20 dB implies that the ground system loss is 10X the inverted-L radiation resistance.
This would result in an input resistance of 250 ohms and a minimum VSWR if 5:1. I don't think that is what the real deal will deliver, do you? Dave WX7G On Dec 12, 2012 12:54 PM, "Guy Olinger K2AV" <[email protected]> wrote: > With the following caveat: The very sparse and short buried radial systems > he is showing are FAR more lossy in practice than shown in his gain tables. > Four twenty foot buried radials beneath a 1/4 wave L on 160, could place > you down 20 dB. You really can't do that as your 160 meter counter poise > and expect decent results. You can end feed the same wire on 80/40/30 > meters (full wave worth of wire in the L on 80m) with four buried 20 foot > radials and it will be an excellent antenna. This is due to the high Z > feed at the ground with current max AWAY from the feed point. > > A quarter wave L on 160 MUST deal with the counterpoise loss issues, one > way or another. > > 73, Guy > > On Wed, Dec 12, 2012 at 2:07 PM, Ashton Lee <[email protected] > >wrote: > > > This wonderful article written by L.B.Cebic W4RNL sure can make you a > > believer in a simple wire inverted L. It is the last antenna discussed. > > http://www.users.on.net/~bcr/files/backyard%20wire%20antennaes.pdf > > > > A $3 wire pulled up into a tree will beat just about any commercial > > antenna… because it is longer. So on low bands it has increased band > width > > and efficiency, and on higher bands it has gain. Yes, I know , some of > that > > high band gain is horizontally polarized, but that's not all bad. Just > get > > the vertical portion 33 feet or so and you'll be happy as Larry. The > > article shows that an extensive radial field may not be necessary. > > > > And a wire is a lot less visible than a big hunk of aluminum. Without > > trees, just top load a 43 foot (or possibly even shorter) vertical. The > top > > loading could be a T just as easily as an L. People can argue that one > all > > day. > > > > > > > > > > On Dec 12, 2012, at 11:30 AM, k6xt <[email protected]> wrote: > > > > > My first antenna, still in use, on moving to CO is a GAP Titan, > > advertised to load up 80 thru 10 including WARC bands. The Titan is a bit > > shorter than Voyager, 28 feet or something like it. The advertising is > > correct, it loads up 180 thru 10. > > > > > > But wait. Is it effective on all those bands? No. > > > > > > On 80 its a dummy load. On 40 it works extremely well after I added a > > one foot extension to the bottom wire that encircles the antenna. In some > > cases it is the equal of my shorty HyGain 40 at 70 ft - which probably > says > > more about the HyGain than the GAP. For the rest its better on the > > traditional bands than the WARC bands. It worked a lot of DX for me for > the > > couple years it was my only antenna. > > > > > > Carrying my experience to the few feet taller Voyager, and from what > > I've been told by Voyager users, the ant will meet its spec which is to > > load up on the low bands. Expectation wise I'd expect it to be like the > > Titan. It loads up but is otherwise a dummy load. Maybe with a batch of > > radials it could be made to work as well as any other extremely short > > vertical or GP. > > > > > > Not to say there's anything wrong with GAP. My brother had up an R7 > > which he rated about like the GAP on bands both cover. Those multiband > > halfwave short verticals work but you get what you pay for. > > > > > > 73 Art K6XT~~ > > > Success is going from failure to failure without a loss of enthusiasm. > > > ARRL, GMCC, CW OPS, NAQCC > > > ARRL TA > > > > > > On 12/12/2012 10:00 AM, [email protected] wrote: > > >> With the prospect of downsizing and moving into senior housing in the > > future > > >> I am starting to look at vertical antennas that will allow me to > > continue > > >> this wonderful hobby.? I have heard "some" good things about the GAP > > series > > >> of antennas but the company says they do not need radials on most of > > them > > >> and that worries me.? Over the years I have become very skeptical > about > > >> claims and the other BS put out by most companies ( maybe it is a > > function > > >> of age I dunno) so I wonder if these antennas really work.? The two > > antennas > > >> that I am interested are the Voyager DX for 160/80/40? and the Eagle > DX > > for > > >> the rest of the bands. > > >> > > >> So my question is.... does anyone have actual experience with these > > antennas > > >> (especially the voyager) as compared to other antennas for a specific > > >> frequency.? Now guys .. I know you cant really compare a 6 element > beam > > to a > > >> vertical of this kind but I am talking about a comparison that is > > >> realistic.. like how does it hear, tune, match & get out compared to > > >> something like another vertical or a dipole up some reasonable > distance. > > >> > > >> I sure hope this has not opend another can of worms.. some how I seem > > to do > > >> that .. private emails are ok..especially it the topic gets out of > hand > > and > > >> we get a large volume of comments (Tree please dont shoot me before > > >> Christmas my wife will miss me.) > > > > > > _______________________________________________ > > > Topband reflector - [email protected] > > > > > > > _______________________________________________ > > Topband reflector - [email protected] > > > _______________________________________________ > Topband reflector - [email protected] > _______________________________________________ Topband reflector - [email protected]
