Random Wire Antennas for Ham Radio

[@azoriandan]

I love listening to you explain everything on your videos. I am new to this hobby but you are wise and the way you teach is amazing. Thank you so much.

[@tallperson9422]

Enjoyed this presentation on random wires. Also liked the plane pictures. I'm a big WWII fan and actually got to meet Bob Stanford Tuck and Geoffrey Page in 1983. Fabulous men! Would love to see you have a pic of a Beaufighter or a Whirlwind. 73, NF7Y.

[@davidportch8837]

Great advice as usual Peter....

[@watersstanton]

Many thanks

[@vinniec5286]

I have a question. I have not googled it, but wanted to run it by you and anyone else who may see this. With regards to random wire lengths, do we need to account for velocity factor? Apologies if this has been asked and answered before. The thought occurred to me when you had mentioned the 71 foot of wire.

[@watersstanton]

Velocity factor included.

[@vinniec5286]

@@watersstanton Thank you :)

[@TheMrConservator]

Thank you very much for very clear technical information, Peter! You have a warm voice, which delights me.

[@Majorme2]

Thank you from Kentucky USA. I’m new to radio…I have a random wire up now with a 49:1. I ordered a 9:1. And it will go up in a couple days it in the mail as we speak. I enjoyed you vid and I really did learn a lot….thanks HOWARD KQ4KDR

[@watersstanton]

Many thanks Howard. Hope new antenna works out well.

[@radiotec76]

Nice explanation on random wire antennas. I especially liked, “ Random doesn’t mean random.”

[@watersstanton]

Many thanks.

[@marklappin234]

Mr Waters. I'm pretty new to the amateur radio hobby and I very much enjoy your videos. I bought a Yaesu 991 from a guy at the amateur club I attend and at the moment it's sitting in its box as there's a lot of contradictory advice out there! Anyway I would like to try a random wire antenna. I have about 80 ft of garden to play with. What would you advise re length of wire for all HF bands. Also will the internal ATU be able to match the wire. Some have said with a random wire I should use an external ATU. Your advice would be appreciated. M7LPN

[@user-cg7uw9uh6n]

The David Attenborough of Ham Radio

[@watersstanton]

It’s my age I guess!

[@user-cg7uw9uh6n]

@@watersstanton Personal I think you are equally a national treasure who has contributed to our hobby

[@marshalmyhan8267]

Is a 423-foot long wire antenna 6 times better than the 71-foot version? Thanks for your fun & educational videos! Marshal

[@edtruthseeker3337]

Mr Waters, a very well done video as always. I have had my General License in the USA for 1 year this month. I have experimented with dipoles, and end fed halve wave antenna, and vertical antennas. I decided to experiment with an end fed long wire antenna. I asked for advice on the QRZ forums and other various places. I was advised not to use one, but rather a resonant antenna. I live in town and have a small yard (garden). I decided to experiment. My final configuration is a 141 foot length of wire. I have used both a 9:1 unun and a remote Icom tuner at the antenna. I cannot tell much difference. I am currently using the 9:1 unun and a remote tuner in my radio room. I raise the wire up 26 feet. An inverted L. I then take the wire to the and of my yard to a peak of 42 feet to a carbon spider mast. I then angle it down and turn it. I is 3 feet off of the ground at the input side and final side. I did not ground anything. I have an elevated counterpoise. It is 3 feet high. I used moveable electric fence posts. The counterpoise wire is 3 feet from the ground and I ran it under the wire. I also ran a length of counterpoise approximately 45 degrees from the antenna wire. I have been able to make DX contacts on 160 meters as far as Indiana. I transmitted my signal over the Great Smokey Mountains. I am able to operate from 160 to 10 meters. With the opposing counterpoise it directs the energy so that I can achieve propagation even on the 160 meter band even with an antenna so low to the ground. I love long wire antennas. Thank you again for sharing the video. I have learned so very much from you in the last year. 73 sir. Ed, KM4MMD

[@watersstanton]

Hi Ed, many thanks for sharing that info.

[@WilliamParmley]

Good job! A couple of winters ago I put up a very similar antenna and used it on Top Band (160 meters). It performed very well, even snagging a few European stations. Once we get back to long nights with little chance of thunderstorm activity (i.e., winter) I think you will be amazed at what you can accomplish on 160.

[@edtruthseeker3337]

@@WilliamParmley Thank you for sharing that information. I appreciate it very much. You have given me encouragement to leave my antenna configuration the way it is. I may go back to the remote tuner instead of the unun, but I haven't noticed much of a loss using the unun.

[@johnm7249]

Palomar Engineers is an excellent place to obtain antenna parts, they offer ferrite beads and rings in several different mixes and suggestions on where and when to use them. Hope that shiner improves quickly. 73

[@watersstanton]

Many thanks

[@UABFWSS]

My favorite and most frequently used antennas are my random wires, with 9:1 nelson matchboxes, a 41ft vertical and an 84ft sloper. Tried countless antennas prior. The band hopping the randoms allow, just spoiled me.

[@brian-g4dvb384]

Hi Peter - I hope the eye is much better now - After 49 years as a class A licencee it's never too late to learn or go over the basics again. Thanks for this video. I run a 135ft of wire wrapped around the garden with a short feeder (9ft) into the shack via a coaxial isolator into a LDG tuner. The UnUn is earthed to a fairly substantial earth rod system and radials. To be honest I have never had much luck with a 9:1 UnUn but a 4:1 UnUn seems to do the trick. Is this as a result of the wire length or any other factors ?

[@ChrisMichael-x8j]

Peter, is there a length of coax for each length of wire that makes a better counterpoise. I ask as that would be the place at which to place a choke. Cordially, KF0KEO

[@ponttokamera]

How long should the coax be berween balun and choke compared to the wire and how should it be placed?

[@KD9ZHF]

@watersstanton - I use the Palomar antenna; however, it is exactly the same antenna as their OCF dipole for 500w, 1500w, and surprisingly 5000w PEP. I use the 500 and 5000w. The only difference is they took the one radiator and replaced it with the coax and the toroid. Their products are very, very good, but the original engineers that started the company sold it some time back to a couple. While I have seen no difference in their products, there are a couple naysayers on the internet who hawk their own antennas who say that they are poor quality. All I can say is I’ve made several thousand DX contacts with mine from the city of Chicago on a small lot!

[@peterharris7682]

Very interesting. I am about to set up to get back on the air after a 30 year break and this would provide a quick way of getting started until I work out other antenna options. I am fortunate to have a garden 40 metres long. I have a question about ground connection. I have seen your other video questioning whether a ground wire really is a ground wire and whether it is necessary. I am very happy not to fit an earth but there is so much conflicting information that I am confused, One commercial 49:1 Unun has an earth connection and the accompanying advice is the it must be earthed for safety. What is the truth of the matter? Peter G3WHO

[@watersstanton]

That safety warning is simply not true. That terminal will go directly to the outer sheath of the coax cable.

[@imeoutis4910]

Peter, another great video, thank you once more for your effort. Hope your eye is all well soon.

[@mariuszstefaniaksq2ode646]

Hello Thank you for the video. Super job. I don't know if you mentioned what should be the length of the fider - the power cable to the unun 9:1 with 71 feet of radiant? Greetings Mariusz SQ2ODE

[@watersstanton]

Any length.

[@mariuszstefaniaksq2ode646]

Thank you for your response. Much strength and health SQ2ODE Mariusz

[@dekcap503]

Thank you Peter for sharing your expertise and knowledge - especially on antennas. Your videos have proven very educational and helpful to me. 73! David, K7KDE

[@watersstanton]

You are very welcome

[@W4BIN]

The first antenna that I transmitted with was a center feed 100.' long piece copperweld (copper coated steel wire) feed with a home made balanced tuner via an open wire feedline. (a white plastic peg every foot) It worked FB on eighty and forty meters. (as a novice that is all that I could use it on) Resonance is not mandatory if you can properly tune it. Ron W4BIN

[@watersstanton]

Yes I am a great fan of doublets.

[@johnsnyder7021]

Hello Peter. This is the best explanation I have ever heard on this subject. One question though: You mentioned that 71 feet seems to be a common length used, but that longer would be better. What would you suggest for a longer length for the wire? Might that be 124.5 feet? Thank you and 73. de AB3JS.

[@watersstanton]

Hi. Key in a search for optimum random wire lengths. There are a number of tables on the internet. I am not at home at the mment.

[@JayDeeH3]

Hmm. With an SWR of about 4 you'll have a powerloss of 35%, which is about 5 dB's, not the mentioned '1/1.5' dB... Plús most transceivers won't like so much reflected power and could well fail.

[@paulsengupta971]

That's why you have to use a tuner/matching unit.

[@alanharding8762]

Very good highly understandable information,

[@BusDriverRFI]

Just doing an EZNEC simulation on the 71ft stretch end fed, the input impedance at 7.15MHz is 2000 ohms, @10.15MHz, it's 8852 ohms, @14.15MHz it's 2068 ohms, @18.1MHz it's 159 ohms, @21.15MHz it's 1927 ohms, @24.95MHz it's 150 ohms, and @28.3MHz it's 1470 ohms. All of these are the resistive portions of the impedance. Nothing is particularly close to 450 ohms. There as a lot of reactive values all over the place though.

[@watersstanton]

Did you include a feeder length? Remember the feeder is part of the antenna.

[@BusDriverRFI]

@@watersstanton Well, I don't want my feeder to radiate so I guess this is the wrong antenna for me.

[@TheMicrofox]

​@@BusDriverRFIIf you don't want your coax feedline to resonate, put a choke right behind the 1:9 UnUn. Then use a counterpoise on the UnUn with at least 1/20 of the wavelength of the lowest band you intend to use, eg. 8m for 160m.

[@BusDriverRFI]

@@TheMicrofox ​ @TheMicrofox I was trying to model the antenna. If you understand Kirchoffs Current Law, it states that “The algebraic sum of all currents entering and exiting a node must equal zero.” So if there's current before a choke, then there has to be current, the same amount of current, after the choke. The choke isn't stopping anything. Now traps work on antennas because of their placement in a point that is measured out to be at a current null anyway for the higher frequency. But the lower frequency passes through. That is unless Kirchoff's Current Law has been repealed by the Supreme Court.

[@kapapatence6423]

Is there a noticeable difference in running a sloper vs. a horizontal with the long wire? Does the take-off angle matter as much?? Many thanks for your wonderful teachings. Joe.

[@watersstanton]

There is a small benefit in the direction of the wire slope. But fir many, it is simply the convenience of the installation.

[@dennisjoiner3717]

Greetings, I like using the not so random wire when I go camping. It seems to work quite well on 40 - 10, but by using 71’ or 119’ I can rag chew on 80 meters. Also it’s shorter than the 80 meter EFHW counterpart which is easier to work with. I have a 119’ end fed up that isn’t much if any different than my 135’ Doublet (which I want to shorten to 115’) both are in an Inverted V configuration.

[@watersstanton]

Thanks for sharing

[@fakechecknumber1198]

How about i dipole antenna. I tried to like your video but is was not letting me enjoyed your prospective on things that i am interested in HAVE A GREAT DAY

[@watersstanton]

I covered the dipo;le a little while ago.

[@wshanney]

My first portable antenna was a 41' random wire. It worked well on 40-10M with a 25' length of coax and a line isolator/choke. I've since built several others and use a switched 9:1/4:1 UnUn to optimize the match for each band. Antennas are sure fun! 73, Bill, W6QR

[@watersstanton]

Thanks Bill

[@sleeve8651]

Good Day Peter ! Been licensed some 44 years last count, here in the U.S. ! Cut my teeth as a Novice on a Forty meter inverted Vee. Then over the years experimented with verticals, inverted L , Fan Dipoles, etc. ! But never an end fed Long Wire, until very recently ! And to be honest, quite by accident ! I had purchased a tiny new Short Wave radio and having just rid myself of Cable Tv and Ma Bell aka AT&T, I Had available, some pre drilled holes in the walls to take advantage of ! Planing for my antenna, I didn't necessarily need or want any monster size cabling for an antenna, so I happened upon what is called Super Antenna wire ! It is a multi strand 18 gauge wire ! Of which I purchased 135 feet ! To keep a long story from getting longer, I will say that the wire went through several iterations before I landed on this configuration. That being, the wire begins next to my easy chair, exits the wall thru the hole now absent Ma Bell Telephone line, up over the vinyl siding window frame to an insulator, there again left by Ma Bell, at the peak of the House, then up to a stand off I made on the side of a tower at about 33 feet, or 10 meters, which ever you prefer, and then the rest of the wire running to the Northwest and held by a bungee cord wrapped around a Telephone pole, and held about 10 feet above the ground ! And I must say, it made a wonderful Short Wave antenna, until it didn't ! It was great until my mind began to wonder, and since I had been absent from the HF Bands for those, Life take precedence over amateur radio moments, I remembered that I had an old QRP Transceiver buried somewhere in all my collection of 44 years, actually more, worth of junk ! Finding it, I also remembered buying a Z tuner for QRP, that I never had tried ! One thing led to another, and next thing you know, I'm holding my QRP rig and tumer on my lap, and going crazy playing C.W. again, after being off HF for several years ! And being my first time stringing up a Long Wire, I am simply amazed at how well this thing plays ! The radio puts out 4 Watts ! Thats it ! And thankfully through utilizing the Reverse Beacon Network, I have saw reports from their Skimmers across America, into Canada as far as B.C., and into the Caribbean, to include CO2OQ in Cuba ! Not to mention the numerous contacts I've managed to make in the short Two weeks I've had this up and running ! Yes I still use it from time to time as my Short Wave antenna, but it's mostly sitting on the QRP rig, while I'm working whomever hears my signal ! My point, if I have one, is kicking myself for never trying just a piece of wire ! Of course this would never work without the Z tuner to which I give all the credit ! It is an EMTECH QRP Model ZM - 2 ATU ! Super easy to tune ! And quite honestly the simplest and cheapest tuner I have ever used ! I would encourage operators to try a long wire ! I wish I had many yesterdays ago ! And if my enthusiasm isn't showing here, it's not because I am not excited, as this is the most fun I've had since a Novice ! As a matter of fact, Iam headed to 40 meters now ! Hopefully the Sun is behaving ! As I forgot to mention I put this station up during the time we had Solar Flairs, one after another, after another, and was still able to eek out contacts ! Put up a Long Wire ! Try it, you'll like it ! '73 to One and All !

[@full_metal2452]

How about K6ARK’s end fed half wave antennas that he made me. Why was 4:1 chosen over 49:1? “#1) SMA connector, 4:1 unun on an FT37-43 toroid, and 20m of 28 ga wire that can be laid on the ground in a loop or just strung out as a long wire. As a loop, received signals will be notably stronger on 20m, and possibly 10m as well. #2) BC connector, 4:1 unun on an FT50-43 toroid, and 15 ft "radiator" and 7.5 ft counterpoise 26 ga copper clad steel antenna wire. The 4:1 matching units will make for a better match and less loss if you decide to connect a length of coax. Wires are connected to the matching units with 2mm banana plugs. You can swap wires between the matching units if you want, or even remove the counterpoise from the 2nd unit. It won't affect RX performance all that much. If you want to TX with it, #2 should tune up on 40-10m with a G-90, KX3, KX2, or KH1. I would recommend staying under 10w SSB and 5w CW/Digital.”

[@g1cpu]

What was the value before 29 on your caption, I cant read it as it seems to be cut off. I'm trying to fit one in a 21ft attic. Already have a fan dipole for 10m, 15m, and 20m in the attic. So it may be a bit of a squeeze. No antennas allowed outside etc etc.

[@Inkling777]

I suspect there's nothing cut off. I have several lists of random wire lengths and none are less than 29 feet.

[@watersstanton]

25ft but I would go for longer length and bend it around.

[@g1cpu]

@@Inkling777 thanks for the insight

[@g1cpu]

@@watersstanton thanks for the feedback

[@billtheslink4541]

I am on a downtown city lot with no supports. Can I run a random wire under the eves of the house off insulated standoffs sort of like an open loop?

[@paulsengupta971]

Yes. The beauty of something random is that it can be something random and it'll mostly work. Some people have metal roof gutters and they can connect a 9:1 transformer to those to make them work. I was watching a video early of someone connecting a 9:1 to a barbed wire fence.

[@haunter_1845]

I used to categorize random wire antennas next to other pursuits like dowsing, but not anymore. Thanks Peter.

[@paulthompson1988]

"Tune for Maximum Smoke" LOL . I have not heard that since my days in the RAAF. Great videos. Thanks (VK5PT)

[@DavidThomas-mb8ew]

Very clear and instructive explanation of the random wire antenna, thanks Peter. What are your thoughts on clipping an EFHW/random wire to plastic guttering around the house if you cannot erect towers or poles? 73 Dave M0OOR.

[@mcdeadsquirrel]

Many thanks from Upstate NY '73

[@KD9ZHF]

Get well soon, Mr. Waters.

[@andy2E0JIU]

Thanks peter,whens your next video about the spy stories as enjoy those.also one on earthing equipment would be great.73

[@brianfields4479]

Thanks for sharing mate, always interesting to listen to. Now the eye, if you were swinging around on your hexbeam and went flying just say so, I won't tell anyone hi. Hope your both ok. Bands poor here. 73 zl3xdj.

[@watersstanton]

Hi Brian, just hit a bad pot hole on my bike! Yes bands in doldrums and we are having a terrible summer.. Not much better than winter in ZL! Hope you both OK.

[@brianfields4479]

@@watersstanton roads are bad in places, got a ebike here, just pop down to the beach with dog in basket hi. Heavy rain here and snow on tops. Bands quiet, but not too bad. 73

[@FrancoDX]

Pleased you covered this. I have tried one of the commercially available Random Wire antennas, the LWHF-40 to be specific which interestingly is only 32.8 feet (10m) long. I’m sure there is some theory behind that although it doesn’t appear to be one of the measurements recommended. It works okay from 6 to 40 meters (with an ATU) and doesn’t look an eyesore in the small garden to neighbours and the XYL. I would like to try an EFHW at some point but that would take some bending around. 73

[@Al-zv9br]

I'm a fan of your channel and would like to know when a 1:1 Unun can be used and how. Thanks!

[@nigelparr4994]

Are they Bowers And Wilkins speakers in the background

[@alanrobnett336]

Hi Peter Have you thought of a video about catsync for people with a high noise level unfortunately I have to use catsync due to high noise levels and it works very well

[@ThumpMaster6]

Oh Peter, hope you stuck the landing! May your recovery be a fast one, like this antenna build.

[@Roddy1965]

Normally use an EFHW, but in some cases I use a 41ft 'random' wire. In mygarden I get 20, 17, 10, 6m on it, can't get 15m. I find it quite fussy with the length. It's only about 12 ft off the ground, and I've been shocked more than once at the DX on 100W.

[@watersstanton]

Thanks for sharing

[@arcticradio]

I use a random wire - it’s 220m long into the forest. I use receivers with 500ohm connectors and I have a deep good ground. The antenna has received MW signals over 9000km away. It’s been superbly quiet and great on all SW frequencies. It even works on FM picking up stations 300km away that I cannot receive in the car or at home with a dedicated FM antenna. I’ve been blasted about my antenna so much as it has multiple angles and acts omni-directional. It’s picked up Alaska to Mozambique to Taiwan to Thailand to Pakistan…..It seems to work very well despite being ‘random’.

[@watersstanton]

Sounds like a larger than normal backyard.

[@jeremyolive1132]

Thank you Peter for all your advice. I would really appreciate it if you could do a item on tuning boat anchor radios. I have an old Yeasu 101zd which I love using now and then but never got to grips with the tuning of it. Takes me ages but I get there in the end. Just an idea 💡 God bless John G7GNS

[@watersstanton]

Noted. Thanks John.

[@haraldlonn898]

The RF choke is when you use a autotransformer UNUN. What if you use a full transformer. I have been thinking in this direction due to I for the moment use a SDR reciver. I don't want any buildup of HV in the antenna that can kick back into the SDR. I may be completly of but I want to be safe. Have had so much HV from a antenna so I could lite up a Glimmerlamp kontinulsy and without I had a spark every 5 seconds in the PL 259. Scary. Would like to have some creative feedback on my idea.

[@watersstanton]

There is an easy way to avoid static build up. Put a 1k Ohm resistor across the antenna terminal. That should dissipate any build up.

[@EI6DP]

Hello Peter, great food for thought in that video. The LW antenna can also be fed with 450Ω feeder which may be a better choice of feeder which would make an End Fed Zepp ? 73 Ger

[@watersstanton]

Yes an option

[@GordonHudson]

When I was young a "long wire" usually meant a 132 foot end fed. Lots of voltage at the shack end. A lot of older amateurs favoured the W3EDP.

[@watersstanton]

I am not sure I ever measured mine!

[@Jan_Talcott_100]

Thank you so much. Great video. Because of you I've been using a random wire with 9:1 unun since winter with great success. Thank you.🙂

[@watersstanton]

Glad it helped

[@jonthebru]

I recommend the "random" or long wire antenna. I have a 71 ft wire up right now that fills in very well in the space it is in. I also have a 155 ft wire that is essentially all band but the place it would be installed has a doublet up instead. The fact that all the bands can be easily tuned makes the long wire with a 9:1 Unun a very functional antenna. Look at it as if it is an off center fed dipole and tune it by moving the Common current choke on the cable. My tuner is an LDG autotuner.

[@watersstanton]

Good advice

[@dandypoint]

Good video. I will just add a bit of history that you brought to my mind. I remember being 14 years old and having a long single wire. It was truly random. I was able to load it somewhat by sticking the wire into the SO-239 output of the DX-60 I had just built. Then I built a L network in a cardboard cigar box. I wound the coil around a 2 1/2 diameter insulator. Maybe 5 inches long. I has a small 140 pf variable. The ground was two short galvanized pipes just outside my bedroom window. I could work all the Novice bands. Over the past 60 years I found any length ( preferably over 1/4 wavelength) will work. Length can be truly random except the matching device must match the impedance to 50 ohm coax. Half wave end fed wires can be matched with 49:1 transformers or a quarter wave transmission line or an L network. Other lengths are matched with the appropriate transformer to suit the impedance at the feed point. Starting at the far end of the wire the impedance is high then as you move back it decreases to low or 50 ohms at 1/4 wave then increases until it is high again at 1/2 wave long. Mostly an L network works. Some lengths are more adaptable or easier for multiband use than others. All these names for antennas did not exist when we started they were all end fed wires. However they were all there, they just have new names! I don’t think anyone has invented any new antennas in recent years. I have many old books with forgotten antennas that are being rediscovered and renamed.

[@watersstanton]

interesting historical information. Much appreciated

[@feste1012000]

This is, as usual, so helpful. Expert but well paced delivery. I’m on a steep learning curve and these videos from you give me hope!

[@watersstanton]

Or maybe send you to sleep!

[@drjtgill]

Good presentation! Have you looked at the Terminated End Fed V Antenna? Looks very interesting.

[@watersstanton]

I will check it out but the load resistor maybe a problem for some.

[@WessexWeather]

Thanks for this Peter. Brilliant explanation on the difference between EFHW and random wire antennas.

[@watersstanton]

Glad it was helpful!

[@robertallbright]

Peter, you are the master broadcaster😊 Thankyou 73 Robert G3RCE

[@watersstanton]

I wish! But thanks Robert.

[@pixeluser175]

Shortcut to the music: 1:51

[@newsles2]

Great, thanks. As a beginner I've made a random end-fed going up into my locust tree, of about 41ft in length (I will do a longer one at some point) into a 9:1 unun and to the transciever. Re: the coax as counterpoise and the use of a choke, I was told by a Ham Radio Outlet assistant to run a counterpoise from the ground terminal on the unun directly underneath the actual antenna wire and it seems to work fairly well, particularly on 40m. Does this method obviate the need for the choke described? Les. KK7TPM

[@watersstanton]

i always advocate a choke as that coax sheath is live and also can result in false VSWR readings.

[@newsles2]

@@watersstanton Ah, ok, understood. I'd best order a toroid then. Thank you sir!

[@peterpatterson6593]

Shame owned by diamond

[@dougbrokeit7406]

Thankyou Peter great vid i have a 71ft random wire antenna but its running through 49:1 unun and 7 clip on ferits and 15ft counterpoise seams to work alright should i change out the unun for a 9:1 ??? Thanks

[@watersstanton]

I hesitate to recommend you change something that is working well. Logic says a 9:1 would be a better option.

[@dougbrokeit7406]

@@watersstanton Ill swop it out and see what happens cant hurt thanks for the reply

[@KutWrite]

Is this concept different for receive-only?

[@paulsengupta971]

No. But it doesn't really need the choke for receive only.

[@ROBByJONEs-2]

question please. 71ft is my backyard [ish] now bewcause outer braid radiates can i use 71' and call it efficient . or what random length would most oppl use for hf harmonics please..yes i have chokes i just need ask can it equal radiator wire please

[@ROBByJONEs-2]

i mean using 71 feet of coax before choke..

[@watersstanton]

The key length is the wire from the UnUn. The coax is secondary and does not form part of the length in the table.

[@ROBByJONEs-2]

@@watersstanton TY Peter i love your educational videos..73 cheers

[@williamkizer3445]

I have one up at 71’. Works well

[@watersstanton]

Thanks

[@imeoutis4910]

I have a random (~20m long) wire antenna where the 9:1 connects to 3m of coax into a 1:1 choke unun which in turn connects through a 10m coax to the transceiver. Does it matter how long the coax is between the 9:1 and the 1:1? Should it be a particular length? Or alternatively if not, is it better to have the 1:1 nearer the 9:1 or nearer the transceiver?

[@watersstanton]

There is no magic length but I would be inclined to make more use of the coax and move the rf choke nearer the transceiver so that more of the coax acts as a counterpoise.

[@imeoutis4910]

@@watersstanton Thank you Peter, I'll try that.

[@imeoutis4910]

@@watersstanton btw, I would assume that probably the same would apply for an EFHW (ie. using 49:1)?

[@Tiger404]

I love you!

[@johnemmons9087]

Great explanation. Best one I have seen. Thank you. I have a question…. Can I put a random wire on the roof of my RV? We will be doing a lot of traveling in it. It’s 37 feet long. If so how high off the metal roof would it need to be? Any ideas will be welcomed. Want to get 6 to 80 meters. Thanx!

[@watersstanton]

I would tend to run the wire from the RV to a tree or other support. There is a risk of the RF triggering lights and other devices in the RV. But if that is not possible try it and see!

[@johnemmons9087]

@@watersstanton thank you for your opinions. Appreciate them. My goal was to be on air whilst driving. Maybe…just maybe! you could do a video on it! After some fun trial and error of course! 73!

[@petemillis4666]

Loop it around the roof and see how it goes; bet it'll work ok. And string it out when parked up. 73 M3KXZ

[@johnemmons9087]

@@petemillis4666thank you. Do you have a gut feeling of how high off the roof I might go? I’m thinking maybe 10” ?

[@petemillis4666]

@@johnemmons9087 that's what I would do, and just see how it goes. It'll be an interesting experiment. I've seen similar done before with a horizontal loop on a roof rack.

[@Thump2030]

that 4:1 antenna is a rybakov antenna

[@KD9ZHF]

I think traditionally it is a Rybakov if it is 25-27 feet because it was the length of a long fishing rod.

[@paulsengupta971]

Looks like an Off Centre Fed Dipole to me. It's 25ft on one leg, 7ft on the other, giving 32ft total, or around 10m, a half wave dipole for 20m. It just puts the 4:1 transformer directly in the antenna. Sometimes an OCFD uses 300 or 450 ohm ladder line to feed the dipole at the off centre fed bit before putting the transformer/tuner/matching unit at the bottom of that ladder line. Although this is resonant on 20m and 10m, the beauty of an OCFD is that it has similar characteristics of the random wire antenna in that it presents an impedance which can be transformed down, in this case by a 4:1 rather than a 9:1 as it's closer to the centre) and then fed into a tuner/matcher.

[@WilliamParmley]

Brilliant! Best discussion of this subject that I have ever heard. Top drawer stuff as usual!!! I have to say, I get slightly annoyed when I hear someone use the expression "end fed random wire", which you clearly avoid here. After all, a "random wire" is, by its very nature, fed at the end! 😁 And yes, "long wire antenna" is (I think) the original term that I remember. Although maybe that fell out of favor because some long wire antennas aren't really very long. But as you say, they aren't very random, either! 😉

[@watersstanton]

In my early days we used the term “long wire” for any end fed wire. It had no relationship with the actual length!

[@shagitup]

Thank you sir for all that you do! Your wisdom is a blessing for this rookie!

[@watersstanton]

You are very welcome

[@neeleshrana4719]

Good information 73s vu3iub.

[@watersstanton]

Thanks for watching