[Milsurplus] BC-9: NETTED! WoooHOOO!

[Richard]

An inexpensive substitute (relatively speaking) for the VT-25 or 801-A 
is a triode connected 6L6, with an adapter.  It has the same 
amplification factor, and is good up to 500 volts.  I tried one in my 
TBW, substituting for an 801-A, and there was no difference.

Richard, AA1P


On 02/19/2017 06:57 PM, David Stinson wrote:
> You know, I am grateful to The Almighty for getting me in touch with 
> such a grand community
> of  sharp people who are generous of spirit.
>
> The BC-9 is Netted!  WooHoo!
> The solution was indeed to insert a *real*
> RF Choke in the DC shunt feed to the Osc.
> Plate.  C6 is no longer needed (nor has
> any effect) and the external RF chokes on the 120VDC line are 
> eliminated.  Here's the revised diagram:
> https://goo.gl/photos/y6mJsdF9RrYDZzJN9
> All you folks working on replicas, take note.
>
> I'm still impressed with how stable this rig
> is and how little chirp.  Of course, the DC/DC
> converters provide excellent voltage regulation
> at such low load levels.
>
> The receiver and transmitter net to within
> just a couple of  hundred cycles from one
> end of the band to the other.  And this is consistant across tube types.
> I tested 01A, Triode-connnected 6AQ5
> and VT-25A.  All behaved similarlly.
> Note that, with the loop, the 6AQ5 is
> not the best tube.  It does something at high bias levels that causes 
> the audio
> amps to motor-boat.  Don't know what.
> The VT-25A is the best for both TX and RX.
> And that's with only 6.5 V on the filament
> of a 7.5V tube.  Tight fit but it goes.
> Figures; Can't get a $600 tube, so
> the best one is just $125, LOL.
>
> I will be tinkering with the rig on the big
> copper loop tonight around 3555 KC +/-.
> If you hear a little signal with a little
> wobble, let me know, HI.
> Discovered that the radio might even work
> on 40 meters.  Already pushed it to 6 MC
> and it worked.  Another time.
>
> Gentleman, I lift my soldering iron and
> doff my hat to every one of you who contributed thoughts and suggestions.
> You are the very best.
>
> GL OM ES 73 DE Dave AB5S
>
>
> ______________________________________________________________