BC-221 as VFO ??
 

At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??

BC-221 as VFO ??
 

Its been many years since I've owned a BC-221, but I remember that
they were very harmonic 'rich'. Thats OK for a freq meter, not so
good for a VFO. Might be worth taking a look at before putting it on
the air.

Steve

William Mutch wrote in message
ell.edu...
At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??

BC-221 as VFO ??
 

William Mutch ) writes:
At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??

I can't help you with specifics, but it was definitely done. I can picture
an article in CQ from the late fifties or early sixties that used a BC-221
as a VFO, though that might have been an SSB rig.

Old books would describe how to couple a VFO into a crystal socket. There
was often a coupling network right at the crystal socket.

Michael VE2BVW

BC-221 as VFO ?? - yes
 

1947 RADIO Handbook ( not ARRL ) has construction detail on using 221 as
vfo . 6AG7 as driver etc.




"William Mutch" wrote in message
ell.edu...
At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??

BC-221 as VFO ??
 

On 11/1/05 7:48 AM, in article
, "William Mutch"
wrote:

At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??

Given the configuration you describe, I can't imagine anything short of a
lightning strike on the interconnecting cable, would cause harm to the vfo.

Don

BC-221 as VFO ??
 

1. You will not harm the vfo. Remember, they were used during a war.

2. There is not enough output from the BC-221 to drive the 12BY7 directly,
and it is true that the harmonics are lively in it. So, you can build a
tuned class A amplifier to build up the voltage, provide selectivity and
also isolate the BC-221 from the rig to prevent frequency pulling.

I have used a number of BC-221/LM frequency meters into vfos, turned one
into a regen receiver and presently have a solid state LM meter as a vfo in
my Central Electronics 20A. It has a crystal controlled mixer for output on
the different bands.

Sorry if I offended the tube purists with the last paragraph. The
calibration book was lost and I got bored one night.

Colin K7FM

BC-221 as VFO ??
 

Your mention of the Central Electronics 20A brings back fond memories of my
shack shortly after graduation from HS. I bought a brand new 20A from a
store in Philadelphia's electronics row. I used a conversion kit sold by CE
to create a VFO from a war surplus "command set". In addition to the 20A, I
also bought a "signal slicer" kit from CE and used it with my Hammarlund
HQ140X. Finally, my final was a pair of 100TH triodes
http://www.uli.de/tubes/100th.htm running in grounded cathode mode. The
final used a B&W plug-in link coupled tank coil. Yes, those were the good
old days. I had as much fun with that equipment then, as I do now with my
Ten-Tec Orion driving a Drake L-4B.
John, N9JG

"COLIN LAMB" wrote in message
.net...
[stuff]
I have used a number of BC-221/LM frequency meters into vfos, turned one
into a regen receiver and presently have a solid state LM meter as a vfo
in my Central Electronics 20A. It has a crystal controlled mixer for
output on the different bands.
[stuff]

BC-221 as VFO ??
 

In article . edu, wcm1
@NOSPAM.cornell.edu says...


Thanks guys. I've made up a cable with a tuned circuit in the
line to reduce undesired harmonics and will try it out...maybe this
weekend.

as... de KC2LVQ


At last spring AWA meet I picked up a homebrew novice transmitter
of unknown provanence. It has a close resembleance to the one in the
1976 Handbook (except that it uses an electron coupled 12BY7 instead of
a 6DK7) and was built by a fine craftsman who did a first rate job on
it. The previous owner got it at an estate sale and didn't know who
built it.

Last weekend I got around to bringing it slowly up to working
voltage on a variac and tuning it into a dummy load with a variety of
Xtals. The 6146B final will deliver between 40 and 60 watts to the load
on 80, 40 and 20, but I had to stop testing before I got up to 15 meters
as my Tek 922 scope expired.
Since the rig will deliver power to both 40 and 20 I thought to
see if I can put it on 30 meters, but I haven't any Xtals which will
multiply into the band. I thought about using my BC-221 as a VFO.


Will the BC-221 provide enough volts out to stabilize the xtal
oscillator ??

What would be the best way to cable from the output of the BC-221
(some previous owner added a pl-259) to the xtal socket of the rig ??
It sees a 47K resistor to ground from the grid and is DC blocked by a
capacitor.

I need to assure myself that the BC-221 will not be damaged.

Has anyone ever done this ??