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?
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: Building a 160m inverted L and tie it into existing objects?
Hi, It is time for me to add an antenna for 160m. I got large trees on my property and sloping ground in 270 degrees, which works very well for my high band yagi. Should also work well for a vertical I hope. I have done some experiments with a 40 quarter wave vertical hanging from a large fir tree and 4 elevated radials. The vertical works pretty well. Now on to 160. Everything is bigger and I am thinking about hooking it into some things I have. 1. I have a zip line for the kids that runs down slope (well a zip line needs a slope), about 5 - 10 degrees. Direction is to EU. It is 210 feet long and made out of strong 1/4 inch galvanized steel cable. I am wondering if I can hang off the vertical section of the tree the top of the zip line is on, and then hook the zip line to the coax outer jacket as the first radial. Off course I would have to consider safety here, kids should not be on the zip line when I operate. I can see the line from the shack window, so that should be ok. I cannot cut the length of the zip line off course. Is it too long? 2. The top of the zip line starts a few feet above a metal roof of a wood shed. Should I tie into the metal roof? Picture here: http://sdrv.ms/13YkcHi 3. About 150 feet away, in a different direction I got a large old metal object (decommissioned water boiler or oil tank) in the woods. Does it make sense to run an elevated radial and have its end connect to it. In general, my 40 vertical was tunable by cutting the lengths of the radiator and the elevated radials. With the proposed idea for the 160m L I will not be able to trim anything except the length of the vertical portion. Is that enough to tune the antenna for say 1835? Overall, I think I could manage to do 4 elevated radials. I know that is not perfect, but with tying into some of the proposed things should do it if possible... Thanks Andy, KU7T All good topband ops know how to put up a beverage at night. _ Topband Reflector
