Doublet aerials for HF amateur ham radio and broadcast bands. A dipole fed with 300 ohm feeder can be used on all short wave bands. If you don't have Google+ you can comment on this video via my Facebook page here... / radioworkshop
My Dad got me into radio he was also a GM4 and from a young age I spent most of my time as a SW listener, later in life *38* I decided to go for my Armature Licence, My dad had all the knowledge and always had the answers, He gave me instructions on how to build a doublet exactly as you have described I managed around 80 feet - 40ft both ways then ladder line into a Smart Tuner and have worked many contacts on 40m using a mere 10 watts. Only difference was rather than use 300 ohm feeder and so forth I used wire spreaders at my centre down to the Smart tuner. Tunes on all bands works flawless. you many have guessed but my dad is no longer with me however the doublet still hangs high. Great Video many thanks 73's to you and your's.
Chris R Hi Chris, it's nice to hear from you. The doublet is a brilliant aerial, and so simple! It must have been lovely to have your dad pass on his knowledge. Take care and the best, Ray.
Today I changed my feeder on my 40m dipole to home made open wire.... it was obviously fine on 40m and 15m before. It is difficult to express how much difference the open wire has made to the bands where VSWR was always bad such as 20m.
I spoke from the French Alpes to Alabama this morning with 100W on 80M. I have a home made Vertical 1/4 full length. Around 4M of rg58 going to a tin roof just next to my shack then i have a car gutter mount with the wire screwed straight to the bolt that holds the screw in socket for the main element in place. From this point the antenna is perfectly vertical for around 3 or 4M and then it bends off towards a nearby tree where it is attached with a pulley to around half way up a larger vertical antenna that is already mounted above the tree. Exactly 20M to the shed roof with not much sag. It's been working very well and if i use a T connector at the radio and connect the other vertical antenna at the same time i can get a low swr on many bands without any tuners or baluns nor chokes. Next project is to raise the feed-point to the top of the current 1/4 wave with 300 ohm ladder line and try a type of doublet or inverted v/z from the higher feed-point. I have to be a bit stealth here so thinking to try black enamelled wire if i can find hard drawn copper in black and then use high strength fishing line to attach the various points so as to make it fit the best possible in my garden. I'm currently looking for a suitable tuner to go to the 300 ohm ladder line. I'm just a bit worried if it will all stand up to snow and ice loading. Thinking 16 SWG but i want to keep the feed point pulley attached via a stronger cord such as the one i am using now to hoist the 1/4 wave up. I left the last 10" folded over at 90 degrees or so so it becomes a bit of a capacitance hat, i think i measured it to around 20.2M long but never ended up cutting it. Vertical might not be best in the long run but it seems to be working great for now. In the past I've had great results on other bands with unloaded *(full length 1/4 waves) and the shed roof seems to be doing a great job as a counterpoise. I've no earth connection at all. the only link to earth is via the radio chassis and back through the power supply but thats a switching supply and i just checked and bad me thats not even earthed, i must have been lazy when fitting the flex and only had 2 core in my box that already had a plug on it. I don't think the earth would carry through to the DC side of the PSU as it should all be isolated between the high voltage side and the DC side. I will go add an earth to the supply rail of the PSU i should take more care.
Thanks so much for this excellent tutorial which is so easy to understand. A great help as I am coming back to amateur radio after a break of almost 30 years & have a lot to learn & re-learn.
Thanks for an excellent video. I moved to balanced line for HF years ago. I wasted so much time dealing with coax, high swr and power losses before the move to balanced line. Even use balanced line for SOTA and POTA with excellent results. I do not use the 4:1 balun in the transmatch but use and external 1:1 balun. 73s KG5IF
Watching this great RU-vid video over two years after you created it. Just what I needed. So clear...so interesting. I am a 'yank' living in America privileged to have a 'British Bride' who grew up on the St. Mary's Island off the coast of Cornwall. My goal is to chat with folks in the U.K. once I earn my General Class privileges here in the U.S. I'm taking the exam on 12/17/16. Thanks so much for your hard work and your great videos. Paul, New Paltz, NY, USA, KD2LXQ
Ray, you have a new fan. I just sat for my US Tech and General licenses in one go. Waiting for my call sign grant and shopping for gear (and trying not to go broke in the process), and you're certainly helping!!
A much appreciated validation of what I have experienced. No more guessing about what kind of antenna to put up. I'll always go to a doublet fed with 600 ohm ladder line. While having to tweak everything else (equipment, grounds, power, etc) I never have to worry much about that antenna. Now I have to go convince a friend of mine that the G5RV isn't the king of antennas! ;)
I previously commented via my other account. The doublet fed by open-wire is a very effective aerial. I still hear plenty of nonsense on the bands extolling the virtues of resonant aerials. Resonance is not a good thing in some cases... a 40m half wave dipole on 20m is resonant but it is a crazy high impedance. The best thing I ever did for my HF operation was to ditch coax and not worry about the SWR... my doublet is far shorter than yours, just 66ft, 80m is obviously poor performing but I will add some more wire... open wire feed runs to a 4:1 current balun... which uses two seperate FT240-43 ferrite rings. Easy to do the bifilar winding using ordinary mains flex! Easily withstands a pair of 3-500s up it....
Ho is that why I got a Distinction and credits on my City and Guilds certificate. I'll try better next time. I might even go on a cource instead of teaching myself. But there again I did do a Class 1 Combat Radioman cource a number of years ago and got a first place pass on that. So I supose "I know now't. Takes all sorts does'nt it.
urbex2007 I am not sure who that comment was aimed at, resonance is not a magical thing, it is purely about the reactive part of the impedance. If the reactance can be catered for without incurring huge losses in the feeder or matching network it isn’t a problem. Arguably an aerial should be designed to achieve the desired radiation pattern and worry about feeding it as a secondary issue. For general HF use a doublet is a versatile multi band solution.
Hi Ray very good video very clear. And I've spent a lot of work trying to explain the same thing to many friends, it is difficult to make them understand. The doublet works wonders. I've been using them for a few years. But I think you already know that, that's why you made the video. Greetings
Another great video, my 40m aerial is cut to length and fed with crappy coax, it works indecently well for what it is. The ground here is very conductive and the feedpoint of the aerial is about 1/4 wavelength up. The doublet is a better idea but quite a few of us lazy people go for aerials which the rigs own auto atus can cope with. I am getting fantastic reports around the UK and Europe with this aerial but it isn't a great DX aerial. Good to see some myths debunked... I remember at one of my previous addresses using a trapped inverted L fed against ground, friends were mystified when I started putting more and more buried wires in the lawn "because the swr was too low".... what they didn't understand is that the aerial should have been under 10 ohms on 160m and that the vswr was acceptable only because of massive ground losses and inefficiency.
Good practical advice. Recently setup 44 feet TRUELADDERLINE Doublet with Balun Designs 4114 Transformer, great combination, quality components, functions as designed for fair price.
It all depends if your using your feed line as part of a transformer. It's not throwing theory out the window. The antenna you describe by 'design' is not expected to be resonant and is expected to 'need' a tuner. Other antennas that do have an expected resonance will need to be accurate to design.
A great multiband antenna Ray and cost pennies when built yourself. I used to have a doublet fed with homebrew ladder line. Saves having too many antennas for different bands and as you say low loss. My doublet was a sloping inverted V configuration to fit available space but performed very well. I know they out perform many costly antennas for the sake of a few quid and bits of wire. Great video 73 M0DAD
This is brilliant, thanks! You've provided probably the best description of what's actually happening that I've ever heard. For the longest time I've been wanting to build the kinds of aerials I'd string up when I was a kid, which by the way was incredibly fun. Unfortunately I've been a bit deterred by what I refer to as the Aerial Nazis who endlessly spout numbers, statistics, and alchemical drivel. Of course, they don't dare build anything, because they can buy it! But besides being ripped off, where's the fun in that? Anyway, now I can't wait to get out there and start stringing some wire for a doublet and some scandalously long ladder line. And I won't even notify the authorities! ;-)
Excellent! I'm so pleased that you found the video useful. For me, experimenting with aerials is the best part of the hobby. Let me know how you get on. Cheers, Ray.
Carrying on from my previous... with coax feed my 40m dipole was direly deaf on 20m as you might expect... ATU is a high pass T-match... cannot believe how much difference changing to ladder line has made.., though twiddling ATU is like cracking a safe!
Usual absolutely superb 'hands on" stuff from Ray, stuff which can only be explained with such ease by someone who has come to terms with techno-details and turned them into "actually doing it !" Only then can you attack the horrible things which go wrong with the theory, (and it DOES!!) put 'em right and then explain it in comfortable terms to folks looking for experienced, sensible advice. Ray gives it! If I might add a little to confirm Ray's very wise promotion of balanced feeder in order to make an antenna work on at least 2 bands and maybe more, this may help. When a coax fed dipole, superbly tuned & matched for 40 metres, is fed with 20 metre RF, the antenna suddenly becomes a full wave, with a nuisance voltage, high impedance centre-feed point. The 50 ohm coax is quite unimpressed! Miffed even. This sets up a hi VSWR on the feeder but sure enough, as Ray says, with a decent antenna matcher, it can be adjusted to (appear to) match what ever random impedance (and unknown reactance) appears at the bottom. It shows 1:1 on the swr meter but that is only on the bit of coax (patch lead. Ray hates that term!) between SWR meter and rig. As Ray says "The rig is happy and protected from SWR damage, safely delivering power." However the SWR on the coax to antenna feed point, IS STILL there. Un-flippn' changed! Coax ain't too good at handling that & is V lossy. Real QRO would show heat spots at Hi voltage points on the SWR where your expensive RF, strains the polythene inner insulation, forcing energy between inner and outer conductor. At least it's ice free every half wave! Change to 300 ohm or any other Z (impedance) parallel feeder, and the High SWR still doesn't disappear but the feeder can now handle it readily with very much reduced losses and as a bonus, the unbalance problem is also solved, needing no balun. Neat eh? Good stuff Ray. You remind me of stuff I thought that I'd forgotten AND HAD!! Thanks a million. You serve Ham Radio well! You use 300 ohm. I would too except that the stuff given to me for free is 450. When life gives you freelemons, make lemonade. 73 G3NBY
I'm just getting into ham radio but for my first aerial I can get a dipole in my garden 140 feet long, 40 feet above the ground and made of 4mm2 cable. After a bit more working out I'm hoping this will work as part of a doublet system. The other good thing is that it will be at a right angle to the mainland of Britain.
I have learned that in ham radio, if you want five different ideas on antenna operation, ask four people. The fellow that sold me my first commercial OCF dipole sounded like this fellow. Told me to get it as high as I can and use good coax, it will tune fine. He was right. Sometimes we try to out engineer ourselves. Simple is better 9 times out of 10. Do you have a shack and equipment tour video mate?
You mention how reflected power is rereflected back to antenna at the atu, this is correct and same happens with coax only that coax has more loss with swr on the line, however if a low loss coax is used then more of this reflected power will get back to antenna like it does with balance feeder, so all is not lost if you have to use coax on a multi band antenna into a tuner that's tuning the system to resonance
Hi Paul, I use 300 ohm ladder line and it’s great. I understand what you’re saying about coax having more loss. I try to avoid coax if I can. Cheers, Ray.
@@g4nsj yeah its fine for moni band antennas but you are limited to that one band, I think also the whole concept of multi band antennas into tuners is totally misunderstood mainly due to swr myths that power is automatically lost if you have any reflected power at all or that it get absorbed in the atu, glad you mentioned it at the end, perhaps you could do a video on this subject to help dispel some of the myths surrounding the subject 👍
When it comes to the dipole length, if necessary you can zig-zag and fold down the ends to make it fit. (Just be careful to keep folded ends high enough above ground to avoid them being a safety hazard.)
I'm now licenced since January 2018 and use a "Ray" inspired doublet. it's compromised because of space i.e. there is a dogleg in one of the "wires". It's been great so far - have had lots of contacts on my 100W radio, including on 17m & 15m. I only tried it on 80m for the first time last weekend and it worked very well. It's opened up a whole load of local contacts I never knew where there. I even got a contact with an IOTA expedition on the normally uninhabited Blasket Islands off Co. Kerry! I know a just licenced Ham (last month) and he's going with the Doublet too! btw Ray do you go on 80m much? 73 Adrian EI9HAB
Thanks for another informative video Ray in layman's language which is a great help for me as a novice. I am just a shortwave listener and just dying to have a go at a doublet. I have an awkward shaped garden so the antenna wire might be a bit higgelty piggelty, like a Z shape with maybe a bit more on the ends to get length. Would that shape work for RX only. Best wishes.
I have a 24x8x.375 aluminum plate in my window that my feeders come thru via coax. If I drill two holes for the wire feeder, will the metal between the feed wires be a problem?
I am looking to upgrade my outdoor antenna and have been looking at a doublet antenna as a replacement. I understand the basic principals of the doublet antenna and heard a comment you made about the twin lead feeder. You pointed out that it does not radiate. It was always my understanding that it actually does radiate that is why it is so successful as a multi-band antenna. I was also under the impression that a number of hams didn't like the idea of bringing the twin lead feeder into the shack just for that reason. Additionally from my readings I have learned that the twin lead must be some distance away from things like rain leaders/gutters to avoid interaction with them. If the twin lead didn't radiate wouldn't this be a non issue? With that said, regardless of this, I still think it will be a viable replacement over what I'm presently using which is an end-fed 65' wire up at about 30'. The other issue I see is bringing the twin lead into the shack. I figure I can do this a number of ways including penetrating the existing outer wall. Best 73 ES HNY Kurt - W2MW
Kurt Zimmerman Hi Kurt. The feeder doesn't radiate because it's balanced, any radiation is cancelled out. 300 ohm feeder can be dragged through bushes but it is best kept clear of metal objects. It's a very good aerial and well worth trying. Cheers, Ray.
Ray, thanks for your explanation which is very helpful. My next concern is bringing the twin-lead into the shack. I have thought about penetrating the outer wall with about a 1 inch drill. (this is actually one of the top ideas I'm considering). I do have a casement window behind my station which opens/closes by sliding the window left/right. The window frame is made from aluminium which would prevent me from simply pass the twin-lead between the window and the frame (I'm assuming). What are your thoughts? Thanks in advance, Kurt
Hi ray...if when checking the swr of my 42mtr long doublet that I have just erected fed with 20ft of 450ohm ladder line....using my antenna Analyzer...I find the swr on 80m up around 9.5 to 1....its even higher on some bands. I feed the 450ohm ladder line to my balance line input on my MFJ tuner with its built in 4-1 balun for balanced lines. Is such high swr reading to be expected with the doublet?
Silly question, but to get coax in the shack you drill one neat hole ,,,how do you get ladder lint in the building ? Through an open window ,, sorry for dumb ass question cheers Shane ct1017
shaneweightman it's a good question. I take the line under the gutter through the wood or plastic into the loft. Then, down through the ceiling. Cheers, Ray.
If you put power to rhe antenna and get the power to be in the antenna. (with matcher or not) the antenna will radiate the power! An other thing is is it radiating heat or rf...
Agree its about getting the power to the antenna, length of radiator isn't too much of a concern if it's fed correctly, LB Cebik has information stating that the radiator length can go as short as 20% of its half wave length on the frequency of operation before significant and noticeable loss is encured
I don’t have a separate ATU But the radio has a built-in tuner so what do you recommend in that situation, would I need any type of transformer like a 9 to 1 Balun or can I just connect a short piece of coax to the radio and then splice that directly to the twin lead inside the shack and then run the twin lead up to the dipole
I use open wire line up to the wall of my house and then 450 ohm plastic ladder line in to my shack because it dose not need to be kept under tension to keep its impedance My atu is a home brew job link coupled with two tuning caps one in each leg of the feeder line on to a taped coil for balancing the feed line and electricaly shorting the feeder to its correct lenght .
Very True only prob I've found is using a PC in shack and twin feeder into a balanced or unbalanced with balun causes the PC to go wild, had to use coax into the shack with choke to reduce common mode currents
Ray can you clip ribbon feed to a wooden fence as long as its away from metal...or for that matter could you run its through bushes to aid keeping it up off the ground. Nick.
I wonder if a doublet with coils near the feedpoint will act as a electrical extender or its a silly approach for that? I dont have enough space to deploy a 40m doublet nor 80m! My idea is to make a rigid doublet (12m full lenght) feeded with 600ohms ladder and a link-coupled tunner. Thanks again
Hi Ray, totally agree about the doublet, I'm in a low rise block of flats which means an outside aerial is a no-goer. So I have a 66ft doublet up in the loft, it's bent into a funny shape but it is symmetrical! The whole system is homemade including the open wire line and single coil balanced z-match atu My doublet works great for an internal aerial on all bands from 40m down to 10m on 5 watts qrp!. - But because of it's shape and the fact that it's indoors, if you listen to the "experts" it shouldn't work at all! Cheers. Kevin GW4WOV
Hi Kevin, nice to hear from you. It's a good idea to forget the "experts" and do your own thing. Sounds like your doublet is working really well. Cheers, Ray.
Hi Ray... Good stuff as usual. I wonder...and I will try at some point....to feed a 2/70 dipole with 300 ohm feeder....and I am going to see what happens with the shop bought 2/70 vertical feeding it with 300 ohm balanced feed too. Have you ever tried this ?? I am working on the none radiation of balanced feeder v coax principal you mention....will it work...we'll see.
Hi Ray. Thanks for answering the ferrite ring question. Sorry to bother - about grounding. My mast will be mounted on the back corner of the house - using T and K brackets i.e. no contact with ground. The 300 ohm ribbon will run into the attic through a hole (wife not aware of that one, yet!) - to an ATU. Should I run the ribbon through some sort of lightening protection (just before it enters the house) and connect to a common ground with the mast? Or should I ground the mast and leave the balanced line i.e. just disconnect from the ATU when not in use? Many thanks in advance, Adrian
Could you talk about "bending" the legs on a doublet - or even have the ends just hanging in the air? I've heard you can do that, and still have an efficient antenna.
An "all band doublet" as a an inverted v is the best multi-band antenna your going to find. I've used this for years with great results. People often want to dismiss this because it's easy, simple and cheap. Look here if you want more information: w4neq.com/htm/doublet.htm The key to this antenna is the ultra low loss in the feedline when compared to coax. 73!
Is it possible to make a doublin in a U-shape? I am curious if it would be possible to use zink gutters on both sides of my house and join them together into one big dipole.
thanks for this really great explanation! I wonder why all doublet is horizontal, does not work ok in inverted vee set up? Best regards from Argentina LU1MAW
I've linked a short but comprehensive article explaining the properties & differences between both: www.w1npp.org/events/2010/2010-F~1/ANTENNAS/WIRE/910702~1.PDF I'm newly licensed (i.e. I know nothing) and went with an open wire doublet for its multi-band properties. I have limited space and wanted to get the most out of a simple antenna. It was cheap to make and it's very effective (thanks Ray!). Constructing your own antennas is a great way to learn about radio in general. Read the article but Ray's video is probably the best there is on the subject best of luck EI9HAB
Ray, this is basic, but so am I (newbie), I have a coax antenna connector on my transceiver, how do I get the twin feed line from the antenna (300-450) to meet at the antenna tuner?
I'm new to this and very limited for space I have about twenty five feet of height and length can I get an inverted v on this? Also rig is a galaxy DX 959 straight out of the box no amp, what MTR band am I looking for?
Has daft has may be coat the 6" nail in copper (Electro-chemicaly) and with a 1/2" length of coax centre conductore connected from a coax feed. Setup 4x 6 1/2" groundplains connected to the shield of the coax. Hey presto a ground plane antenna for 70cm.
Not a radio ham, but I listen to Air band as I am under one of the Heathrow 'stacks'. The aerial I use is a vertical dipole (2x450mm elements.) It works OK. Would you say this is about right Ray? The main frequency I tune to is 134.975MHz.
Hi Ray.. Good video! Question... If you haven't a 'balanced ATU' and you need to use coax to connect to the radio, should you use a balun? And should it be 4:1 or 1:1??? My Yaesu FT920 has an auto ATU and I'd like to try a doublet!! Dave
Hi Dave, glad you liked the video. I'd use a 4:1 balun, that should be fine. In fact, try and find out what type of balun they use in the MFJ tuners, you might be able to get a circuit from somewhere. The doublet really is a brilliant aerial so well worth a try. Cheers, Ray.
Ray Heffer Cheers Ray.. That's what I thought so I'll be putting up a doublet this summer... We moved a year last January (how time flies) and I've sacrificed my tower and A3S beam which I had at the old QTH for something much more accessible (I'm too old for long ladders and harnesses!!) as soon as I get time to put one up! Not able to transmit at all at the moment! Callsign G0PUD 73
Dabhandradio Dave Shaw Shame about the tower and beam but I take your point about ladders and harnesses. Let me know when you're on the air, perhaps we can have a contact.
Hi there Ray, I wonder at your patience with some of the seemingly daft questions you get asked. Have people lost the ability to read ?. I was a member of our local public library when I was in junior school. I used to read up on all sorts of rubish, like "A" Level Physics and chemistry. Military Engineering. Metalwork and woodworking principles. The only subject that I did neglect was Maths. Or should I say standard arithmatic. I use to borrow my elder brothers slide rule to help out . Wish I had been able to use a calculatore back in those days. That did help in using a military protractore to work out the bearings to guide an aircraft onto target, as in "Forward Air Contol" Any way I'm waffeling on here. Keep up the good work 73 de G0WXU - John.
Ray, appreciate your time on this Video, i saw a design with 300ohm TV line used as the antenna legs connected at the ends, then also fed with same line to a tuner, they called for 1/4 wave legs and 1/2 wave feeder length, what do you think ? I have plenty of this line, and want to take it portable 80-10 meters, or 40-10 if i have to , Thanks, Aj
Hi Ray. I'm really interested in this doublet. I only SW listen at the moment, on long wire out the back - its about 80ft up/down/around - all over the place, and it's quite good. I like the idea of experimenting with different set ups and would eventually like to go for my license and therefore would like to put up something that will transmit and receive. The only issue is the size om my garden, as long as it is wide - which is the width of a standard semi-D. However, I could get a longer doublet going in an L around the perimeter of the property. Would an angle of 90degree compromise the doublet too much? Thanks, Adrian.
Hi Adrian, I've used aerials in the past with several 90 degree angles and, while they may not be as good as in line wires, they work pretty well. Give it a try. Cheers, Ray.
Thanks for responding Ray. I think the major thing I take away from all your advice is to utilise the space you have as best you can and give it a shot. So I will! Thanks again. Adrian.
Hello Ray, I use 450ohm window line from my inverted V dipole into a balanced tuner for my amateur radio hobby. I can load all bands from 80M through 10M with a 1:1 swr and am very happy with it.Cheap and effective. I'm wanting to try 160M but live in Philadelphia and have little room for more wire.My question is can I load the antennas ends with coils and still use my ATU ? Thanks in advance for any info you can provide.Happy New Year! Tom,AB3YK
Radio Workshop Ok, you mean the feeder(ladder line) that is 300-400 ohm goes all the way into the antennatuner? And regular coax 50 ohm into your radio from the antennatuner.
Hello Ray a great video. I have the following space to play with: horizontally 28 feet, sloper 30.5 feet. I don't have the opportunity to have a pole midway for an inverted vee. My question: if I droop about 2 feet of the wire on each end down each pole to squeeze in a half wave length of wire for 20m would the doublet fed by 300ohm ladder line work? Also do you think this might work at all for 40m? Cheers Tim.
Hi Tim, dropping the ends down will be fine. 29 feet isn't very long but it will work with 300 ohm line. As to how good it will be, you'll have to try it and see. Give it a go, it might be pretty good. Cheers, Ray.
Hi Ray. I've got all the parts required for my doublet and will put it up over the summer. I got an old antenna off a club member to scavenge for parts. There was a ferrite ring with it. Is it worth incorporating the ferrite ring into my doublet, perhaps where the ribbon meets the radiating element?
Thanks a mil Ray. Have you any advice on grounding? This will be a receive only antenna (for now). Clearly I don't want to leave it connected to my SDR when not in use. Is there a way of grounding an open wire before entering the house?
There's no way to ground open wire other than taking the two conductor directly down to earth. Some kind of plug and socket arrangement just before it enters the house, maybe?
@UCgWLwfDMmGPv0nMk1dw1uTQ now I see why you recommended adding 5 feet as a place to start. 5 feet represents approximately 1/8 wavelength at 20 meters :)
@@redman840 I read about the doublet and watched a number of videos yet remained undecided if I wanted to build one UNTIL I saw this video. Thanks for all the help
Thanks for this very informative video, I am going to ditch the coax now, all ready ordered 50' of 300ohm of ebay in last ten mins...lol. I was wondering if you have had much to do with long wire antenna's as I was thinking of trying one out of curiousity? I am new to wire antenna's even though I have had radio's since 1978 but always used vertical ones, gonna make a Dipole now, I think I could stretch to about 120ish feet if I use whole length of garden and will use the ladder line ive ordered Sod coax!...lol....Cheers, from Gobowen.....
TY Sir you answerred exactly the question i needed to know..i did not measure my diplole either. from my front ]footpath tree] to mu back fence trees is around 110' so i just off set feed so 450 bal would miss iron roof,only for that reason. but i wanted to know how long to make bal feeder. mine IS all the way into shack and bal tuner... youve set my mind at easy Sir. ty and 73..rod vk4fr
Brilliant video. I have long thought that the Doublet was the best multi-band wire aerial that is relatively simple to install. I made my own 4 inch wide spaced balanced feed line, and fed that via a 1:1 balun into a remotely located Auto-ATU in the garden shed. The ATU then fed back into the operating position in the house via RG213 coaxial cable. Neat and effective Thank you for the video! 73, Mike M0MTJ (P.S. - I think it was Magnus Pike, by the way! :-) )
Ray, just to add some information, 80ft of RG58 feeding a 40m dipole... only losing about 15% of the power..,not much scope for a huge improvement. 10m though was losing roughly 95% of the power. 20m was losing about 93% of the power... Losses with open line are very low, granted my openwire is shorter... about 30ft. Typically now only losing a few percent in feeder loss. I had always intended to run openwire, but until now had never done the maths. Coax even at these low frequencies is a disaster with high VSWR... feedpoint of a fullwave dipole is about 5000 ohms.. Makes you wonder about ATUs with coax ouputs... hardly worth having...
If you want to run it at a much lower frequency, you can short the ends of the line together, and operate it with ground radials or a counterpoise, as a Marconi. Don't ask me what the radiation pattern will be (it might be great!...or... :) ), but you'll get a nice 1.00 VSWR, with a tuner.
Hi Clyde, I have tried that without much success because the ladder line goes up through the attic. It would work well if the line was outside in the open. Great to hear from you. Cheers, Ray.
It's not necessary really. Mine goes through bushes and up the wall and through the attic with no problems. Having said that, don't tape it to a metal pole.
Ray I am always trying to learn from yours and other videos and very helpful they are. I am a listener only and I very rarely hear whether these antennas are as good for receiving as they are for transmitting. there is always a SWR meter involved but that is for bringing the SWR down for TX purposes. I haven't a SWR meter since my CB days. So my question will be are these antennas just as good for listening. Hope this isn't as daft as it sounds.
This was brilliant! I agree with many of the other comments and want to say that this is the first time I had any chance of understanding many of these concepts. I am located in the America, a new ham and want to make European contacts. I am limited to wire since my wife would divorce me over a highly visible antenna. Would I be correct in assuming from this video that I should hang as much wire as possible, as vertical as possible, with a ladder feed line with an amplifier (suggestions?) and tuner (suggestions?)? Again, thanks. It takes true brilliance to explain many of these concepts to less than brilliant people such as myself. KC3ITL
Thanks, Andy. I appreciate your kind comments. Yes, as mush wire as poss as high as poss. I don't know about amps but a decent balanced tuner such as MFJ. Cheers, Ray.
Hello Ray...I am a SWL and also learning as hard as I can. I watch all of your videos with interest. I love mucking around with bits of wire and making aerials and am amazed how it all works. Where I live on the Romney Marsh in Lydd my wife likes to listen to Radio Sussex on 405.1 but where we live the reception is lousy. So I made a simple wire dipole cut for the frequency stuck it in the loft and fed 50 ohm coax down to the kitchen and soldered a crocodile clip from one side only of the dipole to the tip of the whip aerial (no aerial inputs on the radio) and so amazed that it works. My wife thinks I am a genius and I am leaving her thinking that. Anyway I only listen as I have said and have a Tecsun S2000 radio and a random wire aerial. I made my self a PI match atu. My radio has two inputs for shortwave, one 500 ohms and the other input 50 ohm. The random wire goes through the atu and into the 500 ohm socket. But now I am wondering if the atu is needed if I use the 500 ohm input on the radio, can you enlighten me on this. I also use my scanner aerial (1300 Discone) into the 50 ohm socket at the same time and it seems to improve reception. I have received some what I call half decent stations from as far as Radio Havana in the west and Trans World Radio Swaziland to the east, and most of Europe and a few SSB amateur radio chaps. Some years ago I had a Radio Shack DX-394, and a homemade atu with a bit of broomstick and copper wire wound around it. One day I couldn't believe my ears as I was clipping this crocodile clip up and down the inductor and heard New Zealand south island weather forecast. That peaked my interest but the radio was mullered as one of the grand kids spilt water on it and that was the end of that. Now grand kids grown up and not so clumsy I have found the interest again. I am trying to work out if I have the room in my garden for a doublet aerial for HF, or would it be wasted for reception only. My random wire is about 70 feet long in a sort of dogleg configuration 25 feet in the air and the into and around the loft then into the atu and the radio. Would a doublet be better for reception than a random wire?. Sorry about the waffling but gleaning as much as I can. Thanks for the videos.
Hi Mike, The thing is with aerials is to experiment. To use an ATU or not? I#d usually use one but, with your particular set-up. it might not be necessary. Broomstick and copper wire... excellent! Experiment. Cheers, Ray.
I forgot to say that the balanced line picks up much less local QRM and other trash like coax does so you can hear weaker signals with it! Great for just swling as well!
