Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Mark K3MSB 
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" <kedwa...@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-boun...@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" <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,
> >
> &g

Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Kip Edwards 
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-boun...@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" <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 oh

Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Charlie Young 
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  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"  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' 
>> 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 ; Topband 
>> 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  on behalf of Lloyd - N9LB
>> 
>> 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

Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Lloyd - N9LB 
Just to be clear, my original 200 foot BOG was a success – much quieter on RX 
than the vertical !

 

In my particular environment, based on my particular soil conditions, I was not 
seeing a significant directional characteristic on 160m, but the 200 foot BOG 
still outperformed the vertical and allowed me to work Heard Island, South 
Sandwich and South Georgia last season!

 

If you only have 200 feet or even a bit less than 200 feet, I still think the 
BOG is definitely the way to go.

 

I apologize if anyone was misled.

 

73

 

Lloyd – N9LB

 

From: Mark K3MSB [mailto:mark.k3...@gmail.com] 
Sent: Monday, October 17, 2016 10:35 AM
To: Lloyd - N9LB <lloydb...@charter.net>
Cc: topBand List <topband@contesting.com>
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" <lloydb...@charter.net 
<mailto: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 
<mailto:topband-boun...@contesting.com> ] On Behalf Of Lloyd -
N9LB
Sent: Sunday, October 16, 2016 11:06 PM
To: 'Topband' <topband@contesting.com <mailto: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 
<mailto:topband-boun...@contesting.com> ] On Behalf Of Charles
Moizeau
Sent: Sunday, October 16, 2016 10:20 PM
To: Lloyd - N9LB <lloydb...@charter.net <mailto:lloydb...@charter.net> >; 
Topband <topband@contesting.com <mailto: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 
<mailto:topband-boun...@contesting.com> > on behalf of Lloyd - N9LB
<lloydb...@charter.net <mailto:lloydb...@charter.net> >
Sent: Sunday, October 16, 2016 7:15 PM
To: topband@contesting.com <mailto: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...@contesti

Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Mark K3MSB 
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"  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' 
> 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 ; Topband 
> 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  on behalf of Lloyd - N9LB
> 
> 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

Re: Topband: BOG - Selecting the Optimum Length

2016-10-17 Thread Lloyd - N9LB 
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' 
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 ; Topband 
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  on behalf of Lloyd - N9LB

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
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