HT-44/SX-117 CW Offset Solution

#31346
Edited

I've finished testing my modification for providing a CW offset when running the HT-44 and SX-117 in transceive mode under control of the receiver VFO.? This is a "no-holes" modification that's inexpensive to implement and provides true CW transceive operation.? In other words, with your slide switch in XCVR position, you can tune the receiver to a station and call him and you'll be zero beat with him (or very nearly).? Without the modification, using transceive mode on CW is useless as calling a station you hear results in you being off his frequency by a difference equal to the frequency of the tone you're listening to.? The circuitry resides on a small board mounted near the VFO capacitor leads under the SX-117 chassis.? A cable between the HT-44 octal plug and the RCA jack labeled ANT on the SX-117 connects the circuit to a N/O relay contact in the HT-44.? When the HT-44 goes to transmit, the relay causes the SX-117 VFO offset to occur.

?

The mod does not affect the stability of the VFO and is easily removed.? When operating SSB in transceive mode, you unplug the cable mentioned above and then the offset does not occur.? Schematic follows.? Probably unreadable and no way to increase the size here, so if interested, let me know and I'll email it to you.

?

73, Floyd - K8AC

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Re: CW Sidetone ideas

#31345

开云体育

It's been a long while, but I recall a simple battery powered stand-alone side tone generator that worked quite well by simply responding to RF . No attachment at all to the transmitter or receiver. When I have time, I'll look back in my archives for schematics and other data. I was also using the HT-44 / SX-117 combo.? (Currently stored away now, but in pristine condition).?

Re: CW Sidetone ideas

#31344
Edited

开云体育

Thanks for sharing.

Walt Cates, WD0GOF

?

A majority of acceptance is not proof of correctness.

Show quoted text

From: [email protected] <[email protected]> on behalf of Floyd - K8AC via groups.io <floydsense@...>
Sent: Friday, December 13, 2024 11:16 AM
To: [email protected] <[email protected]>
Subject: Re: [HallicraftersRadios] CW Sidetone ideas

?

Walt - The sidetone generator is complete and working well.? The generator circuitry is housed in an external minibox and there are zero modifications to the SX-117 or HT-44.? All connections to the gear are external.? No special parts required other than the high voltage PNP transistor.? I'm not an engineer and I suspect there are more elegant ways to accomplish this, but it does work well for me.? Here is the schematic and a photo of the unit.

?

73, Floyd - K8AC

Re: CW Sidetone ideas

#31343
Edited

Walt - The sidetone generator is complete and working well.? The generator circuitry is housed in an external minibox and there are zero modifications to the SX-117 or HT-44.? All connections to the gear are external.? No special parts required other than the high voltage PNP transistor.? I'm not an engineer and I suspect there are more elegant ways to accomplish this, but it does work well for me.? Here is the schematic and a photo of the unit.

?

73, Floyd - K8AC

Hallicrafters Radios Prices in 1959

#31342

开云体育

Hi all,

Digging in old museum papers sometimes provide some interesting views to the past.

See attached.

The prices are in 1959 Canadian dollars.

Payette Radio was the biggest consumer/industrial electronics supplier in eastern Canada then.

?

73, Jacques, VE2JFE in Montreal

HallicraftersPricesAugust1959_Payette.pdf

Re: HT-45 tuning

#31341

Brian, be careful working on this amp, those voltages in the amp can kill you !

--

K2WH

Re: HT-45 tuning

#31340

Brian,

?

If the power supply is wired properly, as Ed indicated, the "PLATE" light will only illuminate when AC is provided to the HV relay.? (I.E. the PLATE switch is ON? and the FIL switch is ON)

?

Also, if HV is available, the NE51 on the power supply box will only illuminate if actual HV is present

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The FIL switch provides AC to the Blower and filament transformer and to the HV SWITCH powering the HV relay in the power supply such that HV cannot be switched on unless the FIL switch is on.?

?

The operator has to wait after powering the filaments so as to allow time for? mercury vapor rectifiers to heat (use 3B28's and the time is much less....and if you replace with solid state rectifiers, you essentially eliminate the need to wait at all.....the 3-400 like the 4-400 & 3-500 filaments are essentially "instant-ON" (R & L Drake applies FIL and HV simultaneously in the?? L-4/L-4B/L-7 amplfiers)

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But to your question, IF the HV "light" (on the power supply)? is illuminated with the HV switch OFF (after waiting for the filter cap to discharge) .....it would appear the HV switch is either staying closed or the relay contacts are "welded" --ON.?

?

Note that the primary power is ALWAYS present at the relay regardless of switch position.? Closing the relay then applies power to the plate transformer.?

?

When I rebuilt my power supply using the Drake L-4B transformer, I eliminated the rectifier filament transformer, the original plate transformer, oil cap and choke.? I used? pair of SEMTEC 5000V solid state rectifiers PLUS a (Harbach) filter-cap board for a Heathkit SB220.? I wired the entire mess similar to an L-4B using a voltage doubler.

?

I also eliminated the relay and used a pair of solid state relays in each leg of? 240VAC? powering the transformer.

?

I did however keep the HV "light" which only illuminates with HV present.? It's a great safety feature.

?

Brian <1codetech@...> wrote
I have a question. I just noticed that when I switch on the "fil" switch the "plate" and "filiments" lights both come on. If I switch the plate to "on" the light still stays on. Is this normal? If not what could be the issue?

--

73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux

Re: HT-45 tuning

Brian

#31339

Thank you very much for the reply. I will look at the switch. They are old. The original power supply for the HT-45 did not come with the AMP. The power supply that came with the amp has been converted to not use tubes. DC voltage is not present with the "filament" switch turned off but does show 2600 when the "filament" switch is turned on.

The amp does put out 500 watts with 45w from the exciter. I just do not want to damage the 400Z tube.

?

Thank you always.

W6BPT

Re: HT-45 tuning

#31338

Brian <1codetech@...> wrote
I have a question. I just noticed that when I switch on the "fil" switch the "plate" and "filiments" lights both come on. If I switch the plate to "on" the light still stays on. Is this normal? If not what could be the issue?

Hi, Brian

Does the HV power supply still use 866A or 3B28 rectifier tubes?
If a previous owner had changed to solid state rectifiers,
he would not need the heaters on, but plate voltage off preliminary
warm-up for the rectifier tubes before plate voltage is applied.
Hallicrafters says a 4 minute warm up is needed, Collins in the KWS-1
only used a 30 second warm up. You can ruin the rectifier tubes
if HV is applied immediately, because the mercury within the tube
needs preheating.

Is the DC Voltage still indicated on the HT-45 panel meter when the HV switch is off? If so, that's a problem. The "plate" indicator is a neon
lamp, so even a very high resistance path across the plate switch
contacts would be enough for it to light, without necessarily
passing enough current to turn on the relay in the HV supply.

Does the neon light in the HV power supply stay on when the HV switch is switched off? It should take a few minutes for it to go off completely,
as the bleeder resistors in the HV supply drain the capacitor.

The most likely failure is a that the plate switch of the HT-45 is stuck "on". That switch connects to the relay coil in the power supply,
which applies AC to the primary of the HV transformer.

I don't own an HT-45, I'm just going by the manual downloaded from BAMA.

73,
Ed Knobloch K4PF

Re: HT-45 tuning

Brian

#31337

Thanks,

?

I have a question. I just noticed that when I switch on the "fil" switch the "plate" and "filiments" lights both come on. If I switch the plate to "on" the light still stays on. Is this normal? If not what could be the issue?

?

Thank you very much.

?

73's and Semper Fi

?

Brian (W6BPT)

Re: CW Sidetone ideas

#31336

Great.

Please email me info?

W8tow.sm@...?

73

Steve

Re: HT-45 tuning

#31335

Hi Brian,

?

Congratulations on your "new" amp!

?

I have one of those!? Just tune it using a watt meter for max output!? Drive it with no more than 40-50W so as not to exceed max grid current.?

?

You can peak "ballpark" plate and load settings by driving with very low power (5-10w) to get the approx settings, and then finish at (briefly) full output?

?

Keep tuning sessions as short as possible when approaching high grid currents "single-tone" .?

?

Expect to see color in the tube.? It's quite normal!

?

I get around 500-600w out of mine with around 2700V on the plate.

?

What are you driving it with?

?

--

73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux

Re: CW Sidetone ideas

#31334

On Fri, Dec 6, 2024 at 01:08 PM, John K5MO wrote:

I use the several Curtis keyers that are boatanchor proof, and can be set for paddles or manual keying.

?

?

Found on Ebay

?

John K5MO

On Fri, Dec 6, 2024 at 11:57?AM Steve Marquie via <=[email protected]> wrote:

Good day all

I enjoy using various vintage "separates" on CW, with a bug.

The common issue is what to do for sidetone when using a straight key or bug. Typically,? not music the Rx, and have a fast hand on the RF gain control works well.

But, Collins and Drake have a sidetone.?

Has anyone added a sidetone to HT44/ SX117 or HT32B/SX101 SX115 combos?

73

W8tow

?

?

Steve--I have a? T O. Keyer I'll send you for $20 plus shipping.? ?It works fine

Re: HT-45 tuning

#31333

Welcome to the group.

?

I am not familiar with the Loudenboomer but, the settings of the amp would have to be determined experimentally since it is not or does not have a tuner or auto-tuner.? The quick reference would have to be made by you as you run low power and adjust the plate and load controls for peak output.? Then you can start an excel of word document to save the settings.? I have attached my setting document for my Ameritron amp to this posting as an example.

?

Good luck with it.

K2WH

AL-800 Tune Settings for Voice Frequencies.docx

AL-800H Tune Settings for Digital.docx

New Member

Brian

#31332

Hello all,

?

I am a new member to the group but have been a HAM for awhile now. My main station now is a tentec omni VI with a HT45 amp. My callsign is W6BPT.?

I am looking forward to talking with everyone and I hope to chat with you on 15,20, or 40 meters someday.

?

73's and Semper Fi

?

Brian

HT-45 tuning

Brian

#31331

Hello all.

?

I am excited to have found this group. My callsign is W6BPT. I recently acquired a hallicrafters ht-45 loudenboomer. I did the initial tuning via the downloadable manual and the amp works great. My question to the forum is this:

Is there a writeup only on the tuning of the amp.?

I was hoping for something like this so when I go from 40 meters to 20 to 15 it would be a quick reference for quick tuning.

?

Thank you and 73's

?

Brian

Re: CW Sidetone ideas

#31330

When using a straight key, I do ok by listening to the sound of the key,
but I can't do that with a bug. Back in the '50s I had a 100TH with 866
rectifiers. The humming of the transformer laminations when I pressed
the key was all I needed.

73,

Maynard
W6PAP

Show quoted text

On 12/9/24 19:07, Richard Knoppow via groups.io wrote:

A note: some old CW practice oscillators were set up to be keyed by
a sample of RF from the transmitter to provide a side tone. For instance
the Bud Radio oscillators. Should not be difficult to do this with a
solid state oscillator although I don't have a circuit. A simple pick up
loop will trigger the oscillator. I have not tried my Bud oscillator but
it can probably feed the receiver speaker of phones with a simple
parallel connection.
I used to mostly listen to my own signal via the station receiver
but that doesn't work if you are using two separate frequencies.

On 12/9/2024 4:51 PM, waltcates via groups.io wrote:

*Floyd,*
*
*
*When you get all the kinks out of?the side-tone mod, post a schematic
of your project.*
*

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

Re: CW Sidetone ideas

#31329

A note: some old CW practice oscillators were set up to be keyed by
a sample of RF from the transmitter to provide a side tone. For instance
the Bud Radio oscillators. Should not be difficult to do this with a
solid state oscillator although I don't have a circuit. A simple pick up
loop will trigger the oscillator. I have not tried my Bud oscillator but
it can probably feed the receiver speaker of phones with a simple
parallel connection.
I used to mostly listen to my own signal via the station receiver
but that doesn't work if you are using two separate frequencies.

Show quoted text

On 12/9/2024 4:51 PM, waltcates via groups.io wrote:

*Floyd,*
*
*
*When you get all the kinks out of?the side-tone mod, post a schematic
of your project.*
*

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

Re: CW Sidetone ideas

#31328

开云体育

Floyd,

When you get all the kinks out of?the side-tone mod, post a schematic of your project.

Walt Cates, WD0GOF

?

A majority of acceptance is not proof of correctness.

Show quoted text

From: [email protected] <[email protected]> on behalf of Floyd - K8AC via groups.io <floydsense@...>
Sent: Monday, December 9, 2024 6:49 PM
To: [email protected] <[email protected]>
Subject: Re: [HallicraftersRadios] CW Sidetone ideas

?

On Fri, Dec 6, 2024 at 03:33 PM, Don VE3IDS wrote:

It was powerful enough to just parallel across the speaker lines and drive the speaker directly.?

I've just started to work on a CW sidetone technique for the HT-44.? Great idea of Walt's to use a diode and pin 8 of the octal plug to accomplish the keying.? I built a little LM555 based sidetone oscillator based on the design at AA8V's website.? I found that I could connect the output to the 500 Ohm terminal on the rear of the SX-117 and that enables you to hear the sidetone in the headphones or the speaker.? Haven't worked out any volume differences yet.

?

73, Floyd - K8AC

Re: CW Sidetone ideas

#31327

On Fri, Dec 6, 2024 at 03:33 PM, Don VE3IDS wrote:

It was powerful enough to just parallel across the speaker lines and drive the speaker directly.?

I've just started to work on a CW sidetone technique for the HT-44.? Great idea of Walt's to use a diode and pin 8 of the octal plug to accomplish the keying.? I built a little LM555 based sidetone oscillator based on the design at AA8V's website.? I found that I could connect the output to the 500 Ohm terminal on the rear of the SX-117 and that enables you to hear the sidetone in the headphones or the speaker.? Haven't worked out any volume differences yet.

?

73, Floyd - K8AC