[Milsurplus] BC-9 Project Update: 18 Jan 2016

[David Stinson]

Got another 30 minutes to "play radio" tonight.
Beginning to look like a triode-connected 6AQ5 
is going to be the "right" tube to sub for the 
un-buy-able Western Electric VT-1.  
Non-destructive "tweeks" needed to get it
to work:  Bias voltage divider fixed-resistance
reduced by bypassing from 10K Ohms to 5K.
Take 220K across the plate resistor to reduce
it from 100K to 69K.

I will be building the loop from 3/8ths rigid
copper pipe.  In the mean time, I'm fooling
with connecting a coil in place of the loop
and link-coupling it to my Delta Loop.
The result was nice- good sensitivity.
There's a CW contest going on so great signals.
I've got a little "common mode" noise and
the headphone cable and hand capacitance
is causing a bit of "wibble-wobble" but the 
concept seems to work well.  Tank is the 
small winding on the right.  Remember the
thing is expecting a single-turn loop so the 
capacitor has a large value.  Winding on the 
left is primary for Ant/Gnd.  
This video was made using a lower-Z headset
so the volume is lower.  When using the "normal"
Hi-Z headset, signals are so loud I have to move
the elements forward off my ears.
https://goo.gl/photos/r7rWPuWKw2jTvuzM7

I'm getting enough TX power out to tickle the 
Wattmeter a little.  Don't have a good 
reading on power yet because I don't trust 
what my scope is saying.  

20 minutes here, an hour there.  Slow but 
steady wins the race ;-)
73 Dave AB5S