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" <[email protected]> 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:[email protected]] On Behalf Of Lloyd - > N9LB > Sent: Sunday, October 16, 2016 11:06 PM > To: 'Topband' <[email protected]> > 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:[email protected]] On Behalf Of Charles > Moizeau > Sent: Sunday, October 16, 2016 10:20 PM > To: Lloyd - N9LB <[email protected]>; Topband <[email protected]> > 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 <[email protected]> on behalf of Lloyd - N9LB > <[email protected]> > Sent: Sunday, October 16, 2016 7:15 PM > To: [email protected] > 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:[email protected]] On Behalf Of N2TK, > Tony > Sent: Sunday, October 16, 2016 5:15 PM > To: [email protected] > 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
