Tape Measure Yagi Beam Antenna - Ham Radio Q&A
HTML-код
- Опубликовано: 4 фев 2025
- The 2 Meter band tape measure beam antenna is a 3 element Yagi with about 7.2 db of forward gain. This lightweight antenna is perfect to use for fox hunts or as a portable directional antenna for public service events.
Instructions:
www.jpole-anten...
Parts List
1 25 foot 1 inch wide steel tape measure
1 10 foot piece of 3/4 inch Schedule 40 PVC Tube
2 3/4 inch PVC Cross connectors
2 3/4 inch PVC T connector
6 3/4 to 1 1/2 inch stainless Hose Clamps
1 5 inch piece of 14 ga wire
1 length of RG-58 cable, approx 6 foot
Solder and Flux
Electrical Tape
Tools
Soldering Iron
Tin Snips
Wire Cutter
Screw driver or nut driver
PVC cutter or fine tooth saw
Sand paper or Dremel tool with sanding disk
Ruler or tape measure
Based on the design by WB2HOL: theleggios.net/...
Support Ham Radio Q&A by shopping at Amazon: amzn.to/2kO6LH7
Read my blog: www.jpole-anten...
Music by license:
www.premiumbeat...
Funky Chunk Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
creativecommons...
WOW!! What a great video. All you you tube video producers should watch listen and learn. 1. Great audio, nice and even and at a proper level. 2, Great subject, something people may really be intrested in. 3. To the point and not endless talking heads. 4. Showed
proper assembly, quick to the point assembly instructions, not a 2 hour video of some guy who left his camera on. 5. Great presentation and commentary, not some guy saying UUh and whatnot for and hour. GREAT video keep up the good work, and Thanks. (I'm Gonna build one)
Thanks for the compliments, I'm glad you enjoyed the video. It's been my experience that there is a dearth of good amateur radio DIY videos. So I'm using my expertise in video production and experience of amateur radio to create tutorials that are interesting and well produced.
i was wondering what mount u used to mount the yagi while you was testing it
Yep, and he talks at a good pace. Many times I have to crank up the speed to 1.25 because of slow talkers.
@@KB9VBRAntennas please please don’t ever stop making videos 😊
Subbed. This was probably the most concise video on building your own yagi I have seen. I pulled a hat trick on Saturday and went from unlicensed to Amateur Extra in one shot. Now I'm just waiting for a call sign.
Congrats on the license!
I know it's almost a year later, but I would like to know how you passed all three exams in one shot. Did you already have some background in the field?
@@tradedate -- Most certainly, as there's enough info at each level to prevent guessing at the answers and passing.
I have a BS - EEE, and have studied a bit, so that I'm hitting 90% on Tech practise exams, but only 65% on the General practise exams. Doing all three at once is a great achievement.
@@CycleRayinOK for sure. I decided to pace myself since it was all new subject matter for me. I studied hard for the technician license. I aced that, so they offered me the general exam. I missed it by two questions, having not studied for that one at all.
No regrets though. I didn't want to overwhelm myself and fail the tech.
6 years later your video's still helping people. Built my first yagi following your directions and it works great! Hope to find a fox hunt this summer. Thank you!
Could you give the formula for calculating the reflector and boom length @matthewnovak5440 ??
@@Chalan_Chitramu I can't help you, sorry. I just followed the instructions provided in the video, and that was a year ago, so I don't recall them of the top of my head. If he doesn't provide that info in the video, I wouldn't know it anyway since that's where I got my info.
@@matthewnovak5440 Could you suggest any book for designing the yagi uda antenna ??
I built one of these and my first attempt on 2m simplex was a brand new ham calling out! He had just got his technician license at the DARA hq just a few days ago. He was super excited to reach me as his first contact ever, and I was super excited because he proved this new antenna worked fabulously!!!! Thanks for posting!
I built one of these at a local ham club meeting. They talked about it being great for fox hunts, but nobody mentioned you could use it with an HT to hit a repeater 60 miles away! This thing may become part of my go kit, since it folds up pretty easily. Thanks for the step by step walk through... excellent video how-to!
73,
Brett
You are correct‚ you can transmit with them. I did a video last month where I used mine to make a sideband contact 40+ miles away: ruclips.net/video/uvH8NQy-T84/видео.html
Michael, I watched this a couple times last night (friday.) I managed to copy a rough idea of this (2 meter, tuned with the nano) and made a contact 52 miles away with a UV5R, yes you heard that right, a little 3 watt radio. I think the real lesson here can bring up a multitude of topics which I will discuss with some other people soon here: hams have the privilege of building their own stuff, our signals can travel much farther, that topic of possible interference could possibly happen if it's zipping around the earth or bouncing off of things and lastly and most importantly never underestimate the ability of underrated equipment in the right conditions. I really think this was dumb luck but I did use a Google distance calculator, a compass bearing and found a good spot. Thanks for all you are doing with this channel and being a servant to others. The information you taught might save somebody else's life one day.
I just wanted to say Thank you! I used your design here and substituted a wooden yardstick in place of the PVC pipe because I couldn't get PVC pipe where I was deployed. The antenna was fantastic! Using my Yaesu FT-817 I was pushing 5 watts QRP with zero watts reflected as measured on a Bird Thruline wattmeter making contacts that I never would have thought possible. Great design that has me wanting to make more antennas in the future when I get home. Thanks again. 73's KX4IG
I'm curious how far that 5 watts will reach out with this thing?
I built this antenna last month and i just sent my APRS beacon to the International Space Station with this. It works perfectly well. Thank you. TB1CLR, 73.
Great video! I did laugh out loud when you used a tape measure to measure the tape measure to cut it...
I'm fairly new to ham radio, but im fascinated by antenna and antenna design. Thanks for the information...
Combustion Kills : I agree, couldn't get any easier could it???.
Agree, I though that was insulting to the tape. If you have to cut up a tape for this, at least have the decency to use it to determine its own length!
@@AlessioSangalli Heck no! That would be savagely!
Just made this antenna with the stuff I had in my shop. Was my first antenna build and worked great out of the box. Hit a repeater 32 miles away.
A friend of mine built one of these. This is only based on a test of one antenna. I measured performance in a clear open area. Since the intended use was hidden transmitter hunting, my only concern was the antenna pattern.
I found two important things with the antenna brought to me:
1.) It had terrible common mode on the coax. I could touch the VNA analyzer case, or slide my hand along the coax, and see a fairly large change in impedance.
2.) It had generally poor directivity in the 2M Ham band. It lacked a good deep null off the rear. It actually seemed to have better directivity on the weather band than2 meters.
I did two things.
1.) I altered the spacing. We just swapped the director and reflector around on spacing so the reflector is wider spacing like almost all 3 element Yagis are. This improved the back null quite a bit. I made no efforts to trim elements, but suggested he make the elements slightly long in a future model so we could trim them in.
2.) I grounded the coax shield to the center point of the reflector. We had about 18 inches of coax spiraled around the boom to the hairpin match. This forms a high impedance on the shield at the hairpin. This completely eliminated the noticeable SWR changes as I moved my hands along the coax.
Your build is very similar to the way I typically make them. I like to dip the ends of each element in that liquid plastic stuff they sell at hardware store for coating tool handles. It makes the ends more visible and prevents the ends from scratching or poking anyone. Also, I always put a cross on the director end as well. Once you’re close to a hidden transmitter, it’s often easier to zero in on the location using the null on the reflector end, so the extra cross allows you to hold the antenna ‘backwards’.
Just finished building this antenna and it is amazing. Thanks for putting this video together. Made a few contacts over 50 miles away with an HT.
Good to hear that the antenna is working great for you.
Was that a simplex contact?
Just made contact with the ISS via APRS using this tape measure antenna and my Yaesu FTM400XDR. Thank you for posting this video Michael! 73s from KI5BWY.
Me too!
@@111TMX Did you mail in for your postcard?
You build the antenna yourself to learn how antennas work (and save money in the process). That is what this is about. Those who buy "off the shelf" really do not learn anything regarding Amateur Radio, only create excessive cost and no knowledge regarding antennas as a whole. We can try to build our transceivers and do a pretty good job of it, but those who build antennas really know radio.
Great Ham Radio project Michael. Excellent easy to understand video. Especially like the method you use to speed up the construction portions of the project. It is refreshing for a ham to give the parts lists and step by step instructions. FIRST CLASS PRESENTATION. Very professional, I thought you must be a teacher with many years of experience. I built two of the antennas for an upcoming ham club fox hunting event. No problems, worked just as you said and showed in your video. Other Amateur Radio operators could learn many good tips and methods to present and do videos on ham radio projects if they watched your videos. Keep up the good work Michael. Great Job! Howard WB0ATB
Thanks for the compliments. I'm glad you found the video easy to follow and were able to build working antennas by watching it. I never was a professional teacher, but I did stay at a Holiday Inn Express once :). I do have a degree in Communication Arts, so it's good to put my Liberal Arts education to use in benefitting the amateur radio community.
I built one of these over the weekend and it works very well. I got the SWRs down to 1.1:1 and instead of soldering the coax to the driven elements, I decided to use an SO-239 connector with 3 inches of wire for the center conductor and ground, each. My house is in a 100 ft valley (compared to surrounding terrain) and I am still able to talk to my brother 4 miles away on 1 watt of power. Also, I'm using RG-8X coax to connect to the antenna.
I could listen to funky music and watch people build antennas all day. Great stuff man. Can't wait to try this out!
The music is great for sure!
Thanks for the great video. Thanks to this antenna I was able to participate in the ISS SSTV event this morning. Thank you
Hey I've been a wood flooring contractor for 32 years that little tape measure you got from Harbor Freight is one of the best tape measures you can spend three bucks on better than a Stanley I originally bought three of them one lasted like 3-4 months and it was just so dirty that It was hard to read but it still worked nice project I'm going to build me one thanks
I just built this and it looks like I am hitting towers about 50 miles away. However, please tape up the ends of the tape measure, my ten year old son was holding the antenna while I taped the cable and he dropped it on my leg,
And it cut an inch and half gash, I am headed to the clinic now to see if it needs stiches.
Cool... Great presentation. As a former teacher, I can really compliment your style and AV methods. Solid and easy to understand instructions. I don't even really need one, but it looks like a fun project. I think I will build one to keep handy. I wonder how much of Harbor Freight's business is from hams? 😀
The is K4DGC Chris in Tampa Fl. I built my own 2m yagi per your instructions and it turned out great. I am the Deputy EM for Hillsborough Co ARES/RACES and I recently brought this idea to my training officer who put together a class to build and test these tape measure antennas. We were able to get a few made and tested each one and they worked perfect. The steed TS were so thrilled that they proposed a Fox Hunt with their antennas so that is in the works as well as a possible build class for a 70cm yagi. Great job sir!! 73!!
Neat trick I learned for cutting the tape measure: you don't need any tools at all! If you fold the tape back on itself inwards (numbers touching numbers), and then press the fold flat to make a crease, it will snap and leave you with a perfectly straight line! Unfortunately, I learned this too late to save myself from a half-hour long battle with my dremel (most of it searching for the pieces).
This is a very informative and clear video. I built this antenna with one minor modification -- instead of soldering coax directly to the feed point, I instead soldered an N-type socket, and use an N-type to SMA cable to connect to my HT. (I have bad luck when it comes to stripping and separating coax. My approach ain't pretty, but it works.) I also covered the tips (last 1/2 inch) of the elements with electrical tape to avoid cuts and scratches.
Analysis with a NanoVNA showed my version had an impedance of 52 Ohms and minimum SWR of 1.1:1 at 148.5 MHz. The SWR increases rapidly from that minimum, but still seems reasonable within the 2-m amateur band. On 70 cm, the antenna has an SWR of 1.6:1 at 449 MHz. I'll try playing around with the spacing of the driven elements to see if I can bring the resonant frequency/ies into the right range.
I am stunned by the excellent presentation on the subject. Believe that you covered all the bases of a video. Last but not least, I am amazed of you thinking out of the box using such simple materials and making a really nice Yagi. Good day too.
UPDATE:
Picked up a MicroFox (15mw output) and built a couple of these using an active offset attenuator. I use them specifically to teach scouts for Merit Badge Requirement #9, partake in ARDF, but I also use it as a DEMO for a variety of youth events.
I set the FOX a distance away, and show them how to use the setup. My attenuator offsets the main frequency by 4MHz, making it cleaner to find the fox.
The original antennas still work, but I am building a couple more so multiple sets of Scouts can look at the same time.
I also have a few full power HTs (6watt) that are crossband I have used for a greater distance fox hunt.
However, this is still, as far as I am considered, the gold standard for the homebrew Yagi.
It is simple, it is cheap, and it is fast to assemble.
I used my NanoVNA and tuned it to 1.2:1 on 2Meter, and it was also 1.8:1 on 70cm
I use it to contact the ISS Repeater and have had a QSO from FMo5 to EM26 through the ISS Repeater.
NOW THAT WAS COOL!!!
Thanks,
Chris Cancilla
de W4CEC
Super brand new to this hobby.... thank you for using plan English... easy to understand
Hi from IU4OOB. I’ve just built mine and it works great! It doesn’t look as good as your but it works. Thx a lot!!
I built this antenna today per your instructions and it turned out amazing! Thank you for the clear and concise video. 73, KF0OVB
Built one today. I don't have the means for tuning so i just measured and assembled it as precisely as i could. I was able to receive voice from AO-92 (VHF downlink) and SO-50 (UHF down) loud and clear. However, it is not a magic wand! and I was NOT able to transmit successfully to a friend 1 mile away through medium dense forest/trees (this is not surprising). Without so many trees blocking, I was loud and clear TXing at 4 watts from 1 mile. Don't expect to beat the laws of physics or anything with this, but even without tuning you'll be able to recieve MUCH better than you might with the rubber ducky. Tune it for best possible TX capability!
Thanks VBR for the awesome design! de N0CALL ;)
Just built five of these antennas with my students today and they work great! Sadly, the cost of each antenna was $40 😢 Darn inflation! Thanks for making these videos!!!
They shouldn’t have cost that much. Harbor Frieght tape measures are cheap and work great.
That looks like too much fun. Going to Harbor Freight to get my free antenna tape measure
Just got back from harbor freight.
Good luck building. Edges are sharp
@@frankwc0o I'd go with non-metallic paint
Just bought a J pole from you on ebay yesterday and stubled on this video! Looking forward to using it! Great video! Small world!
Glad you enjoyed the video and thanks for your purchase.
That is just plain cool! This is why I like the ham radio hobby! Simple, field expedient and gives your signal from the ht a kick in the butt!! Thank you for sharing your project!!
Thank you for sharing your knowledge and expertise with your videos. I’m just getting back into amateur radio and the new technology and information that is available is staggering and somewhat overwhelming at times. I find your videos to be clear, concise and welcoming to those of us who are new to this great hobby. Living in an apartment building makes antennae’s somewhat challenging as I have to be rather stealthy with them. Most of my activity ( when I’m licensed in the new year ) will be field transmitting and I’m gathering various radios and antenna styles to experiment with. I’m really looking forward to using my QRP radios as well as my stronger radios under field conditions.
73
John in Toronto Canada. 😀
Thanks for the video. I just finished building this antenna. My regular 17in omni on 2 meter was only receiving at 1/3 scale this receives at full scale, full quieting to a repeater. I'm really amazed that this works, now I just need to tune it so I can Tx with it. Great video and thanks for the parts list on your blog, I took a picture of the list and found everything at home depot. The list does say 10Ft of PVC I got away with 2 2FT pieces, I'm not sure what the extra would be for unless you were making a stand for it.
Glad to hear the antenna is working well for you. I mentioned 10 feet of PVC in the parts list as that's the length you usually but the tubing at the home improvement store. But really any amount of scrap tubing will work, it doesn't have to be a certain thickness or diameter.
Very good video, the pace was great. Simple down and dirty Yagi and you could easily add a couple more elements for 9db of gain.
Never thought about using tape measure as an element. Great idea.
It’s ALIVE! Followed along and built my first antenna. Thanks!
If anyone new is in doubt, cut the metal tape, tape to plywood sheet, position on wood saw horse, off the floor away from other metal, then hook up the feed line and check results on a NanoVNA! Then cut your boom material!
It is unfortunate public high schools have eliminated basic electronics shops along with wood, metal and auto shops. Thank you for the videos. I don't know anything about anything related to electronics. Can I ask why are the "elements" (?) cut at such a precise length? Why are broadcasts called "2 meter"? If an antenna element had to be exactly two meters would it matter if you took the two meter antenna and rolled it into a coil? There certainly is a plethora of panel antennas and antennas of every configuration. It would be nice to have an illustrated up to date book with photos of every sort of antenna with a paragraph of the name, type and function of an antenna. Satellite and other antennas are popping up everywhere.
I'd agree with you that technical education is lacking in many high schools. Bucking the trend, our local high school just expanded its technical and industrial arts program. They did it in partnership with the area technical college.
As for antennas, a 'field guide' of types of antennas would be really handy. I'll have to do some research to see if anything exists.
What makes an antenna work is its resonance to a particular frequency. Radio Frequency energy travels in waves. When an antenna is resonant, it will easily transmit and receive the RF energy that is traveling at that frequency. That is why the elements of an antenna are precisely cut. These RF energy waves are described by the frequency they travel at, such at 146 MegaHertz, or by the size of their wavelength, like 2 meters. 146 Mhz is a frequency that has a wavelength of 2 meters. We could use a coil of wire to detect the radio waves, but fashioning the elements of the antenna in the style and orientation described in the video is more efficient than a coil of wire. This is a very simple explanation, but hopefully it answers your question.
Short description... 2 meter refers to a frequency band where the "center freq" is around 146 MHz (144 MHz - 148 MHz, allocated by FCC in USA for ham radio).... the length of the electromagnetic wave used to transmist and receive is around 2 meters (some calculation required). In order for the antenna to receive/transmit efficiently their lengths must be precise (although some >5% tolerance is usually accepted). Antennas are some diverse and so many.... depending mostly on applications.... The American Radio Relay League (ARRL) is a good start to look for antenna books.... look in their site and in Amazon.
Great video, however plumbers don't use a 3/4" cpvc cross piece. So our local stores don't sell these. I had to cut down a 3/4" nipple and glue it to a "T" to make a cross piece. I haven't used it yet, so don't know how durable it is.
I used schedule 40 PVC for my mast and cross pieces. I don't believe you can get CPVC in 3/4 inch, but 1/2 inch CPVC should be sturdy enough for this antenna. But is sounds like your modifications to the mast should do the job.
This is the best video I've seen for a beam antenna beautiful job well explained!
My 12 year old son and I just built this. Thanks for a great how to vid.
Interesting and well explained video and I am going to try and build my 2 meter beam from the instructions here.
I like how you you use one tape measure to measure the other tape measure.
After following your instructions it works great! Any plans to put out a video on building a 70cm Yagi?
Nice video, and thanks for the quality J-Pole. I'm wanting to build a Yagi for the GMRS band. My question concerns the hair pin match. Is it only required here because it's a 2-meter build, or would the same apply to a GMRS build?
Built one this afternoon. Thanks for the video!
Would the flexing of the measurement tape affect the SWR or the radiation pattern?
Why is there a wire soldered between the drive antenna?
Why is the power should be limited on this antenna?
Sorry for the endless questions. lol I’m curious about building my own yagi antenna.
Can I substitute zip ties for the screw clamps, or is the metal in the clamps part of the performance of the antenna? I understand that the tape measure segments should be held firmly and straight, and aligned with each other.
Eliminating the hose clamps doesn't affect the performance. I've built these antennas with both hose clamps and self tapping screws. Zip ties should work as long as you can get them tight enough.
hey bud just found you on youtube as I am preparing to write my ham licence here in Canada and I must say I find your vids rather interesting so 73s from Canada sir
Glad you found my videos. I'm not very familiar with Canada's licensing procedure, but I bet there is a fair amount of overlap in the exam material. Good luck on the test!
i made this antenna a week ago and its strong its about 80km thanks KB9VBR
How effective would this antenna be for satellite repeater communication of talking to the iss space station when there over my area🤔 this looks easy to build I want a Yagi antenna for satellite communication fun🤔😁
Thanks for posting this...very clear, concise and easy to follow. I do have a question thought...what would the changes be...if any...if this was made with the tape fixed at 90 degrees to how you have made it? That is, the flat side of the tape would be directed to the repeater, not the thin side of the tape as you have made it.? I'm thinking it would fold up better and be easier for transport as the tape could be folded along the boom. Just a thought. Thanks again for posting. de Ian VK3YIC
Kids are wanting to try a fox hunt so we will be building this first. How narrow of a single azimuth would we be able to detect. Never done a fox hunt and wanting to understand how it correlates to map and compass navigation.
Okay, stupid question, why are the transmitting elements wired together? Electrically, isn't that exactly the same as shorting the center and the shield of the coax together?
W4CEC here......I am building a couple of these for the Legion Club, WF4TAL. I think this is fun!
You positioned the antenna for vertical polarization. But which way should you attach the tape elements for horizontal use? That is, should you be able to read the tape facing upwards when holding it during a fox hunt, or must they be facing downwards (which I don't think a tape measure will support)?
It really doesn't make a difference on how the tape elements are attached. But for horizontal polarization the tape should be facing upwards so the element doesn't droop.
Hi Michael, would I get the same results by using aluminum boom and aluminum elements?
Hey love the vid, could I use this to communicate with the ISS?
I love your videos. You make them understandable! I’m working on my antenna now. I used plastidip on the ends to prevent cuts. 73 and thank you!
I thought about the plastic dip as well. I will probably also round off the sharp corners with a Dremel or a file first.
Thank you Mike, i’m working on building my third 2m tape measure antenna, they work great!
I'm not a Ham but seeking info for a directional antenna for different purposes. The measurements you gave were very precise. I'm assuming the antenna you built was designed for a specific frequency. Where can I find out how to change the measurements for a different (but very close) frequency? What kind of frequency range would this antenna manage? Thanks for the great video!
What an awesome yagi, but i noticed toward end of video how the tape measure fluttered in the wind/breeze!
Would this affect it's performance?
Cheers!
VBQ543
Mick
Great! I really enjoy your videos and the detail you put into them. I'm going to build one of these to try to work the FM satellites. For us new hams, can you put together a video on how to prep the RG-58 cable for a project like this?
Can this be spray painted to camouflage it a bit without causing interference?
A very nice build of a tape measure yagi antenna. I wanna build one myself after I get my Tech. license and a HT.
I built this and got the swr down to 1.2, but I still can't get into any distant repeaters. It works with the more local repeaters, but so does the rubber duck.
Great Video! liked and subscribed. Your method of instruction was easy to understand even for a Newbie like me. The video was well produced and easy to follow. I built my first yagi today. Thank you KB9VBR. 73
I'd love to see a build video on a larger yagi, something like 4-6 elements, something that could be hiked up to a summit but be relatively lightweight
Wow that's very impressive. I could use this for some other projects. Having a 2m 70cm yagi is a good idea anyway
Love this antenna idea! Any thoughts on making a 70cm version? Or making this a dual bander by putting 70cm 90° off from the 2m elements?
One more question. On the site that you based the antenna on (and in your video), the coax is soldered on after you mount the tape measure to the PVC. Can you do all of the soldering beforehand, so you don't have to worry about melting the pipe?
You could certainly solder the wire to the elements before attaching it the the pipe. While you do run the risk of melting the plastic a bit by soldering after the attach the elements, you also don't have to worry about the elements moving around as you do the solder work. But either method is fine.
Sir what is hair pin math in the process of making antenna, why it's required ?? and how it's calculated??
Please guide me sir.
Thank you 😊.
Very nicely done. Just one question, what's all that white stuff on the ground? We don't get that here in the desert of Southern Nevada. Looks fun!
So what do the front and rear bits do if they are not attached to the coax?
What a magic project, many thanks ~ ZL4MB - New Zealand.
Hello Mike nice tape yahi video ,i he one question,,,, why you use hairpin connection to driven element ??
The hairpin match is easy to construct, lightweight, and works well for this antenna. Other matches commonly found on Yagis, like gamma or coax shunt matches, are heavier and more cumbersome.
Silly question but have to ask.......you have soldered a black wire across the dipole. Can I ask how that affects the performance as for a newcomer like me, it appears you have shorted out the elements as if they were one piece and not two seperate elements???
The connecting wire is called a Hairpin Match. It raises the impedance of the feed point to 50 ohms so it matches the transceiver. I've got a follow-up video that better addresses your question: ruclips.net/video/bQndXvCW54Q/видео.html
Doesn't this antenna need some sort of balun? One of the driven elements is directly soldered to the outer shield a 4ft long coax...
Hello, love your video. I'm looking to build one for a homemade reciever in 216.055 mhz. Just curious how I would have to change the instructions yo get into that frequency? Or where I may learn that info. Thank you for the help
can you explain the purpose in simple terms, of the hairpin wire connecting the pos and negative driven elements? not all 70cm and 2m home-made yagi designs i see have them. i see people talk about they improve matching impedance, but for receive-only antennas does it matter?
Just learning about this hobby. Few questions... Can the antenna be painted or would that disrupt/muffle the signal in any way? Also for "tuning" the gap between the tapes could you solder a nut onto it and use a bolt to easily and quickly adjust the distance between them? The further you thread it in the smaller the gap.
KD6UKH...Great video Michael!
Michael thanks for the outstanding instruction. I plan on building this for SOTA activations. Do you think you could repeatedly roll this up in a Fly rod case for strapping to a backpack?
whats the point of the front and back bits not wired up ???
I enjoyed the video but I found something confusing. I don't have much experience with antennas so maybe this is a very naive question.
I understood where you connected the core of the coax to the left side of the driven element, and then took the shield part of the coax and connected it to the right part of the driven element. The part that I didn't understand was the wire that arced above. Isn't this just shorting the shield and core elements of the coax? In other words, why would any self-respecting electron be bothered to follow the path into the tape measure when you have a short? I must be missing something
The connecting wire is called a Hairpin Match. It raises the impedance of the feed point to 50 ohms so it matches the transceiver. I've got a follow-up video that better addresses your question: ruclips.net/video/bQndXvCW54Q/видео.html
This might seem like a silly question, but would painting the antenna affect the performance of the antenna? As I said in an earlier posting below, I live in a high rise in the west end of Toronto Canada so most of my transmitting will be done in a field day/ mobile environment. Having a more subdued colour would prevent any potential problems and possibly allow me to actually transmit from my apartment occasionally. Any help is very much appreciated !
Regards
John
Toronto Canada.
Paint away John without fear; it will have no effect on performance whatsoever.
@KB9VBR Antennas What would happen if I did put 50W into the antenna? Would it reflect most of the power, or would it work for a short amount of time before overheating?
My concern would be the hairpin match heating up since that is a pretty thin piece of wire. But other users of this antenna say they've used it with 50 watts of power, so you could certainly give it a shot.
@@KB9VBRAntennas Thanks! I'll give it a shot and tell you how it went. I have the exact same 50W dual-band radio (Yaesu FTM-400XDR) you use in your APRS videos.
Quick question does it matter how long the coax is?
I like this design!. Do you know if painting the whole thing would ruin any of its characteristics?
Super good video, thanks for making and posting it.
Hi Michael, just also checked out your Q and A video as I hoped the Q might be on there as I'm trying to calculate the distance if I added another director, I can't find the calculation you have used for the dimensions of the tape measure yagi, however I think from using what I can find it would be around 16" spacing with a length of 32" do you think I'm anywhere close... ? Thanks G6CTX
Hello, just curious - why is there a 5inch wire shorting the positive and negative sides of the driving element?
The connecting wire is called a Hairpin Match. It raises the impedance of the feed point to 50 ohms so it matches the transceiver. I've got a follow-up video that better addresses your question: ruclips.net/video/bQndXvCW54Q/видео.html
Great video! By changing the gap you would change the distance between the elements but leave the length of wire the same length ?
Thanks for the vid. Why did the repeater come back with Morse code when you tested at the end?
That would be the callsign of the repeater. When a repeater identifies itself, it can do so in morse code or with a digital voice.
I'm still learning antennas. I'm curious what exactly the wire between the sides of the driven element does.
The connecting wire is called a Hairpin Match. It raises the impedance of the feed point to 50 ohms so it matches the transceiver. I've got a follow-up video that better addresses your question: ruclips.net/video/bQndXvCW54Q/видео.html
Hi Michael, Nice Video. I notice at the co-axial feed point to the driven element the loop of wire connects between the 2 halves of the driven element. I thought that would short out the co-axial cable. Can you explain - I may be dumb haha.
My concern as well.
Gonzo Buddy so is the “shorting wire” required? I can accept they are different, but can you tell us how and why? It still looks funny to me.