What is the bandwidth in the AM position? I think it was something like 8khz at the 6 db points, and 25Khz at the 60 db points. I had two of them, and they were so wide as to be unusable under normal conditions where you have AM signals every 5 kc.
Worlds best receiver? What makes it so great? The large selectivity choices? The hi power hi fi audio output? The passband tuning? I notice that the 75s-3 added the provision for an AM filter, so Collins saw the need for one. The 75s-3 sells for a lot of money, but the 75s-1 can be got quite reasonable, partly because of the improvements in the 75s-3 along with the provision for more filters. I would just do what Collins did, and add a good filter for AM reception. Brett N2DTS > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Jim Isbell > Sent: Thursday, December 11, 2003 2:23 PM > To: [email protected] > Subject: Re: [AMRadio] AM from a HW-101 > > > I find the 75S-1 to be an excelent receiver on AM/CW/SSB without any > modification. I wouldnt do anything to mine for fear of > screwing up one > of the best designed receivers in the world. > > I might try to get AM out of the 32S-1 however. There is a > mod for that > on the 32S-3 and I am sure it could be adapted to the 32S-1 > > Brett Gazdzinski wrote: > > >The resale value aside, I think the 32s-1 would do better, > >I think it actually uses a 455khz IF, you might be able to > do something > >with that. > >The 75s-1 type receiver could likely make a real nice AM > receiver, top > >quality, > >with the addition of a good kiwa filter in line with the back to back > >IF transformers used on AM. > >Standard setup is way to wide, but a 5.5khz filter between > the transformers > >(tacked on) would do wonders. > >it would only be in circuit when the AM mode is selected. > >It could be tacked on without any modifications, and you > >could power it from rectified filament voltage, or even batteries. > > > >Some slight circuit changes and an external audio amp, and > you have a great > >overall receiver for cw, ssb and AM. > > > >Any rig that runs 100 watts pep output on ssb is only going > to be good for > >10 to 20 watts of AM, but driving an amp would be useful indeed. > > > >Its easy to unbalance the modulator using a small pot > >(for carrier level control), getting both sidebands I would have to > >look at the design.... > > > >It would be quite neat to have a nice sounding well working > >Collins S line on AM and ssb. > > > >Perhaps trade the hw101 for a less nice 32s-1 and try > experimenting on that. > > > >What about screen modulation of the amp? > >That would likely get you a few hundred watts of AM out, > with very little > >audio power. > >Modulation can be very nice if kept on the low side, don't > expect 150% > >positive, but I have heard some really nice DX60b transmitters > >running screen modulation...very good fidelity overall. > > > >If space is at a premium, take over the basement, put a > couple of small > >rack cabinets on the desk, one big 6 foot rack in the shack, a > >shelf above the S line, or get something like a Gonset G76. > >The G76 runs about 70 watts of plate modulated AM output in a unit > >smaller than a 75s-1, and its a trans-receiver. > >The receiver uses a 262Khz IF, which works well, its quite > attractive, > >stable, accurate, and fun to operate. > >It does 80 through 6 meters, AM and cw, and can copy ssb. > > > >Its got problems, audio quality is not top notch, but they are > >extremely robust radios. > >I operate mine at higher voltages then you are supposed to, its been > >abused at pre hamfest drunken campouts, complete with rain, excessive > >beer, wires thrown up in trees, and it just always works. > > > >I used to have two of them, but sold one for some reason. > > > >They seem quite rare these days, I don't know why. > >Its smaller than a ranger, puts out more power, and has a > good receiver > >built in. > > > >I made some changes to mine, removing the receiver audio > output section > >that used the transmitter audio driver tube and transformer, > and installed > >a small IC chip that does 6 watts of hi fi audio. > >Lots of feedback around the modulator cleaned things up nicely, > >low frequencies do not pass the driver and mod transformer well, > >the driver transformer could likely be improved, but there is no room > >for a bigger mod transformer if you want it inside the nice slide > >off case. > >I might look into something like a pair of AB1 tubes as modulators > >instead of the triode connected 6DQ6 tubes. > >Crazy setup, triode connected, the suppressor grid gets the audio > >signal input I think! > > > >They are easy and fun to work on, two screws and the case slides off. > >It weighs about 10 pounds, easy to toss about. > > > >Did I mention its FUN to operate, and quite attractive with > its backlit > >tuning dial and meter? > > > >Takes a D104, an antenna, and away you go. > >Anything will work as an antenna, even a wet noodle, nothing > >seems to bother the rig. > >Its got a low power mode (10 watts) and a high power mode, > >depending on how much you load it, 70 to 90 watts out. > > > >If I could only have one very small radio, the G76 would be it. > > > >Brett > >N2DTS > > > > > > > > > >>-----Original Message----- > >>From: [EMAIL PROTECTED] > >>[mailto:[EMAIL PROTECTED] Behalf Of Jim Isbell > >>Sent: Thursday, December 11, 2003 10:02 AM > >>To: [email protected] > >>Subject: Re: [AMRadio] AM from a HW-101 > >> > >> > >>Brett Gazdzinski wrote: > >> > >> > >> > >>>Why would you want to do that? > >>> > >>> > >>> > >>> > >>Well, to answer your question,....because there is not more > >>room on my > >>desk for ANOTHER piece of equipment. I already have a 32S-1, 75S-1, > >>Station Console, and Power supply for the full S-Line, a > >>4-1000A Linear > >>amp, a computer and now the HW-101, . There is no more room. > >> If I want > >>AM it has to be from the 32S-1 (wonder why the 75S-1 has AM > >>but the TX > >>doesn't??) or from the HW-101. But then I could plate modulate the > >>4-1000A with a pair of 833As in push pull...but I think that would > >>really take up some room, and the winters are not cold enough > >>for that > >>down here on the Third Coast. > >> > >>I have a Viking Ranger, but no room on the desk for it. > >> > >> > >> > >>_______________________________________________ > >>AMRadio mailing list > >>[email protected] > >>http://mailman.qth.net/mailman/listinfo/amradio > >> > >> > > > >_______________________________________________ > >AMRadio mailing list > >[email protected] > >http://mailman.qth.net/mailman/listinfo/amradio > > > > > > > > > _______________________________________________ > AMRadio mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/amradio
