Ham Radio T2LT Antenna for 10m DX (or other bands) - Home or Portable - Low Cost Easy Build.
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- If you are looking for a low cost single band DX Antenna, the T2LT is worth considering. The chances are that you may already have everything you need to build one. It's also ideal for portable operation.
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Thank you Peter, I love the easily built at home equipment. For me it’s the essence of our varied hobby.
You are not alone there!
I made one of these for 2m years ago, inside a plastic pipe with the coax coming out through a hole, winding the choke around the outside and then back in through a hole. It was up for years and worked surprisingly well.
It really looks as if the Ham Radio side of Kenwood is either on hold or worse still! No sign of anything new.
+1 for using as a sloper, that configuration worked well for me when I tried it. Also as an inverted V, but the V took a bit more tuning of both ends to get it to tuned correctly.
Yes I never tried it as an inverted V.
If you have the room try a 120ft inverted vee end fed up 30ft at the centre with 30ft ground wire under the vee LC tuner is needed to match for best swr outstanding for inter G and some European countries i used to use a ft817 with 2 to 3 watts
You need a biger atu for moor power 😊😊
Thanks Peter! Its obviously good practice to waterproof the trimmed end of the coax very well (especially if using the coax inner for the top secton). Self amalgamating tape is OK for a year or two, but I've found that a dab of glue from an inexpensive hobbyist hot glue gun does a really great sealing job. On my own antenna, I've then covered this with self amalgamating tape as a kind of "belt & brace" approach. As one who has experienced the effects of rainwater wicking its way along many metres of coax feeder, I reckon its very worthwhile to complete this simple antenna by this (also simple) weatherproofing method...
Yes agreed.
I believe these are also called coaxial vertical dipoles, or flower pot antennas.
In the summer of 2021, this was the first HF antenna I made. Very simple and effective. Mounted on a fibreglass pole with the top about ~8m above ground level. I did quite a bit of FT8 on 5W and worked as far as Argentina. It could do with being tuned as the resonant frequency came in about 27.8MHz but as with so many things, it was up and working, so I just got on and used it as-is! 😁
Nice work!
It would make a good stealth antenna. Communication companies are running their coax on the outside of houses. Just mount the center conductor horizontal under the eaves.
Hey Peter, if you are stuck for content, just shout.. I have about 100 videos that I don't have time to make old bean. I'll send you the list.
i have built these antennas, they work very well, easy to make.
I have been experimenting with this antenna over the last month. I was bothered by the shorter than expected length. I had it taped to PVC pipe which was lashed to a star picket. I also had a reflector and director to get gain. It is pointed towards America ( from Australia). Anyway, I dug some holes and put in wood posts to attach the PVC masts to, to get rid of any effects from the star pickets. I ended up getting rid of the coax type antenna and used a standard wire dipole with a coax connector. I used a NanoVNA to analyze the dipole and found that the resonant frequency was indeed about 20cm shorter than calculated. I am supposing that the closeness of the ground causes the change. I added a reflector which is 5% longer and a director which is 5% shorter than the dipole. They are all taped to 6 metre lengths of PVC drainpipe. The tops of each element are level with the top ends of the pipes. The pipes stand vertically, slid over wood lengths that are stuck in the ground. Lengths in metres are 5.04, 4.8, 4.56 for Ref, Driven and director. Spacing is 2.35 between Ref and driven, and 1.6 between driven and director. SWR minimum is about 1.2 at about 28.6 Mhz. (I'd like it a fraction lower.) Next step is to build another set, but pointing north-west towards Europe. I will be able to switch between the two systems. I think the coax design would be fine with the corrected (shorter) lengths. Modeling shows that the height of the wires being about a metre off the ground gives a good radiation pattern and low elevation angle, and works in well with the 6 metre lengths of 90mm diameter pipe. Marty Wallace - VK6ABC.
I am using one of these on 20m and it will tune to 10m. However, the ratio of top section and bottom section is more like 3 to 1. I regularly make contacts from Australia into Europe using it attached to a 10m squid pole
Sounds good.
I have a thunder bolt version ìts 5/8 wave it has extra things on it like a coxal stub part way up the lower part of the dipole and a 2.5cm coxal capacitor at the start of the upper dipole i have this sat on a 12m mast ( taped to it) best anttena i have had in my small garden i have tryed 1/2 waves with 49:1 transformer found
Them poor i have 4 anttenas 10/15/17/20m i have 2 x 12m masts up so just covering 15/12/10m
I made my first t2lt for 50mhz i built my choke on a 3in dia pipe going to make one for 70mhz so i can use
Them portable with my ic705 thanks for putting the video out a simple anttena that works well
Best antenna I ever build I love it 73s from 9z4apa.
You can multi band them, they work on odd harmonics of the fundamental frequency in your configuration and if fed off center can be made to work on and even harmonic with a good match. I have been using one for many years as a 2m, 70cm vertical with a sleeve fitted over the center making it 2x1/2 waves in phase on 70cm and a straight 1/2 wave on 2. Cheers Dave
Yes agreed, but on the HF bands this only works on 40m where the third harmonic is 15m.
I made a T2LT recently for 15M. It was a fun project. However, I found out it doesn't perform nearly as well as my Solartron A99 CB antenna, which will tune all the way to 15 meters with fantastic SWR and performance. Yes I know it is a CB antenna. But it's 17 feet long, made of fiberglass, and is hard to beat. I knoiw many hams won't consider something just because it says "CB." But facts are stubborn things. However, the T2LT is a fine antenna in a pinch and for the field.
If it works, go with it.
I use a similar antenna and it works well on 10, 11, 12 and 15 meters.
It always makes me laugh!
If cab is so bad, why are there so many hams on the bands? 😂
Hi Chuck. Some people make this from one continuous piece of coax. They strip the outer shield off for the radiating element. Some people attach a piece of wire. Or Peter is using the term flex, it's just wire..
I got a length of coax just over 8.5m long, exposed the inner core at one end about 2.5cms and measured 2.47m down the coax and wound 16 turns of coax (diameter 66mm, just so happens to be the size of wd40 can, remember to remove the can) and I soldered a pl259 plug at the coax. Then I got 2.5m of enameled copper wire soldered to the exposed centre of the coax and put glue lined heat shrink over the connection to stop water ingress. I then bent the "top" of the copper wire to make a loop and secured the loop with a tiewrap, hoisted up a fibreglass pole and it tuned to 28.010MHz and was a lovely swr reading and quite wide band as well. By making the loop bigger (ie shortening the antenna it would go further up towards 28.500 MHz and if I made the loop smaller, it would go down into the 11m band. So easy to make and can be perfect for portable use. De Will G1YYU
Many thanks for sharing that info. 73. Peter
A problem with this concept is that the bottom of the lower element (0.25λ down from the feed-point) is a current minimum and a voltage maximum. And the concept here is trying to use a *choke* at a point where current is *minimum* - Hint: chokes 'work' with current, and have little effect on voltage. The quite-similar vertical Sleeve Dipole is a better concept, as the lower end of the lower element has an actual open circuit in the right place. If one insists on using the T2LT concept, then might be best to add another choke another 0.25λ down the feedline where the current maximum is located.
All that said, perhaps the feedline common mode currents and thus radiation is useful for some. 🙂
Excellent video!
Many thanks.
73' de K4WRF
Thank you!!!! from America
You are welcome!. 73 from UK.
Great video Peter, very informative. How do you calculate the lengths for two sections of the antenna well as the length of cable for the choke? Is there a software calculator for this? I went looking for such a calculator, so far no luck. Any help would be appreciated. 73's Ernest Bazzinotti, KC1LKB
The coax from centre to choke is a quarter wave. Cable beyond that cjoke can be any length.
Thank you Peter. 🙂
I am still trying to figure out which antenna should be the first one I build or buy when hopefully getting my license next month (German class E). The 10m and 15m are the most interesting ones included in that license and I am currently thinking of either buying hamsticks to build hamstick dipoles for these bands, or either building 2 of these T2LTs.
As I am new to the ham radio hobby, I am not really sure which one of those is superior, but I tend to think the T2LT is the better choice as it does not have this compromise of that thin wire coil to allow for shortening the sticks (as the hamstick have) and is has these pure Lamda/4 elements instead.
Does that make sense, I mean, would you also consider the T2LT being a better choice than hamstick dipoles? 🤔
Thanks for an interesting video. I wonder if it is any quieter than an end fed half wave?
Great description highly rated information from Florida US; sadly TH-cam required me to watch no less than six ads to view the video. 73, de N4FLF.
Peter, Thxs. from Holland ! 73, Theo PA0HTY
de KI5DPA thanks for this. One thing, what do you mean by “flex”?
In the UK we often refer to a single piece of wire as flex. Sorry. 73 Peter
I don't rate this , being a perfectionist I have to call this a fudge , an easy fudge true , but basically it's a coaxial sleeved center fed dipole fudge . A true coaxial sleeve should ensure an unbalanced feed ( to suite your transmitter ). I've made one of these but they are difficult to implement . It's the same as a straight dipole with 1 - 1 balanced to unbalanced transformer at the feed point . Hardly spectacular . Ditch the coil and feed the coax up the lower half of your aluminum dipole is better . Center mount the dipole and you have cracked it . 73's DE G4MXC
How much dB gain does the T2LT has compared to a 1/4 wave vertical ?
What is flex?
Indeed! What IS "flex"?
Ditto
Just wire, speaker wire is twin flex
Thanks to all for the clearing this up for me.
What is this "flex" that you keep mentioning? I'm American, and guessing that it might be a British word for something, possibly some sort of conductor by context.
Twin AC Mains lead or speaker wire. Either work.
Hi have u got instructions on how to make it please I like to have a go thank you
I covered that in the video. Which bit are you unsure of?
Peter, so I don't commit assumicide, is what you refer to as "flex" - are you referring to any suitable 50 ohm flexible coax? Thank you ahead of time for your response. 73//KK0DJ
Just single core flexible wire.
Flex is a word often used in the UK to describe a length of wire, in this case a single conductor wire. Sorry.
I was puzzled too
It's an electrical ' J ' Pole just use a bit of 300ohm ribbon to do the same job.
Feed is different, but result probably the same.
@@watersstanton No its not.....Both fed with 50ohm coax one uses a Choke the other could have its coax choked but there is no need.
The J pole is an end fed half wave with a quarter wave matching section. This is a half wave sleeved dipole, electrically a centre fed dipole.
@@paulsengupta971 You may need to do more research as you are incorrect
@@charlieoscar09 Are you sure?