HAM RADIO: The Doublet Antenna & Ladderline

My 88ft Doublet + big old Dentron Manual ATU is the stalwart of the home antenna set-up! It's been down through summer while I've been away working but it's going back up this week. They just work, oh and they're tuff as old boots, cost next to nothing to make/repair, can be zig-zag'd round to fit almost anywhere and don't draw too much attention! I'd say anyone looking for a multiband HF antenna should give the doublet a whirl first as last. (PS) Top tip buy the biggest manual ATU you can find/afford it will last several lifetimes, never loose money and tune a wet bootlace! 73, Tom.

Well explained! My first 160 or so DXCC countries were worked using a 102' doublet. While I've since used a doublet fed with 450 ohm twin-lead, that first one used 2 runs of RG8x in parallel . At the top the 2 shields were soldered together and the 2 center conductors went to the 2 doublet legs. At the bottom the the shields went to tuner and radio ground and the two center conductors went to a 4:1 balun. A 2:1 would have been better since the Z of the lead-in was 100 ohms. The advantage of this arrangement was that the feedline could be laid on the roof, run across metal window frames and lie against tower or mast metal with no adverse effects. It worked very well!

HEAR HEAR ! I've been a ham since 1972 and my favorite part of the hobby is antennas and the magic they do ! my last antenna was a 160 meter loop fed with 600 ohm up an average of 80 feet and in the shape of a hexagon , I was blessed with very high soil conductivity well beyond the Fresnel Zone. My favorite reports were things said like "that K9TRQ is definitely running illegal power" lol

In my experience over many years of Portable Operations afield, a Doublet remains my favorite antenna. Half-wave End-Feds are easier to deploy, but for best results, doublets.

Thank you for this Tim. I found it a very helpful explanation of the principles so will approach making the doublet with a little more confidence :)

I have been a ham since 1959 and loved every minute of it. My favorite part of this hobby is experimenting with various antenna set ups. I want to share a phenomena I have consistently encountered with a Windom antenna. My set up is a feed point at 1/3 of its total length and feed with 300 ohm Twin lead and an ATU, (cut for 80 Meter band). With the Antenna at a height of 7 to 9 feet off the ground I consistently got 5/9 signal reports (many with 30 to 40 db over S9), and I was running only 75 to 90 watts output. The big signal usually occurred for stations 75 to 200 miles from me both day and night time. Best 73s every one.. The old Elmer Frank WA2NRC

This presentation evoke great thinking. So, I appreciate it, very much.

I just picked up a MFJ-962D manual tuner just my Doublet project. Great video thank you.

I've used a doublet antenna fed with ladder line for 50 years, and it has been quite effective as an all-band antenna--if the tuner can handle the matching. After I bought a NanoVNA, I discovered that there were several frequencies in the HF range at which the impedance presented at the tuner was almost exactly 50-ohms. I currently have a roughly 175-ft doublet fed with about 70-ft of home-brew 400-ohm open-wire line. I discovered this antenna/feedline combination yielded a 50-ohm load around 4.4-MHz. I did some quick calculations and added wire to the antenna to move the 50-ohm frequency down into the 75-m band where I am most often active. Now I have a perfect match with the tuner bypassed; I only need the 1:1 balun to operate. I mentioned tuner range: I still use the tuner for the other bands, but it would not work on 10-m. I swept the 25-30 MHz range and found another 50-ohm impedance at 29.5 MHz. I could have added more wire to move the "resonance" down to the 10-m CW/digital frequencies, but that would also change the 75-m frequency. I experimented instead with a couple of "patch cords" of ladder line added at the shack-end of the feeder. I found that a 2-1/2-ft section of feeder moved the 50-ohm match frequency right to the FT-8 frequency. This allows me to run FT-4/8 without the tuner. So, although the doublet is a good mult-iband antenna, a little experimentation and the right instrumentation can make a doublet/feedline combination into a very effective single-frequency antenna, too.

Wonderful and exciting information. Thanks Tim

Another informative video Tim, thanks very much 👌👍👌

Amazing antenna and amazing video. So easy to follow.

Hi Tim. Very much in agreement with open lines. My experience of years experiencing doublets loops and many more. There is no doubt that we were not the discoverers but we were some good experimented users. I have seen some of the videos you have and they are very good, very well explained and with good content, thank you for that. I think I have read each and every one of the excellent Cebik articles and with a lot of useful information, great job recommending them. Greetings from CX Tierra Ed.

Well presented information, well done. Beware that one of the references in the comparison is "open wire" which is usually wider spaced and with less dielectric than the 450 ohm feeder. I did previously use home made open wire but have now gone the easier route of using 450 ohm ladder line. For operating convenience the ZS6BKW is worth a look, it offers a reasonable SWR on a number of bands for those times you may not want to use a tuner. A common mode choke type balun is obviously advisable.

Thanks for the video, you do an awesome job with this. You're a natural! Best 73 and DX!

Another great video Tim... cheers

Thanks for sharing your insights 👋

Last year I left my 80m OCFD for a 160m doublet. My goal was to have an antenna that would function on as many bands as possible from a single feedline into the shack. The doublet is it. Sure it's a compromise antenna as so many are but I no longer have a common mode issue in the shack as I had with the OCFD and I've noticed a remarkable improvement in overall operation and again nothing hanging around inside like before. Thank you for your video and hope to catch you on the bands sometime, KD5BFF.

Nice Video Tim, some great information.. :) you can see your teaching qualification coming out here.. brilliant

excellent video and explanations sir.