[RFI] Fair-Rite Common Mode Chokes

donovanf at starpower.net donovanf at starpower.net
Thu Jul 18 10:04:30 EDT 2019


Joe, 


We use a fifty foot length of RG-8X on each of the nine dipoles used at 
the W3AO mega-Field Days. We then transition to hundreds of feet of 
RG-213 to reach the centrally located tent on our 1000 foot x 200 foot 
Field Day site. We use lightweight Budwig insulators and lightweight 
dacron rope. 


A choke is unnecessary on a monoband dipole, simply grounding the 
coax shield approximately 1/4 or 3/4 wavelengths from the feedpoint 
is completely adequate. Only a short ground is needed. 


73 
Frank 
W3LPL 


----- Original Message -----

From: "Joe" <nss at mwt.net> 
To: "Roger (K8RI)" <k8ri at rogerhalstead.com>, rfi at contesting.com 
Sent: Thursday, July 18, 2019 1:15:25 PM 
Subject: Re: [RFI] Fair-Rite Common Mode Chokes 

To change the subject some here, 

After a slight mishap at field day, a Dipole fell down in a storm, and a 
ceramic insulator hit a cars window and broke it. 

So the plan is to make an ultra light set of dipoles. Plastic 
insulators, coax fed with 58 size coax. etc. 

Now what cores, how many, etc. should I use instead of a heavy balun to 
make the choke? Low barefoot rigs 100 watts. so trying to keep things as 
light as possible. 

Joe WB9SBD 
Sig 
The Original Rolling Ball Clock 
Idle Tyme 
Idle-Tyme.com 
http://www.idle-tyme.com 
On 7/18/2019 12:22 AM, Roger (K8RI) wrote: 
> I (so far) use ferrite cores only for common mode chokes and I've made 
> and used many particularly for 160. 75, and 40 center fed slopimg 
> dipoles and half slopers. 
> 
> 73, Roger (K8RI) 

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