Rick, I was reading from a Hallicrafters SX-100 receiver manual, Collins KWM-2A and Collins S-360 something or other S-Line 500 KHz-30 MHz receiver service manuals. Written well before you were born. Hi Hi.
Walt/K5YFW -----Original Message----- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Sent: Wednesday, October 04, 2006 9:26 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Rig S-meter comparison Walt, I never knew this strong a signal was equated to S9. Having recently done some Rig S-meter comparisons, with rigs set to the 50 microvolt standard, a 100,000 uV signal would be just a bit over S9+60 on my Kenwood TS-440SAT. My Ten Tec Argonaut V only goes to S9 +40 db at 10,000 uV and my ICOM 756 Pro 2 tops out at 5000 uV for S9 + 60 db. Therefore, a 100,000 uV signal is extremely strong at around -7 dbm. Incidentally, the tracking of the microvolt levels at the various S unit points, is not linear and is not necessarily 5 or 6 db per S unit even though this is often repeated in the amateur press. There can be fairly wide variations in the dbm levels (interpolated from the uV measurements) from S unit to S unit. For example, when reading the lower S units, the Pro 2 can change only one or two dbm and the TS-440SAT around 2 to 3 dbm per S unit. The Argo V tracks 5 to even as much as 10 dbm between S units. If you use the 50 uV standard of today at S9, it is interesting that using a voltage change of 20 times for a 10 db change, you would find that you would be at around 5 uV at roughly S5. My actual Argo V is 5.5 uV at S6. The expected S meter reading at around S2 would be .5 uV. The actual in my case is 0.10 uV at S2 which is -127 dbm. This appears to be the reason that the Argo V never reads much below S2, since the S meter is reading a level close to the MDS which is probably around -133 dbm. Meanwhile the Pro 2 reads 4.8 uV at S1 and the 440 reads 2 uV at S1. So quite a difference between rigs. The measuring equipment is an old SG-85A/URM-25D signal generator and maybe not all that well calibrated, but should give a relative indication. Having said that, the Argo V and the 440 were about as close as you can get at 50 uV at S9 from the reading on the generator's analog meter. 73, Rick, KV9U DuBose Walt Civ AETC CONS/LGCA wrote: >In bygone days, S-9 was to be produced by a 100,000 microvolt carrier at the >receiver's antenna terminal with the RF gain control at min (attenuation?) and >AGC on. > >Also, the S unit was to equal 5.5 dB. > >Rockwell-Colling and a few other manufacturers of amateur radio receivers in >the late 1970's had their receiver signal strength meters measured in dB or >microvolts. The 12 o'clock position was 100,000 microvolts...I have forgotten >what dB it was. > >Walt/K5YFW > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
