Wanted Supplier of Band 2 Beam Antennas

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AndyG6OHM
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Wanted Supplier of Band 2 Beam Antennas

Post by AndyG6OHM » 17 Apr 2016 08:54

Hello everyone.

Is there any suppliers out there were i can compare / buy band 2 Yagi antennas.
I looked on Ebay but all i could find was round folded dipoles.

Any websites appreciated
73 Andy G6OHM
My Email g6ohm@talktalk.net
My website http://g6ohm.webs.com/

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John Faulkner, Skegness
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by John Faulkner, Skegness » 17 Apr 2016 12:37

This is a tricky one Andy. Getting a properly optimised antenna for band 2 is not as easy as you might expect these days. We are all told to go DIGITAL (AAAAGH!). If you can find a second hand Triax FM5 or FM5 on ebay or similar then that might be your only option. Triax do not make band 2 antennas anymore. Triax were generally regarded as being better optmised compared to some others.

I don't think the Körner 9.2 is currently available from Antennenland. Hopefully it will be again soon. http://www.antennenland.net/navi.php?su ... f734q9m5l4 I have their 9.2 (nine element) antenna, but there are larger beasts at 15 and 18 elements.

If you are keen, you can always make one - http://ham-radio.com/k6sti/korn92.htm / http://ham-radio.com/k6sti/ It may be the best option.

satnipper
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by satnipper » 17 Apr 2016 13:30

HS Pubs do Band II antennas - do a Google search for the catalogue. Actually didn't someone post it in here few weeks ago?

Stuart

Andrew Webster,Wigan
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Andrew Webster,Wigan » 17 Apr 2016 13:34

Yes Stuart it's here.

viewtopic.php?f=38&t=2127

Andy
Receiving equipment: 2 Sony ST-S311, 1 Sony ST-SE520, 1 Sony ST-SE700 2 crossed FM 5s rotatable, 1 homemade FM 3 horizontal beaming S/E, 1 vertical FM 3 fixed beaming at Ireland, 2 element band 1.

daveB
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by daveB » 17 Apr 2016 16:59

Actually didn't someone post it in here few weeks ago?
Yes I did - and Garry will make aerials to your specifications to order - so I'm sure he would make a 5-ele beam for you to the dimensions of the Antiference 5 element. He does an FM60 - but make sure, if you consider it, that it has been modified to give full 88-108 MHz as some of the designs go back to the 1970's before we had the full FM Band. We checked the performance with 4nec2 and found some changes needed to be made to rod lengths.

And just a point about the Triax FM5 - the reflector is too short and you get a miserable 6-7 dB f/b ratio at the low end. And an extra inch to each element makes a big improvement - at the cost of a dB less mid band.

If you can get a Korner 9.2 the f/b ratio is so much better - as already said - from Antenenland in Germany - and f/b ratio on a crowded band is all important.

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

AndyG6OHM
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by AndyG6OHM » 18 Apr 2016 09:15

Sorry David i have only just joined.
Have seen HS Publications website. Hmm thought they were a bit pricey.
But i suppose you are paying for a Specialist Company.
I might end up building my own,as i enjoy building antennas.
73 Andy G6OHM
My Email g6ohm@talktalk.net
My website http://g6ohm.webs.com/

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John Faulkner, Skegness
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by John Faulkner, Skegness » 18 Apr 2016 10:39

HS Publications built a four element wideband (45 - 80 MHZ) antenna for me some years ago. Garry's antennas are very well constructed. This was an excellent performer too. I had some fantastic transatlantic band 1 reception on it.

satnipper
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by satnipper » 18 Apr 2016 14:26

I fully agree - antennas are well constructed and Garry is a nice bloke to deal with.

Stuart

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Chris Howles
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Chris Howles » 18 Apr 2016 15:57

Ditto re HS Pubs.... Gary is a very experienced DXer since the 1960s he really knows his stuff and will go out of his way to help you. He was a great mentor to me when I started off DXing in the mid 80s
Sony XDR-F1HD, Rotel RT-955, Denon TU-580RD, Denon TU-1500RD, Denon TU-425RD,
FM5 rotateable, K6STI 5 el (HS Pubs) rotateable, 2 el FM vert, 48- 82MHz dipole
Icom IC-R7100, D100 x2, JVC CX-610,
RDS Spy,

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Julian Hardstone
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Julian Hardstone » 19 Apr 2016 23:46

'Cheap' domestic FM Yagis have all but disappeared. Peter Körner optimised some small Yagis and designed the very large multi-reflector antennas with from 9 to 19 elements, which offer unprecedented performance but really need a large lattice tower with a heavy-duty rotator, the sort of arrangement you would use for a 3-ele 40m Ham array! If you want good performance from anything smaller we now have Brian K6STI's 'compact five' which has been discussed in the forum, and clearly offers the highest performance/size ratio of any Band II antenna.

Garry Smith is now manufacturing these and I would not now consider anything else for dx on Band II. I bought one recently and am very pleased with the construction and the price - I am just looking for an opportunity to get it on the rotator here, when I shall do some detailed measurements of the performance. Computer modelling shows it to be superior to larger domestic Yagis. If you feel you can find a better design I'm sure Garry would be happy to construct one to your specifications.

I share the opinions posted above re Garry's contribution to VHF broadcast dx in the UK, which apply also to Keith, his colleague on the construction side

- Julian

k6sti
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by k6sti » 20 Apr 2016 01:02

Julian Hardstone wrote:Peter Körner optimised some small Yagis and designed the very large multi-reflector antennas with from 9 to 19 elements, which offer unprecedented performance but really need a large lattice tower with a heavy-duty rotator...
Take a look at the 13 photos of Körner 19.3 installations here:

http://ham-radio.com/k6sti/korn193.htm

None of the antennas is mounted on a tower. I do wonder whether several with small TV rotors might sustain gear damage in high winds.
If you want good performance from anything smaller we now have Brian K6STI's 'compact five' which has been discussed in the forum, and clearly offers the highest performance/size ratio of any Band II antenna.
Not clear to me. I'd say it's the smallest and simplest FM broadcast Yagi with decent performance. But this 5-element antenna is only 15" longer with flatter forward gain and a much better pattern:

http://ham-radio.com/k6sti/ly.htm

The Körner 9.2 has about the same boom length and pattern as the log-Yagi but higher forward gain:

http://ham-radio.com/k6sti/korn92.htm

Finally, this antenna is 17" longer than the 9.2. It has the highest gain of any of these antennas and its pattern is among the best:

http://ham-radio.com/k6sti/ten.htm

You can compare forward gain and F/R of the antennas here:

http://ham-radio.com/k6sti/curves.htm

For some reason I've always assumed that FM broadcast in England uses horizontal polarization. Evidently that hasn't been the case for decades. This reference gives the polarization for BBC transmitters:

http://downloads.bbc.co.uk/reception/pd ... otrans.pdf

There are advantages to using a circularly polarized receiving antenna. Not only will it receive vertically polarized signals, it can increase signal strength 3-4 dB over a similar horizontally polarized antenna when receiving an ideal circularly polarized signal. It can also reject multipath interference in a way that a linearly polarized antenna cannot. But there are complications and limitations. See the following reference for details. I would add the 2- and 4-element circularly polarized quads to the antenna list above. They are small, simple, and cheap to construct.

http://ham-radio.com/k6sti/cpquad.htm

I just added the small 5-element Yagi to the gain comparison curves near the end of the article. Note that the 25" quad has 2 dB more gain than the 64" Yagi at the low end of the FM band and higher gain up to 102 MHz. The 2-element quad gets my vote for the highest gain for its size among small FM antennas. You'll have to decide whether you can live with the poor pattern for interfering signals with unfavorable polarization.

Brian

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Julian Hardstone
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Julian Hardstone » 21 Apr 2016 00:25

Thanks for your quick answers to my points above, Brian. I know your subsequent and larger designs can out-perform the 'Small Five' but I am surprised you seem to be dismissing this as a useful antenna for dx-ing.

Andy's original post was requesting advice on purchasing an antenna, though he has now expressed an interest in building his own to keep the cost down below the £50 of the HS Publications. If he does not intend to install a guyed mast with a substantial rotator, I think he would be best advised to avoid the multi-reflector models with their weight and wind-load penalties.

You mention some examples of the larger Körner designs being mounted in what I consider a flimsy manner, and I doubt the one in Wittenberg stayed up long, the example in Suhl is what is needed. I think Mike Fallon has his guyed too. Even the smaller 9.2 presents a high wind-load and needs careful attention to the mounting and rotator. I just managed to get a 19.3 on my roof, but I couldn't get it guyed so it had to come down quickly: I physically couldn't get it up there again now :(

If home-brew is on the cards, the Log-Yagi might be a good choice, but to anyone looking to purchase an antenna my advice remains the same.

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Julian Hardstone
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Julian Hardstone » 21 Apr 2016 00:29

Brian - I see that you have just added some comments above on the mixed polarisation environment we have to contend with in the UK. I was just preparing to open a new thread on the subject, so I will do that forthwith

k6sti
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by k6sti » 21 Apr 2016 00:47

Julian Hardstone wrote:...but I am surprised you seem to be dismissing this as a useful antenna for dx-ing.
I did no such thing. I simply don't agree that it "clearly offers the highest performance/size ratio of any Band II antenna." I think it's a nice starter design. I would never recommend it to someone who is serious about FM reception unless they could not possibly accommodate a larger antenna. I have used FM antennas with 30+ dB rejection to the rear. It can make a world of difference over the 20-22 dB the small Yagi provides. It can be like listening in another universe when weak signals are involved.

I don't understand your remarks about guying. Of course you guy longer masts.

Most antennas seem to be mounted so that their weight is balanced. It is better to locate the mast at the point where there is no torque on the rotor in steady wind. This point may not be the same as where where the antenna weight is balanced. You can make the two points coincide without increasing wind load by adding weight inside the light end of the boom. Then the rotor only needs to handle the torque from wind gusts that do not apply the same force to all parts of the antenna simultaneously. I don't think VHF antenna dead weight is an issue for any rotor.

Brian

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Julian Hardstone
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by Julian Hardstone » 21 Apr 2016 01:09

Don't forget that cost is often also a limitation :)

daveB
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by daveB » 21 Apr 2016 10:03

The force due to wind on the elements is in the direction of the boom and does not cause rotor torque.
A good point to remember - fortunately I normally leave my aerial pointing in the same alignment as the prevailing winds
Andy's original post was requesting advice on purchasing an antenna, though he has now expressed an interest in building his own to keep the cost down below the £50 of the HS Publications
Building is much more satisfying than buying but it will cost more - unless you are in walking distance of the suppliers. My total build cost was £57.01 - as p&p for the tubing was £14.99! I bought it down to just under £50 by buying extra ali tubing to use in the garden and charged half the delivery cost to housekeeping. :D

My 5 ele compact is mounted 18 ft or so above ground on an unguyed mast - and has withstood all of last winter's gales including Katie with a peak gust of 80 mph recorded at a weather station a couple of miles away. Normally I would have pivoted down but conditions didn't allow me to do so. I've posted details previously but basically it's a 10 ft scaffold pole sunk in concrete leaving 8 foot above ground. A 12ft 16 gauge 2" ali tube is clamped to this with universal clamps so that the top clamp can be released and the mast swivelled down. On top of this is a cheap rotator and the aerial is on a short stub mast about 2 ft long. It has been up 3 years without problem.
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

daveB
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by daveB » 22 Apr 2016 22:15

Of the smaller aerials the 5 ele log yagi seems to offer the best [size/]performance [ratio] but is more complex to construct - my concern is the phasing wires and protecting the coax feed from water ingress as it doesn't appear to lend itself to easy enclosure because of the feedpoint coil. But I am tempted to have a serious attempt at it.
One point that needs to be addressed as 1/8" wire is a bit thick to bend - which grade of aluminium? A company in the UK offers 3.25 mm extra soft aluminium wire as well as what I presume is standard material. There is also available 1/8" armature wire.

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

k6sti
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by k6sti » 22 Apr 2016 23:11

Dave, what I had in mind for the phasing lines was the 1/8" soft aluminum wire I used to find in 25- or 50-foot rolls at hardware stores. I've used it for all kinds of antenna projects over the years including inductors.

You can seal coax with goop if you can't build an enclosure. Don't use anything that smells like vinegar. Its acetic acid will corrode metal.

Brian

k6sti
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Re: Wanted Supplier of Band 2 Beam Antennas

Post by k6sti » 23 Apr 2016 14:49

Image

I added a design optimized at 20 feet above ground to the 5-element log-Yagi writeup. At practical installation heights it provides a better pattern than does the free-space design.

Image

I did the same thing at 30 feet for the stacked 6-element log-Yagis.

See the writeup for details.

http://ham-radio.com/k6sti/ly.htm

Brian

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