Same reply. At our contest station, we have a 300M beverage just running through the woods and tree branches in Northern Ontario
No scientific testing, but it just worked. Mike va3mw On Mon, Nov 14, 2016 at 7:49 AM, Paul Mclaren <[email protected]> wrote: > On a similar note can I ask about beverages touching leaves and other > vegetagian. Will this result in poor performance and if so is it > significant? > > Regards > > Paul MM0ZBH > > On 14 November 2016 at 12:41, Michael Walker <[email protected]> wrote: > >> For my 80CW and 160 verticals, I have wires suspended through 90 ft tall >> evergreens. I have been doing that for years and I put them in place >> using >> a drone (long before everyone was doing it). >> >> I have radials underneath. In fact, they are on a common feedpoint. >> >> Based on my 160M or 80M WSPR / JT65 testing, I would be hard pressed to >> say >> that much if any RF is being absorbed by the trees. >> >> In my case, I work with what I have available. For me, they just work. >> >> Mike va3mw >> >> >> On Mon, Nov 14, 2016 at 12:54 AM, Lee STRAHAN <[email protected]> wrote: >> >> > >> > >> > Greetings Top-Banders, I have been away for a couple days, sorry for >> the >> > late comments. >> > The fact is, for me there is no definitive answer to the effect of >> > trees on the Hi-Z arrays. I have made tests measuring phase shifts and >> > amplitude changes with a variety of objects around these elements. My >> > original thoughts after the tests were that any tree or large foliage >> would >> > have to a minimum of 5 feet distance from the elements. There are not >> many >> > trees where I live so this sort of test is very difficult. One of the >> > things I did was to measure the capacitance of the elements as a source >> > impedance to the amps. Changes in this capacitance would make amplitude >> > changes at the amplifiers. The only real changes I measured after >> numerous >> > tests were when I would approach the element with the capacitance meter >> in >> > operation. When a 6 foot person approached the elements I could see >> changes >> > in the element at about 3 feet separation. Nothing at 5 feet. This was >> with >> > a 24 foot aluminum element and a low capacity mounting insulator. This >> > capacitance test was more sensitive than my voltage and phase >> measurements. >> > Mike NI7T installed a 4 square system in the forest behind his cabin. >> > Many pine and redwood trees were within 5 feet of the elements. We were >> > never able to discern any negative affects to his array. Front to back >> > rejection was well within nominal and front patterns seemed proper. The >> > array remained sensitive to weak signals. Larry K1UO had his array in a >> > brush patch. As I recall I suggested a 5 foot spacing which he did. If >> you >> > have not seen the DX Larry posts from Maine you are missing something. >> In >> > other words it was apparently adequate spacing. >> > So with the 24 foot elements ¾ inch diameter that have around a 75pf >> > source capacitance I would say you are pretty safe at 5 feet. Shorter >> > elements with significantly less source capacitance would surely need >> more >> > spacing. A 12 foot similar element drops clear down to 42pf source >> > capacitance. I would hazard a guess that arrays using short whip >> elements >> > at around 25pf would be quite sensitive to close trees or foliage. >> > Barring all this I am confident you would be absolutely safe in my >> > estimation at 10 feet distance of brush, tall foliage, and trees from >> the >> > elements. >> > >> > Lee K7TJR >> > >> > >>Hello Jim >> > >> > My HI-Z 4 square has trees about 15 feet away from two of the elements >> (I >> > can make exact distance measurements if that would help you). >> > >> > I do not "think" the trees interact in my setup - but I am not 100% >> sure. >> > Even my HI-Z 8 circle has trees pretty close to 3 elements (10 feet). >> > Without measuring changes (impedance) to these elements due to >> location, I >> > am not sure how else to know. However, given Frank's comments - I will >> be >> > trimming some trees today! >> > >> > I am certain K7TJR is the expert on this has he has heard from users >> about >> > element location and performance for years. >> > >> > I wish you the best. >> > >> > 73 >> > Tim K3LR >> > >> > ________________________________ >> > From: [email protected]<mailto:[email protected]> [mailto: >> > [email protected]] >> > Sent: Saturday, November 12, 2016 6:57 PM >> > To: [email protected]<mailto:[email protected]> >> > Cc: Lee K7TJR; [email protected]<mailto:[email protected]>; Joel Harrison >> > Subject: Re: Hi-Z Around Trees >> > >> > Hi Jim, >> > >> > My comments about short verticals not performing well near trees >> > applies only to high impedance verticals. Low impedance are >> > little affected. >> > >> > 73 >> > Frank >> > W3LPL >> > ________________________________ >> > >> > _________________ >> > Topband Reflector Archives - http://www.contesting.com/_topband >> > >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
