Topband: Commond mode choke for Beverage

[Filipe Lopes]

Thanks JC,

I am reading it right now, very interesting indeed.

73's Filipe Lopes
CT1ILT - CR6K
F4VPX - TM3M

2015-10-12 22:27 GMT+02:00 JC <n4is at comcast.net>:

> Hi Felipe
>
>
>
> It works like a voltage divider where the impedance to ground should be
> lower as possible to give you more attenuation  like 1k/500ohms versus 1K/5
> ohms divider. You should use the choke near a good ground before entering
> the station. If you switch box have a good ground it’s a good place to
> install  it.
>
> More turns better, but it is limited by the diameter of the coaxial cable,
> like RG58/RG142 allows 12 to14 turns. RG213  only 8 turns.
>
>
>
> Jim K9YC and a fantastic documentation about chokes. Please read this
> document
>
>
>
> http://audiosystemsgroup.com/RFI-Ham.pdf
>
>
>
> You will be a specialist after reading this guide.
>
>
>
> Regards
>
> JC
>
> N4IS
>
>
>
> *From:* Filipe Lopes [mailto:ct1ilt at gmail.com]
> *Sent:* Monday, October 12, 2015 9:52 AM
> *To:* JC <n4is at comcast.net>
> *Cc:* topBand <topband at contesting.com>
> *Subject:* Re: Topband: Commond mode choke for Beverage
>
>
>
> Hello JC,
>
>
>
> Thanks for your answer.
>
>
>
> I just ordered a few 2631803802 and 5943003801 from mouser.
>
>
>
> With these ferrites I ask the same question, should I put the choke close
> to the 9:1 Balun or near the switching box and how many turns? some bevs
> have the feed point at +- 60m away from the switching box.
>
>
>
>
> 73's Filipe Lopes
>
> CT1ILT - CR6K
>
> F4VPX - TM3M
>
>
>
> 2015-10-12 15:40 GMT+02:00 JC <n4is at comcast.net>:
>
> Hi Filipe
>
> Zero , you should use material #31  or #77 , The core you have is not good
> for low bands.
>
> JC
> N4IS
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Filipe
> Lopes
> Sent: Monday, October 12, 2015 8:46 AM
> To: topBand <topband at contesting.com>
> Subject: Topband: Commond mode choke for Beverage
>
> Hi guys,
>
> I am about to add a common mode choke to isolate the antenna from its
> feedline to each of my beverages and I only have FT240-61 ferrites. My
> question is how many turns should I do on the ferrite using RG58 (all my
> bevs are fed with RG58). Also should I put the choke near the 9:1 balun or
> near my bev switching box?
>
> Thanks in advance.
>
> 73's Filipe Lopes
> CT1ILT - CR6K
> F4VPX - TM3M
>
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>
>
>