Re: Topband: RF choke/balun

[Charles Moizeau]

That could be true, but for several years my inverted L (86 feet up and 68 feet 
out, over 1.5 miles of in-ground radials) is significantly less noisy on 
receive than my 270-foot center-fed dipole sloping (intentionally) from 83 feet 
to 7 feet.


Your comments please.


73,


Charles, W2SH


From: Topband <topband-boun...@contesting.com> on behalf of Rob Atkinson 
<ranchoro...@gmail.com>
Sent: Saturday, September 16, 2017 8:40 AM
To: Arthur Delibert
Cc: topband@contesting.com
Subject: Re: Topband: RF choke/balun

Unless you like listening to noise you don't use an inverted L on 160
(or 80) for receiving.

Rob
K5UJ

On Sat, Sep 16, 2017 at 6:58 AM, Arthur Delibert <radio7...@msn.com> wrote:
> I think that’s right if the only issue is your own transmit signal bouncing
> back from the antenna junction and traveling along the exterior of the
> feedline.  But for receiving, I think a choke at each end of the feedline is
> important unless you’re in an exceptionally low noise location.  K9YC
> recommends putting a choke at the antenna end of the feedline, and I’ve
> found it makes quite a difference in the amount of local noise on the
> received signal.  If I understand it right, the outside of the feedline
> picks up the noise signal and carries it to the antenna junction, from where
> it gets mixed in with the desired signal.
>
>
>
>
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Re: Topband: RF choke/balun

[Rob Atkinson]

Unless you like listening to noise you don't use an inverted L on 160
(or 80) for receiving.

Rob
K5UJ

On Sat, Sep 16, 2017 at 6:58 AM, Arthur Delibert  wrote:
> I think that’s right if the only issue is your own transmit signal bouncing
> back from the antenna junction and traveling along the exterior of the
> feedline.  But for receiving, I think a choke at each end of the feedline is
> important unless you’re in an exceptionally low noise location.  K9YC
> recommends putting a choke at the antenna end of the feedline, and I’ve
> found it makes quite a difference in the amount of local noise on the
> received signal.  If I understand it right, the outside of the feedline
> picks up the noise signal and carries it to the antenna junction, from where
> it gets mixed in with the desired signal.
>
>
>
>
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: RF choke/balun

[Arthur Delibert]

I think that’s right if the only issue is your own transmit signal bouncing 
back from the antenna junction and traveling along the exterior of the 
feedline.  But for receiving, I think a choke at each end of the feedline is 
important unless you’re in an exceptionally low noise location.  K9YC 
recommends putting a choke at the antenna end of the feedline, and I’ve found 
it makes quite a difference in the amount of local noise on the received 
signal.  If I understand it right, the outside of the feedline picks up the 
noise signal and carries it to the antenna junction, from where it gets mixed 
in with the desired signal.

Art Delibert, KB3FJO

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: Rob Atkinson<mailto:ranchoro...@gmail.com>
Sent: Friday, September 15, 2017 12:34 PM
To: topband@contesting.com<mailto:topband@contesting.com>
Subject: Topband: RF choke/balun

If you have enough radials at or below ground you won't need a common
mode choke.  You don't say if your inverted L will have an elevated
ground system or not.  If the ground system consists of 60 or more
radials you can probably put a matching network out and the feedpoint
and forget about fooling around with common mode chokes and all that.
The RF current on the exterior of your feed line will be so small it
won't matter.

73

Rob
K5UJ
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Re: Topband: RF choke/balun

[David Cutter via Topband]

To get the best performance from your choke, K9YC recommends you make a coil 
of about 7" diameter from memory.  His document has lots of curves to choose 
the best assembly.


David
G3UNA

- Original Message - 
From: "MR TREVOR DUNNE" <ei2...@eircom.net>

To: "topband List" <TOPBAND@contesting.com>
Sent: Saturday, September 16, 2017 8:07 AM
Subject: Re: Topband: RF choke/balun



Hi

Thanks for the replies, no I will be using radials on the ground, amount 
unknown,


Thanks
Trevor
EI2GLB

- Original Message -
From: "Mike Waters" <mikew...@gmail.com>
To: "MR TREVOR DUNNE" <ei2...@eircom.net>
Cc: "topband List" <TOPBAND@contesting.com>
Sent: Friday, 15 September, 2017 18:56:59
Subject: Re: Topband: RF choke/balun

If you're going with elevated radials, then a feedline choke is a must.
Place it within a few feet of the feedpoint.

Use four or five stacked 2.4" diameter #31 ferrite toroid cores with about
six turns of coax wound through them.  See K9YC's excellent reference to 
be

sure.

73, Mike
www.w0btu.com

On Sep 15, 2017 9:24 AM, "MR TREVOR DUNNE" <ei2...@eircom.net> wrote:


Hi All

I am planning on making an RD Choke for my 160m inverted L and was
wondering what others use,

I was thinking of 3 stacked ft240-43 cores and maybe 10-12 turns of some
rg316 or the like small coax,

With 61 or 31 be a better material to use and do I need more or less 
turns,


I'm loosely working from the G3TXQ website where he did like of
measurements on different chokes, but not we're great on 160m,

I'd like to end up with something like a balun design 1116d but with a 
lot

less money in it,

Thanks
Trevor
EI2GLB
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Re: Topband: RF choke/balun

[MR TREVOR DUNNE]

Hi 

Thanks for the replies, no I will be using radials on the ground, amount 
unknown,

Thanks
Trevor
EI2GLB

- Original Message -
From: "Mike Waters" <mikew...@gmail.com>
To: "MR TREVOR DUNNE" <ei2...@eircom.net>
Cc: "topband List" <TOPBAND@contesting.com>
Sent: Friday, 15 September, 2017 18:56:59
Subject: Re: Topband: RF choke/balun

If you're going with elevated radials, then a feedline choke is a must.
Place it within a few feet of the feedpoint.

Use four or five stacked 2.4" diameter #31 ferrite toroid cores with about
six turns of coax wound through them.  See K9YC's excellent reference to be
sure.

73, Mike
www.w0btu.com

On Sep 15, 2017 9:24 AM, "MR TREVOR DUNNE" <ei2...@eircom.net> wrote:

> Hi All
>
> I am planning on making an RD Choke for my 160m inverted L and was
> wondering what others use,
>
> I was thinking of 3 stacked ft240-43 cores and maybe 10-12 turns of some
> rg316 or the like small coax,
>
> With 61 or 31 be a better material to use and do I need more or less turns,
>
> I'm loosely working from the G3TXQ website where he did like of
> measurements on different chokes, but not we're great on 160m,
>
> I'd like to end up with something like a balun design 1116d but with a lot
> less money in it,
>
> Thanks
> Trevor
> EI2GLB
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
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Re: Topband: RF choke/balun

[Mike Waters]

If you're going with elevated radials, then a feedline choke is a must.
Place it within a few feet of the feedpoint.

Use four or five stacked 2.4" diameter #31 ferrite toroid cores with about
six turns of coax wound through them.  See K9YC's excellent reference to be
sure.

73, Mike
www.w0btu.com

On Sep 15, 2017 9:24 AM, "MR TREVOR DUNNE"  wrote:

> Hi All
>
> I am planning on making an RD Choke for my 160m inverted L and was
> wondering what others use,
>
> I was thinking of 3 stacked ft240-43 cores and maybe 10-12 turns of some
> rg316 or the like small coax,
>
> With 61 or 31 be a better material to use and do I need more or less turns,
>
> I'm loosely working from the G3TXQ website where he did like of
> measurements on different chokes, but not we're great on 160m,
>
> I'd like to end up with something like a balun design 1116d but with a lot
> less money in it,
>
> Thanks
> Trevor
> EI2GLB
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
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Topband: RF choke/balun

[Rob Atkinson]

If you have enough radials at or below ground you won't need a common
mode choke.  You don't say if your inverted L will have an elevated
ground system or not.  If the ground system consists of 60 or more
radials you can probably put a matching network out and the feedpoint
and forget about fooling around with common mode chokes and all that.
The RF current on the exterior of your feed line will be so small it
won't matter.

73

Rob
K5UJ
_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: RF choke/balun

[MR TREVOR DUNNE]

Hi All

I am planning on making an RD Choke for my 160m inverted L and was wondering 
what others use,

I was thinking of 3 stacked ft240-43 cores and maybe 10-12 turns of some rg316 
or the like small coax,

With 61 or 31 be a better material to use and do I need more or less turns,

I'm loosely working from the G3TXQ website where he did like of measurements on 
different chokes, but not we're great on 160m,

I'd like to end up with something like a balun design 1116d but with a lot less 
money in it,

Thanks
Trevor
EI2GLB 
_
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