have u guys seen these 11m beams at Manufacturers of Innovative Yagi Antennas - home of the LFA Yagi by G0KSC i wonder if their any good
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Loop Fed Yagi
- Thread starter 33 the kid
- Start date
Hello all,
The antenna type for sure is a nice antenna...nothing wrong with it.
A while ago we were the first to make the LFA commercial available for the 11 meter community. That was already quite some years ago. And in all honesty I was really impressed with it at that time.
The term "low noise" can be seen in such a way that the elevation pattern is rather tight, together with the closed loop configuration. This of course in reference to the traditional types. Whether or not this is noticeable on 11 meters is debatable.
It doesnt seem wise to use those terms for our band is my opinion.
At this point we don’t produce the lfa anymore and stepped forward towards an antennas with a folded dipole and/or bend elements.
Thankfully there is a nice competition going on who is "best" in all aspects.
I’m confident that from a electrical point of view, your with "his"or "mine" at the top of what is possible these days.
Whether or not the present supplier equals the mechanical aspects would be for others to discuss.
Looking at the future. It is my personal believe that the future lies in "types" will make more and more use of bending the elements.
Kind regards,
Henry HPSD
ah..almost forgot !, be carefull with what drawing you use. There are a couple nec2 drawings availible on the internet for 27 Mhz which are lets say less..accurate. One will need nec4 to model such antennas.
The antenna type for sure is a nice antenna...nothing wrong with it.
A while ago we were the first to make the LFA commercial available for the 11 meter community. That was already quite some years ago. And in all honesty I was really impressed with it at that time.
The term "low noise" can be seen in such a way that the elevation pattern is rather tight, together with the closed loop configuration. This of course in reference to the traditional types. Whether or not this is noticeable on 11 meters is debatable.
It doesnt seem wise to use those terms for our band is my opinion.
At this point we don’t produce the lfa anymore and stepped forward towards an antennas with a folded dipole and/or bend elements.
Thankfully there is a nice competition going on who is "best" in all aspects.
I’m confident that from a electrical point of view, your with "his"or "mine" at the top of what is possible these days.
Whether or not the present supplier equals the mechanical aspects would be for others to discuss.
Looking at the future. It is my personal believe that the future lies in "types" will make more and more use of bending the elements.
Kind regards,
Henry HPSD
ah..almost forgot !, be carefull with what drawing you use. There are a couple nec2 drawings availible on the internet for 27 Mhz which are lets say less..accurate. One will need nec4 to model such antennas.
It should perform as well as any other yagi antenna. Wanna call it a 'loop' fed antenna? Do so. It is also called a folded dipole fed antenna. Who was it, Mosley, that made them also? And yes, a 1:1 balun would be nice on one.
- 'Doc
- 'Doc
Hi Doc !
There are some who don’t think they are all equal.
If expanded to the extreme one could say a quad element is a folded dipole as well hihi.
(yes I know the currents etc)
The lfa loop, the guys are talking about is has a "different" loop compared to the folded dipole. roughly its 4 meters wide and about 1 meter long.
Besides that it is placed horizontal on the boom instead of vertical.
Im with you that the "lfa" loop already excisted a while but not mosley.
There was a German professor, who invented the LFA to my believe in the second world war.
DK7ZB had some pictures.
If it wasnt that German it must have been a Spanish guy who used a similiar loop for satelliet communication way before the rest of the ham community heard about it.
The folded dipole i use is a well known application, perhaps mosley used it as well ?
However the present idea behind it is different.
The philosophy behind it:
For a very long time people always thought that high gain yagi's means low impedance and small bandwidth. But with present day knowledge we can produce "wide band" low impedance yagi's. (and thus high gain/ tight pattern).
Sadly you wont find anyone else having the knowledge to do so at this moment. (for 11 meters). Most (99 percent) have "traditional" yagi's.
A traditional yagi say 30 ohms will have less gain and a worse pattern.
So, if we design our antenna at 12,5 ohms, add a folded dipole we have made it a 50 ohms impedance antenna. With the benefits of the "low impedance" one.
And being a higher impedance antenna it has less issues with noise from rain/snow etc and swr influence of near by obstacles.
Thats just so irritating..having the s-needle moving upwards with rain and snow...
Anyway im on the “bending” elements mode these days….
Perhaps its something to provide a improved “maco’ on this forum ..
Sunday is over here …so soon to bed !
73s.
Kind regards,
H.
edit : didnt wilson beams had a folded dipole in the past ?
There are some who don’t think they are all equal.
If expanded to the extreme one could say a quad element is a folded dipole as well hihi.
(yes I know the currents etc)
The lfa loop, the guys are talking about is has a "different" loop compared to the folded dipole. roughly its 4 meters wide and about 1 meter long.
Besides that it is placed horizontal on the boom instead of vertical.
Im with you that the "lfa" loop already excisted a while but not mosley.
There was a German professor, who invented the LFA to my believe in the second world war.
DK7ZB had some pictures.
If it wasnt that German it must have been a Spanish guy who used a similiar loop for satelliet communication way before the rest of the ham community heard about it.
The folded dipole i use is a well known application, perhaps mosley used it as well ?
However the present idea behind it is different.
The philosophy behind it:
For a very long time people always thought that high gain yagi's means low impedance and small bandwidth. But with present day knowledge we can produce "wide band" low impedance yagi's. (and thus high gain/ tight pattern).
Sadly you wont find anyone else having the knowledge to do so at this moment. (for 11 meters). Most (99 percent) have "traditional" yagi's.
A traditional yagi say 30 ohms will have less gain and a worse pattern.
So, if we design our antenna at 12,5 ohms, add a folded dipole we have made it a 50 ohms impedance antenna. With the benefits of the "low impedance" one.
And being a higher impedance antenna it has less issues with noise from rain/snow etc and swr influence of near by obstacles.
Thats just so irritating..having the s-needle moving upwards with rain and snow...
Anyway im on the “bending” elements mode these days….
Perhaps its something to provide a improved “maco’ on this forum ..
Sunday is over here …so soon to bed !
73s.
Kind regards,
H.
edit : didnt wilson beams had a folded dipole in the past ?
Hi All,
Another option would be to build one yourself, it is not hard. One of the only areas in our hobby where you can still make something as good or better than you can buy commercially is the antenna. if you visit www.g0ksc.co.uk you can find many ham designs there. While there are no 11m designs listed, when asked I will provide details of both the LFA (Loop Fed Array) and the OP-DES (Oppossing Phase Driven Element System) which has the bent back driven element.
The useful feature of the OP-DES is it can be modelled to present a very flat SWR curve (less than 1.2:1) over as much as 1.2MHz at 27/28MHz which ensures no expensive ATU's are required when big amplifers are in use.
You need to understand what you are doing on these bands to model appropriate antennas that cover any respective frequency with the appropriate return loss. Mostly you will find acceptable SWR is only delivered over 500khz or so. It is better to have more if you can have it right?
Below is a report from an Australian contest station on they 6el LFA that was in use at the ARRL 10m event this year.
Hi mate,
I put this on Youtube the other day. I managed to grab some footage on the weekend of the LFA against the TH6.
Very impressed with not only the overall gain (between 4-6 S points better) but the low noise levels of the antenna
in general.
I would go as far as saying without the LFA we would not have worked over 30 % of the stations we did.
The low signal detection ability is outstanding as you will see.
cheers,
Pete
VK2PV
LFA v's TH6 (10m Antenna Comparison) - YouTube
Finally, CW5W reports having won the 10m contest using 3 x 5el OP-DES Yagis.
More info is available on our facebook page with all recent customer successes. If you want to build your own, write to me and I will model it for you (accuratley).
Justin G0KSC
Another option would be to build one yourself, it is not hard. One of the only areas in our hobby where you can still make something as good or better than you can buy commercially is the antenna. if you visit www.g0ksc.co.uk you can find many ham designs there. While there are no 11m designs listed, when asked I will provide details of both the LFA (Loop Fed Array) and the OP-DES (Oppossing Phase Driven Element System) which has the bent back driven element.
The useful feature of the OP-DES is it can be modelled to present a very flat SWR curve (less than 1.2:1) over as much as 1.2MHz at 27/28MHz which ensures no expensive ATU's are required when big amplifers are in use.
You need to understand what you are doing on these bands to model appropriate antennas that cover any respective frequency with the appropriate return loss. Mostly you will find acceptable SWR is only delivered over 500khz or so. It is better to have more if you can have it right?
Below is a report from an Australian contest station on they 6el LFA that was in use at the ARRL 10m event this year.
Hi mate,
I put this on Youtube the other day. I managed to grab some footage on the weekend of the LFA against the TH6.
Very impressed with not only the overall gain (between 4-6 S points better) but the low noise levels of the antenna
in general.
I would go as far as saying without the LFA we would not have worked over 30 % of the stations we did.
The low signal detection ability is outstanding as you will see.
cheers,
Pete
VK2PV
LFA v's TH6 (10m Antenna Comparison) - YouTube
Finally, CW5W reports having won the 10m contest using 3 x 5el OP-DES Yagis.
More info is available on our facebook page with all recent customer successes. If you want to build your own, write to me and I will model it for you (accuratley).
Justin G0KSC
Here is some customer feedback:
Customer Comment - G0FWZ on his recently installed 7el 28MHz OP-DES Yagi:
Hi Justin, hope you are well? Just to let you know this is a Killer Antenna !! By far the best signals from the UK! Opens and closes the band (10m). Do a search on DX summit for G0FWX and see what people say.
Thank you!
7 element 28MHz OP-DES Yagi (13m)
If you want the best....
Customer Comment - G0FWZ on his recently installed 7el 28MHz OP-DES Yagi:
Hi Justin, hope you are well? Just to let you know this is a Killer Antenna !! By far the best signals from the UK! Opens and closes the band (10m). Do a search on DX summit for G0FWX and see what people say.
Thank you!
7 element 28MHz OP-DES Yagi (13m)
If you want the best....