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Old June 7th 06, 02:44 PM posted to rec.radio.amateur.antenna
Ken Bessler
 
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Default Quad feedpoint

I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?

--
73's de Ken KG0WX - Kadiddlehopper #11808,
Flying Pigs #-1055, Grid EM17io, FT-857D, AL-84,
Elecraft XG2, 4SQRP Tenna Dipper, Heath GD-1B


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Old June 7th 06, 03:04 PM posted to rec.radio.amateur.antenna
Reg Edwards
 
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Default Quad feedpoint


I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?

====================================

Only if it doesn't work without it.


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Old June 7th 06, 03:13 PM posted to rec.radio.amateur.antenna
Cecil Moore
 
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Default Quad feedpoint

Ken Bessler wrote:
I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?


How about ~5 feet of wire? From an earlier posting:


--
73, Cecil http://www.qsl.net/w5dxp
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Old June 7th 06, 03:19 PM posted to rec.radio.amateur.antenna
Cecil Moore
 
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Default Quad feedpoint

Ken Bessler wrote:
I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?


A few turns of coax will do the trick for 6m.
How about this solution from an earlier posting?

|
|
| Driven
| Element
|
+====================================coax braid

+------------------------------------coax center conductor
|
| ==============================+===coax braid
| spacing |
+--------------------------------+
| 1/4WL wire (~4.7')
|

--
73, Cecil http://www.qsl.net/w5dxp
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Old June 7th 06, 05:31 PM posted to rec.radio.amateur.antenna
Ian White GM3SEK
 
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Default Quad feedpoint

Cecil Moore wrote:
Ken Bessler wrote:
I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?


A few turns of coax will do the trick for 6m.
How about this solution from an earlier posting?

|
|
| Driven
| Element
|
+====================================coax braid

+------------------------------------coax center conductor
|
| ==============================+===coax braid
| spacing |
+--------------------------------+
| 1/4WL wire (~4.7')
|

The choke balun made from a small coil of coax would be easier to make.
At my previous QTH, four turns of about 6in diameter made a big
reduction in the levels of noise and birdies on 6m (even though those
coil dimensions weren't optimized in any way).

This kind of feedline choke is simple, cheap and low-loss, so by all
means go ahead and use one. With a 3-element quad, you should be able to
position the coil at the feedpoint while supporting its weight from the
mast.





--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek


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Old June 9th 06, 10:51 PM posted to rec.radio.amateur.antenna
Jimmie D
 
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Default Quad feedpoint


"Ian White GM3SEK" wrote in message
...
Cecil Moore wrote:
Ken Bessler wrote:
I just built a 3el 6m quad. Should I put a choke or balun
at the feedpoint? What type?


A few turns of coax will do the trick for 6m.
How about this solution from an earlier posting?

|
|
| Driven
| Element
|
+====================================coax braid

+------------------------------------coax center conductor
|
| ==============================+===coax braid
| spacing |
+--------------------------------+
| 1/4WL wire (~4.7')
|

The choke balun made from a small coil of coax would be easier to make. At
my previous QTH, four turns of about 6in diameter made a big reduction in
the levels of noise and birdies on 6m (even though those coil dimensions
weren't optimized in any way).

This kind of feedline choke is simple, cheap and low-loss, so by all means
go ahead and use one. With a 3-element quad, you should be able to
position the coil at the feedpoint while supporting its weight from the
mast.





--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek


Using a choke made a big difference in TVI for me.


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Old June 10th 06, 10:39 AM posted to rec.radio.amateur.antenna
Ian White GM3SEK
 
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Default Quad feedpoint

Jimmie D wrote:

"Ian White GM3SEK" wrote

The choke balun made from a small coil of coax would be easier to make. At
my previous QTH, four turns of about 6in diameter made a big reduction in
the levels of noise and birdies on 6m (even though those coil dimensions
weren't optimized in any way).


Using a choke made a big difference in TVI for me.

Others have reported the same.

If you have RFI, either on transmit or on receive, then a feedline choke
("current balun") at the antenna feedpoint would be the first thing to
try. It's easy to install - but even easier if you install it at the
same time as the antenna.

"Prevention is better than cure" is a very good principle.


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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Old June 10th 06, 12:14 PM posted to rec.radio.amateur.antenna
 
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Default Quad feedpoint



Ian wrote:
The choke balun made from a small coil of coax would be easier to make. At
my previous QTH, four turns of about 6in diameter made a big reduction in
the levels of noise and birdies on 6m (even though those coil dimensions
weren't optimized in any way).


Jimmie D wrote:
Using a choke made a big difference in TVI for me.


Ian wrote:
Others have reported the same.

If you have RFI, either on transmit or on receive, then a feedline choke
("current balun") at the antenna feedpoint would be the first thing to
try. It's easy to install - but even easier if you install it at the
same time as the antenna.


Why would anyone wanting the antenna to radiate and not the feedline
ever make a direct connection without some planning???

It seems foolish to go through the effort of puting up an antenna and
not doing something so simple in advance rather than waiting for
problems.

73 Tom

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