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Author Topic: Hallicrafters S-19R & Q Multiplier  (Read 2354 times)
N8FVJ
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« on: August 06, 2017, 06:34:15 PM »

The S-19R has an accessory socket on rear. I heard a Q Multiplier can be added thru the rear socket. Anyone know how to wire it? I am not sure how Q Multipliers connect to receivers, but believe it ties into the 455kz I.F. Tube filament & B+ is a no brainer.
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KAPT4560
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« Reply #1 on: August 07, 2017, 01:07:53 AM »

 The rear panel socket can power an external Q-multiplier (xtal cal or other accessory), run the receiver on external DC or attach a break-in (T/R) switch. A Q-mult is an adjustable regenerative amplifier. An eHam thread of Q-mult here:
 http://www.eham.net/ehamforum/smf/index.php?topic=31022.0;wap2
« Last Edit: August 07, 2017, 01:18:54 AM by KAPT4560 » Logged
N8FVJ
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« Reply #2 on: August 07, 2017, 05:35:31 AM »

Thanks for link, but did not explain where to tie into 455hz IF? In-between first & second IF? The Q-Multiplier was before my time in ham radio.
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AC2EU
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« Reply #3 on: August 07, 2017, 06:25:17 AM »

Thanks for link, but did not explain where to tie into 455hz IF? In-between first & second IF? The Q-Multiplier was before my time in ham radio.

The Q mult was coupled to the plate of the IF via a cap.
It was usually in parallel with the IF stage, plate to plate.
The adaptor socket looks like it was for a battery operation option and external standby sw.
( in fact it is mis-drawn. The filament winding is most likely connected to pin 7 of the socket)
You would have to bring a connection from the IF to that socket ,if that is what you want to use.
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KM1H
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« Reply #4 on: August 07, 2017, 12:44:22 PM »

The Heath QF-1 and a later version have manuals that give all installation details.
Ive used them since 1956 on boatanchor radios.
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N8FVJ
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« Reply #5 on: August 08, 2017, 05:49:14 AM »

Thanks all.
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G3RZP
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« Reply #6 on: August 08, 2017, 07:03:04 AM »

Where there is no crystal filter, it is usually connected to the mixer plate. The 1961 - 65 ARRL handbooks explain how they work, and provides a transistorized design and suggests how to connect a Q multiplier.  If restoring or using boat anchors, the old ARRL  and Radio Handbooks are useful.
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W5RKL
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« Reply #7 on: August 11, 2017, 11:11:04 AM »

The S-19R has an accessory socket on rear. I heard a Q Multiplier can be added thru the rear socket. Anyone know how to wire it? I am not sure how Q Multipliers connect to receivers, but believe it ties into the 455kz I.F. Tube filament & B+ is a no brainer.

Connect a shielded cable's center conductor from the plate of V1 (6K8 pin 3) to an unused pin on the rear panel octal socket.
Connect the shield to a ground closest to V1.

Connect the other end of the shielded cable's center conductor to an unused pin on the rear panel's octal socket, say pin 2.
Connect the shield to the rear panel's octal socket pin 1 or 8

The output of V1 will be the 455Khz IF frequency.

I use a QF-1 with my Hallicrafters S40B and Heathkit AR3.

The QF1 can be made to provide a BFO signal by placing the Function switch to BROAD and rotating the PEAK ADJ control fully CW.
The QF-1 will oscillate providing a nice 455Khz RF "BFO" signal to the receiver. Adjust the Tuning control so the knob
points to 12 o'clock. further adjusting the Tuning control will vary the QF-1 BFO signal making tuning CW and SSB signals
much easier. Leave the S19R BFO switch set to "OFF" when using the QF1 as a BFO signal. When using the QF1 as a BFO signals,
the normal selectivity provided by the QF-1 is not available.

I recommend building a simply power supply for the QF-1. I do not recommend powering the QF-1 from the S19R. The QF-1 requires
6.3VAC at 300ma and B+ from approximately 150VDC to 250VDC at 2ma.

73
Mike W5RKL

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N8FVJ
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« Reply #8 on: August 11, 2017, 06:20:59 PM »

Thanks Mike
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G3RZP
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« Reply #9 on: August 12, 2017, 06:28:54 AM »

Unless the Q multiplier has a suitable tuned input, the capacity of the screened cable will seriously detune the  first IF transformer. Most Q multipliers did have an input circuit with a coil to compensate for the effect: the coil needs adjusting, usually with the Q multiplier off, for maximum signal. The other coil in the Q multiplier affects the frequency at which it will oscillate.
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KAPT4560
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« Reply #10 on: August 12, 2017, 06:43:50 AM »

 Yes the wiring will introduce extra capacitance that may have to be compensated for. It can always be put back the way it was if debugging the circuit doesn't prove helpful. The Q-mult is a simple circuit with some compensating adjustment already.
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W5RKL
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« Reply #11 on: August 12, 2017, 03:04:51 PM »

Unless the Q multiplier has a suitable tuned input, the capacity of the screened cable will seriously detune the  first IF transformer. Most Q multipliers did have an input circuit with a coil to compensate for the effect: the coil needs adjusting, usually with the Q multiplier off, for maximum signal. The other coil in the Q multiplier affects the frequency at which it will oscillate.

Quote from: KAPT4560
Yes the wiring will introduce extra capacitance that may have to be compensated for. It can always be put back the way it was if debugging the circuit doesn't prove helpful. The Q-mult is a simple circuit with some compensating adjustment already.

All of those considerations and adjustments are covered on page 11 and 12 in the QF-1 manual. It is also recommended that James have
the manual for the S-19R that include the alignment steps. I recommend James power the QF-1 from a separate power supply. The QF-1
schematic shows the 12AX7 filaments wired in parallel for 6.3VAC. 6VAC is applied to the 'White' wire and the ground to the Black wire.
To power the 12AX7 filaments from 12VAC, disconnect the jumper wire from pins 4 and 5. Disconnect the wire from pin 9 and reconnect
the wire to pin 5. This put the filaments in "series" for 12VAC.

If James, N8FVJ, does not have the Heathkit QF-1 manual then he can download the QF-1 manual from my website by clicking the
following link:

http://w5rkl.com/wp-content/uploads/2015/02/QF-1.pdf

The S19R receiver schematic and manual files that contains the schematic, RF and IF alignment steps can be downloaded by clicking
the following inks:

S19R Manual
http://w5rkl.com/wp-content/uploads/2015/02/Hallicrafters_S19R-HF-Reciever_Technical-Manual.pdf

S19R Schematic ONLY
http://w5rkl.com/wp-content/uploads/2015/02/s19r_schem.pdf

I use a short length of RG-174 coax cable between my QF-1 and my S40B. I performed the steps called out in the QF-1 manual and
the IF adjustments in the S40B manual. The QF-1 and S40B works perfectly.

73
Mike W5RKL
www.w5rkl.com


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G3RZP
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« Reply #12 on: August 12, 2017, 04:25:32 PM »

I don't see anywhere that it is stated that the OP actually has a QF-1.
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AC2EU
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« Reply #13 on: August 12, 2017, 04:33:03 PM »

I don't see anywhere that it is stated that the OP actually has a QF-1.
No report of a "smoke test" either...
Inquiring minds want to know.
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G3RZP
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Posts: 8223




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« Reply #14 on: August 13, 2017, 04:08:48 PM »

If you think it would help, send me your email address to peterdotchadwick at ieeedotorg, substituting for the dots and the 'at', and I'll send you a scan of the old RSGB handbook with details of a Q multiplier design using a 12AX7. 12AT7 worked as well.....
73

Peter G3RZP
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