[Amps] (Perhaps) A plate choke too far ...

[Radio WC6W]

Hi Jim,
  To my knowledge, rods are not made (as standard parts) in 43...  a few cable cores could be stacked.

  Rod cores don't have anywhere near the effective mu of a toroid.  Because of the open magnetic structure they're less susceptible to DC saturation.  I haven't looked at the DC flux in a rod core since they can't match the performance of the toroid in my original post.  

  Looking at the Harris RF-110A, for instance, which uses a 115uH choke...

  Figuring the free air value of the coil dimensions results in a value around 20uH therefore, the core has an effective mu of around 6.

   This is a relatively low stress application for the choke as the plate load impedance is only in the vicinity of 1000 ohms.  Significant RF current will flow in this part down on 160.

   The task would be more difficult using a 4-1000A with 5KV on the plate & 5K ohms plate impedance!  :-)

73 & Good morning,
  Marv WC6W

http://wc6w.50webs.com/

> 
> ##  OK... why wouldn't just plane  16-24 ga 
> magnet wire,  wound like a solenoid, on say type 43 rod
> work ?   [ like polyimide /kapton magnet
> wire..  with the 10-15 kv insulation]    Why
> would .5 to 2 amps of dc plate current  saturate the
> type 43 material ?? 
> It's a RF plate choke.. so should present a high Z. 
> 
> ##  I have see pix of the harris  plate chokes...
> and they used a HUGE  chunk of ferrite inside a form..
> with the usual magnet wire [ with way less turns than a typ
> ham choke]  wound on top of the same form.  It
> worked down to 1.6 mhz.. and no series resonances from 
> 1.6 to  32 mhz.  
> 
> Jim  VE7RF 
> 
> 
>