Heath HW32 conversion

[W9LCE]

I have a several pieces of Heath equipment - and want to do a conversion to AM Plate Modulation.  I will end up radically converting a recent purchase of a "parts" HW32.

I recently found a block diagram of the HW12 - one of the transmitter operation, another of the receiver operation - I have not been able to find such for the HW32.   I am especially interested in the rf frequencies at the several stages - from the VFO to the Heterodyne Mixer and IF and on to the 20 meter RF.  (Do I want to change the VFO frequency?)   I'll see what's left in that parts HW32, when it arrives.  I am working on one CB unit for 10 Meters, and now this for 20.  (I'm not interested in high power, had enough of that!  - although downstairs, I do still have the power supply and modulator from a kilowatt rig! - half rack, less tubes)

Is any such block diagram available?  I have ordered an HW32 Manual - any further suggestions would be appreciated.

I am a retired TV Chief Engineer and have designed equipment before.  I haven't done AM since back in the 50s and early 60s (Knight T60), and am interested in it again.  I like the working space in tube sets.

[N2DTS]

Nice looking rigs, but that seems like a hard project, to take a ssb only rig and convert it to AM.
Most ssb rigs were very light duty with marginal power supplies and tank components.
I guess you need an AM detector/agc and some sort of AM filter on the RX side, and Heathkit tended to use odd IF frequencies and poor filters.
Is there much AM on 20 meters? I never heard any, but I do not spend much time up there.

It sounds like its a Gonset G76 you want, plate modulated trans receiver 80 to 6 meters and smaller then an HW32...

[W4RFM]

Hello Merle, I also was in the broadcast biz for ever.. radio for me though.  I would try the route of finding a 50 to 100 watt PA amp, getting a matching mod transformer, or using a output transformer of the proper wattage- backwards, to handle the audio side, and try to copy one of the ARRL or west coast handbook designs. That way you could stuff the ingredients into that cabinet. Which really boils down to: keep the output tank and tube, and start fresh at the front. I have lots of pieces-parts if your run into to something you can't find, try me.
Have fun, you deserve it.
Bob

[Pete, WA2CWA]

HW-32 Block attached

[W9LCE]

Thanks for the block diagram - it confirms some of the things I was suspecting.  So - I did what I should have done earlier - I remembered that I had one each of both the HW32 and HW32b down in the basement (been sitting a LONG time) - so I pulled the cover off, and read the crystals. 

From the block diagram - the HW32 uses a crystal (heterodyne oscillator/ mixer) at 18.750 MHz with the VFO at 1.6183 to 1.7683 MHz to give a bandspread of 150 KHz.  This is mixed with the crystal filter (and "carrier oscillator" crystal at 2.3067 MHz) to obtain the 20 meter frequencies of 14.2 to 14.350 MHz.

My intention WAS (note the WAS) to use the transmitter heterodyne crystal (18.750) and VFO (1.7) plus the Carrier Oscillator crystal (2.3067) to give the transmitter frequency (bypassing the crystal filter and IFs).    I hadn't determined exactly what I would do for Power Amplifier (until observation showed there wasn't enough headroom for an intended 6883 tube (12 v equiv of the 6146) - OK, I do have some 829s) and plate modulator (tubes and transformer - ?on a deck off the back of the rig - maybe with the homebrew "HP-23").
Similarly, in receive - I was considering using the Upper and Lower Sideband Crystals (2.3033 and 23067 MHz) to make an old-fashioned half-lattice filter for AM (removing the SSB crystal filter).  For detector I was considering using regeneration on the V3 IF (6au6)(capacitive regen control - course and fine) and the coil of the SSB crystal filter with a tickler winding. 
I intended to use nuvistors for the VFO.  And also change the receive RF Amplifier to a 6cw6 nuvistor (or a pair of them).

BUT - after a close look at the ONE BOARD construction of the HW32 - I decided there were better things to do.  and YES - the Gonset G76 does look very good - but I do have a Heath DX100 that needs serious work, a couple receivers that can go with it (been sitting for a while).  So I decided to let good enough alone.   - and maybe check out and sell a couple HW32s and some other of the Heath gear that are down there (been using the SB101).

AND - I discovered that I had picked up the Vernon Chambers W1JEQ 813 Transmitter and a big 6L6 Plate Modulator with a 2500v Power Supply.  (well, I knew there were some things down there - just hadn't looked).

Cliff

So - I have another HW32b coming - in some kind of "parts" condition - guess I'll work on it, too.  Do need to start getting busy - even at Christmas.

[Pete, WA2CWA]

HW-32A; there was no HW-32B.

[W9LCE]

corrected

I have one HW-32 and one HW-32a

the "parts" one I have bought is an HW-32

and I have surprised myself -with how much "stuff" I have collected over the years.

Cliff

[w3jn]

It's really easy to convert one of these to a hifi transmitter, but not using plate modulation.

Remove and bypass the crystal filter.
Remove the ALC line to the final
Feed the line level audio at the input of the balanced modulator
Adjust the balanced modulator pot for the proper amount of carrier (~20-25W)

The downside of doing this is the receiver is absolutely unusable due to the extremely wide selectivity after the xtal filter is removed.  You also need to do some low-pass filtering in the audio chain because the modulator bandpass is about 100KHz.  Using a scope while transmitting is mandatory; the mod balance will drift a bit and will need a bit of touchup even during transmissions.

[W9LCE]

Considering everything - I do not think I will try to convert the HW32 [3] (or other transceivers - HW12 [3]; HW22; HW16; HW18; HW101) - eventually checking them out and selling them (I was a TV Chief Engineer, and have a bench with most of the test equipments I used in Television).

I have other equipments in the basement, have reviewed them, and will use some, instead of trying to hold them for maintenance and sale.  I will be keeping one rig for SSB and PSK31 operations (probably the SB102 or the SB300/400)

Since 20M, 10M (and 6 meters) are my preferred bands - I have been going through all the past mailings on AMfone - with especial reference to my intentions (I am refusing here to go solid state, for reasons stated later)

The HR10b - works poorly but is operational.  I want to upgrade it.  I will try adding a push-push diode doubler (using a toroid) from the output of the VFO to the Mixer for the two HF bands.  (I will [somehow] remove that if/ when I use 80 or 40.)  I will be converting the oscillators to low voltage for more stabilization.  Possibly I will replace the 6bz6 RF amp with a recommended 6gm6 or 6es8 (or even Cascode Nuvistor 6cw4 or a 6dj8).    I likely will change the detector -  I am considering an Infinite Impedance (replacing the 6bj7, possibly using the 6sq7)  or Control-Condenser Regenerative (using the "BFO", possibly as "crystal-controlled").

The DX60 -  I have to work on, including some of the modifications.  I would like to upgrade it some, by going to plate modulation - possibly Heising.  (I also have a DX35 and a DX40, and want one or other to become a PW rig)

The DX100b - needs much work, and will come later.  I will match it with the station National NC57 (and get rid of the humongous SX101).

The VF-1 will be the first VFO - I likely will put in low voltage, possibly a Nuvistor in place of the tube.  Similarly later, with the HG-10b.

I have a strong interest in emergency operation.  As a Scientist (Physics Prof) I am hearing Government and Scientific Warnings about EMP, either from solar flare or from Iran nuclear (warnings now are for - "within the year").  Tube equipment has a better chance of survival.  I have acquired an older 220V generator, being now converted to propane.  I am converting a couple old CBs (Citiphone), with vibrator power supplies, for immediate 12 volt operation on 10M and 20M.  I used to have a couple dynamotors - maybe get one or more again (esp for the DX40/HR-10b)  (I was getting a solar panel for charging the batteries, but saw a warning that EMP is disastrous to them - does anyone know anything about this?)

My main problem right now is antennae - The old tribander was essentially destroyed in trying to take it down (got older, and moved from my small rural town, to my daughter's house here in the city - this is become a totally new installation).  Because of cable and AC wires, there is not room here on this small lot for the old "long wire" - or even a "wire" dipole (bye-bye 80M/40M) - everything will have to go up on the roof.  I have obtained a CB 5/8 wave vertical for 10M and am still considering what to do for 20M (maybe a 2 element yagi?).  Any recommendations?

Cliff

[KD6VXI]

I've fed my Cb base 5/8 with both coass and ladder line,  multibanding it.

What I found was this.....

You want at least 4 resonant radials per band.

Or,  cut for the lower freq.   Ie,  the same antenna works good with radials cut for 12 meters on ten and 12.  Little more common mode problem with just cut for 12 meter radials on 10, but usable.

I settled on 17 and 12 meter length radials,  and a 5/8 wavelength on 10.

Works great,  using a Johnson kw matchbox.

--Shane
KD6VXI