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AMfone's Online AM Handbook => Transmitters => Topic started by: VE3LYX on December 03, 2015, 10:56:12 PM

Title: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 03, 2015, 10:56:12 PM
I came into to a pair of these old WW2 sets last year. One was serviceable and I have used it on Am quite a bit however they are really short on power. Less the 8 watts on AM. You have to be lucky and I was a few times however I was not happy. An 807 final and that poor a power output did not make sense to me even though many assured me that was all that was possible. You see I have a homebrew AM rig with a 6sn7/6l6 Am transmitter that produced the same amount of AM output and on half the PA voltage. So I went on a hunt. I could not accept the idea that 5 or 6 watts of AM was all an 807 could produce at over 500 plate volts and 250+ screen under load. Were these sets range or power limited because of their intended use mainly as inter tank communication units? I was suspicious they had been perhaps "over engineered". Took me a long while (probably 50 to 75 experiments) and a lot of tests but it turns out they were. The 6h6 hobbles them by auto controlling or effectively limiting the drive. I had a spare 6h6 so I casterated it and left the heater circuit intact. I plugged it in and hooked it to the dummy load. BINGO almost 20 Watts of AM and  noticeably more on CW. I worked a few contacts in both modes. One with VE3CL who was most helpful in me getting my mic habits right with the new found power. I now have a most enjoyable vintage rig to use. The difference is like night and day. I haven't turned on my DX60B since. Maybe you have one still stashed away. Might surprise you how much nicer it can work.
No 19 is behind me as I check the UTC clock in prep for a sked.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: WD5JKO on December 04, 2015, 01:50:01 PM


   Those #19 Wireless sets look pretty neat. Good deal with uncorking the power capability by bypassing the power limiter. I wonder if the modulator is up to the task to modulate at the higher power? Do those things PM when they AM modulate? I sometimes observe a WW2 vintage transmitter with my SDR receiver, and quite often one sideband is reduced, or missing completely. Perhaps this is from incidental phase modulation of the VFO working to do some sort of sideband offset. Many Johnson transmitters do that on 40 meters.

   Hey, aren't you the guy who raced MOPAR slant 6 powered automobiles?


Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 04, 2015, 03:14:01 PM
How do you know that? Yes  retired now. Had a crash and fractured my spine so radio has replaced racing. Car survived fine but I was kaput for about 7 months. Still sore 15 month later  but at least I can walk so I won't whine. I am sure the audio is a long ways from perfect. They downward modulate too which really throws the SDR folks but other then the power hobble are a fairly effective radio. I was able to even on around 5 or 6 watts AM, to work as far as Indiana or 512 Mi ATCF. I only did it once but worked into Maine and NYC several times during good propagation. Craig VE3CL helped me this week learn to properly modulate with the new set up. I had basically to make sure I spoke up and not mumble or turn away from the mic. We did a few exchanges and he helped me with that. He said when I spoke up and proper copy was good even through QSB. (XYL tells me the same thing at least once a week "Stop mumbling".) I use an original mic. I don't want to modify the set. Not this one as it is almost NOS so anything I did had to be plug in. I want it to sound like it did in 1943 and I think it does. In finding the hobble I used the same methods I use wring power from mundane engine combos. Start with almost nothing and hunt in every nook and cranny for hidden power. It is how I have lived my Automotive life so no reason to be different in radio. I am still though a little startled at how big the improvement was in the No 19. I have rechecked it several times just to be sure I wasn't dreaming. It is best on 80M and about 90% that on 40M. I did rework the Parasitic on the 807 and added a RFC in the plate supply. Just because I want it that way.  Don't like them not there even if it runs ok that way. What helped the most was having the set on a hb Ac supply and being able to play with screen voltages  and plate voltages rather then being stuck on the old military supply. I noticed early on that anytime I pushed it I got neg results. I was suspicious from day one these radio had been hobbled after early testing. After all you don't want inter-tank communication being heard at a distance. I was pretty nervous when I came up with the idea what was wrong. However after years of experimenting in my other life I knew the feeling well and understood you can talk and worry till you are blue in the face or you can try it. I choose to try. At first I could hardly believe it. It is now a fun set to run. It has its own distinctive sound even on CW however it is now a practical set with these  power levels. I am still pinching myself though. I hope others will find the info useful. There are still quite a few of these sets around. The Canadian sets had labels in English and Russian because of our lend lease equipment agreements with them during WW2. I am not real fond of that but it is a fun radio to use. If it wasn't in such good condition I would probably buy a set of British labels and re-label it.
Got up early this morning and was able to use the No 19 to check in to the OMRN. Very happy with it now. I think I am going to leave it alone now as it is now a very useable set. (Some of you were there I think.)

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: AJ1G on December 05, 2015, 04:30:18 PM
Don - very interesting on your approach to de-limit the drive.  Will have to try that with my 19 set, I too have never gotten more than about 10 watts carrier on AM from it, see maybe 25 watts on CW.  I suppose if you don't have a 6H6 to castrate you could use any 6 v filament octal tube with the same filament current rating and filament pin out as the  6H6 since you will be cutting off the other pins anyway.  Haven't looked at a 6H6 lately but octal receiving tubes typically used pins 2 and 7 for filaments.

If you were on the OMRN this morning, it must have been before I showed up late after 1100Z.  Would have liked to hear your 19 set.  A good morning for it.  Most stations were much louder than usual by at least 10 dB on my Wandell & Goltermann AT-611 selective carrier level meter.  Lots of 30 over 9 signals from the bigger guns.  Was thinking about bringing on the19 set at one point but then the net signed off.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 05, 2015, 05:19:40 PM
I was on quite early. Was on the first call in at 5 PM (Man that is early!)although it was about the third "come now" I made it. Not everyone could hear me but then when I think I have never been able to check in before I am happy. Discovered I knew a couple. I had worked Marty _____RF a few weeks back with a homebrew CW one tuber. I stayed in just for a quick one. It is no fun when some can't hear you and I had made contact and logged in so I was happy and excused myself. I read the mail for awhile though. Marty Emailed later in the morning. Your assumption is bang on. 2 and 7 so a tired 6y6, 6l6 6v6 etc would do for a victim. I have come to realize if I hadn't been running the rig on a HB ac power I would probably never have even thought about this. It was the clue. When I tried to optimize the power supplied to the 807 it almost shut down. I was always suspicious they had been hobbled anyway. I had it on this afternoon for a bit. It works about like my DX60B when running barefoot. I mean as effective, not specifically equal power wise. I can answer a CQ and be reasonably assured I will be heard. I am very pleased with it now. Would be fun to to a 19 to 19. Even if CW to make the initial connection. It pushes the Amp very well. I changed the circuit in the tuner to totally isolate the Amp from the transmitter DC wise and it really likes that. It appears to be well above 100 watts when driving the AMP.   

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: AJ1G on December 05, 2015, 06:12:24 PM
Back in the mid to late 80s the WS19 was the rig that got me back to AM operation, and also played a part in the establishment of the OMRN.  I used to get on in the early morning hours on Saturday with Walt, KJ4JV, running the 19 set either barefoot or through the SB-200 of my SB line setup.  It would easily drive the 200 to about 60 to 80 watts output on 75 meters.  Walt, who at the time was doing the ER in Uniform column in Electric Radio, came up with the idea of the Old Milrad Net as a venue for us afflicted with an affection for green, gray, and black wrinkle military sets to get together and operate them, sort if like a radio version  of a car guys' cruise night. . He put the word out via the ERIU column in the magazine and that's how the net ended up in the bizarre 0 dark hundred (0500 Eastern) start time, at a time when the band was relatively quiet and low power sets could be heard.  I think the first official session of the net was sometime in early 1989.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: WD5JKO on December 05, 2015, 08:58:32 PM

I remember working Ohio, and further at 5am, and that was from Texas using my Retro75.

Don, any chance you got a higher resolution photo of that dragster? We talked about that car here on this board in a thread regarding a home made PTO, and another feller wanted my 1964 Rambler car radio. I stripped that radio for the audio output transformer as they were really a tapped auto-transformer, and useful to use as a modulation transformer with Low Z 12v stuff. My Avatar is based on that GEM of a radio.

I was a Plymouth owner, and my first car had a slant 6. Later I had a 340 Duster, and two 273 Barracuda's. I always wanted to hot rod a slant six.  :P
In later years I did a few quarter mile passes with a 85 Turbo I Chrysler Lebaron (2.2L 4-banger). With a few tweaks, I could keep up with a 5.0 Liter Mustang of the day from 0-100 MPH. At the drag strip I could never get traction off the line; I'd burn out and settle for a mid 15 second pass.


Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: AJ1G on December 05, 2015, 09:15:37 PM
I never had a real Mopar with a slant-six, but as a pre-JN in my model making days, I made the Revell slant-six engine kit, think it was 1/8  or 1/4 scale, Revell's answer to Monogram's Visible V-8.  It wasn't "visible" like the V-8, but did have a cut-away section of the block that lifted out so  you could see the pistons move and also, I believe, see the valves operate.  I believe there was a small DC motor in the  "starter" that would crank the engine over.  The assembly was partially glued, and partially assembled with very small fasteners.  I distinctly remember that the end caps of the connecting rods were secured around the crankshaft with some really small machine screws and nuts.  I also made Mongram's huge  "Big T" hot rod kit, but now we are really getting OT!  I did learn a lot about the basics of how an engine worked from building that slant six kit.

Big T image (not mine!):

Slant Six kit in operation video (again not mine):

Pretty cool to see that slant six model cranking away, I never got mine to run like in the video ... mine only ever turned over with my fingers pushing on the crankshaft with the oil pan removed.  If I am not mistaken, as part of the assembly, you had to coat the pistons and the crankshaft journals with Vaseline prior to inserting them in the cylinders.

And people think we're somewhat crazy for playing around with old radios powered by dynamotors!  Check this out....

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 05, 2015, 10:31:19 PM
oh heck come on for a ride.
Back to radios. I have often read the mail on the OMRN but today was the first time I could sign in. There used to be a bunch , I think they were AWA guys on 3705 weekends who used old Mil stuff as well. Joe W3GMS I think was NC and Dave (K2CJ I think or something similar) was very helpful . Offered to fire up early a couple of times so as to help me get my ARC5 cathode modulator dialed in. Most helpful fellow. I don't hear them any more. Most of the OMRN are not in my area so I have to reach to work them. Not much AM around me. Some north west and west but here is almost an AM desert. I couldn't get that kind of power before on my linear but it is only a twin 811A with untuned input. Before I could get 25 watts about on  AM . I never tried it on the linear when doing CW ops. Used to running under 5 watts on CW  most of the time so big power on CW is not how I think I guess. (For instance tonight I was running my TNt and Hartley on the Bruce Kelly AWA deal and worked NC , almost 600 mi ATCF on my TNT with under 5 watts CW)Now I can't really push it when doing tune up on the linear as my Dummy load is a wee bit past its max and I am afraid I am going to pop it. I am being careful with all now as it is working good enough to suit me and I don't want to hurt it.
As to pics, Aside from the fact it is OT here I am on dialup internet so hi def pics are for me Verboten. It would take hours to send or receive. Once spent 2 hours and 43 minutes receiving an email containing a hi def photo. Messed me up good because once started I had to let it finish before I could do anything else.
Further, I have been using it everyday and now can talk to anyone I can hear or so it seems. It has become a comfortable radio to use and my AM rig of choice. I am running it barefoot.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: KD3ZK on December 10, 2015, 02:59:02 PM
This is a great tip. I had a bad 6X5 rectifier tube which I clipped all the pins but the heaters and used that. With the 6H6 I was getting about 5 watts out AM. With the mod I'm up to 17 watts out using the stock dynamotor PS dipping under load to about 425V and a retune. I'm anxious to try it out. Every little bit helps with low power.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 10, 2015, 10:50:26 PM
Great! If you are operational with it and have an interest in a No 19 to No 19 contact on AM , 40M I would be interested. I checked, We are almost exactly 300 mi apart. Based on my No 19 AM activity this week that should not be a problem. I can pretty well now talk to anyone I can hear. I talked to Frank SQP today and he is a bit farther distance wise. Thanks for the measurements on your D motor HV. I have wondered what they would be or should be when I built my PSU. I am in the ball park.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: M0VRF on December 17, 2015, 02:38:15 AM
HI Don.

OK the H.F. set is for the tank to base comms.

There's a UHF set with a super reg Rx in there that was for tank to tank and also the intercom system for the tank too.

I had a couple for a while and actually spoke to someone at the royal signals who explained all about them.

Great you're using it.

Regards from the U.K.

Title: Re: Power Improvement for the old No 19 Wireless sets
Post by: VE3LYX on December 17, 2015, 08:18:31 PM
Yes. Over here in Canada we used our version a bit broader. Trucks Jeep etc were often equipped with No 19s. Re the Supreg transceiver, mine still has the 235 VHF set in it but I don't bother with that as VHF in any form isn't my thing. I guess it could be pulled down to 220mhz quite easily which would be ham But'''?However, Being able to triple the HF set's power out without butchering or modifying the radio internally sure made the radio much more usable. Currently in decent conditions who I can hear I  can work. Before it was useable but distance was limited severely. you needed to be super lucky. Now it is adequate for daily use. Tripling power makes quite a difference.
Yesterday I was listening on 40M and heard some talking quite a ways west of me. Conditions were not great although I tried a couple of times barefoot. Unsure did they not hear me or were they just absorbed in converstation I pumped the No 19 through my twin 811A amp. It now since the mod  drives it very well , much better then my DX60B so output is , well above my shacks ability to measure it safely. I gave my call quickly on a change over. Instant success. Before it would just drive it and that is all. Output then was less then it runs barefoot now, even when going through the same amp.
Feb22, update used the No 19 barefoot all weekend in the AWA AM QSo party. It did a fine job. Still smiling All were able to copy me. Not strong but clear. Clear copy is all you need. Has become my go to AM set. Photo is from QSO party Sun aft. XYL took it.

Just got word today on the AWA AM QSO party as in the photo. I won for 2016 using mostly only the No 19 modded as mentioned above. I'd say it works pretty darn good!
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