Typing on my iPhone from the woods now. I am testing a JK BevFlex 4 deployed as a bog now. Early stages. I think the optimum length will be determined by the local earth characteristics. Started by measuring a wire dipole resonance on the ground to determine the shortening factor from earth proximity. Based on this started at 225'. Antenna hears well and shows good f/b but condx have been poor. Waiting for more favorable conditions to try optimizing. Have Hi Z triangle and normal bev to test against. I can already say it works much better than my tx inv L on 160. Another update after more testing. Back to work now.
73 Charlie N8RR Sent from my iPhone > On Oct 17, 2016, at 11:35 AM, Mark K3MSB <mark.k3...@gmail.com> wrote: > > Based upon N9LB’s comments, I just emailed Bruce and told him to hold my > order for a KB-1. > > I have just enough room for 200 ft for a BOG. Extending it to 250, 290 > feet etc is NOT an option for me. > > From my reading, I understood that 200 feet was not exact, but I didn’t > expect it to be 250 to 290 feet. If I had known that I would not have > even considered a BOG. > > With the cable, KB-1 etc (my BOG will be unidirectional to EU only, not > bidirectional), I really don’t want to invest close to $200 on an antenna > that will not do any better on RX than my Inverted-L. Saving it for a > Hi-Z 3 may be the better option. > > So, with only 200 feet to play with, is it worth it? > > I've no doubt BOGs work, I may not have the room for them. > > 73 Mark K3MSB > >> On Oct 17, 2016 9:35 AM, "Lloyd - N9LB" <lloydb...@charter.net> wrote: >> >> I have been asked how I arrived at the 290 foot BOG length. >> >> My original 200 foot BOG had a good F/B on 80m but showed almost no >> directivity on 160m, so this indicated to me that the BOG needed to be >> longer to improve the 160m performance with my particular soil conditions >> and environment. >> >> A search on the Internet produced recommendations for 160m BOG lengths of >> 247 to 290 feet. Knowing that I could always shorten the wire, I went with >> the longer number as a starting point. That produced a greatly improved 15 >> to 20 dB Front-to-Back ratio. >> >> The 290 foot length was not chosen for a good match, but that length just >> happened to result in a good match. >> >> Unfortunately, I did not measure the match on my 200 ft BOG before it was >> dismantled. >> >> The optimum 160m BOG length in your environment might be much different >> from >> what I found at my QTH. >> >> - - - I think the group would benefit from hearing what others have found >> to >> be their optimum BOG lengths - - - >> >> >> -----Original Message----- >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Lloyd - >> N9LB >> Sent: Sunday, October 16, 2016 11:06 PM >> To: 'Topband' <topband@contesting.com> >> Subject: Re: Topband: BOG >> >> My Reversible Bog uses the KD9SV transformer set. It was originally 200 >> feet long, just increased to 290 feet and that made a very significant >> improvement on 160m front-to-back ratio, but hurt 80m performance. >> >> Conditions here are: >> Wire run across a weedy field, as close to ground as possible (weeds >> trampled down to allow the wire to be close to ground - mostly 2-4 inches >> above the actual ground). Soil is a few inches of decent dirt, about one >> to >> two feet of clay, about one to two feet of sand, and then bedrock. Tops of >> the five foot ground rods can't be driven completely below the ground's >> surface. >> >> WX - a wetter than normal Summer and Fall here in Southern Wisconsin. >> >> My Antenna Analyzer shows a 1.45 : 1 match at 1825 KHz ( 75 ohm system ). >> >> I can send the analyzer plots to anyone that is interested. >> >> 73 >> >> Lloyd - N9LB >> >> -----Original Message----- >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charles >> Moizeau >> Sent: Sunday, October 16, 2016 10:20 PM >> To: Lloyd - N9LB <lloydb...@charter.net>; Topband <topband@contesting.com> >> Subject: Re: Topband: BOG >> >> Thanks Lloyd, >> >> But pls tell us your wire height and approximate description of gnd condx >> for your otherwise well-described bog. >> >> 73, >> >> Charles W2SH >> ________________________________ >> From: Topband <topband-boun...@contesting.com> on behalf of Lloyd - N9LB >> <lloydb...@charter.net> >> Sent: Sunday, October 16, 2016 7:15 PM >> To: topband@contesting.com >> Subject: Re: Topband: BOG >> >> Hello Tony! >> >> Ground conditions and wire height above ground make a huge difference in >> best length. >> >> I found the optimum for my BOG, using WD-1A wire and operating at 1825 KHz, >> at my QTH is 290 feet. >> >> 73 >> >> Lloyd - N9LB >> >> -----Original Message----- >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of N2TK, >> Tony >> Sent: Sunday, October 16, 2016 5:15 PM >> To: topband@contesting.com >> Subject: Topband: BOG >> >> Stretched out 200' of WD-1A along a stone wall. Kept it about 2" above the >> ground and right up against the stones. Fed it with a 300 ohm secondary >> transformer and left the far end unterminated. >> >> Used the MFJ-259 to sweep the bands starting at 1.67 MHZ. Saw on K1FZ >> notes >> that to find the best single wire length for 160M is to sweep the bands and >> check where the SWR goes to a low value and stays there. >> >> I couldn't find that frequency. I get dips at >> >> 2.58 MHZ 4.3:1 >> 3.36 MHZ 1.5:1 >> 4.39 MHZ 1.4:1 >> 6.033 MHZ 1.3:1 >> 9.807 MHZ 1.2:1 >> >> I didn't check any higher in freq. I only care about listening on 160M with >> it. >> I twisted both wires together at the feedpoint. >> Want to check it out first as a single ended BOG to see how it works before >> I go to the trouble of making it a two direction BOG. >> At one point the BOG is only 35' from my tower. >> Is it too high and does it need to be against the ground? >> >> Any feedback appreciated. >> >> N2TK, Tony >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband