7118 to 7120 Loop modulator trials

[VE3LYX]

I will be trying the loop modulator as installed on the pre 1929 style TNT transmitter. I am currently tuned up and calling CQ on 7118 but will move as low as 7115 and as high as 7120 to avoid QRMing anyone. I have now about 5 to 6 watts out. If you are not good for Am in this freq a CW answer will be fine as I have the key in my hand all the time I am talking and can switch. I am good on CW but not fast should you need that mode to reply.
I would like to try this mode of AM on the air. It is from the very early days of radio and was set aside or never popular here in NA. I will be using a TNT transmitter with a single 45 tube. Since the modulator is electromechanical in nature no other tube is used or needed. I will be using a # 3 carbon hand mic WW11 vintage and feeding a long wire thru my Hb antenna tuner. Range I expect will not be great. Probably Rochestor , Cobourg or Cornwall would be a reasonable expectation but who knows. Band seems good this morning.  I will be calling at 1/4 past the hour. with the exception of 9:15 which is my regular weekend QSO time on 80 with "The lads" . Signal reports in AM CW or even email would be appreciated. Thanks to any who would care to lend an ear.
Don VE3LYX
Transmitter is pictured below

[kd1nw]

Took a listen, but didnt hear you. But, I'm not suprised my my noisy location. 73

[VE3LYX]

At approx. 10:19 Am I made a successful contact with Tim VE6PG on 7120 +or-. He could barely hear but we were able to contact and 73 . Seeing as how it is about 160miles atcf and I have a 5 to 6 watt TNT transmitter I am stoked. So now I know it works. I was also powering my oscilloscope direct at the time to see if I could see any sidebands. Thanks Tim for listening and coming back to me. 1920s technology still works even today. Tim has a good setup and is especially good on the rx side of AM work. I probably wont sleep for a day or so. WOW!!!!!!!!!!!!
Don VE3LYX
Just checked the distance , 179.6 miles

[VE3LYX]

Had a second exchange on the last test. Two changeovers but he didn't (wouldn't?)ID for some reason. Accent was hard to understand probably because I wasn't expecting it.
Don

[VE3LYX]

Nothing this time.
Don VE3LYX

[VE3LYX]

Trials suspended. I have over 1/2 inch of ice on my longwire due to freezing rain. Tis pointless to try and transmit through that with 5 to 6 watts. Day was already a success. Thanks for those who took the time to listen.
Due to forced inactivity (antenna loaded with ice from ice storm and almost down. ) I looked at loop  modulation on the monitor scope. Different to say the least.
Tried the 5 watt and a 60-70 watt rig with loop modulation installed. Video taped it.
Don

[WA1LGQ]

Fun stuff Don, congratulations. Someone I know had a similar transmitter that he "plate" modulated. That is tuning capacitor plate modulation. He yelled directly into the big oscillator tuning cap, his voice vibrated the plates and  modulated the thing. I could actually copy it.
....Larry

[VE3LYX]

Thanks Larry. The trials went very well. It was very interesting and I will use it from time to time. Lou VE3AWA found some test in 1921 QST where ARRL Labs tested it on 200 meters and got 97 miles on 5 watts.  It is a British idea though and will never be popular over here. Still is always interesting to explore some of the ideas of our forefathers.
Today I am going down to fire up this monster. A 211 tubed Hartley.  If I put it on AM though I will use my cathode modulator as the loop is a low level deal. I have tested it up to 60watts but it works best at transmitters around 2 to 5 watts of which I have both.  Above that the induction coil becomes wieldy. Most put too many loops in now when they try it. 1 is enuf. You want to absorb a small  portion of the RF , not pull the osc which a coil with too much Q could do. You are looking for a usable (copyable) modulation level , not 150%+ on the positive peaks!:>) Still back in the 1918s to 1920s it must have seemed wonderful. I did a scope test and videoed it for my own enjoyment. Is quite narrow on my transmitter which is fairly stable for its type. Microphones make a huge difference too. Telephone mic works, but not well. A old Military WWII mic shows a MAJOR improvement
I found your tale interesting too. I often wondered how a funnel around a "microphonic" tube would work. I have a couple that went that way.
Anyway other then the odd QSO with those who are really interested I am quite satisfied with the experiment . Probably my most exciting ham adventure ever when Tim (---PG)heard me last Sat 179.6 miles away and right on frequency.
Thanks for you interest and comments. If Lou VE3AWA hadn't showed it to me I would never have known anything about it. I owe him.

Don

[VE3LYX]

Its been a steep learning curve but the loop modulation thing is real interesting. Today I completed it successful installation on a three transistor QRP rig of the Lew McCoy variety. It is crystal controlled and I had added a VXO circuit. Max output is just under 5 watts. I built it about 30 years ago and dragged it out again last weekend.
I installed the absorbtion loop where the osc link meets the buffer coil. It took me a few trys. The coils of this rig were made from Radio Shack RF chokes if anyone remembers it. It was popular in its day. It took a few trials to figure out how much loop was needed on a such  small coil. I wound up with 8 turns and it works about as perfect as it could. I recorded it on a nearby receiver and you can hear me breathing in the mic.. This has been a real interesting adventure. So if I am on 40M AM chances are real good I am using one of my rigs with an absorbtion loop. (Now have installed it on four of them. )
Don  

[VE3LYX]

I now have loop modulation installed on ALL my CW transmitters including my ARC5s. I am testing my 45 tube ,loop modulated TNT 1920s style transmitter on 7120 at approx.  15 minutes past the hour whenever I am in the shack and it is usable. So far I have had one AM QSO and one CW QSO. I use 7120 because it is away from most of the big guns and is generally quiet. I would enjoy any contact from this . Generally speaking I am down there afternoons  but often mornings between 10 and 12 as well. I am running maybe 5 watts out(during power surge.)
Don VE3LYX