[AMRadio] RF Chokes

[Jim Isbell]

What do the cost?  I am interested.

David Knepper wrote:

>Anyone interested in several large BW butterfly capacitors with a full set
>of KW swinging link coils?
>
>
>Dave, W3ST
>Secretary to the Collins Radio Association
>Publisher of the Collins Journal
>www.collinsra.com
>----- Original Message -----
>From: "John Coleman, ARS WA5BXO" <wa5bxo at pctechref.com>
>To: <amradio at mailman.qth.net>
>Sent: Saturday, November 22, 2003 12:15 PM
>Subject: RE: [AMRadio] RF Chokes
>
>
>  
>
>>Hey Jeff, why don't you build a linear grounded grid out of a pair or
>>all three 450s?
>>1. You would have the plate dissipation capability.
>>2. No high level modulator required.
>>3. Pi Net output.
>>4. No need to neutralize on the lower frequency HF bands.
>>5. Same filament source required as with class C and plate Modulator.
>>6. Full output beyond the legal limit.
>>6. Easy Solid State Biasing.
>>7. One HV supply.
>>8. Less distortion.
>>9. Less TVI.
>>10. No arcing when over modulated!
>>11. Smaller foot print (the amp, not you)
>>12. Good on all modes.
>>
>>
>>Disadvantages
>>1. Due to high filament current you will probably have to wind your own
>>filament RF choke of # 6 wire or bigger.
>>
>>
>>
>>-----Original Message-----
>>From: amradio-admin at mailman.qth.net
>>[mailto:amradio-admin at mailman.qth.net] On Behalf Of Geoff/W5OMR
>>Sent: Saturday, November 22, 2003 9:55 AM
>>To: amradio at mailman.qth.net
>>Subject: [AMRadio] RF Chokes
>>
>>A while back, some ham came over, and we got to talking about
>>homebrewing.
>>He was building something, and needed an RF choke.  I had a brand new,
>>never
>>used, National RF choke, still in the original box.  At the time I never
>>had
>>any plans of building anything.  I have my push-pull, link-coupled 250TH
>>
>>final, and even though it was built in the 50's, it will probably
>>outlive me.
>>
>>But, recently I got the urge to build.  I think the conversation here
>>about
>>all the homebrewing that's been going on had a heavy hand to spark that
>>interest.  I thank y'all for that.
>>
>>The plan is to build up a final, using a single tube in the final.
>>Either a
>>450TL, or a 304TL.  I'm leaning towards the 450TL, because I've got
>>three of them, and a single tube, modulated by a pair interests me.
>>
>>I've got the main tuning capacitor (B&W Butterfly w/neutralization caps
>>on the back) an HDVL jack-bar, all the plug in coils for 80 thru 10, an
>>aluminum chassis to mount it on, and most of the necessary associated
>>hardware... except for the RF choke.
>>
>>I found a couple on E-bay... but $8.oo to $10.oo?  Are they really that
>>expensive, even still today?
>>
>>Does anyone have a spare they wouldn't mind parting with?
>>
>>73 = Best Regards,
>>-Geoff/W5OMR
>>
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