiostore.co.uk

[@robzingarelli2609]

I love these "yes, you *can* get on the air from that small space" videos. They're so encouraging, and they show what experimentation can produce. Thanks Peter! FWIW, my current apartment roof antenna is one of those weird 21' ladder line / W3DP 1/4-size things (home brewed of course), and it has brought in all kinds of regional contacts. Can I make sense of how it works? No not really, but that doesn't matter so much because it does work. As you regularly encourage, just try it and get on the air.

[@AndyDoz]

Catchy tune that - just found myself whistling it round the kitchen! I'm just about to experiment with a "stealth" linear-loaded doublet, that shouldn't upset my wife or the neighbours. I'll put a video up on my channel when it's done. Just waiting on a couple of pullies to turn up.

[@gtretroworld]

I actually ran a Doublet as my first ever wire antenna years ago as limited space was a thing.Ideal for a Holiday Home or for that matter anywhere.And as our cycling club always says next time pedal faster!😅 Thanks for sharing 73’s

[@watersstanton]

Many thanks.

[@DonzLockz]

Very impressive, especially for being so short and low.

[@watersstanton]

Yes indeed.

[@Rubedo777]

Thanks Peter… I enjoy your presentations. The doublet interests me, I fancy running it around the plastic U brackets that hold the plastic guttering on the roof. I’ll use little cable ties to sling the cable and I’m sure the neighbour will let me do it on his gutters too… the plans are still in my head but it’s encouraging to see what you do… bit amazing really. As a Ham Radio Operator who isn’t the brightest bulb in the socket specially when doing maths my brain fogs over sometimes and I rely on a retired forces buddy to get his pencil out and draw it, I colour it in with crayons after…😊 I struggle understanding bal uns un uns + impedances ( how did this guy pass… hard struggle + desire ) … I’ve got all the Icon equipment that I bought ages ago plus a nice old Kenwood ATU and I reckon watching your channel has fired a spark up the old coax to get going again, there has been several obstacles in the past that made me go dead wire but hopefully I’ll get reconnected again in the months to come… I’ll need to re educate first… your presentations and approach are really encouraging. Thank you… Does anyone use 6 mtrs anymore Peter? at all ? Anyway. Mind how you go everyone… 73s G0 UVL Wigan 😉

[@watersstanton]

hi there. Good to hear from you. That antenna project should work well so give it a try. As far as I know, I think a lot of six meter operation is on a digital. Shame really, but others may know better than I do. 73 Peter.

[@davem0udb]

Excellent Peter, i’ve got enough 450ohm ladder line to use as a loaded doublet, i’ll give that a try👍

[@watersstanton]

Good to hear Dave.

[@32_bits]

I agree for Xiegu radios and have a G90, it tunes a 3m whip even with no loading coil from 40m to 10m. I am sure it would prob tune a wet dog. Once the radio fixes the swr, the question is knowing how efficient an aerial is and how much power it is radiating?

[@AlexeyDXman]

Nice informative video! I'm also love to ride compact folding bikes on 16"-20" wheel's))

[@chris_debian5368]

Great video, Peter; nice Brompton, too. Chris (2E0FRU)

[@watersstanton]

Thanks Chris but not Brompton. Much cheaper 7 year old Tern!

[@chris_debian5368]

@@watersstanton Looking good, anyway :-)

[@johnsinclair3067]

Rain projected all weekend. Time to build an Agile Antenna and maybe add a couple of loading coil pigtails (110microH and 6ft/2m of wire) to the ends.

[@watersstanton]

Sounds good.

[@billmillar8148]

hi peter , the caravan park i go to, most of the tv antennas have mast head power amps to improve tv signals , hows your tv signal when your on the radio ,,, any interference

[@massimoilduca7903]

Very interesting, is the length of the balanced line mandatory? Why a 4:1 balun? I have always seen 1:1 baluns with the balanced line. Thanks for the reply. have a nice day. (before Brexit I bought many things in your shop in Friedrichshafen.)

[@ronjoseph7973]

Doublets are extremely robust provided you keep the window line away from large metal objects such as poles, roofing, gutters, patio covers, etc. I use a 90’ doublet about 20’ in the air in my 30’x50’ garden. I can tune 80,40,20,17,12, and 10 meters. Using 100 watts, I have no problem talking to just about every State in the USA and country in North America. When band conditions are good on 10 meters I have no problem reaching Europe and occasionally Japan and Hawaii. They are extremely easy to make and maintain. I prefer 450 ohm window line and 1:1 choke balun with 15’ of LMR 240 going into my Yaesu FT-840 oldie but goodie.

[@watersstanton]

Thanks for sharing that Ron

[@m1cxf]

Have you ever made a doublet using speaker wire to feed it? Some quite surprising results to be had.

[@watersstanton]

That is very much like 70 Ohm balanced line - it works but is lossy.

[@phillipbrotheridge7740]

Hi Peter. I don't have any 450 ohm ladder line, but I do have some 300 ohm and a 4:1 balun. Would using 300 ohm cause me any problems. Thanks

[@watersstanton]

300 Ohm is fine.

[@phillipbrotheridge7740]

Thank you Pete

[@m7trsradio]

Great video Peter. I have a doublet in the attic i think its deaf. Mine is about 7.3m each side. Mine goes straight into my Chinese tuner. Would it be better with rx if i use a 4:1? Might be tempted to try and cut it to 7+m total and see if that help. Mine seem deaf on 40m and 10m but ok on 20m 73

[@watersstanton]

If the tuner has a balanced connection for balance line, the you should not need a balun. If it is designed for coax the you most certainly fo need a balun. The test is to see what VSWR your transceiver is seeing between tuner and transceiver.

[@m7trsradio]

@@watersstanton thank you Peter I will have another look at it it been up there about 2 weeks but not had a lot of time with it. Thanks for the feedback. Great work. Motters M7TRS 73 👍

[@ehayes5217]

Vry interesting antenna & tnx for posting; since u & I both have an IC-7300, I wonder how that ant wud work with that rig's internal AT? Moreover, if matching was a problem, perhaps reducing RF out to QRP level wud help🤔 always enjoy ur great vids & 73 de WA4ELW in TN 🇺🇸 dit dit 😃

[@watersstanton]

The IC-7300 tuner will not handle the antenna, you would need an external one.

[@butchdingle1000]

Emergency compromise antenna for CW or FT8... But if your going to put up a doublet put one up. Educational as always Peter 73.

[@benjaminon5bgo636]

Thanks once more for your explanations Peter. A small drawing would be really useful to non-full-english people. Is 25ft the total wire length ? Is it 8ft for the ladder line ? and which is the heigh above ground of the 4:1 balun ? Many Thx Peter. 73, Ben - ON5BGO

[@watersstanton]

Yes those dimensions are correct.

[@Inkling777]

@@watersstanton I'm a native English speaker, and I faced the same problem Ben faced. Words can be ambiguous. Never assume your listeners know what you know. How long is each leg of the doublet? Just tell us or better yet show a diagram. And don't talk vaguely about 25 feet, which may or may not be the antenna length plus the ladder line length. Also 8 feet of ladder line may be too short for many locations. Does that matter? I suspect it doesn't, but the wrong feed line length can cause issues as the impedance at the feed depends on it.

[@StreakyP]

Not far off a quarter size g5rv 😋

[@jeromegrzelak8236]

You need a Brain Bucket when your riding that bike wou abt bike mobile kg6mn

[@forgetyourlife]

The vast majority of vehicle injuries are head injuries. I suggest the same for you.