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THE AM BULLETIN BOARD => Military Amateur Radio Section => Topic started by: KA3EKH on May 24, 2019, 10:05:48 AM



Title: Navy MAK and the HY1269
Post by: KA3EKH on May 24, 2019, 10:05:48 AM
So a WW2 Navy model MAK 25 watt HF AM transceiver followed me home from Dayton. Been looking into using it for a portable 3.885 transceiver at various field nets and the like with others who are using things like BC-611, pogo Stick and other WW2 AM transceivers. Think itís a good choice being it relatively small and low power and built to work with a short vertical antenna. In the process of building external Dc to DC converter power supply that will probably attach to the back of the radio out of sight and run everything from twelve volt DC source.
Lot of this is easy, being the filament strings are already configured for twelve volt operation, all the tubes in the receiver are twelve volt like 12SK7, 12A6 and the like and figure the receiver will work just fine at around 180 to 190 volts DC for the plates but the real question is whatís going on in the transmitter.
The transmitter is a four channel crystal control using a 12A6 as the oscillator that drives a HY1269 PA tube, that tube is plate modulated by two more HY1269 tubes in parallel.
This is my first exposure to the HY1269 tube and it appears to me to be a quick heating power pentode rated at 30 watts, 750 volts max DC plate at a max current of 120 MA.
Just playing around with lighting up the filament string at eight or ten volts the filament appears to be real bright. Looking at the specs I can find it shows the tube can be used at six or twelve volts with a center taped filament. The filament, cathode and suppressor grid are all tied together internally in the tube. All three tubes have their suppressor filament center taps tied together decoupled to ground thru a capacitor but also a variable resistor is involved with that circuit. From what I can determine the whole mess was feed from the common DC input with a separate switch that powered the transmitter section by itself that brought in a relay to power up the filament string and the dynamotor for the high DC voltage was activated by the PTT line.
First question: How bright are the HY1269 tubes supposed to burn? They light up real bright, almost like light bulb filaments at ten volts and being that itís hardly the most common tube donít want to risk burning open any of them.
Second question: what should I plan for a plate voltage for the transmitter? I figure itís going to be around 400 DC or should I be higher? Maybe something like 500 or 650 DC being the tube is rated good to 750?
Attached is the only schematic I have been able to come up with and itís not very good. The key thing here is to build up an external power supply but not one that puts the tubes in danger, will also be looking at things like the voltage ratings of all the bypass capacitors and the plate coupling capacitor and thinking maybe the key maybe too go with half the rated voltages?



Title: Re: Navy MAK and the HY1269
Post by: PA0NVD on May 24, 2019, 11:40:27 AM
The HY1269 seems to have an 8 V filament!!!


Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on May 24, 2019, 01:53:02 PM
I saw that but have also seen it listed as a 12.0, not 12.6 volt tube. Itís a very strange bottle. Assuming that has something to do with being able to turn the transmitter on separate from the receiver and not having to wait to transmit?
The base is the same as an 807! Wonder if I can stuff three of them in there and run them at 6.3 volts?


Title: Re: Navy MAK and the HY1269
Post by: PA0NVD on May 25, 2019, 10:20:28 AM
you may use a 2E22, same connections and appearance and 6.3V fast heating. They are used in the final of the AN/GRC9


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 25, 2019, 01:43:11 PM
Is it possible for you to post a clearer picture of the schematic or suggest a place where I could download it? As far as the filament brightness is concerned I would bring one of the tubes up on a filament transformer connected to a variac to the rated voltage of 6 volts to see how bright it should look. (I know it runs on 12 volts as well) Then compare how it looks in the rig. If its way brighter, something is wrong. My experience with quick heating filament tubes, is that they run at an orange to yellow color but never white hot.


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 25, 2019, 02:04:21 PM
Unless you're a purist, give some thought to replacing the HY1269's with 1625's. Change the tube sockets, do a bit of re-wiring, and save a total of 40 watts heater power. Those HY1269's will eat your battery for lunch!

Don


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 25, 2019, 02:39:15 PM
Quote
Those HY1269's will eat your battery for lunch!

If he is going to run it off a battery, 1625 tubes would be a bad choice if your doing push to talk, therefore the reason for instant heating filaments. But after re-reading his post and unless I missed it, I didn't see any mention of operation from a battery? Then again, I am somewhat a Mr. Magoo........


Title: Re: Navy MAK and the HY1269
Post by: PA0NVD on May 25, 2019, 06:24:33 PM
The 2e22 uses less filament power than the 1625, is 6.3 Volts and has the same connections and dissipation as the HY1269, so no chages. It is a very similar tube as the HY1269 except the filament.


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 25, 2019, 07:54:58 PM
I get it now. The HY1269's are part of the PTT circuit and heat "instantly" at key-down. D'oh!

The thing that looks weird to me is that the radio may use the HY69 (6v) or the HY1269 (12V) depending on source voltage, yet G3 is connected to the fil CT on the HY1269 and not on the HY69. Best to make sure the correct schematic is used, if there's more than one.


Don


Title: Re: Navy MAK and the HY1269
Post by: KA0HCP on May 25, 2019, 08:50:40 PM
http://www.navy-radio.com/xmtr-ww2-port.htm

Link to navy radio site.  Scroll down to "MAK".


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 25, 2019, 11:23:04 PM
Quote
The 2e22 uses less filament power than the 1625

RISKING A HIJACK HERE. That 2E22 tube has always intrigued me with its massive plate?? The hi fi guys have done some projects with it and while it preformed ok, they didn't go nuts over it which is a good thing! I know of no other tube that has a such physically large plate area in its category? I wonder if it could take a piss beating atomic yelllooooww and not melt with about 1000 volts on the plate in a triode connected modulator circuit?

Now back to your regular reading pleasure..............


Title: Re: Navy MAK and the HY1269
Post by: Opcom on May 26, 2019, 12:35:52 AM
looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.


Title: Re: Navy MAK and the HY1269
Post by: K4NYW on May 26, 2019, 01:27:24 PM
looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick



Title: Re: Navy MAK and the HY1269
Post by: KA0HCP on May 26, 2019, 03:11:27 PM
Thanks for your work Nick.  Its good to see that a schematic exists.  bill

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick


[/quote]


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 26, 2019, 06:45:20 PM
I'm a little confused? Is there an actual schematic posted on these pages?


Title: Re: Navy MAK and the HY1269
Post by: KA0HCP on May 26, 2019, 10:56:53 PM
I'm a little confused? Is there an actual schematic posted on these pages?
Yes, there is. I posted a link to navy radio page, above.  Scroll down to the "MAK" radio. Photo is there of double page schematic.  It is essentially unreadable, but here it is:

(http://www.navy-radio.com/xmtrs/ww2/mak/mo1-mak-03.jpg)


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 27, 2019, 09:08:08 AM
Maybe this is a little easier to read...


Title: Re: Navy MAK and the HY1269
Post by: K4NYW on May 27, 2019, 10:16:18 AM
Thanks for the image processing!
Is it OK if I put your version on my web page?
Nick


Title: Re: Navy MAK and the HY1269
Post by: Opcom on May 27, 2019, 01:31:23 PM
looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick

Oh sorry I mistook the purpose of it. It has a lot of good pictures.




Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on May 27, 2019, 02:17:26 PM
Schematics are a luxury! Have to use whatís available. If I wanted easy would do something like an ARC-5 or for that matter a Bofoung. But the MAK is a strange little radio that I feel will be ideal for field operation on 3.885 and building up a power supply for field operation wonít be a big deal. The three tubes suck down around 4 amps when lit and that will be an unusual load for the battery to deal with but not an insurmountable problem. Most of the time is spent receiving anyway and with the separate switches for receiver and transmitter power can keep the transmitter filament off until needed.
Going to start with using a little solid state power supply left over from another project that will provide about 220 volts for the receiver and oscillator and around 400 for the plate of the transmitter. This power supply was from a Narco aircraft radio and also has a high level modulator included and may use that as a external modulation system and remove the two tubes in the transmitter that were used in parallel as modulators.
The transmitter is using Hessing or something like that modulation where the modulators load down the plate voltage of the PA to produce modulation but the original design requires an external modulation reactor and it may be best to dispose of the original modulation system and just modulate external. Will have to run at reduced power of maybe five watts or so but remember that this radio will be used primarily at events for short range to net with other field radios from WW2 so donít need high power.
The other idea would be to use a hissing or what ever its called modulation reactor external of the radio but finding just such a transformer may be an issue as opposed to a regular external modulation transformer.


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 27, 2019, 06:43:54 PM
Thanks for the image processing!
Is it OK if I put your version on my web page?
Nick

You have my blessing! :D


Title: Re: Navy MAK and the HY1269
Post by: w4bfs on May 28, 2019, 08:12:36 AM
I wonder how bigga battery needed for a Timtron transmission ?


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 28, 2019, 03:02:30 PM
Quote
I wonder how bigga battery needed for a Timtron transmission ?

NO battery needed! His QSO's are powered by the farts & belching that are customary in his QSO's :D :D :D i.e gas =
methane=internal combustion engine=generator in parallel with Maine Power makes his QSO's self sustaining.


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 28, 2019, 06:31:56 PM
Quote
I wonder how bigga battery needed for a Timtron transmission ?

NO battery needed! His QSO's are powered by the farts & belching that are customary in his QSO's :D :D :D i.e gas =
methane=internal combustion engine=generator in parallel with Maine Power makes his QSO's self sustaining.

I'd always imagined copper and zinc plates hung in a spittoon.


Title: Re: Navy MAK and the HY1269
Post by: W2PFY on May 28, 2019, 07:24:19 PM
Quote
I'd always imagined copper and zinc plates hung in a spittoon.

As a matter of factor, I found a brass spittoon probably made in India and gave it to him on one of my visits. I envisioned it to be filled with some ungodly mixture of bacterial goodness but alas, his wife made a planter out of it per Tim ??? ??? ???


Title: Re: Navy MAK and the HY1269
Post by: KK4YY on May 28, 2019, 07:57:39 PM
Quote
I'd always imagined copper and zinc plates hung in a spittoon.

As a matter of factor, I found a brass spittoon probably made in India and gave it to him on one of my visits. I envisioned it to be filled with some ungodly mixture of bacterial goodness but alas, his wife made a planter out of it per Tim ??? ??? ???

Leaves one to wonder then...


Title: Re: Navy MAK and the HY1269
Post by: Opcom on May 28, 2019, 10:11:47 PM
I wonder how bigga battery needed for a Timtron transmission ?

I recall a hand cranked generator on a little stand with a built in seat that I was introduced to when I joined the Texas State Guard.
Fortunately the introduction was from another soldier's collection and not something for use during what they call "summer camp" which is a week long anual training in August. Haha that was pretty rough on some of us city boys, vs. the outdoorsmen and former military.
There were some big AGM batteries - but we moved them on ATVs or trucks and only carried a short ditance to a desk or ground pad.

So.. field day - ya get more points for battery ops. I bet a couple of 92AH AGMs would last the day especially if you used a static converter instead of a dynamotor.



Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on June 11, 2019, 02:58:15 PM
The project so far. Using a NARCO power supply modulator that provides +190 for the receiver plates and 350 volts with modulation for the PA. Everything runs from 12 volts DC for use in the field. The issue now is that at full power, about ten watts the modulation is distorted and the plate current is very low. If I tune to either side of the plate current dip to around 50 MA plate current modulation is good but power drops down to around four watts. Canít understand why the plate dips to almost no plate current and although that he highest output it produces the worst modulation.
If I use the internal modulator donít have this issue but the two additional modulator tubes suck an additional four amps of current and do not appear to get a lot of gain from the internal modulator but it will work. Using the external modulator I pull the two tubes out that were in parallel with the PA tube forming the hessing modulator.




Title: Re: Navy MAK and the HY1269
Post by: kg7bz on June 11, 2019, 06:10:19 PM
If the externally modulated B+ is having to go through the internal modulation choke to reach the PA tube, you have a major impedance in series that's going to choke off the audio modulation. Running higher current probably partially saturates the choke, reducing it's impedance and letting more audio frequencies through.

August KG7BZ


Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on July 18, 2019, 09:32:37 AM
Ok, here is a question for the Brain Trust. Been working on the MAK project for a while now and now have a radio that works well on the original channels. The highest current channel is 3.00 MHz
I am including my latest drawing that shows the modified Heathkit HP-13 power supply that provides the B+ and HV for the radio. I am running the radio at reduced voltages of 165 for B+ and 400 for the HV and getting an output of around ten watts into fifty ohms.
The new problem is I can only get HCU-6 rocks and the radio uses something that looks like a DC-34/35, built an adapter and tried to get the transmitters oscillator up and running but no joy, I can take a crystal that was for the receive channel on 3.0 MHz thatís at 3.455 and that crystal worked in the transmitter and it ran on 3.455 with no issue so the question is whatís the difference between the two crystal types? And what can I do to adapt the 12A6 oscillator to get it to work? Think maybe the old series huge crystals had more capacitance and possibly a padding capacitor may help but have not tried that yet. Spent most of last night building the adapter and when it did not oscillate was too late to mess with it.
The plan would be to build something into the crystal adapter and not modify or change the original design of the radio. Donít want to result to installing an external chip oscillator and want to try to keep this using a crystal.
Can this be an issue with the 12A6 not having enough gain? Think the 12A6 is just a twelve volt version of the 6V6 and they make great crystal oscillators.
Also itís not clear from my drawing but the oscillator stage uses tuned slugs to set the oscillator frequency and you peak the tuning coil by reading the grid drive via the ľ plug on the front of the radio.
Wasted a lot of time using a HV supply that was grounded and a separate Bias supply and having all sort of issues with getting the modulation right and lots of additional stuff to make it work and finally looked at the original design where the dynamotor had the negative side of the HV supply used for providing Bias and microphone voltage and did the same thing with isolating the HV supply and found the radio works a lot better, just goes to show that sometimes the original design is better then what you can hack together and thinking that I can  maybe find an equal solution to this crystal problem but just canít see finding any of the original DC-34 rocks for 3885.



Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on July 19, 2019, 09:06:01 AM
Spent a little time playing with the MAK last night and developed a new theory. Although the radio has a published specification of being capable of operating from anywhere in the 2 to 4 MHz band the four channels that were in the radio when I got it were all within 2.1 to 3.0 MHz The output tank has six taps that can be selected in advance for each channel depending on the frequency of that channel and thatís how they match the PA for the band that the radio is using but the oscillator only has a signal LC circuit for each of the four channels. Using old school techniques learned from Mr. Smith brought out the AN/PRM-10 grid dip meter and found that I can check the resonance of the four oscillator tank coils and found that with the coil backed out to the end of its range it only peaks at around 3.7 MHz, and thatís with the slug backed all the way out of the coil. There are four capacitors located just under the coils, one for each coil and I am going to now speculate that maybe the reason the capacitors are so easy to get at is because they were intended to be swapped out depending on what section of the band the radio was on? And perhaps by changing out to a lower value I will be able to get the oscillator to osculate. Know for a certainty that until the LC tank for the oscillator tunes to 3.885 the oscillator wonít work, just need to figure out what capacitor I need. If I were smart I would know two things. First, whatís the value of the existing capacitors? Take a look at the picture. And second, what would the value of the new capacitor be? Recall something about determining resonate frequency of a tuned circuit and knowing the value of C can determine the value of L and with that knowledge be able to determine what C would be at 3.9 MHz but just not that smart. If someone can tell me the value of the capacitors, all four are the same then I will know where to start with smaller value capacitors and try to determine where the tuned circuit is at that time.
Think that they are 50 pf being green is 5 and red for a multiplier is two zeros? Or would that be 500 pf?




Title: Re: Navy MAK and the HY1269
Post by: KA0HCP on July 21, 2019, 12:09:12 PM
You are making good progress!

www.RadioDaze has an excellent chart for component codes. I keep a copy on my bench within reach.
http://www.radiodaze.com/vintage-component-color-code/

From the chart, this would be a 250pF, 500V, 20% capacitor.

You could find the coil Inductance via
1. Disconnect one end and measure with LCR Meter
2. Count turns, measure coil inside diameter, measure wire AWG, use an online calculator or chart from old Handbook.

Engineer Method:
Use the parallel and series LC formulas to confirm the installed resonance, then plug in values for the installed coil; Desired Frequency to solve for required capacitor.

Technician Method
Alternatively, hook up a variable capacitor in place of original capacitor. Using dip meter, adjust variable cap until you reach desired frequency resonance.  Use LCR meter to measure value of variable capacitor.  Install new cap of nearest value.  Adjust slug of inductor for peak.

bill


Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on July 23, 2019, 03:17:26 PM
Used my old LCR Bridge and found it was a 250pf capacitor. Replaced it with a 120pf cap and now the LC circuit resonates in the high end of the 80 meter band without issue. Developing around 11 watts at 3.885 with 375 VDC at 0.05 Ma into 50 Ohms.
The output tank was ok being on its forth strap that I think covers 3 to 4 MHz
Next step is the receiver.



Title: Re: Navy MAK and the HY1269
Post by: KA3EKH on July 30, 2019, 03:44:04 PM
Video of the radio in operation on 3885, built up DC power supply so the radio will be run from twelve volt power source like a car battery. The next step is to try to come up with an antenna for use in the field.
See it at:
https://www.youtube.com/watch?v=X7iniVgFOxk


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