[Heathkit] HO-13 - SB-620 Coils - repost

[Tom NØJMY - AAR7FV]

REPOST- 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: ( mH) 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 the high IF coil for the HO-13:
Range: ( mH) 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
the have a 4th (dummy) lug at 3 o'clock.

Jim, if you have any luck, please let us all know.

Tom

Tom
----- Original Message ----- 
From: "Jim Brannigan" <jbrannig@optonline.net>
To: <heathkit@mailman.qth.net>
Sent: Thursday, June 12, 2003 6:51 AM
Subject: [Heathkit] SB-620 info


> I am taking another run at converting the SB-620 "Scanalyzer" to a 455kc.
IF
>
> Does anyone know the mixer oscillator injection frequency for a 455kc
> conversion?  It is not
> stipulated in the manual or on-line sources.
>
> Here is my guess:
> The IF of the Heath "Scanalyzer" is 350kc.
> To convert 455kc., the oscillator may be either 805 or 105kc.
> The "high" injection of 805kc produces first order products of 350 and
> 1260kc.
> "low injection of 105kc produces 350 and 560kc.
>
> The "High" injection products are further apart and it would be easier to
> filter the unwanted sum frequency.
> So my "guess" is 805kc.
> I know the value of the parallel capacitance.  If the oscillator frequency
> is known, I can calculate the coil inductance.
>
> Any help or ideas greatly appreciated.
>
> Jim
>