[Elecraft] Bad Ham Radio Day

[jerry]

On 2021-09-04 14:31, Jim Brown wrote:
> On 9/4/2021 2:03 PM, jerry wrote:
>> I made up a short length of RG8/U with 4 Palomar 31-mix giant ferrite 
>> beads
> 
> Palomar SELLS these cores, at high prices. Fair-Rite MAKES them.

31-mix is supposed to be the hot ticket for HF common mode
chokes.  One turn through one core is supposed to be 98 ohms at 5MHz.  
So four cores should give me about 400 ohms, which should give a 
worthwhile attenuation in a 50 ohm system.  Thanks for the references.

   It's interesting that I am not having any such problems with any
other equipment.  My TS590S works fine.  So did the K2/10 with my tiny 
linear.
And a QRP-labs transceiver.  And a uBITX transceiver.  And a ICOM 
IC706MKII.
None of this stuff is doing anything strange.

                      - Jerry KF6VB



> 
>  - a common mode choke.  No difference.
> 
> This is only a good choke at VHF. If your problem is HF, multiple
> turns must be wound through the core. Study choke recommendations
> here.
> 
> http://k9yc.com/KillingReceiveNoise.pdf
> 
> And here. http://k9yc.com/RFI-Ham.pdf
> 
> 73, Jim K9YC
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