Re: Topband: Double L antenna as an alternative for the radial-challenged?
Here is a follow up... I got a few responses, mostly with people telling me to model it or giving me examples of their antennas. I did not model it yet (I will eventually), but did some more reading. I want to restate my issue. A few radials are ok, but staying 2-dimensional would really help me to achieve my goals of adding multiple mono band antennas (80 and 160) and also place them close to the property line. Now, I came across N6LF's article (http://rudys.typepad.com/ant/files/antenna_vertical_loaded.pdf) about the Lazy H vertical. That article is a good read and includes modelling as well. It is similar to the double L but should work better as one more radial and top wire. Also, the article includes comparisons to half-wave and quarter-wave vertical in terms of peak gain, peak angle, wire loss, and SWR. Even though the article includes modelling and comparisons already, I would still like to ask if anyone is using the Lazy H vertical? Are you happy with it, do you work DX with it? DX and contesting is my main interest. Also, I probably would be able to go as high as 80 feet for the vertical dimension (90 feet horizontal). Thanks again for the great tips and information, Andy, KU7T -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andreas Hofmann Sent: Tuesday, September 24, 2013 11:24 AM To: 'topband@contesting.com' Subject: Topband: Double L antenna as an alternative for the radial-challenged? Hi, I am looking into what it would take to put a decent 160m antenna up. I got many large trees, but also rather thick woods, and the radials are always something that I do not enjoy much. Also, I cannot see myself to do 16 radials. 4 elevated radials may be tough as well. Terrain is just not as easy to get around. Now, I am looking at options that do not require radials and still have a decent radiation angle for DX. I am looking at this antenna http://www.yccc.org/Articles/double_l.htm, the double L antenna. Has anyone experience with it? What is the pattern of it and can it be compared to a quarter wave vertical? I would assume since it somehow resembles a vertical dipole and therefore does not require any radials, that its efficiency should be much better than a quarter wave vertical with less than adequate number of radials... Are my assumptions correct, and are there any other gotchas? Thanks and cu soon on topband Andy, KU7T _ Topband Reflector _ Topband Reflector
Topband: Double L antenna as an alternative for the radial-challenged?
Andy, I used the "double-L" which, I agree, is really a bent vertical dipole (BVD). After rewarding performance on 160m when hung from an 80-ft tower with about 3-ft separation and the bottom leg about 6 ft above (very poor) ground, I added an 80m element in parallel - the "double double-L" or double BVD. I don't have many tall trees for supports so, in contrast to K2KQ's recommendation to separate the legs of the antennas as much as possible in azimuth, I was only able to separate them by about 18 inches using PVC spreaders. According to a NEC2 model, the antennas are quite omnidirectional - much like the inverted-L. - but the close spacing and parallel configuration narrowed the bandwidth compared to legs separated in azimuth. See also page 3 of the December 2009 YCCC Scuttlebutt for a picture of the hole that one of the legs burned in the tree against which it rubbed. Keep the high-voltage points away from flammable materials. 73 -- Brian K1LI _ Topband Reflector
Re: Topband: Double L antenna as an alternative for the radial-challenged?
Hi, Andreas Well, it's interesting. I could try modeling it in EZNEC, Have you tried that? I wonder a bit about how good the cancellation is between the horizontal wires, when the lower one is only 10' off the ground, but a model might provide some insight! (I'd wonder a bit too about the proximity of the vertical portion to the tower!) Good luck with it! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andreas Hofmann Sent: Tuesday, September 24, 2013 2:24 PM To: 'topband@contesting.com' Subject: Topband: Double L antenna as an alternative for the radial-challenged? Hi, I am looking into what it would take to put a decent 160m antenna up. I got many large trees, but also rather thick woods, and the radials are always something that I do not enjoy much. Also, I cannot see myself to do 16 radials. 4 elevated radials may be tough as well. Terrain is just not as easy to get around. Now, I am looking at options that do not require radials and still have a decent radiation angle for DX. I am looking at this antenna http://www.yccc.org/Articles/double_l.htm, the double L antenna. Has anyone experience with it? What is the pattern of it and can it be compared to a quarter wave vertical? I would assume since it somehow resembles a vertical dipole and therefore does not require any radials, that its efficiency should be much better than a quarter wave vertical with less than adequate number of radials... Are my assumptions correct, and are there any other gotchas? Thanks and cu soon on topband Andy, KU7T _ Topband Reflector _ Topband Reflector
Topband: Double L antenna as an alternative for the radial-challenged?
Hi, I am looking into what it would take to put a decent 160m antenna up. I got many large trees, but also rather thick woods, and the radials are always something that I do not enjoy much. Also, I cannot see myself to do 16 radials. 4 elevated radials may be tough as well. Terrain is just not as easy to get around. Now, I am looking at options that do not require radials and still have a decent radiation angle for DX. I am looking at this antenna http://www.yccc.org/Articles/double_l.htm, the double L antenna. Has anyone experience with it? What is the pattern of it and can it be compared to a quarter wave vertical? I would assume since it somehow resembles a vertical dipole and therefore does not require any radials, that its efficiency should be much better than a quarter wave vertical with less than adequate number of radials... Are my assumptions correct, and are there any other gotchas? Thanks and cu soon on topband Andy, KU7T _ Topband Reflector
