EMRFD Message Archive 87
Message Date From Subject 87 2006-08-15 10:38:54 Stan Have you considered cloning a 50s era receiver or transmitter? Something to think about
Have you ever considered taking something like the Drake 1-A
receiver specifications and building a solid state homebrew unit.
I think that would be a much better project than the way I read the
ARRL challenge. I first thought the challenge was a neat idea,
but then I got to thinking about it and fellows we have had good $50
single band QRP transceivers for a long time; both homebrew designs
But still looking for a challenge of what to build next, I turned to
the receivers and transmitters themselves from the 1950 era. The
Drake 1-A seems like a good choice. Straight forward design,
reasonable specifications which could be improved with modern
Transmitter wise; the Central Electronics 10A SSB transmitter would
also be a good choice.
I believe both would be something one would use on his bench.
Even a new ham, but do not think we should steer a new ham to a
single band QRP rig. It's all ready been done; but a modern day 1A
and 10A would get a lot of use on my bench, what about yours? They
would look nice next to my K2 or FT1000 MKV
Would you be interested in working with a group building either a
modern day Solid State 1A or 10B. The hard part on the 10A is
really all ready done just need the Rf and mechanics added to Wes
designs. The 10A even used plug-in coils so it would not be
difficult. On a $50 budget each I expect half of the funds would be
just for a custom case
Comments ? Pro and Con
Cheers, stan ak0b
90 2006-08-16 09:28:10 kilocycles Re: Have you considered cloning a 50s era receiver or transmitter? Stan,
That's a very interesting idea, and I'm a born sucker for interesting
ideas. There are several different concepts to play with. For the
last couple of years, I've been accumulating the switch gangs,
heterodyne crystals and crystal filters with the intent of recreating
one of my favorites, the Heathkit SB-series transceivers, in all solid
One of the necessary tasks in any such effort, say for the Drake 1-A,
assuming one was working from the 1A schematics, would be the
translation to low impedances for the circuits to replace the J.W.
Miller/Millen tuning coils, etc. Several years ago, the idea was
floated around about replacing all the lower-level tube stages in a
receiver with dual-gate MOSFETs, and keeping the same tuning
components, and I saw a few implementations of that. Since finding
the old-style tuned circuit components would be a chore, I don't think
that's a good plan in this case.
Regardless of the components issue, replication in modern form would
seem to make the most sense for an existing carcass of a 1-A. But, I
think that unless one intentionally "designed down", the result would
be a better-performing receiver than the original.
On the other hand, if working strictly from the block diagram of the
1-A, would it be a virtual 1-A, or simply a receiver? Of course, it
could be shrunk considerably and styled like a 1-A, sort of like a
91 2006-08-16 10:03:43 larry allen Re: Have you considered cloning a 50s era receiver or transmitter? hi.. I like your idea of updating an older radio....
At one time, during my time with my hw-100, I thought it would be nice to
up-date the transceiver by converting it to solid state.. slowly, as I
gained solid state knowledge....
For example, replacing the audio final receiving tube with transistorized
audio amplifier. This would require me to build a d.c. supply to feed the
I was also going to replace the vfo with the sb's lmo...
----- Original Message -----
92 2006-08-16 11:40:56 Stan Re: Have you considered cloning a 50s era receiver or transmitter? Thanks for comments fellows. I do not want to rework an old 1A but
want to build a clone that has same basic approach as the orginial
design. I would expect the clone to meet better specs than the
orginial when I got done.
I reworked a TCS receiver one time to SS and was always sorry, so
this time I will go new route.
A few have suggested I consider the 2B series IF/conversions and
they do appear to be a better way to go than the 1A. I am not sure
if one would need the 50 khz IF stage today with other improvements
we can now make to the design.
I also do not want to use any surplus parts as that would prevent
others from duplicating the design.
Lot of ideas to kick around. But believe it would be a rewarding
93 2006-08-16 13:03:50 Steven S. Coles Re: Have you considered cloning a 50s era receiver or transmitter? Stan,
Converting vacuum-tube style circuits to solid state certainly
follows a fine tradition. The first 6-transistor AM broadcast
receivers has schematics close to the cabinet radios with class-AB
Even before that some engineers noted the dual of a 6SN7 common-
cathode equivalent circuit provided a usable equivalent circuit for
early germanium transistors in common-base configuration. Some
advocated using the duality principle to convert vacuum tube
circuits to BJT circuits.
By 1977 73 Magazine's "Master Handbook of Ham Radio Circuits" (pages
48-57) contained a description of the homebrewed Q2 receiver, a
solid-state implementation of the Drake 2B. The most obvious update
would be using improved transistors. The coils are wound
110 2006-08-25 12:21:07 topossibilities Re: Have you considered cloning a 50s era receiver or transmitter? > By 1977 73 Magazine's "Master Handbook of Ham Radio Circuits" (pagesThe Spring 1991 issue of Communications Quarterly has a 17 page
> 48-57) contained a description of the homebrewed Q2 receiver, a
> solid-state implementation of the Drake 2B. The most obvious update
> would be using improved transistors. The coils are wound on T-68-2
> and T-50-6 cores.
article by Jim Larson KF7M who updated a 75S-3 completely to solid
state devices. He shows each tube circuit and then it's solid state
replacement. He used BJTs, JFETs, MOSFETs, diodes (sometimes cascaded
together). He previously did a 75A4 that was published in the Novenber
1988 issue of Ham Radio.
Lot's of books, parts and kits for sale at: