[Hammarlund] Early super pros

[Roy Morgan]

At 11:52 AM 2/28/2007, you wrote:
>HI hammarlund guys. I have a nice BC-779, the low freq version and would
>like to convert it to the bc  .54 to 1.24 mc

Jack,

You may have more on your hands than you expect. It *may* be that the 
BC-779 low frequency radio was a TRF design. That means it has no local 
oscillator and no IF amplifier section. (I don't know this for sure.  I 
think that the SP-600 LF was a TRF radio.)

If that is the case, you would be stripping the entire chassis except for 
audio amp and power supply and starting all over to re-create a new radio.

By the way, I think that the military BC-779 I have has three low frequency 
bands and then other bands in the HF region.  The low frequency bands are 
something like 100 to 200 Kc and 200 kc to 400 kc. and 300 to 540 KC.  Here 
is a message from Robert Downs that gives some details.  Note that he says 
they are all five band units, so the five bands would be chosen from the 
more than five he lists.

>Date: Mon, 24 Jul 2000 08:38:55 -0400
>From: "ROBERT W. DOWNS" <RWDowns_WA5CAB at compuserve.com>
>Subject: RE: SP-200 Question
>To: Old Tube Radios <boatanchors at theporch.com>
>Cc: "[unknown]" <provero at connix.com>,
>Old Tube Radios <boatanchors at theporch.com>,
>
>John, Josh & Group,
>Comments interspersed:
>Message text written by john
> >The supply is a RA84 (not sure whether
>this is original or not....) which is marked "MWO 11-866-2" " RA84" "LSD 
>MFP Jul 48"
> >
>I don't have that MWO (Modification Work Order) but it is possible that it
>is referenced in one of the changes to TM 11-866. If I find anything, I'll
>let you know. The bottom line indicates that the power supply was Moisture
>and Fungus Proofed by Lexington Signal Depot in July 1948.
> >It does have a mil tag, indicating:
>Order # 1428 PH42
>SN 118
><
>The power supply was ordered between July 1941 and June 1942. There were
>three military supplies made for the Super Pro's, RA-74-(*), RA-84-(*) and
>RA-94-(*), and up to four revisions of each. The differences between the
>three supplies are mainly in the primary voltage and frequency ranges of
>the power supplies. The generic Super Pro manual that I have shows a
>nameplate on the back of the power supply dust cover (no front view photos)
>that says "SUPER PRO POWER SUPPLY", plus a serial number and
>"HAMMARLUND....". There was a table model with a small front panel and a
>rack mount model with a 19" panel. The input voltage is 105/115/125VAC @
>50-60CPS, which happens to be the same as for the RA-84-(*). The input for
>the RA-74-(*) was 95-130 and 190-260 @ 25-60. The RA-94-(*) was 115/230 @
>50-60.
> >Now...can someone explain why Moore doesnt show a SP200, just a 210,
>when this radio clearly says SP-200X on the back plate....?
><
>The commercial manual that I have (undated) originally said just "Super Pro
>Receiver" on the cover and title page. Someone has stamped "SP-210LX" and
>"SPR-210LX" on both sheets. I have a postwar manual marked "SP-400-X". No
>explanation of what the "L" indicated either.
>John, I don't believe that you have said what the frequency coverage is in
>the receiver that you have. According to all of the manuals that I have,
>all of the SP-1xx/2xx/4xx and the BC-779, BC-794, BC-1004 and R-129/U are
>5-band. The bands that were supplied that I know of are 100-200, 200-400,
>and 300-540 KC and 0.54-1.16, 1.16-2.5, 2.5-5.0, 5.0-10.0, 10.0-20.0 and
>20.0-40.0 MC. What does the one that you have cover?
>73,
>Robert Downs
>WA5CAB
>Houston

I have seen a Super Pro which had been modified so that one of the low 
frequency bands was supposed to cover a different band. It never ran while 
I had it, so I am not sure what had been done.

If what you have is a low frequency plus HF radio, then you may well be 
able to change one or more of the LF bands to other frequencies.  You would 
get the needed coils, plug them in and do an alignment

Let's see if anyone else knows more.

Roy



- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing
13033 Downey Mill Road, Lovettsville, VA 20180
Phone 540-822-5911   Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-975-6097
roy.morgan at nist.gov --