[UK-CONTEST] [Fwd: Re: Ferromagnetics Choke Baluns]

[Clive GM3POI]

Another factor would be if you were to use elevated 
radials.
A balun is very much needed then. 73 Clive GM3POI
----- Original Message ----- 
From: "David, G3YYD" <g3yyd at btinternet.com>
To: <uk-contest at contesting.com>
Sent: Saturday, November 14, 2009 3:46 PM
Subject: [UK-CONTEST] [Fwd: Re: Ferromagnetics Choke 
Baluns]


> Bob
>
> With a less than a perfect ground screen (or more 
> likely a very poor
> ground screen) then the outer of the coax will have 
> a lot of RF current
> on it. Fitting a choke to the coax, AKA a choke 
> balun, will help to
> reduce RF in the shack. Personally I do not use one 
> but then my 160m
> vertical has a reasonable ground screen with the 
> coax running underneath
> the ground screen.
>
> For those who are mystified by my terminology of 
> ground screen this is a
> more accurate description of what we are trying to 
> do with something we
> normally call an earth. In other words screening as 
> much RF current from
> the lossy earth as possible.
>
> David G3YYD
>
> Bob Henderson wrote:
>> Hi Jim
>>
>> I hope you don't mind me asking but why would you 
>> be thinking of using a
>> balun to feed unbalanced antennas such as the HF2V 
>> or an inverted L?
>>
>> Bob, 5B4AGN
>>
>> 2009/11/12 MM0BQI <MM0BQI at blueyonder.co.uk>
>>
>>
>>> Hi
>>> I have two of the above but can find nothing on 
>>> the web about them other
>>> than I believe they were made by a Welsh company.
>>> They are approx 11 inches by one inch, white 
>>> plastic tubes with
>>> 'Ferromagnetics Choke' written on them.
>>> Both have an SO239 sockets at one end.  At the 
>>> other end one has a short
>>> pigtail of RG58 to a PL259 and the other has two 
>>> screw terminals (possibly
>>> for a dipole)
>>> Does anyone have any info on them, frequency 
>>> range/ power etc?
>>> Possibly looking to use them on a topband 
>>> inverted L and HF2V for 40/80.
>>> Thanks
>>> Jim
>>> MM0BQI
>>>
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