When S-Meters are Useful (WAS: When do you use fast AGC?)
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When S-Meters are Useful (WAS: When do you use fast AGC?)
 
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Hash: SHA1 I also looked for a solution to the S meter calibration problem. I discussed the problem with Greg Ordy w8wwv Author of the great program called S meter light. Unfortunately the K2 does not return 8 data bits via the serial port so the calibration accuracy would be close to useless. If the K2 did return 8 data bits you could obtain 0.1 db accuracy using Gregs program. 8 data bits returned via the data port is available on the 756PRO and several other radios. Elecraft cloned the Kenwood command set which returns 4 or 5 bits or something like that. Maybe Elecraft would consider this as a future external option for the K2 . It certainly would be a first for a ham radio, that is having a inbuilt calibrated S meter. The crunched up S meter bargraph is highly annoying and close to useless on the k2. Craig VK3HE -----BEGIN PGP SIGNATURE----- Note: This signature can be verified at https://www.hushtools.com/verify Version: Hush 2.5 wpwEAQECAAYFAkU0nagACgkQFO3Fz3YpTj13zwQAglTPukBl74ltyvgFugyGzdWSorR1 cS6JbAj4LN7RgzF/A1teW2plQNddqiYYjd20Qbd6vRgU6CQpuj3F9Y7k78hbNF4jk4YQ lv27yGd6QsTmCndTSyN4rwhona3eORFaFhJxV+0w8udI9Ci/I5A2HwXU1BIi611sMNTk CMNBQx4= =6fqa -----END PGP SIGNATURE----- Concerned about your privacy? Instantly send FREE secure email, no account required http://www.hushmail.com/send?l=480 Get the best prices on SSL certificates from Hushmail https://www.hushssl.com?l=485 _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fast AGC?)
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One possibility for an "add in" S-meter module would be an AD8307 log
amp module paralleling the IF amplifier's input. This will give you an honest 80 to 90 dB linear output (db in, linear output), if you can manage the shielding, and close to 100 dB if you don't mind a bit of non-linearity at the extremes. To avoid loading down the IF amp input, you probably need a isolation amplifier. And, of course, there's always a concern when mucking about inside the signal chain. The buffer amplifier I offer with my Z90 digital panadapter samples the K2's IF at an earlier point, just after the 2N5109 post-mixer amplifier, but the design could easily be used to sample after the filters. (The Z90 uses an AD8307 log amp detector, so I have some experience with it.) The log amp's output could then drive an external moving coil meter, or it could be digitized via an ADC and brought out on a RS-232 compatible port for other purposes. Serial output would require an on-board PIC and would have to carefully constructed to avoid introducing unwanted noise into the K2, but an all-analog solution would be simple enough if the output device is to be a D'Arsonval meter movement. If there's a groundswell of demand for such a beast I will consider it as a future kit offering. Jack K8ZOA www.cliftonlaboratories.com [hidden email] wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I also looked for a solution to the S meter calibration problem. I > discussed the problem with Greg Ordy w8wwv Author of the great > program called S meter light. Unfortunately the K2 does not return > 8 data bits via the serial port so the calibration accuracy would > be close to useless. If the K2 did return 8 data bits you could > obtain 0.1 db accuracy using Gregs program. 8 data bits returned > via the data port is available on the 756PRO and several other > radios. Elecraft cloned the Kenwood command set which returns 4 or > 5 bits or something like that. > > Maybe Elecraft would consider this as a future external option for > the K2 . It certainly would be a first for a ham radio, that is > having a inbuilt calibrated S meter. The crunched up S meter > bargraph is highly annoying and close to useless on the k2. > > Craig > VK3HE > -----BEGIN PGP SIGNATURE----- > Note: This signature can be verified at https://www.hushtools.com/verify > Version: Hush 2.5 > > wpwEAQECAAYFAkU0nagACgkQFO3Fz3YpTj13zwQAglTPukBl74ltyvgFugyGzdWSorR1 > cS6JbAj4LN7RgzF/A1teW2plQNddqiYYjd20Qbd6vRgU6CQpuj3F9Y7k78hbNF4jk4YQ > lv27yGd6QsTmCndTSyN4rwhona3eORFaFhJxV+0w8udI9Ci/I5A2HwXU1BIi611sMNTk > CMNBQx4= > =6fqa > -----END PGP SIGNATURE----- > > > > > Concerned about your privacy? Instantly send FREE secure email, no account required > http://www.hushmail.com/send?l=480 > > Get the best prices on SSL certificates from Hushmail > https://www.hushssl.com?l=485 > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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I rarely look at my S-Meter. Either I can hear them, or not.
Since most signal reports have nothing in common with reality, it Just doesn't matter. Mike AI4NS _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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If all S meters could be referred to uV/m on an isotropic dipole there might be some meaning to the readings. It's nice for relative measurements when someone else is tuning and pruning.
David G3UNA > > From: "Mike Short" <[hidden email]> > Date: 2006/10/17 Tue PM 12:30:10 BST > To: <[hidden email]> > Subject: [Elecraft] When S-Meters are Useful > > I rarely look at my S-Meter. Either I can hear them, or not. > Since most signal reports have nothing in common with reality, it > Just doesn't matter. > > Mike > AI4NS > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 > ----------------------------------------- Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: When S-Meters are Useful (WAS: When do you use fastAGC?)
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In reply to this post by Jack Smith-6
Boy Jack, if there was some small kit that could sample a signal in the
K2 and send something out the back that could drive the LDG S-meter that would be great. It would be even greater if it could just plug into the K2 using one of the option slots. - Keith KD1E - - K2 5411 - -----Original Message----- From: Jack Smith One possibility for an "add in" S-meter module ... If there's a groundswell of demand for such a beast I will consider it as a future kit offering. _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fast AGC?)
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In reply to this post by charliedelta
> Maybe Elecraft would consider this as a future external option for > the K2 . It certainly would be a first for a ham radio, that is > having a inbuilt calibrated S meter. The crunched up S meter > bargraph is highly annoying and close to useless on the k2. > > Craig > VK3HE ================================================== Last year, I posted my intent to recalibrate my K2 S meter to give one bar per S unit. I used my XG-1 50 microvolt output to set the S meter reading to light 9 bars, with the preamp off. Of course, I can't use the calibration scale for signal strength, but I can use the power out scale, up to S9, to ret a reading. I like this method of using the S meter. I don't mind losing the db over 9 readings. Some meters use up to half of the scale on this with S9 being near the middle. I think that is a waste. Not sure what this does to linearity, but it seems to cover the range nicely. As for not having an S meter with the AGC turned off, I have found that setting the AF gain to a given position, like mid scale, and using the RF gain to control AF output, the position of the RF gain control gives me a good enough idea of signal strength to give a meaningfull report to the other operator. I use this method with simple rigs, like my Sierra or Oak Hills 100 A. I have been considering changing the AF gain on my K1 to an RF gain control, with a set and forget internal adjustment for the AF gain. This works well on my Nor Cal 40A. The main reason for changing the receiver gain is to compensate for changing signal strength and I think this is best done as early as possible in the receive chain. Operating without an AGC gives a whole new dimension to the receiver, like depth of field in photography. Sometimes this is desireable, sometimes not. Rick Dettinger K7MW _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: When S-Meters are Useful (WAS: When do you use fastAGC?)
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Hmm, using the full bar graph to show S1 to S9? Not a bad idea. I may
do that once I get the 41 step attenuator. All this AGC talk makes me think TenTec's hang AGC should have been the ideal. In effect it would turn the RF Gain down when a big signal came in and keep it down until the signal went away, then would turn it back up rather quickly. But for some reason it just never caught on. Maybe because it was implemented in rigs with audio derived AGC? Last night I tried listening with Fast AGC on my 830s but didn't like the way the QRN came up between each CW element. But, if I left it on fast then backed the RF gain down, the whole rig sounded better. I just may begin using fast AGC and reduced RF gain for all my operating. - Keith KD1E - - K2 5411 - -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Rick Dettinger Sent: Tuesday, October 17, 2006 12:00 PM To: [hidden email] Subject: Re: [Elecraft] When S-Meters are Useful (WAS: When do you use fastAGC?) Last year, I posted my intent to recalibrate my K2 S meter to give one bar per S unit. I used my XG-1 50 microvolt output to set the S meter reading to light 9 bars, with the preamp off. Of course, I can't use the calibration scale for signal strength, but I can use the power out scale, up to S9, to ret a reading. I like this method of using the S meter. I don't mind losing the db over 9 readings. Some meters use up to half of the scale on this with S9 being near the middle. I think that is a waste. Not sure what this does to linearity, but it seems to cover the range nicely. _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: When S-Meters are Useful (WAS: When do you usefastAGC?)
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Keith wrote:
All this AGC talk makes me think TenTec's hang AGC should have been the ideal. In effect it would turn the RF Gain down when a big signal came in and keep it down until the signal went away, then would turn it back up rather quickly. But for some reason it just never caught on. Maybe because it was implemented in rigs with audio derived AGC? --------------------------- Right on, Keith! Hang AGC filled a specific need. It goes way back - to the 50's at least. Its intent is to avoid turning the gain up immediately when the signal disappears. It keeps the gain turned down for a specific period of time. That's the "hang" time. At the end of that period it is then turned up very quickly. On most hang AGC systems, the "hang" time is adjustable from a few mS to several seconds. It solved a tough problem in early SSB/CW AGC systems: slow attack time. A big problem trying to create an AGC for a SSB or CW receiver was the BFO signal in the I.F. bandpass. The AGC detector would sense that huge BFO signal and turn down the gain accordingly, making the receiver deaf! So early SSB/CW receivers (and the more simple receivers today, including some of the Elecraft line) used audio-derived AGC instead of I.F. derived AGC. That is, instead of rectifying some of the I.F. signal to produce a d-c AGC voltage that corresponded to the strength of the signal, it rectified some of the resulting audio signal to produce the AGC signal. That eliminated the problem of the BFO getting into the AGC system, but it made the attack time slow. That's because, when a signal appears, the detector has to rectify several cycles to produce the AGC voltage. At R.F. that signal may be hundreds of kilohertz or even higher while the audio frequency is typically near 600 Hz. With audio-derived AGC it takes much, much longer to produce the d-c voltage from the AGC rectifier. For example, it would take an AGC detector working at 600 Hz about 200 times longer to produce the d-c voltage required than it does when the detector is using an I.F signal at, say 100 or 200 KHz. That delay to rectify the signal often resulted in a "pop" in the audio every time the signal appeared as it slammed through at full volume for an instant before the AGC voltage built up to turn the gain down. The first solution was to slow down the AGC action so that it only very gradually returned the gain after a strong signal went away. That way, there was less of a "pop" if it returned soon, but it meant that the receiver remained deaf to weaker signals longer. Hang AGC provided a better response by leaving the receiver desensitized for a specific period of time to prevent another "pop" if the station was still transmitting CW or SSB, but then quickly resumed full volume after the hang period elapsed. Hang systems started to disappear as ways were devised to use the I.F. signal for creating the AGC. This is most commonly done by using another mixer and producing a new I.F. just for the AGC far removed from the BFO frequency. The K2, for example, uses an AGC I.F. at about 200 kHz for this purpose. That takes more circuit complexity but the fast attack time allowed truly quick AGC without the "pops" or the delay of a hang time. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: When S-Meters are Useful
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In reply to this post by Rick Dettinger-2
Rick K7MW wrote:
As for not having an S meter with the AGC turned off, I have found that setting the AF gain to a given position, like mid scale, and using the RF gain to control AF output, the position of the RF gain control gives me a good enough idea of signal strength to give a meaningfull report to the other operator. I use this method with simple rigs, like my Sierra or Oak Hills 100 A. ------------------------------------ At least one receiver from the late 1920's/early 1930's featured an AF gain control calibrated in "S" units. I believe it was a popular regenerative receiver made by the National company. You adjusted the gain level for a comfortable volume, then read the S value for signal strength from the position of the volume control knob on a scale that ran from 1 to 9. Of course the scale was backwards so if the gain had to be run full up at maximum volume the pointer was on S-1 indicating a very weak signal. Back when us Hams were struggling to get a decent signal on the air, it made great sense to have the RST system that included "Tone". The "T" report was very useful because many signals were basically modulated CW, with lots and lots of hum from the power supplies. Some rigs actually ran AC on the plates of the tubes, making their signal an extremely broad band of keyed hum compared to a clean d-c note. Others had varying degrees of hum, hence the value of the T report. We don't do that any more. As a result, I much prefer the signal reporting used on commercial circuits: QSA. It means, literally, "What is the strength of my signals?" or "What is the strength of ..... Signals?" if asking about someone else. The report is given in a scale of 1 to 5 as follows: The strength of your signals (or those of ...) is ... 1. scarcely perceptible 2. weak 3. fairly good 4. good 5. very good. So, instead of sending RST 599 a commercial station would send QSA5. That makes a lot more sense to me than using RST, especially since "T" is always 9 unless something is drastically wrong. I notice that some ops are trying to adapt the T report to signify something relating to the keying characteristic. All that does is cause confusion. The T report speaks only to the purity of the note while the key is closed. If there are some additional comments needed, such as to report key clicks or chirp, they can be done with a following letter or in plain language just as is normally done with the RST reports. For example, how about QSD? It means, literally, "Your Keying is Mutilated." I might hear that more often than I'd like... Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fastAGC?)
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In reply to this post by Darwin, Keith
Ron, AC7AC wrote:
> That's the difference between one who tinkers and an engineer <G>. > ------------------------------------------------------------------- I had never thought that there was any difference. 'Develop' is a posh word for 'Tinker' is it not? <g> An AGC controlled IF which provides drive for a S meter that can be calibrated in signal microvolts or dbm was developed by Bill Carver W7AAZ and described in QST May 1996. Using a pair of AD600 dual op-amps, something like it could be useful in the K3 or to homebrewers. Gain is controlled by attenuators inside the op-amp ICs not by changing bias, and based on almost ten years of using the design I can highly recommend it. 73, Geoff GM4ESD _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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> Ron, AC7AC wrote: > > > That's the difference between one who tinkers and an engineer <G>. > > > ------------------------------------------------------------------- Have never heard an answer to that one, but it is said that the difference between an amateur (not necessarily 'ham') and a professional is that the professional knows how to cover up his mistakes! <G>. 73, Don W3FPR _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fastAGC?)
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In reply to this post by Darwin, Keith
Darwin, Keith wrote:
> Hmm, using the full bar graph to show S1 to S9? Not a bad idea. I may > do that once I get the 41 step attenuator. > > All this AGC talk makes me think TenTec's hang AGC should have been the > ideal. In effect it would turn the RF Gain down when a big signal came > in and keep it down until the signal went away, then would turn it back > up rather quickly. Keith I think the problem with hang AGC is in contests. The winning setup there is one where you attenuate the strong station and still hear the weak guy nearby. This you can do with no AGC and a deft hand on the RF gain. If your filter is the right type then you can hear the weak ones. > But for some reason it just never caught on. Maybe > because it was implemented in rigs with audio derived AGC? > > Last night I tried listening with Fast AGC on my 830s but didn't like > the way the QRN came up between each CW element. But, if I left it on > fast then backed the RF gain down, the whole rig sounded better. To make it sound perfect try no AGC and turn up the audio to Max and ride the RF gain. > I just > may begin using fast AGC and reduced RF gain for all my operating. > > - Keith KD1E - > - K2 5411 - > > 72 73 Karl K5DI > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Rick Dettinger > Sent: Tuesday, October 17, 2006 12:00 PM > To: [hidden email] > Subject: Re: [Elecraft] When S-Meters are Useful (WAS: When do you use > fastAGC?) > > > > Last year, I posted my intent to recalibrate my K2 S meter to give one > bar per S unit. I used my XG-1 50 microvolt output to set the S meter > reading to light 9 bars, with the preamp off. Of course, I can't use > the calibration scale for signal strength, but I can use the power out > scale, up to S9, to ret a reading. I like this method of using the S > meter. I don't mind losing the db over 9 readings. Some meters use up > to half of the scale on this with S9 being near the middle. I think > that is a waste. Not sure what this does to linearity, but it seems to > cover the range nicely. > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
RE: Tinkerers and Engineers!
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In reply to this post by Don Wilhelm-3
At 02:33 PM 10/17/2006, Don Wilhelm wrote:
> > Ron, AC7AC wrote: > > > > > That's the difference between one who tinkers and an engineer <G>. > > > > > ------------------------------------------------------------------- > >Have never heard an answer to that one, but it is said that the difference >between an amateur (not necessarily 'ham') and a professional is that the >professional knows how to cover up his mistakes! <G>. > >73, >Don W3FPR Don: I did hear one amusing observation on this point: The Ark was built by amateurs and the Titanic was built by professionals. 73, Steve AA4AK >_______________________________________________ >Elecraft mailing list >Post to: [hidden email] >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: [hidden email] 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 |
Limiting Instead of AGC...(WAS: When S-Meters are Useful)
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In reply to this post by Karl Larsen
Karl, K5DI, wrote:
The winning setup there is one where you attenuate the strong station and still hear the weak guy nearby. This you can do with no AGC and a deft hand on the RF gain. If your filter is the right type then you can hear the weak ones. --------------------------------- I sure agree, and not just contests for me. My favorite setup has a hard limiter that simply clips off everything above a certain signal level. I set it to clip anything above the audio level I'm comfortable with. That way, if a very strong signal appears while I'm listening to a weak signal without using AGC it won't blow my phones off and I can hear a weak one in between dits and dahs just fine. My ears recover from reasonable sound levels faster than the fastest AGC. Sure, the audio from strong signals that are clipped is a harsh tone but I don't mind the sound and can copy it FB, at least long enough to react with the gain control - if I'm so inclined. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you usefastAGC?)
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In reply to this post by Geoffrey Mackenzie-Kennedy-2
Geoffrey Mackenzie-Kennedy wrote:
> Ron, AC7AC wrote: > >> That's the difference between one who tinkers and an engineer <G>. >> > ------------------------------------------------------------------- > > I had never thought that there was any difference. 'Develop' is a > posh word for 'Tinker' is it not? <g> Depends on what kind of an engineer you are. :-) I've always been the tinkering kind, myself, but mostly because I'm not smart enough to be the other kind... I worked for a guy way back in the 1970s (pre-PC days) who would sit down at a nice clean desk with his HP calculator and an engineering pad and pencil, and design a complex analog discrete-transistor circuit without once using the eraser. Then he would write out the voltage, current, frequency response, and gain figures for the circuit on a second piece of paper. These he would hand to me to build and test. Always came out dead nuts. Amazing. But a tinkerer? Man, you did NOT want to let this guy get anywhere near a soldering iron! Extreme danger to self and others!! Bill W5WVO > > An AGC controlled IF which provides drive for a S meter that can be > calibrated in signal microvolts or dbm was developed by Bill Carver > W7AAZ and described in QST May 1996. Using a pair of AD600 dual > op-amps, something like it could be useful in the K3 or to > homebrewers. Gain is controlled by attenuators inside the op-amp ICs > not by changing bias, and based on almost ten years of using the > design I can highly recommend it. > > 73, > Geoff > GM4ESD > > > > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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In reply to this post by Don Wilhelm-3
In a message dated 10/17/06 3:00:09 PM Eastern Daylight Time,
[hidden email] writes: > The Ark was built by amateurs and the Titanic was built by professionals. > Don't blame the builders for mistakes made by the operators. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
RE: When S-Meters are Useful (WAS: When do you usefastAGC?)
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In reply to this post by Bill VanAlstyne W5WVO
Depends on what kind of an engineer you are. :-) I've always been the
tinkering kind, myself, but mostly because I'm not smart enough to be the other kind... I worked for a guy way back in the 1970s (pre-PC days) who would sit down at a nice clean desk with his HP calculator and an engineering pad and pencil, and design a complex analog discrete-transistor circuit without once using the eraser. Then he would write out the voltage, current, frequency response, and gain figures for the circuit on a second piece of paper. These he would hand to me to build and test. Always came out dead nuts. Amazing. But a tinkerer? Man, you did NOT want to let this guy get anywhere near a soldering iron! Extreme danger to self and others!! Bill W5WVO ----------------------------------------- I'm reminded that Guglielmo Marconi called himself the "first Radio Amateur". He never said that he invented wireless, any of the basic principles that define wireless, or even most of the gadgets he used to build his wireless sets. What he did do was tinker with the stuff others had created and put them together into a system that worked. Then he continued tinkering with that system to make it work better. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: Tinkerers and Engineers!
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In reply to this post by N2EY
Jim: Good point. The Ark was operated by amateurs and the Titanic was operated by professionals. Steve AA4AK At 07:15 PM 10/17/2006, [hidden email] wrote: In a message dated 10/17/06 3:00:09 PM Eastern Daylight Time, [hidden email] writes: The Ark was built by amateurs and the Titanic was built by professionals. Don't blame the builders for mistakes made by the operators. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fast AGC?)
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In reply to this post by charliedelta
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 I would be the first to order a unit Jack Theres some excellent plotting software just waiting for a S meter interface as you describe. http://www.g4hfq.co.uk/plphelp/plphelp.htm Theres little alternative available for those seeking a accurate S meter on a ham radio transceiver. Besides i see no harm as hams being professional in our approach to signal measurements. After all who would buy any test instrument today if it had a 200% error in accuracy, but thats what we have today in every radio receiver and transceiver. Craig VK3HE On Tue, 17 Oct 2006 02:30:47 -0700 Jack Smith <[hidden email]> wrote: >One possibility for an "add in" S-meter module would be an AD8307 >log >amp module paralleling the IF amplifier's input. This will give >you an >honest 80 to 90 dB linear output (db in, linear output), if you >can >manage the shielding, and close to 100 dB if you don't mind a bit >of >non-linearity at the extremes. To avoid loading down the IF amp >input, >you probably need a isolation amplifier. > >And, of course, there's always a concern when mucking about inside >the >signal chain. The buffer amplifier I offer with my Z90 digital >panadapter samples the K2's IF at an earlier point, just after the > >2N5109 post-mixer amplifier, but the design could easily be used >to >sample after the filters. (The Z90 uses an AD8307 log amp >detector, so I >have some experience with it.) > >The log amp's output could then drive an external moving coil >meter, or >it could be digitized via an ADC and brought out on a RS-232 >compatible >port for other purposes. Serial output would require an on-board >PIC and >would have to carefully constructed to avoid introducing unwanted >noise >into the K2, but an all-analog solution would be simple enough if >the >output device is to be a D'Arsonval meter movement. > >If there's a groundswell of demand for such a beast I will >consider it >as a future kit offering. > > >Jack K8ZOA >www.cliftonlaboratories.com > > > >[hidden email] wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> I also looked for a solution to the S meter calibration problem. >I >> discussed the problem with Greg Ordy w8wwv Author of the great >> program called S meter light. Unfortunately the K2 does not >return >> 8 data bits via the serial port so the calibration accuracy >would >> be close to useless. If the K2 did return 8 data bits you could >> obtain 0.1 db accuracy using Gregs program. 8 data bits >returned >> via the data port is available on the 756PRO and several other >> radios. Elecraft cloned the Kenwood command set which returns 4 >or >> 5 bits or something like that. >> >> Maybe Elecraft would consider this as a future external option >for >> the K2 . It certainly would be a first for a ham radio, that is >> having a inbuilt calibrated S meter. The crunched up S meter >> bargraph is highly annoying and close to useless on the k2. >> >> Craig >> VK3HE >> -----BEGIN PGP SIGNATURE----- >> Note: This signature can be verified at >https://www.hushtools.com/verify >> Version: Hush 2.5 >> >> >wpwEAQECAAYFAkU0nagACgkQFO3Fz3YpTj13zwQAglTPukBl74ltyvgFugyGzdWSorR >1 >> >cS6JbAj4LN7RgzF/A1teW2plQNddqiYYjd20Qbd6vRgU6CQpuj3F9Y7k78hbNF4jk4Y >Q >> >lv27yGd6QsTmCndTSyN4rwhona3eORFaFhJxV+0w8udI9Ci/I5A2HwXU1BIi611sMNT >k >> CMNBQx4= >> =6fqa >> -----END PGP SIGNATURE----- >> >> >> >> >> Concerned about your privacy? Instantly send FREE secure email, >no account required >> http://www.hushmail.com/send?l=480 >> >> Get the best prices on SSL certificates from Hushmail >> https://www.hushssl.com?l=485 >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> 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 >> >> >> Note: This signature can be verified at https://www.hushtools.com/verify Version: Hush 2.5 wpwEAQECAAYFAkU16CMACgkQFO3Fz3YpTj2/oAQAgXL632lZQzAXBJ+eSNntKH/Xce53 DQuR+u5Qir85qmP18l6fwK7NznpXh1lo9UpuF0UBCfxfXKPjKzXg+YkE17GZI1e+16Pb cPBBNaXiP/vTq6ctkF3+jdLRbgoWtnDY2LCoaQYlojEZsMI1ee4jbhAKE6AtipkLaoUT 2n9war0= =NSwj -----END PGP SIGNATURE----- Concerned about your privacy? Instantly send FREE secure email, no account required http://www.hushmail.com/send?l=480 Get the best prices on SSL certificates from Hushmail https://www.hushssl.com?l=485 _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: When S-Meters are Useful (WAS: When do you use fast AGC?)
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I will think about that as a potential kit. If ADC is essential, it
would make the most sense to take an analog IF sample out of the receiver after the selectivity and have an outboard log amp and ADC converter. My Z10000 buffer amplifier should work as an IF sample isolation amplifier without much change, or an even simpler circuit, such as an FET follower would be possible since there is no need to make it a wide-range universal product as with the Z10000 buffer amplifier. The log amp, ADC and serial output is dead easy. It should have some input bandpass filtering, however, to keep down the broadband noise. If you are looking for a visual indication of level, my Z90/91 digital panadapter provides 60 dB or so of on-screen (and on the data port) dynamic range and an additional 30 dB of selectable attenuation. The overall accuracy is within +/- 2 dB and most do better. There is no provision for absolute calibration as it makes little sense to do this considering the variable gain in the K2 ahead of the broadband sample, so the readings are all relative. The Z90 Control software that I've written includes a provision to log the data to a text file, with values in dB, again arbitrary reference, so a fixed calibration would be required should one be interested in specific absolute dBm values. I have some AD8307 linearity data posted on my web site. It's at Page 29 inside the interim instruction manual that can be found at http://www.cliftonlaboratories.com/Documents/Quick%20Operating%20Instructions.pdf. The full range of 80 dB or so will not be achievable if there are strong nearby signals due to filter skirt issues; hence the 60 dB or so usable range quoted earlier. The Z90/91's serial output protocol is open, so anyone that wants to write their own program is welcome to do so. Jack www.cliftonlaboratories.com [hidden email] wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I would be the first to order a unit Jack > > Theres some excellent plotting software just waiting for a S meter > interface as you describe. > > http://www.g4hfq.co.uk/plphelp/plphelp.htm > > Theres little alternative available for those seeking a accurate S > meter on a ham radio transceiver. Besides i see no harm as hams > being professional in our approach to signal measurements. After > all who would buy any test instrument today if it had a 200% error > in accuracy, but thats what we have today in every radio receiver > and transceiver. > > Craig > VK3HE > > > On Tue, 17 Oct 2006 02:30:47 -0700 Jack Smith > <[hidden email]> wrote: > >> One possibility for an "add in" S-meter module would be an AD8307 >> log >> amp module paralleling the IF amplifier's input. This will give >> you an >> honest 80 to 90 dB linear output (db in, linear output), if you >> can >> manage the shielding, and close to 100 dB if you don't mind a bit >> of >> non-linearity at the extremes. To avoid loading down the IF amp >> input, >> you probably need a isolation amplifier. >> >> And, of course, there's always a concern when mucking about inside >> the >> signal chain. The buffer amplifier I offer with my Z90 digital >> panadapter samples the K2's IF at an earlier point, just after the >> >> 2N5109 post-mixer amplifier, but the design could easily be used >> to >> sample after the filters. (The Z90 uses an AD8307 log amp >> detector, so I >> have some experience with it.) >> >> The log amp's output could then drive an external moving coil >> meter, or >> it could be digitized via an ADC and brought out on a RS-232 >> compatible >> port for other purposes. Serial output would require an on-board >> PIC and >> would have to carefully constructed to avoid introducing unwanted >> noise >> into the K2, but an all-analog solution would be simple enough if >> the >> output device is to be a D'Arsonval meter movement. >> >> If there's a groundswell of demand for such a beast I will >> consider it >> as a future kit offering. >> >> >> Jack K8ZOA >> www.cliftonlaboratories.com >> >> >> >> [hidden email] wrote: >> >>> -----BEGIN PGP SIGNED MESSAGE----- >>> Hash: SHA1 >>> >>> I also looked for a solution to the S meter calibration problem. >>> >> I >> >>> discussed the problem with Greg Ordy w8wwv Author of the great >>> program called S meter light. Unfortunately the K2 does not >>> >> return >> >>> 8 data bits via the serial port so the calibration accuracy >>> >> would >> >>> be close to useless. If the K2 did return 8 data bits you could >>> obtain 0.1 db accuracy using Gregs program. 8 data bits >>> >> returned >> >>> via the data port is available on the 756PRO and several other >>> radios. Elecraft cloned the Kenwood command set which returns 4 >>> >> or >> >>> 5 bits or something like that. >>> >>> Maybe Elecraft would consider this as a future external option >>> >> for >> >>> the K2 . It certainly would be a first for a ham radio, that is >>> having a inbuilt calibrated S meter. The crunched up S meter >>> bargraph is highly annoying and close to useless on the k2. >>> >>> Craig >>> VK3HE >>> -----BEGIN PGP SIGNATURE----- >>> Note: This signature can be verified at >>> >> https://www.hushtools.com/verify >> >>> Version: Hush 2.5 >>> >>> >>> >> wpwEAQECAAYFAkU0nagACgkQFO3Fz3YpTj13zwQAglTPukBl74ltyvgFugyGzdWSorR >> 1 >> >> cS6JbAj4LN7RgzF/A1teW2plQNddqiYYjd20Qbd6vRgU6CQpuj3F9Y7k78hbNF4jk4Y >> Q >> >> lv27yGd6QsTmCndTSyN4rwhona3eORFaFhJxV+0w8udI9Ci/I5A2HwXU1BIi611sMNT >> k >> >>> CMNBQx4= >>> =6fqa >>> -----END PGP SIGNATURE----- >>> >>> >>> >>> >>> Concerned about your privacy? Instantly send FREE secure email, >>> >> no account required >> >>> http://www.hushmail.com/send?l=480 >>> >>> Get the best prices on SSL certificates from Hushmail >>> https://www.hushssl.com?l=485 >>> >>> _______________________________________________ >>> Elecraft mailing list >>> Post to: [hidden email] >>> 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 >>> >>> >>> >>> > -----BEGIN PGP SIGNATURE----- > Note: This signature can be verified at https://www.hushtools.com/verify > Version: Hush 2.5 > > wpwEAQECAAYFAkU16CMACgkQFO3Fz3YpTj2/oAQAgXL632lZQzAXBJ+eSNntKH/Xce53 > DQuR+u5Qir85qmP18l6fwK7NznpXh1lo9UpuF0UBCfxfXKPjKzXg+YkE17GZI1e+16Pb > cPBBNaXiP/vTq6ctkF3+jdLRbgoWtnDY2LCoaQYlojEZsMI1ee4jbhAKE6AtipkLaoUT > 2n9war0= > =NSwj > -----END PGP SIGNATURE----- > > > > > Concerned about your privacy? Instantly send FREE secure email, no account required > http://www.hushmail.com/send?l=480 > > Get the best prices on SSL certificates from Hushmail > https://www.hushssl.com?l=485 > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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