[Milsurplus] [MMRCG] GO-9 Progress Report. 4 Nov 19, First Contact

[Ray Fantini]

I mostly ran on forty meters at 7.29 with around 1200 volts on the plate at 90 MA so that would be around 100 watts or so in indirect power and would assume that it was running about 75 to 80 percent efficiency in class C that would give me around 75 watts or so. The trick for me was I always used AM and with the suppressor modulation scheme that biased the suppressor down to maybe fifty watts or so in AM mode.
Always had plans for building an external plat modulator and getting "BIG" power but never got around to it. Think with your increased B+ and plate you are getting more. Also think the transmitter was maybe more efficient on 80 then 40 but cannot prove that. 
Had a TCS that I was trying to run AM with before but never got much love running the five watts or so that developed at the antenna. Once I started running the TBW started making contacts on AM and finally ended up using my ARC-38 that’s 100 watts of plate modulated AM and have no problems making contacts with that.
I sold the TBW off some time ago and seeing your work makes me miss it. 

Ray F/KA3EKH



-----Original Message-----
From: MMRCG at groups.io <MMRCG at groups.io> On Behalf Of David Stinson via Groups.Io
Sent: Tuesday, November 5, 2019 9:22 AM
To: Ray Fantini <RAFANTINI at salisbury.edu>; MMRCG at groups.io; milsurplus at mailman <milsurplus at mailman.qth.net>
Subject: Re: [Milsurplus] [MMRCG] GO-9 Progress Report. 4 Nov 19, First Contact

Thank you for posting this, Ray, and for sharing your project.  How much carrier power do you get out on 75 meters?  I ask because I don't believe my test equipment.  Even the venerable 803 isn't going to be 
90+% efficient as a Class-C amp, so I think both my scope and wattmeter
are lying to me.  Just Googled a calibration procedure for my Tek 453 scope.  We'll see.
73 Dave AB5S

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