John Wilke K9RZZ
07-22-2007, 06:05 PM
So, last month I'm out on a bike ride ... it was pretty hot, so I stopped at a county park to get some water and sit in the shade for a while. Looking around I start thinking: "Hey, this would be a nice place to sit with a radio. You could string some wires ..." I thought of longwires for HF, MW, then "Hmmmm ... what about a Rhombic for FM? !! Nah, too much work, how about a Vee Beam? " So that was the start of this project. Last week, I just strung up a few wires and it seemed to work okay, so today I put them up 'properly'.
Some of you may ask what's a Vee Beam antenna. Well, dig out your antenna books or take a look here (http://64.233.167.104/search?q=cache:adWEzq1Xi0kJ:www.qsl.net/zs1an/station.html+%22vee+beam%22+vhf&hl=en&ct=clnk&cd=23&gl=us) or here (http://www.cebik.com/gup/gup42.html). Basically, it's two long wires fed together in a V shape to favor a certain direction.
I did some searching and no one has really done any pages with Vee Beams on VHF. I did find this nice table showing leg lengths and optimum angles which I used. (It comes from a QRP email list that requires a password to access, but the "Google Cache" feature pulled the text out link (http://64.233.167.104/search?q=cache:BXIxcs1n6CkJ:www.kkn.net/archives/html/QRP-L/1999-02/msg01847.html+%22vee+beam%22+wire&hl=en&ct=clnk&cd=12&gl=us))>
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Quoted text:
The included angle "V" decreases as the leg length "L"
increases. Here's a chart with Included angle, base on
wavelengths, and (very) approximate gains:
Waves "V" Gain (App'x)
1 110-degrees 3.5 dB
2 71-degrees 5.0 dB
3 60-degrees 6.0 dB
4 52-degrees 7.0 dB
5 45-degrees 8.0 dB
6 40-degrees 9.5 dB
7 37-degrees 10.5 dB
8 35-degrees 12.0 dB
This is not to say that you can't go past 8-waves for a leg
length, but that's as long as most hams can handle in the HF
spectrum, or even the low VHF spectrum. 8-waves on 6 Meters
is about 160 feet, and is almost 65 feet even on 2 Meters.
- - - - - - - - - - - - - - - - - - - - -
So armed with this info I aimed my wires at Chicago. That would give me plenty of targets to hear and see how it works. My first wires were 45 feet long, later lengthened to 60 feet once I knew I could fit them in my lot.
93.1 mhz 60 ft = 6 wave lengths
107.0 mhz 60 ft = 7 wave lengths
So the optimal angle is around 37 to 40 degrees.
I fed my wires with window line, a balun, and RG6.
http://hometown.aol.com/J999w/vee/feed.jpg
http://hometown.aol.com/J999w/vee/balun.jpg
I think eventually, the feed point is going up on the roof for more height, and the balun will be right at the feed, connected directly with RG6 (no ladder line). Right now, the antenna runs from the house out to some low trees. Here's the feed right outside a second floor window.
http://hometown.aol.com/J999w/vee/feed2.jpg
My first wires were about 60 degrees and I varied them down to 30 by moving the end points from bush to bush. It seemed that to error too wide was better than being too narrow. (I made up a nice table, but it doesn't show too well here. You'll just have to take my word for it.) :)
The antenna is about 15 feet above the ground. (and you can see my 7 ft C band satellite dish that has a nice view of those tree branches! :mad: )
http://hometown.aol.com/J999w/vee/wire.jpg
which is the same height as my low yagi:
http://hometown.aol.com/J999w/vee/lobeam.jpg
Of course my high yagi, at 35 feet beat them all during my tests:
http://hometown.aol.com/J999w/vee/hibeam.jpg
(I must say, that little yagi perched on top of my 2m and 6m beam really hauls them in!)
So which antenna is better?
The upside to the wire, is that it also hears off the back which can be a good thing. The wire also hears well across a wide range of frequencies. I had great copy on all the Chicago TV stations (TV 2 and up) in addition to the FM stations, as well as the NOAA weather outlets in that direction. (Try hearing anything at 59 mhz with an FM antenna!) The upside to the yagi, is that it's rotatable so you can point it in any direction to peak or null stations. The yagi should be on a rotator ($$$), the Vee Beam I built for free. :D
When I first started experimenting, I did log a new local pirate on the Vee Beam wire that I couldn't hear with any of my other antennas (link (http://64.233.167.104/search?q=cache:IrbkCQ06CDMJ:www.angelfire.com/wi/Page3/longform.html+%22vee+beam%22+wire&hl=en&ct=clnk&cd=15&gl=us)), so you never know which will perform best!
Right now I've got my Vee Beam pointed to the southwest to favor any stations from Iowa that may come in ( and I need in the log badly ) but since the antenna is actually bi-directional, I'm also hearing stations to my north east which can be a plus, or a negative depending on your point of view. I have all my antennas hooked up to the radio through an antenna switch so I can quickly pick the best one for the station I'm listening to.
http://hometown.aol.com/J999w/Pict5771.jpg
Conclusion:
I think the Vee Beam can work well for FM listening or DXing. Get it up high as you can, and I think it will serve you well for hearing stations from a distant target city, or as an additional tool in your VHF DXing.
73!
John K9RZZ
Some of you may ask what's a Vee Beam antenna. Well, dig out your antenna books or take a look here (http://64.233.167.104/search?q=cache:adWEzq1Xi0kJ:www.qsl.net/zs1an/station.html+%22vee+beam%22+vhf&hl=en&ct=clnk&cd=23&gl=us) or here (http://www.cebik.com/gup/gup42.html). Basically, it's two long wires fed together in a V shape to favor a certain direction.
I did some searching and no one has really done any pages with Vee Beams on VHF. I did find this nice table showing leg lengths and optimum angles which I used. (It comes from a QRP email list that requires a password to access, but the "Google Cache" feature pulled the text out link (http://64.233.167.104/search?q=cache:BXIxcs1n6CkJ:www.kkn.net/archives/html/QRP-L/1999-02/msg01847.html+%22vee+beam%22+wire&hl=en&ct=clnk&cd=12&gl=us))>
- - - - - - - - - - - - - - - - - - - - -
Quoted text:
The included angle "V" decreases as the leg length "L"
increases. Here's a chart with Included angle, base on
wavelengths, and (very) approximate gains:
Waves "V" Gain (App'x)
1 110-degrees 3.5 dB
2 71-degrees 5.0 dB
3 60-degrees 6.0 dB
4 52-degrees 7.0 dB
5 45-degrees 8.0 dB
6 40-degrees 9.5 dB
7 37-degrees 10.5 dB
8 35-degrees 12.0 dB
This is not to say that you can't go past 8-waves for a leg
length, but that's as long as most hams can handle in the HF
spectrum, or even the low VHF spectrum. 8-waves on 6 Meters
is about 160 feet, and is almost 65 feet even on 2 Meters.
- - - - - - - - - - - - - - - - - - - - -
So armed with this info I aimed my wires at Chicago. That would give me plenty of targets to hear and see how it works. My first wires were 45 feet long, later lengthened to 60 feet once I knew I could fit them in my lot.
93.1 mhz 60 ft = 6 wave lengths
107.0 mhz 60 ft = 7 wave lengths
So the optimal angle is around 37 to 40 degrees.
I fed my wires with window line, a balun, and RG6.
http://hometown.aol.com/J999w/vee/feed.jpg
http://hometown.aol.com/J999w/vee/balun.jpg
I think eventually, the feed point is going up on the roof for more height, and the balun will be right at the feed, connected directly with RG6 (no ladder line). Right now, the antenna runs from the house out to some low trees. Here's the feed right outside a second floor window.
http://hometown.aol.com/J999w/vee/feed2.jpg
My first wires were about 60 degrees and I varied them down to 30 by moving the end points from bush to bush. It seemed that to error too wide was better than being too narrow. (I made up a nice table, but it doesn't show too well here. You'll just have to take my word for it.) :)
The antenna is about 15 feet above the ground. (and you can see my 7 ft C band satellite dish that has a nice view of those tree branches! :mad: )
http://hometown.aol.com/J999w/vee/wire.jpg
which is the same height as my low yagi:
http://hometown.aol.com/J999w/vee/lobeam.jpg
Of course my high yagi, at 35 feet beat them all during my tests:
http://hometown.aol.com/J999w/vee/hibeam.jpg
(I must say, that little yagi perched on top of my 2m and 6m beam really hauls them in!)
So which antenna is better?
The upside to the wire, is that it also hears off the back which can be a good thing. The wire also hears well across a wide range of frequencies. I had great copy on all the Chicago TV stations (TV 2 and up) in addition to the FM stations, as well as the NOAA weather outlets in that direction. (Try hearing anything at 59 mhz with an FM antenna!) The upside to the yagi, is that it's rotatable so you can point it in any direction to peak or null stations. The yagi should be on a rotator ($$$), the Vee Beam I built for free. :D
When I first started experimenting, I did log a new local pirate on the Vee Beam wire that I couldn't hear with any of my other antennas (link (http://64.233.167.104/search?q=cache:IrbkCQ06CDMJ:www.angelfire.com/wi/Page3/longform.html+%22vee+beam%22+wire&hl=en&ct=clnk&cd=15&gl=us)), so you never know which will perform best!
Right now I've got my Vee Beam pointed to the southwest to favor any stations from Iowa that may come in ( and I need in the log badly ) but since the antenna is actually bi-directional, I'm also hearing stations to my north east which can be a plus, or a negative depending on your point of view. I have all my antennas hooked up to the radio through an antenna switch so I can quickly pick the best one for the station I'm listening to.
http://hometown.aol.com/J999w/Pict5771.jpg
Conclusion:
I think the Vee Beam can work well for FM listening or DXing. Get it up high as you can, and I think it will serve you well for hearing stations from a distant target city, or as an additional tool in your VHF DXing.
73!
John K9RZZ