I have an SB200 linear and on AM it is equivalent to a DX100. I increased the bias on it so to the point just beyond cutoff for AM so that it requires a little more to drive and it reaches negative 100% modulation slightly before the driver does. But this seemed to help the modulation linearity and efficiency just a little. I really use this position mostly for CW drive to the push pull 250th rig. But I have occasionally put it on the air and switched the driver to AM.
John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim candela Sent: Friday, September 30, 2005 6:47 PM To: Discussion of AM Radio Subject: RE: [AMRadio] GG 813 Linear in GE Ham News Don, So your saying that 4 X 811's at maximum ratings in AM Linear mode are nearly equivalent to 3 6146's class C plate modulated, i.e. a Johnson Valiant? :-) Years ago I bought a book from an ad in the old AM Press Exchange about AM, and there was a detailed explanation of class C plate modulated versus AM linear operation with the same tubes, and it clearly showed the differences. I need to go find that book again... Jim -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Donald Chester Sent: Friday, September 30, 2005 1:58 PM To: [email protected] Subject: Re: [AMRadio] GG 813 Linear in GE Ham News >.hey don,what are your thoughts of am transmission >with 4 811s?..i'm looking to get more output on 160 >am.. In linear service, the maximum carrier output would be half the plate dissipation. The pd of the 811A is 65 watts. So for a quad, the maxumum safe carrier output would be 130 watts. In grounded grid service, some of drive power will feed through, so you might add 10% to that, bringing the carrier output power to 143 watts give or take a few. With the pair of 813's you would add some feedthrough power to the 125 watts. I would say more like 12.5 watts, to bring the total to 137.5 watts. Most g-g linears take about 10% of the output power to drive them. Don K4KYV ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.9/115 - Release Date: 9/29/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.9/115 - Release Date: 9/29/2005 ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami
