I would like to jump in here, I have a converted solid state rig on 20 meters. It runs an adjusted level output of 100 to 650 watts on that band. It uses a derivative of the MRF-150 only requires 100 milliwatts of drive over the whole band. The only drawback if you can call it that is this unit is water cooled. YMMV Jim WB2FCN
----- Original Message ----- From: "Jim candela" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" <amradio@mailman.qth.net> Sent: Monday, January 30, 2006 8:36 PM Subject: RE: [AMRadio] AM Transmitter Advice?? > > > Guys, > > I just looked up the MRF150. For the moment look at the characteristics > below with a big AM final amplifier in mind. > > With a 300 watt Pd rating, this thing might do well as a efficiency > amplifier (modulate the gate bias) to make 100 watts AM, and do so with room > to spare. So with say 33% efficiency (SWAG), 300 watts DC input, you get 100 > watts RF output with 200 watts Pd. With modulation the efficiency improves > (doubles @100% modulation from sine wave tone input). > > If you do a conventional Class C high level modulated amplifier with say 150 > watts Pd, and 75% efficiency (SWAG), that gives you 600 watts DC input X .75 > = 450 watts RF output! There are tons of hi power solid state audio > amplifiers around, so there is your modulator too! > > Sure, the application notes dwell on SSB linear usage, but heck if it works > on SSB, you can make it work on AM! > > Regards, > Jim > > So how much do these things cost? :-) > > > MRF150 > > MAXIMUM RATINGS > Drain-Source Voltage VDSS 125 Vdc > Drain-Gate Voltage VDGO 125 Vdc > Gate-Source Voltage VGS ±40 Vdc > Drain Current - Continuous ID 16 Adc > Total Device Dissipation @ TC = 25°C > Derate above 25°C > PD 300 > 1.71 W/°C > Storage Temperature Range Tstg -65 to +150 °C > Operating Junction Temperature TJ 200 °C > > > MOTOROLA RF DEVICE DATA > ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted.) > Characteristic Symbol Min Typ Max Unit > OFF CHARACTERISTICS > Drain-Source Breakdown Voltage (VGS = 0, ID = 100 mA) V(BR)DSS 125 - - Vdc > Zero Gate Voltage Drain Current (VDS = 50 V, VGS = 0) IDSS - - 5.0 mAdc > Gate-Body Leakage Current (VGS = 20 V, VDS = 0) IGSS - - 1.0 mAdc > > ON CHARACTERISTICS > Gate Threshold Voltage (VDS = 10 V, ID = 100 mA) VGS(th) 1.0 3.0 5.0 Vdc > Drain-Source On-Voltage (VGS = 10 V, ID = 10 A) VDS(on) 1.0 3.0 5.0 Vdc > Forward Transconductance (VDS = 10 V, ID = 5.0 A) gfs 4.0 7.0 - mhos > > DYNAMIC CHARACTERISTICS > Input Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Ciss - 400 - pF > Output Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Coss - 240 - pF > Reverse Transfer Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Crss - 40 - > pF > > FUNCTIONAL TESTS (SSB) > Common Source Amplifier Power Gain f = 30 MHz > (VDD = 50 V, Pout = 150 W (PEP), IDQ = 250 mA) f = 150 MHz > > > Full data sheet: > > http://www.twhrf.net/mkic/mrf150.pdf > > > > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Jim candela > Sent: Monday, January 30, 2006 6:54 PM > To: Discussion of AM Radio > Subject: RE: [AMRadio] AM Transmitter Advice?? > > > > > Larry, > > I am interested in what your friend Jim, KR1S has in mind for that 100 > watt AM solid state exciter for 75 meters. Is that carrier output, or PEP? > In thinking about it, this could vary from a "scaled up CB" rig with a tuned > class C final with high level modulation, or maybe a small AM exciter with a > solid state push pull linear, or maybe a class E setup. We seemed to get > side tracked on the 813 amp idea, and glossed over the exciter concept you > laid out. > > How about a nice juicy MRF-150 with high level drain modulation, or low > level gate bias modulation? I bet no one has ever tried it either way.. > > Regards, > Jim > WD5JKO > > > [mailto:[EMAIL PROTECTED] Behalf Of Larry Keith > > My friend, KR1S (Jim Kearman) is designing an AM > transceiver, for me. We plan for this to be a > solid-state unit that will deliver about 100 watts > out. It will be single band (75 meters) and I have > been considering using that to feed a homebrew linear. > I have the makings of a 2 x 813 amp thanks to my and > Jim's hamfesting efforts. > Larry > KQBY > > Larry Keith > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > > >
