Topband: The First Top Band Conterst

[donovanf at starpower.net]

Hi Dan, 

The 1BCG transmitter was redesigned and rebuilt many times before and during the Transatlantic Test. The transmitter as first built in early December was a "self rectified A.C. self oscillator" design, but Armstrong was very dissatisfied with the roughness of the transmitted signal. On 4 December it was decided that the transmitter should be rebuilt as a Master Oscillator - Power Amplifier" (MOPA) with a 2000 volt DC motor generator power supply. It wasn't until the third day of the Tests (December 9) that the transmitter was fully functional with an estimated 600 watts power output. 

The diagram in my presentation represents the configuration of the transmitter on the night of 11/12 December when the first transoceanic message by amateur radio was sent by 1BCG and received by Godley in Scotland. 

http://topbanddinner.com/page_presentations.html 

Propagation was very poor and atmospheric QRN was very high after the night of 11/12 December, and Godley heard no further transatlantic signals. Out of frustration and with only a few days remaining before Godley was scheduled to depart from Scotland, another 2500 volt motor generator was rushed to 1BCG and connected in series with the original motor generator, with 4500 volts now applied to the PA. That configuration was used for the last few days of the Transatlantic Test and during the next two weeks when 1BCG made two way QSOs with every state of the union. 

Last night someone asked when the first successful amateur two way transatlantic QSO took place. The date was 17 November 1923 on 110 meters, a two way QSO between 8AB in Paris amd 1MO in West Hartford, CT. Of course there is much more to this story, you can read about it in its entirety in on page 9 of January 1924 QST magazine. Just search for: Transatlantic Amateur Communication Accomplished! at: 

http://www.arrl.org/arrl-periodicals-archive-search 

It would be many years before two way transoceanic QSOs took place on 160 meters, for many years all of the effort was focused on opening transoceanic DX on the higher frequencies, all the way up to 5 meters. 

73 
Frank 
W3LPL 

----- Original Message -----

From: "Dan Z" <k2ywe at yahoo.com> 
To: "Frank Donovan" <donovanf at starpower.net> 
Sent: Tuesday, March 19, 2013 1:50:01 AM 
Subject: First Top Band Conterst 

Nice job, Frank. 
Ken didn't read my question: 
"I noticed the diagram of the station showed a 2500 V generator, but you siad they ran 4500 V. A bit of trickery to circumvent the power limitation?" 


Dan Zeitlin - K2YWE 
South Shore ARC - K3AU 
Annapolis, Maryland 
http://danzee.org