A dipole aerial for short wave listening
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- čas přidán 22. 07. 2024
- This video is for those who have asked me for a good aerial design to receive Radio KBC on 6095 kHz. The aerial is designed for the 49 metre broadcast band but you can change the length to suit any shortwave broadcast or amateur band. There will be a mismatch between the coax and the aerial socket on the radio but, for our purposes, that won't present a problem. On the band the aerial is designed for, it will perform far better than a random length of wire.
If you don't have Google+ you can comment on this video via my Facebook page here... / radioworkshop - Věda a technologie
After watching 20+ videos on the SW antenna topic this is the only really useful one. Thank you
II. Gyula thanks!
I agree, somehow ALL of the others just skip over the important step of... actually explaining where to connect things. Very frustrating. I have soldering experience I just don't know anything about wiring antennas.
hi, just beginning in the radio hobby... as a kid i listened a lot to the radio... MW LW SW also FM and AM. Now something woke up this old interest. Watching your videos and other CZcamsrs this old interesent is starting to become a main interest.
A few years back i bought a studybook to become a licenced operator... That book is stil lying ont the shelf never started to learn...
No... i am not a pirate... i am listening on the 11 meter and somethimes i give a shout in the air. Yes CB Radio is fun... but more fun when the skip is rolling in! Or propagation is right! a month or two ago i bought my first CB radio. As kid in the 80's friends had them in the tractors and we played with the CB's... FUN!!!
I love this movie about the dipole antenna!!! and started to calculate for a dipole for the 27MHz...
468:27=17.3
17.3:2=8.6
(17.4x30.5=530.7)
to make it easy: 531:2=265.5 meter each side...
But the number: 468 how is that calculated or is it a standard in the antenna build???
468 is is the standard. Good luck with the hobby. I know you’ll enjoy it. Cheers, Ray.
Love those old radios,I did own a few some years ago including an old radiogram.Fond memories indeed.
I admire all valve radios and admire your skill and ability to repair them.
John Thornton Thanks!
Yet another good video, Thanks Ray
Thank you for a great explaination. All the best to you.
Thanks for a very useful bit of information👍
Thank you for making that clear !..total beginner here
Thank you so much for your videos, it really helps me get results
Thanks!
Hi Ray. Very useful and interesting information. Thank you for sharing and take care.
Thanks Bobby, glad you enjoyed it. Cheers, Ray.
Just what I need for my kenwood trio r1000. Not complicated. Thank you very much. 😀
I am reacquainting myself with the world of Shortwave listening after many years. I have purchased an SDR - RTL to help bridge the technological divide. I had planed on a dipole straight off. But needed to remind myself of the rules and principles. This video was absolutely great in assisting me. I think I can make it work well. I have a 50 ft area, of a 5ft high wooden fence that surrounds my apartment. I know its a bit short of 75 feet for a 6m antenna, but with some different directions taken by the wire I think it may work. It may not be perfect. But I can experiment with shorter bandwidths to see my results I believe. Thank you sir for your video.
Hi Ken, thanks for commenting. Good luck with your aerials. Do let me know how you get on. Cheers, Ray.
You have the best ghost stories bro!!! Thumbs up 👍
Thanks!
Thanks to your video, I was able to make one a few months ago and it works great.
Excellent!
Brilliant !. Thank you Ray. Had been looking all over You Tube for just this type of of antenna . There are scores of Ham antenna videos, But i am not ready for that yet.
I just wanted to listen to SW stations on my Grundig 750 i just bought, But the stock pull out antenna has a lot of fade in and out . This will do the trick i am sure. Thanks again From Jon in Seattle Washington USA
Hi Jon, thanks for commenting. I hope the aerial works well for you, happy listening! Ray.
That's wonderful my friend.I hv subscribed to your channel here.!!!!!
Thanks!
Even a single long wire will help!
I just went out and added a single 5m length of thin wire to my Retekess V115, and I can get clear signals on my frequencies. I just use a test clip to attach it to my aerial.
Hi. My name is Jodie. I really liked your vid. I live in Queensland Australia. I have a Kenwood R-1000 with 2 G5RV antennas one running south-west to north-east and other south-east to north-west , and there were 2 stations I loved to listen to were HCJB Quito Ecuador the voice of the Andes, and Radio Dubai. Unfortunately they don't exist anymore.
HinJodie, it’s nice to hear from you. So many stations have gone. Such a shame.
Good job Ray as always. Vy 73s de WA1UFO, Radio Spacejunk.
Thanks!
thank you....
Thnk u sir so simple i wil sure set up sum wt like ths antenna for my zenith r7000world receiver!
Relevant knowledge has no age limit mate. I'm still using my bamboo fly fishing rod.
Keep on talking.
Haha love it!
Should the general orientation be north- south or east-west? Your information is gold thanks for the generosity.
If the wire runs north south then it will receive better from stations east west. To be honest, signals in the ionosphere get twisted and bent so it doesn’t matter too much.
Thanks for helpful video lesson again Ray. I get brain overload with all this and have to ask daft questions, so there was no mention of a ground rod here, do you need one?. I remember my dad just having a bit of wire going through the window into a iron pipe banged into the ground.
I use a 75 ohm TV cable 200 feet long with a single 70 foot wire and grounded shield the main purpose is to get away from the power lines which wreak havoc when your too close. and is plugged into a Realistic DX-390. I may try a dipole setup at see if it is better I am trying to catch the illusive UVB 76 buzzer. here in western Canada. I caught it only once in Feb 2014.
rEdf196 websdr.ewi.utwente.nl:8901/?tune=4625 about 1900utc-0500 utc / or / isthebuzzerup.org.
rEdf196, I just received a DX-390 last summer and am still learning, do you still have it today? Tell me what you used for an antenna that worked, thanks.
Good Job .
Thanks!
Great advice for aspiring SWListeners Ray, well done!
May I suggest here, if the said antenna is used as intended (i.e. dipole configuration), the noise level will be much lower from being instead, used as a 'Marconi T' configuration.
Am I correct in saying this or, in your experience, there's no difference in QRN levels?
Your videos are both, entertaining and informative as well as, very clear to understand. Thank you!
Arthur Manolopoulos I think the noise should be lower as there’s no vertical element in the dipole.
My Panasonic RF-800U radio does not have a aerial socket behind and does not have a earth socket on the rear. Should I actually modify the radio by drilling holes and bringing out aerial and earth sockets(negative of battery) at the rear of that brand new radio to be able to connect to external aerials? It does have a long 84cm telescopic aerial.
+indiaradioguy That's really up to you. If it was my radio, I would drill holes etc. Bear in mind it will devalue the radio. Cheers, Ray.
Great informative video. I’m interested in making a dipole for my loft space but it’s only 14 feet wide, would the Marconi T idea work for improving SW reception? Currently using a 16m sloper long wire outside but it’s a bit unsightly so would like something out of the way. Thanks.
I think it’s a case of try it and see. The Marconi T might be better for receiving. Cheers, Ray.
Thanks Ray, I’ll give it a try. All the best.
Hi great video ! I have a question... I've seen that sometimes dipoles antennas were built with insulated copper wire (electric cable). Is that non-sense ? You work with electromagnetic (radio) wave so it should not be insulated right ?
Insulations doesn't matter. Many people use insulated wire for their aerials, including me.
Hi Ray. I'm enjoying watching your videos. (Your "informal" style makes for easy listening and learning!) Just a quick question: When you cut the legs of the dipole to exactly half the total length required, do you take into account the short amounts of wire which will end up twisted back on themselves at the insulators and, therefore, not form part of the overall physical length of the dipole?
If you want to, make the two legs slightly longer, then add the feed wire, and then cut the overall length to what's right. It's not that critical (a couple inches.) and no antenna is perfect.
I'm putting together this ariel this weekend, just a bit more advice
Could I put a switch to switch in between the coax ground and core to be able to make the ariel more flexible for short wave bands ?
I'm also worried about any live static coming in, is there a way of protecting , I don't want to grab the end and get a belt
Yes, a switch would be ok. You could try a large RF choke between the aerial and earth to discharge static build up.
Radio Workshop I'm new to the antenna project , I've ordered a
*Inductance: 10mH
* Self Resonant Frequency:
* DC Current Max: 70mA
* DC Resistance: 30R
* Q Factor: 150
* Inductance Tolerance: 10%
choke , would that be OK to reduce static ? also do I place the choke between the coax core and ground ? I understand all this is at my own risk but your non committal advice is much appreciated
Kind regards Shaun
I am using a Marconi T. Speaker wire to the top floor, and then split and run in the windows in a diagonal pattern because of electrical lines along the street. Straight horizontal did not work. The lines were too noisy. I go 10 foot up, split and run in the windows diagonally for 80 feet. I've got 170 foot of wire outside my apartment. I could shorten it and I may. I am going to try a plug and make it a dipole first. Then it may get trimmed. I want to listen to all bands so I am also going to look into a tuner. Those are steep.
That's interesting information, thanks very much. Cheers, Ray.
Hello Sir, I just bought an Eton Satellite 750 sw radio. As I see, the 6 mhz frequencies are capted with an dipole antenna like this: 468/6mhz= 78ft, so 39 ft each side. At that length, can I also receive frequencies higher than 6mhz ? (for example, Band 31 at 9.4-9.9mhz...). Because if I do the math : 468/9 = 52ft, so 26ft each side. The way I understand it, since you need only 52 ft antenna to get the 9.4-9.9mhz frequencies, then at 78 ft (the 6 mhz antenna) would be more than enough. And the higher the frequencies, the shorter antenna will be needed, right? To simplify, with your antenna at 78 ft, it seems like I can also receive all the frequencies higher than 6mhz? But not those under 6mhz. Am I right at my supposition? Please help me....and thanks for answering :).
Hi Bill, Your dipole will receive frequencies above 6mHz but it won#'t be brilliant. Ideally, you need a doublet antenna with a balanced ATU but what you have should be fine.
@@g4nsj Tanks for answering....one more : what's the right way to solder the 2 stranded wires (the 2 horizontal 39 ft long wires) to the coax? One soldered to the center conductor and the other to the metallic shield? Or both on the center conductor? Thanks again :)
@@fon9365 Yes, one soldered to the center conductor and the other to the metallic shield.
@@g4nsj Thanks again sir. 👍
Hello ,,I made an inverted v dipole, yrs ago and used to pirate around 6.6 can't remember what it was called now but 15 watts used to get me everywhere ,,all over Europe and Ireland using the atu in my ts690 cheers shane
Hi Shane, excellent stuff! I love 6.6mHz... and it's still going strong.
Echo Charlie,, must have a listen ,,
Hello Ray, thank you for the excellent video. My question is regarding the 39 wire any specific one or just any wire could make. Second question ....do I need to brade the wire ( 39) Or it should be normal wire with its cover. Many thanks ..Stay successful.
Mohamed Hameedi Hi Mohamed. Virtually any type of wire will do, just normal wire with its cover. Cheers, Ray..
Dear Ray....many thanks.
For reception, I'm using a 30ft horizontal length of copper wire, stung 5ft above my roof deck.
One end of the wire feeds the 500ohm input of my receiver, using just the core of 50ohm coax cable.
The receiver earthed via my steel kitchen sink
It seems to work well between 49M and 31M. That said I have nothing to compare it to.
Is it feasible to add a vertical antenna that shares the 50ohm coax cable with the 30ft wire?
It is but you will need switching and some kind of matching to the coax. It's probably better to have a separate coax feed to the vertical.
Thanks for the reply. I'll do a little bit of experimenting. I'm a bit cautious of going to high with the vertical as we get a lot of lighting here.
OK, well take care!
Hi Ray! Thanks for the great information! I don’t have an earth socket on my radio, where should the braided side of the coax go?
To the chassis, but make sure it's not a live chassis type radio.
@@g4nsj thanks Ray. It’s a nice new Tecsun pl 880 and I don’t want to drill any holes in it. You mentioned using the headphones jack for a ground. Wouldn’t that kill the sound from the speaker?
Can anyone help me.
I have a small portable radio (Kaito KA500 Voyager) with an telescopic aerial. I mainly using the radio outdoors and therefore looking at using (ladder-line) as my feed-line, instead of coaxial cable.
How would I attach the end of the ladder-line to the portable radio's telescopic aerial?
Can I attach both wires to the telescopic aerial?
Or do I need to attach one wire to the telescopic aerial, and the other wire to a ground?
You can attach both wires to thee aerial but, better still, take one to the aerial and the other to the radio chassis. The outer connection to the earphone socket might work as the chassis connection so take the other wire there.
Thanks Ray, I appreciate the advice, great to know.
Hey Ray, if I use the 3.5mm earphone socket; would I use a 3.5mm audio "mono plug" or a "stereo plug"? Or will it not really matter which 3.5mm audio plug is used? Or would one be better than the other.
Kiwi Bushcraft And Survival it doesn’t matter because you’ll only be using the outer connection, not the two inner ones.
What about the length of wire lost attaching it to the insulators? Not critical?
You're right, it's not critical.
Very nice aerial concept. Thank you.
I had not heard widely about dipole aerials being used for SW listening and especially if old valve radio sets could use them effectively. India only had those fine copper mesh between plastic insulators (acting as capacitative hat) with a lead in wire from the mesh bringing signal to radio.
On my 8 band National Ekco A731 valve radio, I have many SW bands as bandspread. But 49m is not bandspread and it is clubbed under single MSW band.
Questions:
1) Will this dipole aerial help me tune other SW bands like 13m, 16m, 19m, 25m, 31m, 41m, SW 60m? and the MW?
2) When I connect the coaxial cable to the two 39 feet dipole sections, should I connect the coaxial braid to the earth socket of my tube radio? Or just leave it?
My valve radio has mains power cord of three terminal and the radio chassis is earthed through the mains power cord. There is no possible of a independent earth for my radio on a RCC highrise in India. RF disturbance is grandest in India due to concrete forest that we have :)
3) Will the length of 39 feet change for SW 60m and SW 90m and MW?
+indiaradioguy Hi, A dipole will only work well on the band it is cut for. Yes, the coax braid goes to earth socket on your radio. If you want to cover all bands, you will need a simple wire aerial with a tuning unit. Regards, Ray.
+Radio Workshop Thank you Ray. Can you please suggest best tuning unit for the long wire aerial? Are they up for sale on www.amazon.co.uk or other websites? Getting those ATUs is impossible in India and building them will is another impossible task as getting a 365pf tuning cap is not so easy now.
+Radio Workshop What is best optimal length for long wire aerial to be put up? Or should I put up inverted "L" to cover all bands?
I think an inverted L will be your best option.
+Radio Workshop Thank you. What should be the length for inverted L aerial wire for all band reception? And, What type of wires should be used for best reception? There are two wires in inverted L; one between the egg insulators and one which is the lead in wire.
Hi...hope to get myself a HF tx rig for when I retire soon...I have an M6 ticket and would like to construct several centre fed half wave wire dipoles and use them in a mobile location...prob strung between 2 trees.
If I use 50ohm coax as my feed line...do I need a balun at the dipole centre...never was able to get my head around Baluns...lot in print re having one but not much telling what they do.
I will be working QRP.
Nick.
Hi Nick, just roll the coax up at the feed point. Say, six or eight turns about six inches diameter. That will help to keep RF off the coax.
no you don't need one.......if you have a newer radio, they have TVI filters in them (i.e., low-pass filter).....I have used 80m and 160m dipoles without baluns and 50 ohm coax, and no issues.....a good insulator in the middle....good solder connections, and a bit of sealant where the coax splits to feed the antenna is helpful......but you don't need one....it is neater, and will have less likelihood of rf travelling down/around the coax, but with low-power (QRP) and less than 200-300watts or so, you should not have problems....for a transmit antenna, just make sure the feedline is at least the length of one side of the dipole, i.e., 33 ft per side? 33 ft of coax, or longer.....not as critical on receive, or below 50 MHz and not much output power.....hope this helps....
Hello, Ray! I 've got a small portable radio that does FM/MW/SW (a Degen DE13--it was the last little luxury I bought before capital controls were instituted here) and I too am interested in listening to the 49m band. My radio doesn't have an aerial input, only a telescoping aerial. Could I attach the aerial you describe here to the telescoping aerial with an alligator clip? If so, what would I do with the earth part of the aerial coming into the house through the coax wire? Does an aerial like this (at the proper length) improve FM reception as well? (Great videos! Any chance you 'll be doing a video on improving MW and FM reception?) Cheers from Greece! -Angelos
tēletheātēs Hi Angelos, Yes, the aerial should be good for your radio. Connect the earth part of the coax to the radio chassis, this will be the metal around the headphone socket, if it has one. If not, connect it to one of the battery leads. It won't improve FM though.
Excellent! It does indeed have a headphone socket, as well as a second battery compartment for AAs, which is currently not in use, as for normal listening I run it off the internal batteries which recharge via solar panel or hand crank. The FM is plenty sensitive on its own, so much so that I usually have to lower the telescoping antenna. The problem with FM arises when trying to pick out a weaker station adjacent to a stronger station (i.e., selectivity). The metropolitan area of Salonika is notorious for its overcrowded FM band, as well as for privately owned stations that routinely broadcast with too much power, thus drowning out public stations adhering to the legal limit.
Could you tell me what you think of those external coil aerials for MW? They 're supposedly good for DXing MW and work without even being physically attached, merely by being in close proximity to and coupling with a radio's internal ferrite aerial.
Thanks so much for all the great videos and useful info. Cheers!
tēletheātēs To be honest I prefer a decent outside wire aerial for medium wave rather than a coil or loop. Having said that, a loop is great for nulling out unwanted stations or interference. Cheers, Ray.
In my case a loop in close proximity to the internal ferrite is the only option, as there is no way to physically connect a wire for MW. Thanks again so much for your input, Ray! Cheers! -Angelos
There is but it involves matching and circuit changes etc.
I realise 75 ohm coax isnt correct, but does anyone have any experience of actually comparing 50 with 75 ohm for SWL? Is it likely to impact signal strength much on a short 5-10m run?
For receiving, I doubt that it will make a great deal of difference. Especially if you use an ATU or preselector.
Receivers with a coaxial connector are usually 75 ohm. Transceivers are normally 50 ohm. A dipole up high enough is nominally around 72 ohm. As mentioned, for listening it'll have virtually no effect.
It would be alot easier if people start using meters instead of feet, since wavelenghts are in meters. If not for anything else, measurements in feet really aren't anything else than measurements in meters, recalculated. The definition of 1 foot = 0.3048 m.
Sir, coaxial cable one wire to radio antenna another to where I connect?
The inner wire to the aerial and the outer to earth or ground.
@@g4nsj
Roger that....
Thank you, Sir..
How to connect this antenna to a radio that doesnt have external antenna jack?
+andre H Is there a telescopic aerial for shortwave? If so, connect the coax inner to the telescopic aerial and the outer braid to the radio chassis.
but would that work if the radio chassis is made of plastic? (non conductive)
+andre H There will be some metal inside the radio. Alternitively, take the braid to the outside of the earphone socket.
+Radio Workshop many thanks man!
Another great tutorial, Ray.
I'd be limited to each leg being 12' long. What band should I expect to receive?
Many thanks!
It will work best from 20 to 30MHz.
@@g4nsj Thank you.
What is the math to figure that out?
@@usernamemykel Metric or imperial? Either way, it's divide the speed of light by the frequency to get the wavelength, or divide the speed of light by the wavelength to get the frequency. A half-wave dipole will be half the wavelength. If we use metric, the wavelength would be 299.8 / F , or / L . Let's take your 12ft, or total length of 24ft. That 48ft wavelength, or about 15 metres. Straight away you can see that would work on the "15 metre" band if there was one. But if you want the frequency, 300 (rounding!) / 15 = 20MHz.
What about portable radios with no earth connections
Try and find a metal part if the radio for the coax braid. For example, the earphone socket.
I'm using dacron rope (paracord) for my insulators. I tie the rope to the end of the poles, so I can stretch the aerial between to poles or trees.
The new silicone self-fusing tape should work well for water-proofing the connections in the centre.
Great idea. Once the better weather is here I might paracord.
A frend passed willed me a thousand foot of rgu 58 cable you bet I'm putting up. Some. I like to listen kv4li
Don't keep a transmitter next to your heart 💔