Building a Delta Loop Antenna For The 30m Band, Part 2.
Вставка
- Опубліковано 6 жов 2024
- Part 1: • Building a Delta Loop ... This time I cut my wire to the correct length and successfully deployed my delta loop antenna for 30m. The 4:1 BALUN turned out to be the best matching option. Great performance, but not as easy to set up as anticipated. The delta loop is probably best for 6 to 20m operations. Get more content and help this channel: / radioprepper DISCLAIMER: The Radio Prepper logo (depicting a microphone) is indeed inspired from a famous flag created in 1775. It is NOTHING BUT a symbol of freedom and independence. It does NOT imply support to any political group. It does NOT imply, represent nor support any ideology with an intent on harming anyone. Freedom means freedom from persecution based on any human trait or belief such as, non exhaustively, race, gender, religion, sexual orientation or nationality. The Radio Prepper channel is a technology and science channel with a focus on preparedness and use of radio technology for disaster relief and small group communications in times of need. It is apolitical and open to anyone sharing the same interests. .
Subscribe to my alternate platforms:
ugetube.com/@R...
odysee.com/@Ra... oops, wrong address! Correct one below:
odysee.com/@Ra...
Now you can buy me a coffee :-) www.buymeacoff... .
Send Bitcoins to: bc1qc5jq4dxt7359sh80lkv9v8rlsgnh322hmn6xyc Send Ethereum : 0xe7cC2e415E0D2d1De91604B2b693f124dfBCf9B8
Send Litecoin : LYwDy55mZSeb1Czx6JUiTS5YkqjfmWKK5H
![[UA] NAVI проти G2 Esports | Blast Premier Fall Final](http://i.ytimg.com/vi/QWlIm4FGESQ/mqdefault.jpg)
Good Day Gil from Florida USA.
I use mostly Delta Loop antennas here for 20-40-60-75-80 and 160 meters. I played around with ladder line, 1/4 wave 75 ohm stubs etc. But on all of loop my antennas are feed with 4:1 Baluns. And I can cover most of the band width on all bands with them. However the baluns are current baluns and not voltage. The voltage baluns burn out to quick. Anyway nice job there. 73's de W4DRA
Thanks. I spent 22 years in Sarasota!
watched both part. interesting, that some antennas work for a particular frequency good.
Enjoyed very much. Interesting about the 75ohm/30m coax. If that's all you had in a perpper situation it would have worked, the the balun worked exactly. 30m is a large delta to get up unless it would stay up for a long time. Always enjoy your field trips to the country side.
Thank you.
If you place the feedpoint 1/4 wavelength from the apex, you will have a better match and pattern.
If you flipped the delta upside down, you could use a much shorter mast. The effective height would then be 1/4 lower than the top horizontal wire, but you will need only shorter vertical mast. You could 3D print a Y-shaped adapter to go on the top of the shorter mast. Then insert a piece of mast in the open end of each "vee" prong of the Y adapter. The loop wire runs along each of the vee masts and then horizontally between them at the top.
Place the feedpoint 1/4 wavelength from the down-pointing bottom apex, up either one of the vee masts.
Keep in mind that this antenna works best close to the ground. 0.2 wavelengths above ground is the "sweet spot."
Although it has less gain than a dipole at the same height (except at 5°, where it surpasses the dipole), it has superior receive characteristics than a dipole and far superior to a vertical. This, because it responds mostly to the magnetic component of radio wave. You may (will) find that often the signals received on the loop will be less strong than on a dipole or vertical, BUT the superior signal-to-noise ratio of the loop reduces noise by 6-12 db or more. Also, if you are able to turn the antenna, you can null out or greatly attenuate signals from stations in the plane of the loop (i.e., with the edges of the loop aligned with the station(s) you want to attenuate).
Remember, these work best for DX at about 0.2 wavelengths above ground; higher up, a high-angle lobe begins to form.
You should be able to use this antenna on its 10m harmonic. But if you feed it at a corner, the feedpoint at the harmonic will be a voltage peak rather than a current peak and although the impedance match should be OK, the Voltage SWR will make your radio reduce power (or if it has no self-protection circuit, may wreck the output transistors).
73 de WA7VTD
Great info, thanks!
Better to be slightly under than slightly over. Good trial and error, with analysis. Some great ranges there.
4 to 1 balloon 🎈
BALUN :-)
I have used many of these loops. I have found the 1/4 open line of 75 ohm works perfectly if it is truly 1/4. I have found that the velocity factors described as standard are not always spot on. The best method is to cut , little by little, the coax (starting longer of course) . Seems like a 3% difference was found, and I believe it needed to be shorter. Worked perfectly when matched with the correct loop length. Another thing that I've dealt with is that when the delta is horrizontal, and low, a 1005/f measurement works. But, when its quite high, 50 to 75 ft, it must be lengthened. An 80 was lengthened 12 ft and worked VERY well once that was done @75ft. I use a 4/1 with that one, and also open wire line (4/1 is in the shack, fed by 450 ohm window line. A contact with D4C on 15m ssb with 5 watts was made, California to Cape Verde Islands, near Sierra Leon, in Atlantic , 80m loop in Delta config vertical. uBITX. Liked, shared, and subscribed.
Re length and size. I live in a wooded area, many trees. I have a air propelled cannon. I shoot rubber balls up, with string attached at first. Then i pull up a small rope with the string. I have been thinking about a CO2 version for putting pressure into the PVC cylinder.
Great info thanks.
When the sending station has lousy spacing, it's hard to tell what the heck they're sending. You could be perfectly rested and sharp as a tack, and if they send mush, you're not going to copy it well. Some hams get in a big rush and don't take the time to put proper timing into their sending, whether on a straight key, cootie, bug, or paddles. It drives me CRAZY when people just send all the characters in a single stream with no spacing between LETTERS, much less WORDS! That's impossible to copy!
Indeed. I realized it after, editing the video.
@@RadioPrepper Have you ever made a linked dipole? I have one I made for 40m, 30m, and 20m. It works great! I went to a local park by our municipal center and raised it on a 7.2m telescoping fiberglass mast, clamped in a drive-on baseplate. The far ends have glow-in-the-dark paracord ties with paracord tensioners, and at this location I clipped the paracord to some photographers' sandbags to hold them down. Some places don't like you pounding stakes in their ground, so I have the sandbags. They're black with day-glo yellow stripes so they're hard to miss.
I worked from Philadelphia to the Upper Peninsula of Michigan, about 800 miles, almost 1300km, on 10 watts, 40m phone. I tuned it to the CW portion of each band, but the tuner in my KX3 tweaks it just that little bit in the phone portion, just to keep things as matched up as possible.
It's nice to be able to work my favorite 3 daytime bands on a single antenna, even if I do have to plug and unplug the links when I change bands. I'm working on a fan dipole made from 2" wide electric horse fence webbing, 15 parallel stainless steel wires woven into poly webbing. I hope to be able to tune it for 40 on 5 wires, clip 5 more to tune it to 30, then clip the last 5 wires to tune it to 20. It'll be tricky, I'm sure, since the wires are so close together, but I hope I can get it to tune up. That way I won't have to do any plugging or unplugging, I can just change bands and go! Much nicer for bad weather, or just so I can hang it up higher in the air!
Excellent little.2 part series gil thanks for sharing. I keep seeing conflicted views about what balun should be used regarding delta loops . Some say a full wave loop is around 100 ohms so a 2:1 balun is best. Others say use a 4:1 balun. Could you explain why there are 2 views of thought cheers
No idea, but 100/2=50, so that should settle it ;-)
I have used a full 40m vertical loop suspended by 2 trees with the top about 15m. I can highly recommend it if you have the space. It was very quiet and a strong performer for dx even with only 100w.
Actually it seems to have 200 Ohm impedance. That’s why 1:4 balun nicely transforms it into 50. At the same time 1/4 75 Ohm coax should transform it into something close to 25 Ohms. And that’s what we saw on your AA.
Many tv coaxes have foam dielectric and vf something close to 0.85. But if you have vector AA it’s very easy now to check vf and see that coax is actually 1/4 on desired frequency. Moreover many cables have impedance different from nominal, and that also could be checked with vector analyzer. Connect a dummy load to you feed line coax and sweep it 1-30MHz and check the results. That could be very interesting ))
Anyway good job! Thanks for video ))
Thanks!
Yep, if my calculation is correct, it would have to have an impedance of about 113 ohms for a quarter wave 75 ohm transformation to result in 50 ohms.
G1EKW.
Add my previous qth I used full wave closed loop Delta loops with quarter wave coaxial Transformers. I almost always had to lengthen the loop element slightly to get a perfect match.
Interesting thanks.
Same here. I think the issue is like with a dipole. If the two wires aren't cut to the same length their resonant freq do not match. Thus the dip for them both never drops its its lowest.
The wire loop has its resonant freq and the 75ohm matching stub has a separate freq. If the two do not match or align properly then the dip suffers.
QRP baluns are fine but QRO baluns are heavy! I just hate hanging one up in the air on a permanent antenna! Added strain on the whole system! Plus plastic only lasts so long in the sun!
Great vid Gil. Informative real-world antenna work. I love watching your vids... very pleasant and always interesting. Thanks! Gil, I've been playing the a scrap material vertical for 4 bands. It could be made out of fishing poles and collapsible if a vertical is someone's thing for portable use. Look for the Michigan cacti if you wanna see it. It's now my favorite most used antenna.. especially for dx... and it was free. 73 OM
Will do. Thank you!
I see that #ELKPAK's insulators are useful! LOL! Good job, Gil! 👍
Nice discussion of getting best feed for the loop and good photo skills here too. I have been on the air for 61 years and continue to love the full-wave loop on 40 meters. Problem: Could somebody please explain to me just exactly what is the "it" that the PREPPERS are preparing for? Do these folks actually believe that when 'it" happens (i.e. the end of the world, a new civil war, etc etc etc) anybody will give half a hoot about talking to anybody else on HF, or VHF, or UHF?
"It" is anything... No different from wearing your seatbelt, as it could be a semi truck or a deer...
Good..mr
Fascinating! This location must be like a balcony overlooking whole Italy! I’m near Toulouse and can hear Italians all the time on the 40m band. I wonder if one when adds a diode just before the antenna (letting the current out but preventing it from going back into the unit) would cut the heat returning to the radio.
Lots of traffic from Italy yes.
That's some bright coax you've got there
Not to confuse it with 50 Ohm coax.
@@RadioPrepper I figured so. Really good idea. I usually just use the stuff they sell at the hardware store but the quality has really gone down hill recently. The stuff they used to sell had a copper foil and thick copper braid. Now it's aluminum foil with a few strands of copper. Still I always put the F type plugs on it they sell for it and use bnc adaptors. I thought you'd find a 30m Delta loop a bit cumbersome. I think I'd go with a half wave end fed too. My 80m halfwave isn't perfect on 30 but it works and gives me most other bands into the bargain. I find the Delta loop to be a good on 6m it's easy to string up on a fishing pole. I thread it through a 2m length of pvc pipe to make a triangle that doesn't need to be roped up and stuff to hold it's shape. I used that for a while until I built a 3 element beam for 6m but the beam is too cumbersome for portable use. It just barely fits on top of the truck when assemebled but I have to take it apart to store it in my garage. The Delta loop folds up nicely and is quick and easy to deploy
Ohh on second watch I noticed you said you weren't sure if your matching stub was the exact length it needed to be. What I do to measure my matching stubs electrical length is hook it up to my analyser and leave the end open. At the resonant frequency it just looks like a short on the analyzer impedance plot. I do the same thing if I want to measure the velocity factor too
Gil, the initial reading without matching seemed strange (34+50j) that should be 100+0j as far as I remember. Instead of trimming for low swr (prior to matching) it might be better to find resonance by aiming for zero reactance. Be careful when matching capacitive or inductive loads with a balun. Nice location, great qsos, great weather btw. Also you brought the foufou, that adds to the outdoor spirit. 73
Thanks. The coax might explain the difference..
@@RadioPrepper Hi Gil, just a question: have you set the reference place at the end of the 50 Ohm cable? That's could be the reason why you get this strange Z= 34,5 + j 55,7 Ohm instead of something similar to Z= 110 + j 0 . Once you have cut the wire in order to set near to zero the X part of the impedance you could find what's the right method to matching the impedance and for example calculate the length of the 75 Ohm cable that give you the better possible result. If you remember the lenght of the 50 Ohm Coxial cable you could also now figure what the Z at the feed point using for example SimSmith and subtracting to Z= 34,5 +j 55,7 the length of the 50 Ohm cable. Thank you for your always interesting videos. 73 de Paolo. IU1CYF
Vos vidéos sont excellentes, informatives et divertissantes. Je suis un peu surpris de voir à quel point le balun 4: 1 fonctionnait bien par rapport au câble de 75 ohm. Avez-vous pensé à faire une boucle delta pour la bande de 20 mètres? 73
Merci! Je l'ai fait pour 30m, fil de 15m...
Hi Gil, the beauty of a delta loop is they work very well low to the ground. I also use one on 6m and it has performed most excellently. 30m delta loop is quite large. The trick is to mark the corners. and also to have the distance out from the mast base marked out. that way you can run it out loosely guy it and than raise the mast and it should go up well.
I guess its all in the planning. Sotabeams wire winders will stop your tangled mess at the end. hee hee.
72 Gil hope to work you on the bands de g0nmy sk pip pip.
Thanks. I hope so :-)
“Have a gun afternoon” hahaha 😆 🤣 😆
Where do you find such good helpers? All my friends are either working, to busy or to lazy! lol
It has to be a location with the perfect lay out of trees somewhere! I just know it! What about that trail ride you took up in the mountains! I bet its a spot near a summit along those trails with the perfect trees spaced 105M or more apart.
I love my 30M horizontal loop! Its about 70ft up! See WW5RM-13 on the APRS map. With 20 Watts I get into Australia a couple times a week or so. I hear Italy a few times a week. But I think he is running big power and or using a hop path in his beacon.
I used a 75 ohm coax matching stub. RG6. I used F connectors and they aren't very good! Plus the shield is pretty weak! So I had to reinforce along the connectors with zip ties and electrical tape. So far its been up for almost a year now.
Im thinking maybe some good BNC connectors. Cut the 75 ohm cable to precise length and put connectors on myself. BNC connectors look like a pain to install though. I did a N type once! I said id never do it again! lol
They found me! How long is your 75 Ohm cable?
@@RadioPrepper I forget. I found a formula online for it. I can research it for you. Anything beyond yesterday tends to get stashed away in file 13 / recycle bin. =]
@@RadioPrepper see how crazy I am? I didn't use F connectors! Wow! I used PL-259 reducers but that shield on the RG-6 I used is pretty weak! So I reinforced it as best i could to take the strain off the connection.
@@RadioPrepper I believe this was the site I used.
www.66pacific.com/calculators/full-wave-loop-antenna-calculator.aspx
Looking back through the log on 30M APRS it looks like the band fell in the water / died out from 0100 UTC to about 1200 UTC. No stations heard during that time. But that seems to happen a lot.
That's usually the time frame I hear Australia but sometimes it falls short. I am anxious to see how 30M conditions are during the peak of the sun cycle. I never really used 30M enough in the past to know. But during the day I get Canada and Mexico regular. Its a guy in Michigan, WA8LMF he has a pipe line to me! He is 1380 miles from me. Its a few others I see on the map everyday. Same time like clock work. 1000 - 1500 miles +-
Puerto Rico was coming in for couple of days. Its over 2000 miles from me. But he is gone now. Some of them are not on it everyday either. So its not always accurate but for the most part a pretty good propagation tool.
In English "balun" is said with a short U sound
It is "impEdance" with a long E sound
I have made a "D" shape using a larger diameter G10 tubing for support. The tube was about 2cm in diameter. Larger Tubes about 30cm long that fit tightly over the smaller tube made the joints.
great info.. wonder if the 75ohm match would work on 40m, not 30, ?. .Great Videos! n5ysw
It has to be a quarter wave..
Yes. I use a sloping delta for 40m. 2 ends high one low. It is 6-7db better than efhw. 75 ohm stub 1/4wl minus velocity factor of cable.
Gil, where did you buy the stand for the K1? It looks really nice and seems to work well...
Hi, I got it with the radio. It is an Elecraft stand...
This CW reminds me of some of the Drivers these days who refuse to slow down always in a rush to get to the next Red light or congestion faster, instead of slowing down a bit and enjoying the scenery.. Please slow down your CW to the speed of the other operators sending speed..Its just common courtesy.😊👍..Not you Gil the ones sending way too fast.
I Never have any trouble copying your CW Gil..I don't think you were tired there was some wonky CW for sure being received.
Thanks guys. I realised that later while editing the video...
Gil!:
Only ONE complaint : ) Bal-Un! Not BalOOn! : )
Otherwise GREAT video!
de seeker/Jeff WA7LFP
Well, at least I spelled it right ;-)
@@RadioPrepper Oui! That is right! : )
20th century motor company :)
Good catch ;-)
Great video! 73, K6YYL
Thank you!