Voice powered 14 MHz transatlantic test on Tuesday

[G4TUT]

Voice powered 14 MHz transatlantic test on Tuesday

On Tuesday November 10 at 1500 UTC Radio Amateurs will attempt to span the Atlantic using a Voice Powered transmitter on 14.055 MHz CW.

Mike AA1TJ and other Radio Amateurs have been experimenting with 'Voice Powered' transmitters, the power comes from rectifying the audio signal from the microphone.

Some remarkable distances have already been achieved using voice powered transmitters, which generate an output of between 2.5 and 15 mW. Now they are going to attempt to get this incredibly low power signal across the Atlantic

Mike writes

"Some of the lads are heading over to the Maine seacoast on Monday morning for what we're calling a "Rexpedition. " W1REX was kind enough to secure the use of his family's beachfront camp for us for a couple of days. He explained the urgency to them, saying, "...a bunch of radio-heads want to talk to Europe with the equivalent of a cellphone with a dead battery."

Rex, Seab, AA1MY and Jim, W1PID, are going to arrive early on Monday to begin putting up the antennas. I plan to show up in time for lunch; hopefully after all the hard work is done.

Seab wants to erect a pair of half-wave phased verticals on 20m. I think the plan is to lift a 160m antenna using one of Seab's big kites.

Our hope is to cross the pond on both 160m QRP and with my voice-powered 20m transmitter. The weather forecast looks great at least through Tuesday.

My "Code Talker" will be rockbound on 14.055MHz; same as last Thursday. We'll begin the voice-powered 20m CW attempt the first thing on Tuesday morning [1500 UTC Nov 10]. Again, the goal is to span the Atlantic, but as always, I'll be very pleased to work anyone that hears me.

By the way, last Thursday's voice-powered operation on 20m was a great success. Altogether, I worked four stations and received one SWL report. The best DX was W4FOA in Chickamauga, GA; a distance of 923 miles. Tony reported that my 15mW signal was "an honest 579".
W4OP - located one hundred miles to the north of Tony - handed me the same report and followed up with an amazing recording (you can hear it on my website).

Later in the day I received an email from AD5VC. Dana reported that he clearly copied my callsign while listening on the LSU club station (K5LSU) in Baton Rouge; a distance of 1375 miles (nearly half the distance between the Maine coast and London, England).

I thought these were remarkable results for 15mW into an endfed wire at 35 feet. It makes this week's attempt from a saltwater QTH, coupled with the low-angle of radiation with a spot of directional gain all the more exciting.

So please keep us in mind come next Tuesday morning. I'm guessing Seab will be operating 160m QRP on both Monday and Tuesday evenings.



Thank you,

Mike, AA1TJ



See details of the first 161 km voice-powered QSO using voice generated CW
http://www.southgatearc.org/news/oct...owered_qso.htm

GQRP Club
http://www.gqrp.com/

GQRP Yahoo Reflector
http://groups.yahoo.com/group/gqrp/

Mike Rainey AA1TJ
http://mjrainey.googlepages.com/






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[K3KO]

So you have to shout into the mike and send CW at the same time?
I can't do that. If I am sending CW and try to speak, I can't. My brain apparently can't multitask this way. Clearly some can. Think of the church organist who can sing, play the organ (including using his feet) and direct the choir at the same time...

73 de Brian/K3KO

[K8ERV]

WOW! Marconi would roll over in his grave---

TOM K8ERV Montrose Colo

[KE4IKY]

So you have to shout into the mike and send CW at the same time?
I can't do that.

Think of all the things you've accomplished so far in life. If you really wanted to and were willing to put the time in to practice for something like this it might just be possible. Give yourself some credit....

Joel

[K8ERV]

Originally Posted by K3KO

So you have to shout into the mike and send CW at the same time?
I can't do that.
73 de Brian/K3KO

I'm still working on patting my head and rubbing my tummy. Or is it the other way around?

TOM K8ERV Montrose Colo

[AB9LM]

Congrats thusfar Mike!
Quite an accomplishment.

73
Jim - AB9LM

[K8ERV]

I hope there is a rep from Guinness to witness.

TOM K8ERV Montrose Colo

[W0IS]

So you have to shout into the mike and send CW at the same time?

I've been following his postings on the QRP-L mailing list. He originally started out with a voice-powered AM transmitter, and he did make some contacts with it. However, the modulation apparently didn't sound all that great (which makes sense, since he was shouting), so he resorted to shouting CW into the "mike", as a sort of A2 emission.

He then switched over to CW, by simply rectifying the output of his "microphone" and using that to power the transmitter. He doesn't use a key--he simply shouts "dih" and "dah" and that keys the transmitter directly.

I haven't had a chance to listen for him, but IMHO, this is amazing.

[KB3X]

This is so 1917.

[K1AO]

On 11 February 1966 Lt Colonel Joseph A. Dombrowski. Chief, Electronic Warfare Division, USAF published the following report:

"RESEARCH AND DEVELOPMENT OF ACOUSTIC POWERED PERSONNEL TRANSMITTER TECHNIQUES" out of the Datametrics Corporation. The Federal document number is AFAL-TR-66-25.

It is also under:

Air Force Avionics Laboratory
Research and Technology Division
Air Force Systems Command
Wright-Patterson Air Force Base, Ohio

Abstract:

"In the absence of the earth's microwatt voice modulated transmitted power will be capable of providing limited range communications between astronauts outside a space capsule and the capsule itself and among the astronauts. Such microwatt RF power can be generated with no external source of power except the acoustic energy of the voice.

To demonstrate the utility of such a system, three miniature transceivers were constructed with provisions to interconnect any of the units into the AN/AIC-18 inter communications system. Subsequent testing of the completed system demonstrated usable communication in excess of 300 feet from the handheld transceivers to the AC-powered transceiver over 2500 feet from the AC-powered transceiver to the handheld transceiver."

The report contains detailed schematics. Perhaps this info might be of use to today's efforts.

There is a related report, AFAL-TR-65-20 that dealt with terrestrial communications, titled "STUDY OF ACOUSTIC-POWERED PERSONAL TRANSMITTER TECHNIQUES. It has a lot of theory. Same source.

K1AO