I use a Kenwood TS-820 as a 10-20 watt carrier generator into a Heath (something 200) 1KW peak amp. I use about 40-50 watts of it to drive the grids of the 250ths. In order for the VFO and receive frequency to look proper on the TS-80 I modified it with a switch to by pass the filter and inject carrier while in either of the SSB modes. I found that that it also allowed me to run AM out at about 10 watts with real good linearity and no kick for the limiter. When the Heath Amp is on I get the about 75 watts out with not to much heat, so it is about equivalent to a DX100 with better audio. Tune up is critical and carrier level to audio level is critical. I also do not recommend this if there is any other way. I hardly ever use the set up for anything other than a carrier generator for the big rig. It is stable in frequency but you have to constantly watch the drive level to keep the grid current on the 250ths correct. I will have to in corporate some feed back circuit for to regulate that in the future.
John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brett Gazdzinski Sent: Thursday, December 11, 2003 7:37 AM To: [email protected] Subject: RE: [AMRadio] AM from a HW-101 Why would you want to do that? You can unbalance the modulator and run carrier and one sideband easy, at about 10 watts of carrier. Running both sidebands and some carrier might require some substantial mods to the circuit. You could put the rig in cw and run screen grid modulation, at about 10 watts of carrier, or plate modulate it at reduced levels, as the power supply and rf parts are not good for plate modulation or a steady carrier. There are likely circuits on the AM web pages for making the rig transmit AM, there seems to be quite a few older ssb transmitters that were modified to transmit low power AM, I don't know why someone would want to do so other than 10 meter work maybe. I just don't understand why some guys modify or run rigs that put out 10 or 20 watts of AM, then put it into an amplifier. Seems like doing things the hard inefficient way, lots of critical adjustments, fair sounding results at best for most rigs and amps, the need for a monster amp to get 300 watts of carrier output while sucking up the amphours, although it does warm the shack up nicely. The HW101 (and SB101) are not great designs, lots of distortion in both transmit and receive, odd IF frequencies that are hard to get good filters for, some tubes that run quite hard, poor VFO tuning in the HW101, etc. They are fun and easy to play with, so as a curiosity or hobby type thing, AM transmission is interesting, but actually running one on AM as a regular transmitter is a bit crazy except for maybe 10 meters AM, where 10 watts might do something. (100 watts out of a 32v3 or dx100 would do more) I can kind of see running a modern rig into an amp on AM, you may want the amp anyway (for ssb or cw), you get all mode, all band operation, all in one station, so why not flip the switch to AM? Just my thoughts. Brett N2DTS > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Jim Isbell > Sent: Wednesday, December 10, 2003 10:49 PM > To: [email protected] > Subject: [AMRadio] AM from a HW-101 > > > Anyone know if there is a mod to make the HW-101 transmit in AM mode? > > _______________________________________________ > AMRadio mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/amradio _______________________________________________ AMRadio mailing list [email protected] http://mailman.qth.net/mailman/listinfo/amradio
