[Heathkit] Heathkit sb-620/ho-13 investigated by CIA

Fri, 5 Dec 2003 08:13:11 -0600

C razy I nsane A mateur has delved into his archives and came up with the
following posts he made sometime in the past.:

Dan, Maybe this will help.  I think if somebody just did a little
experimentation with
available stuff and didn't get bogged down worrying about the details, a
suitable solution could be had.  If you come up with any breakthroughs,
please let the lists know.
----------------------------
Post #1

Every now and then, I see guys on the lists looking for the various coils to
change the HO-13 and SB-620 to different rcvr IF's.  I have uncovered an old
blueprint of those coils and I am posting the pertinent data here to whom it
may concern.

I hope this does someone somewhere out there some good.  Maybe some of you
old Heath guys can look at this and tell us what is pertinent so we can see
if there's anything out there available that is close enough to be a
replacement without to much hassle.

To wit:

The 455 coil for the HO-13 is P/N 588 and has the following characteristics:

Range: (uH ) 117(max) to 275 (min)
Preset:  123 ±5% @ 790 kHz.
"Q": minimum @ 790 kHz.: 57 measured with 2 1/4" leads to Q-meter
Min. wire size: 3/41 litz
Wire type: S. Cel. Poly.
No. of turns:  Universal 133
% of total turns from start to tap:  23%
Viewed from above (screw adj. end):
Start: lug #3 @ 6 o'clock
Tap: lug #2 @ 9 o'clock
Finish: lug #1 @ 12 o'clock
Winding: Clockwise
Staple lugs not to protrude inside coil form
Form to withstand 1000 VAC terminals to core
Must snap into 5/16" hole in 14 ga. aluminum

P/N 589 was this high IF coil for the HO-13:

Range: ( uH) 12(max) to 31(min)
Preset:  23.6 ±10% @ 2.5 MHz.
"Q": minimum @ 2.5 MHz.: 80, measured with 2 1/4" leads to Q-meter
Min. wire size: 3/41 litz
Wire type: S. Cel. Poly.
No. of turns:  Universal 43
% of total turns from start to tap:  20%
Start: lug #3 @ 6 o'clock
Tap: lug #2 @ 9 o'clock
Finish: lug #1 @ 12 o'clock
Winding: Clockwise
Staple lugs not to protrude inside coil form
Form to withstand 1000 VAC terminals to core
Must snap into 5/16" hole in 14 ga. aluminum

On the SB-620, P/N's 775 & 776 are the same as 588 & 589 respectively, but
they have a 4th (dummy) lug at 3 o'clock.

73,
Tom
----------------------------------------------------------------------------
Post #2

Well it took exactly 12 minutes to get my first 2 requests for the rest of
the dope for the SB-620 coils.  So -- here goes

P/N 774 (must have been from earlier production):

Range: ( uH) 2.60(max) to 5.0 (min)
Preset:  3.5 ±10% @ 7.9 MHz.
"Q": minimum @ 7.9 MHz.: 85 measured with 2 1/4" leads to Q-meter
Min. wire size: #30
Wire type: SPTH S. Cel.
No. of turns:  19 1/2
% of total turns from start to tap:  37%
Viewed from above (screw adj. end):
Start: lug #3 @ 6 o'clock
Tap: lug #2 @ 9 o'clock
Finish: lug #1 @ 12 o'clock
Dummy: lug #4 @ 3 o'clock
Winding: Clockwise
Staple lugs not to protrude inside coil form
Form to withstand 1000 VAC terminals to core
Must snap into 5/16" hole in 14 ga. aluminum

P/N 807:

Range: ( uH) 3.8 (max) to 7 (min)
Preset:  4.8 ±10% @ 7.9 MHz.
"Q": minimum @ 7.9 MHz.: 70 measured with 2 1/4" leads to Q-meter
Min. wire size: #38
Wire type: S. Cel. Poly.
No. of turns:  Universal 18 1/2
 Turns from start to tap:  6 1/4
Viewed from above (screw adj. end):
Start: lug #3 @ 6 o'clock
Tap: lug #2 @ 9 o'clock
Finish: lug #1 @ 12 o'clock
Dummy: lug #4 @ 3 o'clock
Winding: Clockwise
Staple lugs not to protrude inside coil form
Form to withstand 1000 VAC terminals to core
Must snap into 5/16" hole in 14 ga. aluminum

and P/N 808:

Range: ( uH) 27(max) to 56 (min)
Preset:  44±10% @ 2.5 MHz.
"Q": minimum @ 2.5 MHz 60 measured with 2 1/4" leads to Q-meter
Min. wire size: #38
Wire type: S. Cel. Poly.
No. of turns:  Universal 57 1/2
 Turns from start to tap:  16 1/4
Viewed from above (screw adj. end):
Start: lug #3 @ 6 o'clock
Tap: lug #2 @ 9 o'clock
Finish: lug #1 @ 12 o'clock
Dummy: lug #4 @ 3 o'clock
Winding: Clockwise
Staple lugs not to protrude inside coil form
Form to withstand 1000 VAC terminals to core
Must snap into 5/16" hole in 14 ga. aluminum

FWIW, the coil forms vary between 1 1/4" and 1 1/2" in length.

You guys please keep the list informed of any breakthroughs.

Tnx,
Tom
------------------------
Post #3

A few more tid-bits:

FWIW: the part nos. I posted should all be preceded by "40-".

Also:  40-588 & 40-589 were vintage 1963 pieces that became obsolete
2/28/66, at which time 40-774, 40-775, and 40-776 were introduced.  Then, on
11/21/66 the 40-774 became obsolete, and the 40-807 & 40-808 were
introduced.  I have no other revisions beyond 9/15/67.

Vy 73,

Tom

----- Original Message ----- 
From: "DAN COTSIRILOS" <[email protected]>
To: <[email protected]>
Sent: Friday, December 05, 2003 9:34 AM
Subject: [Heathkit] sb-620

>Hello

>    I have a sb-620 scanalyzer with a 455 kc coil. Does anyone know if the
other if coils >can be made or are the parts obsolete?