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.
@goinghomesomeday1 fwiw I have the SPC3000D, the rollercoil is a bit wimpy but have only got it hot once. (at far less than 3kW). Very good tuners though. The 300 is a better looking device than the 3000.
My doublet is 102 ft( shhhsssss, She's a old g5rv that I threw away the coax and ran it as doublet.) Works fair on 75m and tunes the rest. 1.2 swr at 6.889Mhz.
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.
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
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
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.
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!
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.
Thank you very much for your encouragement and I agree with you about doublets and loops. So versatile and easy to construct. Thanks again for stopping by and commenting 73
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.
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.
Good video Tim....never looked back from the day I built my doublet 2 years ago....56mts long fed with 450ohm ladder line. The ladder line terminates at a 1to1 current balun on the window sill of my shack...from that its 50ohm coax through the window frame to my manual MFJ 941 tuner 18ins away inside the shack. Lets me tune and get out well on 160m plus 80/60/40/30/20/17/15/10/ and amazingly 6m. To me its the onlt antenna req....its in a Z config to fit inside my plot.
John Portune W6NBC has done a bunch of tests on ladder line and find little problem with it running close to metal siding. He showed you can even burry it in the ground using plastic drainpipe with little loss. AD0TJ
Good advice Tim. Updating antennas here so ordered a 102 foot doublet (basic multi band) from DX Engineering with 450 ohm ladder line and was wondering about a 1:1 Balun. Will build one with grandson as a project. 73.
My first real success was a doublet that was 65 feet long, with 300 ohm open wire feed at about 25 feet in the air. The tuner was a Johnson Matchbox. My setup was to use a coaxial switch with the xmitter as the common and a cantenna on one pole of the switch and the Matchbox on the other. First, on the cantenna (50 ohm dummy load), Dip the final current at the xmitter, then flip the switch to the matchbox and then Dip the SWR. It could be done in a few seconds, and I used it successfully from 80 to 10 meters. This sequence (for those with little experience) got the transmitter output tuned to 50 ohms on the 50 ohm dummy load. Next, the Matchbox matched the doublet to as close to 50 ohms as it could come. This system worked so well, it was difficult to believe.
Hello Tim, I use a cobra doublet, with a ladder line mounted in the centre using 2x 3mtr wooden mast supports o convienience of non conduction I then terminate this in the shack to a mfj 4:1 balun, which then runs through a AT180H auto tuner, an I find it very flexible for band coverage,. I find the ladder line easy to handle, in fact once the feeder comes off the mast to he shack mounted on support poles, my garden allows me to put this antenna straight out., and once it gets back to the shack I bend it and use 30mm water pipe to gain access for easy maintance
220 foot doublet with 180 feet of 300 ohm ladder line. Into the shack through PVC pipe. 4:1 balun on the floor. Short piece of RG-213 into my MFJ-998 auto tuner; 160-10 meters is simply great. NEVER NEED ANOTHER HF ANTENNA! It even does 6 meters with my IC-7300 internal auto tuner. W6PDL
You should use a proper balanced ATU with a doublet, to get most power from the transmitter into the antenna, and not an ATU that has an internal 4:1 balun. Feeder radiation from a doublet is possible, if a proper balanced ATU is not used. Most doublet ham antenna installations are far from ideal, due to antenna height restrictions, nearby building obstructions and difficulty in getting the balanced line into the shack to a balanced ATU. So there will be some induced RF losses because of this, and they will be greater the higher in frequency the doublet is used. From my own my experience with just 10W to a 100ft doublet on 80 and 40 in good NVIS conditions, a signal of 59+ 20 should be possible with stations well over a few hundred miles or so quite easily. Yes just 10Watts!
I suspect that if you use the same lengths as the optimum lengths of the random wire antenna, you will not have any problems with tuning the doublet. Doug VE3MCF
Great ideas. At 10 min 20 sec you said 1:1 balun. Wouldn't it need a different ratio to match 50 ohm coax to 400 ohm ladder line ? I am still low on the learning curve and really enjoying your channel!
No problem! The 450 ohm ladder line would transform the impedance and suffer little loss with high SWR. What it won't do is just have 400 ohms as the impedance. So, to give the tuner a chance to handle the wide range of impedances across all bands the first step should be to use a 1:1 balun to avoid over reducing impedances to low numbers which some tuners will struggle to match. If the tuner struggles on one or two bands then you can either add or trim the ladder line length or try a 4:1 balun. Doublets can be trial and error, but once set they are a very good multi band antenna. 73
Using a doublet, works great, 15 m each side, the last 5m on each side goes down 45 degrees ( to suit the property ),it tunes well all over the bands, great cheap antenna. Now trying to get a vertical attached the same way, ie, inverted v with one leg up in the air ( 10m in my case ). 73 and thanks for the video
Your most efficient doublet will be with any with even 1/2 wave length increments in length and fed by a 1/2 wave of ladder line for your lowest band. This prevents significant radiation from the feed line. Of course you want the antenna height at 1/2 wave above real ground for your typical doughnut radiation pattern to form and multiple lobes on the higher bands. A balanced ATU is the best to use with this antenna.. Best 73s WA2NRC
Hey Tim quick question for you have you ever used a reflector wire on a doublet? Where the reflector would be mounted close to the ground just below the inverted V. And have you also used the director essentially making it a wire YAGI
Agree with you and other hams like Cebik. There is a another linear loaded antenna the Cobra. it can be made with ladder line spanning a total of 12 meters. M0PTZ made one and is only 1 db down to a full length dipole on the cut frequency 80 meters i suppose. Just cut 20-21 feet of 450 Ohm ladder line fold each side 3 times on itself and you get a full length antenna on 80 meters.
Very good video, I am using ZS6BKW and it covers 80m with the automatic tuner. The antenna is not very large and fits nicely my urban lot when installed on a 12m spiderbeam. 5-10W on FT8 gives me pretty much global coverage.
I have tried many size doubles i find the best size is just a bit short or just a bit longer than 1/2 wave on the lowest band . I find more important than length, is try to get it out in the clear and symmetrical, not always easy ? But in the clear and symmetrical as pos . I am a big doublet fan ! I am lucky enough to have the space for a large and medium size doublet 70metre (230 feet )and a 39 metre (128 feet ) both work great . I concur with your findings .
Is there a preferred method of creating a quick-disconnect connection between the coax and the transceiver? Thanks for all the great antenna videos you create! Lots of practical info.
For HTs, I’ve seen people use BNC, with adaptors if need be. Easy on and off, eg for hooking up in the car. I’m just getting into HF so I’m not sure about that, not sure you couldn’t also use BNC though?
I don't know if it is right, but I have my ladder line coming into the shack via separate holes in the wall and then into a good sized knife switch. Line continues on into a auto tuner. I don't know if the switch is good enough for a lightning strike but probably okay to protect from static buildup.
Hi Tim. I am curently making a doublet of 20 meters 10 meters per side so a half wave on 40m, so it should work 40 and up. I have a few questions though. When you say laderline should not be a multiple of a halfwave on any of the bands I dont understand what you meen by a multiple. Could you elaberate on this for me please and give me a rough length to cut my 450 ohm ladder line to for a halfwave on 40m doublet. Also what ballun should I have at the end of the ladder line 9:1 or 4:1? my tuner a LDG Z11 Pro 2 only has so-239 sockets, so need to run a balun before it as I cant feed the lader line directly to the tunner, also it will be in a loft so only laderline in the loft to a balun into the tunner (In the Loft) and then a coax feed of about 25 feet to the shack/bedroom. Sorry for the questions 73 Nathan 2E0LIG
Hi Nathan. My advice is to feed it with the length of 450 ohm required and then see. The thing I would suggest is to use a 1:1 current balun as a 4:1 might reduce the imepedance below what your tuner can cope with. A 9:1 is similarly not advised. 73
I'm a fan of the doublet but have come across the ZS6BKW an antenna that's very easy to match to your radio it's bent in a weird m fashion but works ok perhaps you could do a video on that as well unless you have done so and I missed it
I have a zs2bkw dipole 95 feet AGL flat top. It's a flame thrower on 40 through 15. Almost as good on 20 as my hy gain 203 3 element mono bander up at 40 feet. Sometimes the zs6 does as good or better in certain directions
I'd like to build a doublet for 80 meters and above. But, I live in Arizona, and the trees just don't go much about 20 or 30 feet. So, can you run ladder line straight down and then along the ground? I'd also like to terminate the ladder line into coax before entering the house. Is that alright if you have a balun or choke on the coax, and you keep it short? Thanks! Rick W0SKI
Hi Rick! Unfortunately you can’t run ladderline along the ground as this would cause it to become imbalanced and radiate ... causing you big issues in terms of rf in the shack. You can terminate it into a 1:1 current Balun and then a short as possible coax run to a tuner 73.
@@paulsengupta971 depends on the impedance Match. Some tuners find it harder to match low impedances.. which is what a 4:1 might provide. In my experience 90% of the time a 1:1 provides a better match.
Tim, I recently did some doublet maintenance, remaking connections and looking for any broken wires. After putting everything back together, I wondered how important it is to have all connections the same width as the 450ohm window line itself, say 1 inch. My connection point screws are 1 inch apart, but I wrapped the stranded dipole wires around the screws with a washer below and above, then threaded the nut and sandwiched the wires between the 2 washers. My question is, the distance betweens the washer edges is more like .5 (1/2) inch now. Will this affect the antenna operation in any way, in your opinion? I hope not. It seems to be working well, as before but may be a tad more sensitive to tune w my manual open wire line balanced tuner. Thanks
@@timg5tm941 well, the window line and dipole wires are on the same threaded stud, so the washer dimension of approximately 1 half inch brings everything together, even though rhe stud/posts are 1 inch apart. I can draw what I mean or if unclear, drop the antenna and take a photo sent to your email. Sorry but it's hard to describe. 73
Hi Tim,iam making a 102ft doublet now BUT going to put it at the top of my 12m steel crank up mast which is attached to my house so the legs will run straight down the garden but worried how to run my ladderline straight down without it interfering or touching the metal?? Sorry but racking my brain over this any ideas?? Thankyou
@@timg5tm941 hi Tim yes I did that but too much interaction as could only get an angle of around 40° between the legs so took it down n put the cobweb back up :)
Hi Tim, is it possible to have a doublet without having an external antenna tuner? The radio has a tuner built-in but will only accommodate a 3:1 SWR - Thank you in advance for your time and response
what would happen if I only used a few feet of ladder line in an attic antenna and went to a 4:1 Balun then ran coax from the attic to my tuner and radio?
Ladder line = Don't use a multiple of any half wave? So what lengths should be used? Do you have examples of what should be used? This is what puts me off building a doublet..always feels like dabbling in black magic. The other problem is, you do an Internet search on constructing a doublet you are given conflicting information ie 'combinations of feedline electrical length plus one leg of the radiator that are odd multiples of an eighth-wavelength' what? I am completely baffled. 😂😂
Great video Tim. How does the doublet compare to a 80m ocf dipole using either a 6:1 or 4:1 balun. I presently have a 80m ocf dipole with a 6:1 balun with the longer leg running up the garden then back down, then the shorter leg going down the garden so it covers nearly all points of the compass
Shouldn’t think there’s a lot of difference. I’m just wary of the enhanced probability of common mode with Ocf dipoles but if you can tame it then good on you. 73 and thanks for stopping by and commenting 73
@@timg5tm941 That's one problem I do suffer from is the common mode to an extent, however I am slowly getting to grips with it. I will try the doublet antenna and compare the two
I would struggle to get ladder line into the shack but was wondering could you use ladder line for the legs of a fan dipole with a balun say for 40 and 20? 73
@@timg5tm941 When the cold dark nights set in I will be reading, still got an aerial problem to get round though! I would struggle to get down there on 10 watts though, unless there was a lift on.
One con you don't mention is that a balanced tuner is expensive. A ZS6BKW needs far less tuner the comparison in AUD is like $190 for a manual MFJ tuner to tune a ZS6BKW. The cheapest balanced tuner from the same store is $495. Thanks. Shane VK1NME.
You can, in theory, but I’d be mindful of creating an unbalanced antenna fed with balanced feedline and the likelihood of increased common mode into the shack
Hi Justin it can be bent as long as the angles don’t fall below 90 degrees. Check out an earlier video I did last year on the 80m doublet for proof. 73
Great video Tim. You convinced me to build a Doublet. I have no experiences with ladder-line. Is it a problem to lay it on the ground? Or should I raise it with some plastic tubes? 73, Stephan, DF6PA
Not quite. It relies on a precise length of ladderline to match it on certain frequencies. The issue with a G5 for some is that the coax run from the ladderline to the radio can lead to considerable losses especially on higher HF bands such as 15 and 10m. If you either use a short few feet of low loss coax between a 1:1 Balun and tuner or ladderline all the way to a balanced tuner you would negate so much of these potential losses. The G5 works much better if the coax run from ladderline to radio is a short one. 73
@@timg5tm941 Dear old G3FCM used to describe the G5RV as a wire dummy load. It matches on the bands, but doesn't radiate very well (compared to a resonant dipole).
@goinghomesomeday1 for some reason and i have to admit i have not put much effeort into it right now the half size G5 made with flexweave is much harder to tune will not tune on 17 mtrs at all and objects to 40 mtrs also does not perform as well the hard drawn copper one on the other hand and they are identical sizes you can lay them, on top of each other to with
in about 3 mm they match the hard drawn one tunes no problem on 17 meters works a treat on 40 mtrs works reasonably well on 60 mtrs even 80 mtrs is useable and this is using an MFJ 954E at Yaesu FC757at or my favorite tuner the LDG Z100 best one of the lot
It's easy enough, two equal lengths (or even unequal lengths will work!) of wire fed by ladder line into a tuner, as long as the tuner has a wire input. That's about it. If the tuner doesn't have a built in balun, add a 4:1 balun externally at the end of the ladder line.
An awful lot of wild claims made about this antenna, and why would you want to string up a heavy piece of co-ax rather than a much lighter piece of wire ? owenduffy.net/blog/?p=1941
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.
Spot on Tom!!
@goinghomesomeday1 fwiw I have the SPC3000D, the rollercoil is a bit wimpy but have only got it hot once. (at far less than 3kW). Very good tuners though. The 300 is a better looking device than the 3000.
@goinghomesomeday1 Same here... fantastic bit of kit!!
My doublet is 102 ft( shhhsssss, She's a old g5rv that I threw away the coax and ran it as doublet.) Works fair on 75m and tunes the rest. 1.2 swr at 6.889Mhz.
Do you find it better as a doublet Frank?
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.
Great job - it is hard to match the doublet for multiple bands and simplicity of design and performance.
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
Ha! Sounds a great antenna 73
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
Great information Frank, thank you 73
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.
This presentation evoke great thinking.
So, I appreciate it, very much.
Thank you for your kind comments.
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!
Cheers!
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 :)
Kept watching today again.
Really good reminder 😊
Many greetings,
Matthias 👋
DL1NDG
Thank you! Cheers!
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.
Thank you very much for your encouragement and I agree with you about doublets and loops. So versatile and easy to construct. Thanks again for stopping by and commenting 73
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.
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.
Great to hear the doublet works well for you.
Good video Tim....never looked back from the day I built my doublet 2 years ago....56mts long fed with 450ohm ladder line.
The ladder line terminates at a 1to1 current balun on the window sill of my shack...from that its 50ohm coax through the window frame to my manual MFJ 941 tuner 18ins away inside the shack.
Lets me tune and get out well on 160m plus 80/60/40/30/20/17/15/10/ and amazingly 6m.
To me its the onlt antenna req....its in a Z config to fit inside my plot.
Thanks Nick they are superb antennas I agree. Sounds like you love yours too 73
Can you share your source or design for the 1:1 Balun? I am getting all kinds of conflicting information. Thanks
Thanks for the video, you do an awesome job with this. You're a natural! Best 73 and DX!
Thank you very much!
I just picked up a MFJ-962D manual tuner just my Doublet project.
Great video thank you.
Hope it works well for you. 73
John Portune W6NBC has done a bunch of tests on ladder line and find little problem with it running close to metal siding.
He showed you can even burry it in the ground using plastic drainpipe with little loss.
AD0TJ
Thanks for sharing your insights 👋
My pleasure!
Good advice Tim. Updating antennas here so ordered a 102 foot doublet (basic multi band) from DX Engineering with 450 ohm ladder line and was wondering about a 1:1 Balun. Will build one with grandson as a project. 73.
Hope it goes well!
My first real success was a doublet that was 65 feet long, with 300 ohm open wire feed at about 25 feet in the air. The tuner was a Johnson Matchbox. My setup was to use a coaxial switch with the xmitter as the common and a cantenna on one pole of the switch and the Matchbox on the other. First, on the cantenna (50 ohm dummy load), Dip the final current at the xmitter, then flip the switch to the matchbox and then Dip the SWR. It could be done in a few seconds, and I used it successfully from 80 to 10 meters.
This sequence (for those with little experience) got the transmitter output tuned to 50 ohms on the 50 ohm dummy load. Next, the Matchbox matched the doublet to as close to 50 ohms as it could come. This system worked so well, it was difficult to believe.
Great info!
Hello Tim,
I use a cobra doublet, with a ladder line mounted in the centre using 2x 3mtr wooden mast supports o convienience of non conduction I then terminate this in the shack to a mfj 4:1 balun, which then runs through a AT180H auto tuner, an I find it very flexible for band coverage,.
I find the ladder line easy to handle, in fact once the feeder comes off the mast to he shack mounted on support poles, my garden allows me to put this antenna straight out., and once it gets back to the shack I bend it and use 30mm water pipe to gain access for easy maintance
Sounds a great set up
Nice Video Tim, some great information.. :) you can see your teaching qualification coming out here.. brilliant
Thanks mate, really appreciate this 73
Great stuff! I’m really getting into this antenna building lark thanks to your excellent videos 👍 73 VK4FJST
That’s great to hear thank you! 73
I’ve actually made antennas with ladder line before. And coax so what’s the point?
Another informative video Tim, thanks very much 👌👍👌
Thanks Ray 👍👍
Wonderful and exciting information. Thanks Tim
Thanks!
Amazing antenna and amazing video. So easy to follow.
Glad it helped - many thanks!
220 foot doublet with 180 feet of 300 ohm ladder line. Into the shack through PVC pipe. 4:1 balun on the floor. Short piece of RG-213 into my MFJ-998 auto tuner; 160-10 meters is simply great. NEVER NEED ANOTHER HF ANTENNA! It even does 6 meters with my IC-7300 internal auto tuner.
W6PDL
Agree !
Confirmed over 150 countries on my 80ft doublet fed through a Palstar balanced tuner. Hope to get one up again someday.
Great example 👍
Nice Video Tim, i am looking to make some ladder line slimjims for 6m, 2m, 70cm i could either hang out the window or from the curtain rail.
Superb idea they work well
Made a 2m one for /p , works great , made a second one for 2m and mounted it horizontal, that works great for ssb
You should use a proper balanced ATU with a doublet, to get most power from the transmitter into the antenna, and not an ATU that has an internal 4:1 balun. Feeder radiation from a doublet is possible, if a proper balanced ATU is not used. Most doublet ham antenna installations are far from ideal, due to antenna height restrictions, nearby building obstructions and difficulty in getting the balanced line into the shack to a balanced ATU. So there will be some induced RF losses because of this, and they will be greater the higher in frequency the doublet is used. From my own my experience with just 10W to a 100ft doublet on 80 and 40 in good NVIS conditions, a signal of 59+ 20 should be possible with stations well over a few hundred miles or so quite easily. Yes just 10Watts!
I suspect that if you use the same lengths as the optimum lengths of the random wire antenna, you will not have any problems with tuning the doublet. Doug VE3MCF
Great ideas. At 10 min 20 sec you said 1:1 balun. Wouldn't it need a different ratio to match 50 ohm coax to 400 ohm ladder line ? I am still low on the learning curve and really enjoying your channel!
No problem! The 450 ohm ladder line would transform the impedance and suffer little loss with high SWR. What it won't do is just have 400 ohms as the impedance. So, to give the tuner a chance to handle the wide range of impedances across all bands the first step should be to use a 1:1 balun to avoid over reducing impedances to low numbers which some tuners will struggle to match. If the tuner struggles on one or two bands then you can either add or trim the ladder line length or try a 4:1 balun. Doublets can be trial and error, but once set they are a very good multi band antenna. 73
@@timg5tm941 Thanks for your reply. Will give it a try !
Using a doublet, works great, 15 m each side, the last 5m on each side goes down 45 degrees ( to suit the property ),it tunes well all over the bands, great cheap antenna.
Now trying to get a vertical attached the same way, ie, inverted v with one leg up in the air ( 10m in my case ). 73 and thanks for the video
Sounds a useful experiment. Glad you’ve found these antennas have worked for you too. 73
che59v...A vertical dipole,fed with window line,would achieve the same results,in addition to having a low takeoff angle of radiation
Your most efficient doublet will be with any with even 1/2 wave length increments in length and fed by a 1/2 wave of ladder line for your lowest band. This prevents significant radiation from the feed line. Of course you want the antenna height at 1/2 wave above real ground for your typical doughnut radiation pattern to form and multiple lobes on the higher bands. A balanced ATU is the best to use with this antenna.. Best 73s WA2NRC
Thank you Francis
My 102 ft doublet is old g5rv at 33 ft that I threw away the coax and ran it with 84 ft of ladder line. 75m to 10m.
Better than the G5RV Frank?
Not sure, as I could speak to origional g5rv.
Thanks Tim! Yes, on the horizontal multi-band wire front, there’s pros and cons with doublets, loops and ocfds. You could do a part #2 & part #3 👍🏻
Good idea!
Another great video Tim... cheers
Thank you Roly 73
Some good information here, I'm looking for the video in which you bring the feedline into your new shack now!
I had issues doing that so eventually reverted back to a Balun solution
@@timg5tm941 I seem to remember that now, thanks for the reply. Mine will come through a wood wall, so I might be lucky... I let you know!
Nice one!
Hey Tim quick question for you have you ever used a reflector wire on a doublet? Where the reflector would be mounted close to the ground just below the inverted V. And have you also used the director essentially making it a wire YAGI
No to both Pat but I’d like to try it
Agree with you and other hams like Cebik. There is a another linear loaded antenna the Cobra. it can be made with ladder line spanning a total of 12 meters. M0PTZ made one and is only 1 db down to a full length dipole on the cut frequency 80 meters i suppose. Just cut 20-21 feet of 450 Ohm ladder line fold each side 3 times on itself and you get a full length antenna on 80 meters.
Yes good old linear loading!
Thanks for the tip. It's M0PZT by the way.
excellent video and explanations sir.
Thank you!
Very good video, I am using ZS6BKW and it covers 80m with the automatic tuner. The antenna is not very large and fits nicely my urban lot when installed on a 12m spiderbeam. 5-10W on FT8 gives me pretty much global coverage.
Excellent. You are clearly making the most of your QTH. Thanks for stopping by and commenting 73
I have tried many size doubles i find the best size is just a bit short or just a bit longer than 1/2 wave on the lowest band . I find more important than length, is try to get it out in the clear and symmetrical, not always easy ? But in the clear and symmetrical as pos .
I am a big doublet fan !
I am lucky enough to have the space for a large and medium size doublet 70metre (230 feet )and a 39 metre (128 feet ) both work great . I concur with your findings .
Totally agree with that Rob 73
Is there a preferred method of creating a quick-disconnect connection between the coax and the transceiver? Thanks for all the great antenna videos you create! Lots of practical info.
Hi and thank you. I do not know of such a thing. Can anyone jump in here and assist?
For HTs, I’ve seen people use BNC, with adaptors if need be. Easy on and off, eg for hooking up in the car. I’m just getting into HF so I’m not sure about that, not sure you couldn’t also use BNC though?
I don't know if it is right, but I have my ladder line coming into the shack via separate holes in the wall and then into a good sized knife switch. Line continues on into a auto tuner. I don't know if the switch is good enough for a lightning strike but probably okay to protect from static buildup.
Sounds pretty workable to me 👍
Can you show us your Bolts though your wall ? I would love to get an idea of what it would look like before I start Drilling.
Great Video Thanks
Video being made about the antenna set up and installation.. stay tuned! 73
Hi Tim.
I am curently making a doublet of 20 meters 10 meters per side so a half wave on 40m, so it should work 40 and up.
I have a few questions though.
When you say laderline should not be a multiple of a halfwave on any of the bands I dont understand what you meen by a multiple.
Could you elaberate on this for me please and give me a rough length to cut my 450 ohm ladder line to for a halfwave on 40m doublet.
Also what ballun should I have at the end of the ladder line 9:1 or 4:1? my tuner a LDG Z11 Pro 2 only has so-239 sockets, so need to run a balun before it as I cant feed the lader line directly to the tunner, also it will be in a loft so only laderline in the loft to a balun into the tunner (In the Loft) and then a coax feed of about 25 feet to the shack/bedroom.
Sorry for the questions 73 Nathan 2E0LIG
Hi Nathan. My advice is to feed it with the length of 450 ohm required and then see. The thing I would suggest is to use a 1:1 current balun as a 4:1 might reduce the imepedance below what your tuner can cope with. A 9:1 is similarly not advised. 73
I'm a fan of the doublet but have come across the ZS6BKW an antenna that's very easy to match to your radio it's bent in a weird m fashion but works ok perhaps you could do a video on that as well unless you have done so and I missed it
I’m planning to have a look at the ZS6BKW for sure
Thanks for the video Tim. One question: does the diameter of the wire play any role? Or is length/height more important? Cheers, Chris PA0TVI
Length and height imho
@@timg5tm941 tnx, I will experiment some more 👍
The loss figures using 450 ohm ladder line are impressive, but to those how much loss does the tuner add?
A decent tuner? Less than a dB depending on how much strain you are exerting on it and how short the antenna in comparison to a 1/2 wave
@@timg5tm941 Thanks.
I have a zs2bkw dipole 95 feet AGL flat top. It's a flame thrower on 40 through 15. Almost as good on 20 as my hy gain 203 3 element mono bander up at 40 feet. Sometimes the zs6 does as good or better in certain directions
Nice height
I'd like to build a doublet for 80 meters and above. But, I live in Arizona, and the trees just don't go much about 20 or 30 feet. So, can you run ladder line straight down and then along the ground? I'd also like to terminate the ladder line into coax before entering the house. Is that alright if you have a balun or choke on the coax, and you keep it short? Thanks! Rick W0SKI
Hi Rick! Unfortunately you can’t run ladderline along the ground as this would cause it to become imbalanced and radiate ... causing you big issues in terms of rf in the shack. You can terminate it into a 1:1 current Balun and then a short as possible coax run to a tuner 73.
Wouldn't you want a 4:1 balun?
@@paulsengupta971 depends on the impedance Match. Some tuners find it harder to match low impedances.. which is what a 4:1 might provide. In my experience 90% of the time a 1:1 provides a better match.
Tim, I recently did some doublet maintenance, remaking connections and looking for any broken wires. After putting everything back together, I wondered how important it is to have all connections the same width as the 450ohm window line itself, say 1 inch. My connection point screws are 1 inch apart, but I wrapped the stranded dipole wires around the screws with a washer below and above, then threaded the nut and sandwiched the wires between the 2 washers. My question is, the distance betweens the washer edges is more like .5 (1/2) inch now. Will this affect the antenna operation in any way, in your opinion? I hope not. It seems to be working well, as before but may be a tad more sensitive to tune w my manual open wire line balanced tuner. Thanks
Hi Mike. Can I confirm that the only change is that the two radiating wires are slightly closer together. So the ladderline is therefore the same.
@@timg5tm941 well, the window line and dipole wires are on the same threaded stud, so the washer dimension of approximately 1 half inch brings everything together, even though rhe stud/posts are 1 inch apart. I can draw what I mean or if unclear, drop the antenna and take a photo sent to your email. Sorry but it's hard to describe. 73
I sent an email photo of a sketch I made of my connections
Have replied 👍
Hi Tim,iam making a 102ft doublet now BUT going to put it at the top of my 12m steel crank up mast which is attached to my house so the legs will run straight down the garden but worried how to run my ladderline straight down without it interfering or touching the metal?? Sorry but racking my brain over this any ideas?? Thankyou
Hi Andy - could you attach some sort of plastic stand offs to the pole - a few inches long?
@@timg5tm941 hi Tim yes I did that but too much interaction as could only get an angle of around 40° between the legs so took it down n put the cobweb back up :)
@@andy2E0JIU ah ok Andy
Would this antenna also work well on 160 meters? Great video and very informative... answered a lot of questions I had! Thank you! 73's
It needs to be about a minimum of a 1/3 wave to have a chance of doing a respectable job on 160 so about 170 feet or more could load up ok on 160. 73
@@timg5tm941 thanks for the reply! Look forward to seeing your future videos!
My pleasure and thank you! 73
So, what do you think of the G5RV antenna and should one put a balun at the latter line to coax interface?
They work for many people. I would put a choke balun there yes - just to make doubly sure you avoid any common mode on the coax to the shack.
Hi Tim, is it possible to have a doublet without having an external antenna tuner? The radio has a tuner built-in but will only accommodate a 3:1 SWR - Thank you in advance for your time and response
Hi pat. It is possible but not for all bands and would need a specific length of ladderline. 99% of the time you need an external tuner.
@@timg5tm941 Well I'm the proud papa of a new MFG 491E tuner, so will be joining the ranks of Doubletiers soon enough
what would happen if I only used a few feet of ladder line in an attic antenna and went to a 4:1 Balun then ran coax from the attic to my tuner and radio?
Yep can be done. Just try and keep that run of coax as short as possible to minimise loss
Ladder line = Don't use a multiple of any half wave? So what lengths should be used? Do you have examples of what should be used? This is what puts me off building a doublet..always feels like dabbling in black magic. The other problem is, you do an Internet search on constructing a doublet you are given conflicting information ie 'combinations of feedline electrical length plus one leg of the radiator that are odd multiples of an eighth-wavelength' what? I am completely baffled. 😂😂
To be honest I just whack it up and go from there
as 450 is a 9 to 1 miss match, would a 9 to 1 balun then be the best choice?
No - see my other reply
Hi there also 600 ohm twin feeder why use 450 and not 600 are there any disadvantage between the two ?
600 is slightly less lossy on longer runs
Great video Tim.
How does the doublet compare to a 80m ocf dipole using either a 6:1 or 4:1 balun.
I presently have a 80m ocf dipole with a 6:1 balun with the longer leg running up the garden then back down, then the shorter leg going down the garden so it covers nearly all points of the compass
Shouldn’t think there’s a lot of difference. I’m just wary of the enhanced probability of common mode with Ocf dipoles but if you can tame it then good on you. 73 and thanks for stopping by and commenting 73
@@timg5tm941 That's one problem I do suffer from is the common mode to an extent, however I am slowly getting to grips with it.
I will try the doublet antenna and compare the two
Will be interesting to see how they compare. Good luck
I would struggle to get ladder line into the shack but was wondering could you use ladder line for the legs of a fan dipole with a balun say for 40 and 20? 73
Yes you can I’ve done the same for 10 and 17
Could it work for a inverted V fan dipole.
Absolutely .. have a look at my fan dipole video from the summer
@@timg5tm941 Cheers I will. 73
Maybe hear you on the waves after you put your Doublet up. Though you won't get a reply (yet).
Look forward to a future QSO Bob 73
@@timg5tm941 When the cold dark nights set in I will be reading, still got an aerial problem to get round though! I would struggle to get down there on 10 watts though, unless there was a lift on.
One con you don't mention is that a balanced tuner is expensive. A ZS6BKW needs far less tuner the comparison in AUD is like $190 for a manual MFJ tuner to tune a ZS6BKW. The cheapest balanced tuner from the same store is $495.
Thanks.
Shane VK1NME.
Yep although a 1:1 current Balun and a short piece of coax between the ladder-line and any auto tuner will work just as well in the real world
I was wondering if you ever use a manual tuner for an end fed half wave antenna or do you only use the tuner for doublets
Hi Pat. The efhw does not need a tuner as it is resonant on the main Halfwave plus harmonics. I use a tuner just for my doublets. 73
hi tim , can you off set the feed point on a doublet ? If so would it effect things cheers
You can, in theory, but I’d be mindful of creating an unbalanced antenna fed with balanced feedline and the likelihood of increased common mode into the shack
@@timg5tm941 cheers mate , ill probably stick to the recommended fed in the middle ,, much appreciated
@@rivit90 you’ll enjoy it I’m sure 73
Thanks KQ4CD Paul
Cheers Paul
@@timg5tm941 on your double
You used ladder line or 4-1 to the shack then 4-1 and a short piece of coax. How long was the double. Or iam just confused
How much ladder line can I feed with doublet how many feet?
As much ladder line as you need
Does it have to be a certain increment of feed line to stay away from ? Some ham operators say it effects the performance ?
Great info thx
Pleasure!
Which the best antenna..GP or dipole antenna
All depends on factors such as how high your dipole is for example.
your normally spot on with your helpful videos, but 2 minutes in and you had lost me completely,
Ah! Sorry.
Does a doublet need to be in a straight line or can you bend it?
Hi Justin it can be bent as long as the angles don’t fall below 90 degrees. Check out an earlier video I did last year on the 80m doublet for proof. 73
Great video Tim. You convinced me to build a Doublet. I have no experiences with ladder-line. Is it a problem to lay it on the ground? Or should I raise it with some plastic tubes? 73, Stephan, DF6PA
Hi Stephan thanks for commenting. You need to keep the ladderline off the ground by at least a few feet and avoid coiling it up. Hope that helps 73
@@timg5tm941 Thanks for the fast reply. Good to know! 73
My pleasure, let me know how you progress with the project 73
Will this work with a built in tuner
Unlikely .. you would need an external atu
so the G5RV is a doublet?
Not quite. It relies on a precise length of ladderline to match it on certain frequencies. The issue with a G5 for some is that the coax run from the ladderline to the radio can lead to considerable losses especially on higher HF bands such as 15 and 10m. If you either use a short few feet of low loss coax between a 1:1 Balun and tuner or ladderline all the way to a balanced tuner you would negate so much of these potential losses. The G5 works much better if the coax run from ladderline to radio is a short one. 73
@@timg5tm941 Dear old G3FCM used to describe the G5RV as a wire dummy load. It matches on the bands, but doesn't radiate very well (compared to a resonant dipole).
Half size G5RV but it MUST BE made with hard drawn copper NOT flexweave
@goinghomesomeday1 well this si from experience and every time i have had the same result as have other people
@goinghomesomeday1 for some reason and i have to admit i have not put much effeort into it right now the half size G5 made with flexweave is much harder to tune will not tune on 17 mtrs at all and objects to 40 mtrs also does not perform as well the hard drawn copper one on the other hand and they are identical sizes you can lay them, on top of each other to with
in about 3 mm they match the hard drawn one tunes no problem on 17 meters works a treat on 40 mtrs works reasonably well on 60 mtrs even 80 mtrs is useable and this is using an MFJ 954E at Yaesu FC757at or my favorite tuner the LDG Z100 best one of the lot
Lost me pretty early. I think ill stick with commercial antennas for now.
It's easy enough, two equal lengths (or even unequal lengths will work!) of wire fed by ladder line into a tuner, as long as the tuner has a wire input. That's about it. If the tuner doesn't have a built in balun, add a 4:1 balun externally at the end of the ladder line.
zs6grv " suffers from the creator not being born in England " you know its better and smaller
ZS6BKW - tends to be better on 40. But the G5RV tends to sing on 20. Both antennas are also good and not so good on a mixture of the higher bands.
@@timg5tm941 yes that's what it was designed for , the fact the g5rw works on other bands is lucky ?
How about a Double Bazooka... Just a hint....
Aren’t these single band antennas?
@@timg5tm941 Yes and no...
radioaficion.com/cms/build-a-double-bazooka-antenna/
th-cam.com/video/1zgMa2Djh1s/w-d-xo.html
A double bazooka is always monoband
An awful lot of wild claims made about this antenna, and why would you want to string up a heavy piece of co-ax rather than a much lighter piece of wire ?
owenduffy.net/blog/?p=1941
Himen MeneA AntenFor Kenwood 3207WakeTakeUhfFm Tankyo
Why are the measurement not in the international metrec system, so we all know what you are talking about?!
Divide by 3.29
Ive been using a 80mtr doublet for over 25yrs. Always works every time! 73 kr4wu.
Great antennas