Yes I can confirm it! I got it abt 15 yaers ago and used and had a great succes in QRP/SSB. I still have it, but now I use just CW and don't use the clipper now. Look for this type and you'll have very good results.
Best 72 Alex I0SKK -----Messaggio originale----- Da: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] conto di Stewart Baker Inviato: venerdì 4 marzo 2005 10.10 A: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Oggetto: Re: [Elecraft] XTAL AND DSP simply is the best design A British company called Datong brought out an RF clipper a few years back. It used active filters to tailor the mic audio then CMOS switches to produce a DSB signal at 50kHz, diode clip it, and demod it back to audio. They made 3 products - an upmarket one with switches to select the clip level, one with pots on the front panel, and a board to fit in any suitable box or TX. It worked like a champ. They are still available on the second user market. I believe that a company in Germany now does an updated version. RF speech clipping is the most effective simple audio processing as it does not produce in-filter distortion products, unlike clipping at audio base band. 73 Stewart G3RXQ On Fri, 04 Mar 2005 03:33:31 -0500, Larry Phipps wrote: > I remember I had one of the first of those external rf clipper > > processors about 20 years ago... it was called Com-something. They used > an "if" of about 50 kHz, with LC filters... it worked amazingly well and > was sought after by DXers and contesters. > > Larry N8LP > > > [EMAIL PROTECTED] wrote: > >> You look at the TS-870, 746pro, and many other DSP rigs all make the same >> stupid design flaw. >> >> Dual conversion DSP! No multiple pole xtal filter. >> No computer algorythm can emulate a multipe pole IF filter. These are your >> $2000-$3000 rigs >> >> The TS-850 had dual xtal IFs. However there was much junk from all the >> CPU's and yes up conversion, then downconversion and demod after the 2nd IF >> filter adds to the noise floor. >> >> How the R-7A did it was interesting. A 4 pole Fixed Xtal filter followed >> the upconverter. >> It has a pass band of 12kcs. That's right a 12Khz wide IF. This gives this >> collectors radio >> its used price tag of $2000. The 2nd IF used those 8 pole can filters. >> >> I found the K-2 has crystal clear SSB with the 1.8khz filter position. The >> R-7A the SSB gets muffled at 1.8khz. I use 1.8 khz only on the K2. The TR-7 >> used a 2 pole filter after up conversion. >> >> If you look at the schematic of the TS-850, you see the dual IFs are in >> the back of the receiver. So after upconversion the passband is 50kc wide. >> That >> is a large window for synth junk to get in. HOWEVER IF YOU USE CW filters >> in >> both IFs, your CW reception will be as good as a K2 >> >> The K2 wisely put much non xtal filtering right after the antenna jack. >> The band pass filters are wide enough for the Ham bands and very little >> general >> coverage. You lose general coverage ability of an R-7A. However do you >> really need a short wave rcvr in a ham rig? >> >> So yes one can compare the K2 with up to $3000 dollar rigs. >> However on SSB TX the K2 comes up average. It is average because the SSB >> adapter is a simple design. The all important audio chain is mostly in 2 >> chips. >> However I always get good audio reports. A RF proc of the TS-850's design >> would make the K2 rock. >> >> There is a cheap way of doing this. There are a few speech procs that go >> between the mic and rig. They are true RF procs. Your audio is up >> converted to >> 500kc. The 500Kc RF is processed by using an AGC like amp. At the RFstage >> more compression can be used with out AUDIO DISTORTION. Any RF clipping by >> products are filtered out. The DSB signal is then down converted back to >> audio >> with the exact same phase it entered the device. >> >> So one is feeding in audio that was RF processed. One can use up to 12db >> of RF processing. Audio processing gets distorted after 6db. One company >> makes >> this device for $60. It can be put in the mic or in the rig. >> I am ordering one. I will give on air checks for those that want too. >> _______________________________________________ >> Elecraft mailing list >> Post to: Elecraft@mailman.qth.net >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> >> > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- No virus found in this incoming message. Checked by AVG Anti-Virus. 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