Topband: BOG - Selecting the Optimum Length

Mon Oct 17 13:16:08 EDT 2016

Gents

Thanks for your very quick replies, a lot via private emails – you guys are
great and this 160M JN really appreciates it.

I didn’t realize the Lloyd’s BOG was a few inches above the ground, which
makes a difference.

Mine will be on the ground (with staples at points to make sure it stays
there…..).

73 Mark K3MSB

On Oct 17, 2016 12:29 PM, "Kip Edwards" <kedwards at ltol.com> wrote:

> Mark,
>
>         The BOG here is 190 feet.  It works very well and is quite
> directional.  As a result of my experience so far, I'm thinking of a second
> one for the other directions.
>
>         73 Kip W6SZN
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Mark
> K3MSB
> Sent: Monday, October 17, 2016 8:35 AM
> To: Lloyd - N9LB
> Cc: topBand List
> Subject: Re: Topband: BOG - Selecting the Optimum Length
>
> 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" <lloydberg at 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-bounces at contesting.com] On Behalf Of
> > Lloyd - N9LB
> > Sent: Sunday, October 16, 2016 11:06 PM
> > To: 'Topband' <topband at 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-bounces at contesting.com] On Behalf Of
> > Charles Moizeau
> > Sent: Sunday, October 16, 2016 10:20 PM
> > To: Lloyd - N9LB <lloydberg at charter.net>; Topband
> > <topband at 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-bounces at contesting.com> on behalf of Lloyd -
> > N9LB <lloydberg at charter.net>
> > Sent: Sunday, October 16, 2016 7:15 PM
> > To: topband at 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-bounces at contesting.com] On Behalf Of
> > N2TK, Tony
> > Sent: Sunday, October 16, 2016 5:15 PM
> > To: topband at 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
> > _________________
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> >
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> >
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