Re: [Elecraft] Attenuator and RF Gain Settings
> I wish I could set it higher than 008. I am also in a > relatively quiet location but on 20m with an AGC threshold of > 008 my atmospheric noise is normally above the AGC threshold. If one looks at Jack Smith's graphs, the K2 threshold (between -80 and -90 dBm) would be about 11 or 12 for the K3 and the slope is about 5 or 6. Jack's measurements show that even at 8, the K3's AGC threshold (onset of AGC) is down around -100dBm. Sherwood shows the K3's AGC threshold at 2.1 uV vs. 10 uV (no preamp) for the K2 and .6uV vs. 1.7 uV with the preamp. I find it interesting that Sherwood's measurements of the FT-1000D (6 uV) and FT-1000MP MK V (3 uV) also show higher AGC thresholds with the preamplifier on. 73, ... Joe, W4TV > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of ab2tc > Sent: Tuesday, February 02, 2010 5:08 PM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] Attenuator and RF Gain Settings > > > > Hi, > > I wish I could set it higher than 008. I am also in a > relatively quiet location but on 20m with an AGC threshold of > 008 my atmospheric noise is normally above the AGC threshold. > So when I want comfortable listening I back off the RF gain > until the S-meter shows about S4 or so. Not a big problem, > but I would prefer that the AGC threshold could go higher. > Having it stored per-band, too, would be really, really nice > and it makes sense. > > Knut - AQB2TC > > > Don Wilhelm-4 wrote: > > > > I just thought of something that might help those confused > by the AGC > > Threshold setting. > > One other way to look at the required AGC Threshold level > is to think of > > it as an S-meter level > > If your noise is S-1 or lower (on the K3's S-meter), you > can set the > > Threshold to 002 or higher and all may be well > > OTOH, if you have an S-7 noise level indicated, the AGC > Threshold should > > be set to 008 or higher. > > > > > > -- > View this message in context: > http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505 p4504035.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
At 07:10 PM 2/2/2010 -0500, you wrote: >Brian, > >That is an illusion - yes the K3 gets more quiet (on noise) if the AGC >Threshold is reduced. >BUT what that indicates is that the AGC is being activated by the noise >and the K3 is reducing the gain due to AGC action. >The lowest AGC Threshold that is usable for any given level of >atmospheric noise is the threshold setting just higher than the setting >which begins to reduce the noise. In other words, listen to a spot on >the band where there are no signals, then start at the highest Threshold >setting of 008. >Reduce the value of the AGC Threshold until you sense that the noise >level starts to go down - then move the Threshold up to the next level. > >That setting will produce the most usable sensitivity for that band, >that antenna, and at that particular point in time (atmospheric noise >levels do change with time). If the resulting noise level is >bothersome, then take other steps to reduce that response - Preamp off, >ATT ON, and reduce the RF Gain (in that order) until you can just barely >hear the noise. That will result in the most sensitive setting for the >receiver. >Remember (as Jim Brown just posted) - that atmospheric noise is just >another 'signal' to the receiver that is to be amplified (it is coming >in on the antenna port). One must condition the receiver to place that >noise level at (or just above) your threshold of perception to reduce >your fatigue level when listening to any band. That is what the preamp, >attenuator, and RF Gain controls are for. Hi, I am not an Elecraft owner ... yet ... However I have built (homebrewed) many receivers over the years ... and building a good AGC system is one of the hardest parts (biggest challenge in modern parlance). One of the things I learned after many years is how to make the AGC sensitive to noise. Most of the receivers I built and commercial ones I have used basically relate the AGC level exclusively to received signal. However in designing the AGC detector time constants I found it very useful to have receiver gain controlled by noise level to some degree. As background noise goes up ... receiver gain goes down to a degree ... and as the background gets quieter gain should go up a little. I never did get it just right ... and the general front end attenuator and RF gain control always got used a lot hi hi. I find the topic very interesting and I find it very encouraging the effort put into AGC design in the K3. Jim, VE3CI __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
juergen piezo wrote: > > In the 160m CW contest, because of the QRN I had too use my TS850 and > lowly IC735 which seemed too cope much better in mild QRN conditions. > The K3's AGC under these conditions was making the band sound like I > needed to disconnect the antenna very soon! > You must be kidding! I operated 30 hours in the CQ 160 and never turned my AGC off even once. I was in the middle of the major storm cell that moved across the southeast with QRN SW of me Friday night and NE of me Saturday night. Somehow I still managed to make 1542 QSOs in 58 State/Prov and 68 countries with a total Score of 829,332 (probably 5th overall behind 3 stations in Maine and one on the Chesapeake shore). http://lists.contesting.com/pipermail/3830/2010-February/190837.html I really don't understand your comments. Would you mind sharing your callsign and results in the CQ 160 so we know you are not simply a troll? 73, Bill W4ZV -- View this message in context: http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505p4504898.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Hi Julian, I have posted and E-mailed about this at least a dozen times to no avail. I am convinced that if Elecraft could do this, almost all of the "noisy and hissy" receiver complaints would go away overnight. So I don't understand why they aren't listening to their users on this. This is just about my only complaint (except the 3.9 and and 7.8kHz audio spurs) about the K3. Knut - AB2TC Julian, G4ILO [via Elecraft] wrote: > > ab2tc wrote: > I wish I could set it higher than 008. > > So do I. > Julian, G4ILO. K2 #392 K3 #222. > * G4ILO's Shack - http://www.g4ilo.com > * KComm - http://www.g4ilo.com/kcomm.html > * KTune - http://www.g4ilo.com/ktune.html > > > > View message @ > http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505p4504081.html > > To unsubscribe from Re: Attenuator and RF Gain Settings, click here > < (link removed) >. > > -- View this message in context: http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505p4504793.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
For those who can gather information from graphs, take a look at the AGC behavior Jack Smith has plotted. The information is at http://www.cliftonlaboratories.com/elecraft_k3_agc_and_s-meter.htm#AGC_SLP_and_AGC_THR. 73, Don W3FPR Don Wilhelm wrote: > Brian, > > That is an illusion - yes the K3 gets more quiet (on noise) if the AGC > Threshold is reduced. > BUT what that indicates is that the AGC is being activated by the noise > and the K3 is reducing the gain due to AGC action. > The lowest AGC Threshold that is usable for any given level of > atmospheric noise is the threshold setting just higher than the setting > which begins to reduce the noise. In other words, listen to a spot on > the band where there are no signals, then start at the highest Threshold > setting of 008. > Reduce the value of the AGC Threshold until you sense that the noise > level starts to go down - then move the Threshold up to the next level. > > That setting will produce the most usable sensitivity for that band, > that antenna, and at that particular point in time (atmospheric noise > levels do change with time). If the resulting noise level is > bothersome, then take other steps to reduce that response - Preamp off, > ATT ON, and reduce the RF Gain (in that order) until you can just barely > hear the noise. That will result in the most sensitive setting for the > receiver. > Remember (as Jim Brown just posted) - that atmospheric noise is just > another 'signal' to the receiver that is to be amplified (it is coming > in on the antenna port). One must condition the receiver to place that > noise level at (or just above) your threshold of perception to reduce > your fatigue level when listening to any band. That is what the preamp, > attenuator, and RF Gain controls are for. > > After a bit of experimenting, you may come to the point where you have > achieved a compromise set of AGC Threshold and Slope setting that work > well in all but the most demanding situations. Leave them set at that > point and control the receiver response with the normal controls of > preamp, ATT, and RF Gain. For those digging for signals beneath the > noise level (yes, some ops have very good ears for that), they will have > to suffer with hearing some of the noise as well - just how much is an > individual decision. > > Again, as Jim Brown pointed out - noise arriving from the antenna is > just another signal source - some signals will be above that noise level > and others will be below it. Normally we can only copy signals that are > above the noise level, so why do some insist on setting "all controls to > the right" and having the receiver amplify the noise as well as the > signals - it is all in the quantity called "(signal + noise) to noise > ratio". > > The only way to further reduce noise is to use noise reduction > techniques which search through the signal plus noise to find something > that appears to be coherent and amplify it. That is what the K3 NR > algorithms do. How well it works depends on the type of noise present > at the time, and the K3 offers several settings to handle the differing > situations - do expect distortion with the more aggressive settings, but > if they are able to dig a signal out of the noise for us, perhaps we can > put up with the distortion to complete the contact. This is for use in > extreme situations, and not for normal use when we want more casual copy. > > 73, > Don W3FPR > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Brian, That is an illusion - yes the K3 gets more quiet (on noise) if the AGC Threshold is reduced. BUT what that indicates is that the AGC is being activated by the noise and the K3 is reducing the gain due to AGC action. The lowest AGC Threshold that is usable for any given level of atmospheric noise is the threshold setting just higher than the setting which begins to reduce the noise. In other words, listen to a spot on the band where there are no signals, then start at the highest Threshold setting of 008. Reduce the value of the AGC Threshold until you sense that the noise level starts to go down - then move the Threshold up to the next level. That setting will produce the most usable sensitivity for that band, that antenna, and at that particular point in time (atmospheric noise levels do change with time). If the resulting noise level is bothersome, then take other steps to reduce that response - Preamp off, ATT ON, and reduce the RF Gain (in that order) until you can just barely hear the noise. That will result in the most sensitive setting for the receiver. Remember (as Jim Brown just posted) - that atmospheric noise is just another 'signal' to the receiver that is to be amplified (it is coming in on the antenna port). One must condition the receiver to place that noise level at (or just above) your threshold of perception to reduce your fatigue level when listening to any band. That is what the preamp, attenuator, and RF Gain controls are for. After a bit of experimenting, you may come to the point where you have achieved a compromise set of AGC Threshold and Slope setting that work well in all but the most demanding situations. Leave them set at that point and control the receiver response with the normal controls of preamp, ATT, and RF Gain. For those digging for signals beneath the noise level (yes, some ops have very good ears for that), they will have to suffer with hearing some of the noise as well - just how much is an individual decision. Again, as Jim Brown pointed out - noise arriving from the antenna is just another signal source - some signals will be above that noise level and others will be below it. Normally we can only copy signals that are above the noise level, so why do some insist on setting "all controls to the right" and having the receiver amplify the noise as well as the signals - it is all in the quantity called "(signal + noise) to noise ratio". The only way to further reduce noise is to use noise reduction techniques which search through the signal plus noise to find something that appears to be coherent and amplify it. That is what the K3 NR algorithms do. How well it works depends on the type of noise present at the time, and the K3 offers several settings to handle the differing situations - do expect distortion with the more aggressive settings, but if they are able to dig a signal out of the noise for us, perhaps we can put up with the distortion to complete the contact. This is for use in extreme situations, and not for normal use when we want more casual copy. 73, Don W3FPR Brian Machesney wrote: > Wow, Don, the effect of setting the AGC THR is dramatic! > > I live in a very rural location that seems relatively free of man-made > noise. With antenna connected, the K3 S-meter shows about S-5 background > noise. (S-0 with no antenna!) > > Surprising to me, turning *down* the AGC THR to 002 (was set to 008) really > quieted things down and made signals "pop" out of the noise the way you > describe. (Note: NF and NB are OFF) I could hear the background noise level > rise monotonically as I increased the THR setting and fall as I decreased > it. > > With seven AGC variables to adjust -- DCY, HLD, PLS, SLP, THR, -F and -S -- > setting AGC up for a given operating scenario in a given location seems like > a very complex topic. Is there any way this could be reduced to a tutorial > for the K3 Wiki (like K3NA's entry at > http://www.zerobeat.net/mediawiki/index.php/K3_Receiver_Gain_Configurations, > which addresses the "no AGC" case)? > > This might create a run on N-GENs... > > > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.733 / Virus Database: 271.1.1/2663 - Release Date: 02/02/10 > 02:35:00 > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
In addition to the IF and DSP noise blankers, the K3 incorporates a third feature to help deal with impulse noise. One of the AGC parameters is CONFIG: AGC PLS. "nor" is used to activate a fast-reovery AGC algorithm if the signal that activated the AGC is above a certain dynamic threshold and lasts for less than a specific time. "OFF" allows the AGC to be "pumped" by pulse-type noise. Like any system that deals with suppressing pulse noise, the overall receiver gain is being quickly modified, so there may be IMD or other effects. 73, Lyle KK7P __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
In the K3 there are *TWO* kinds of noise blanking. One is digital and runs inside the firmware program. The other is the same hardware IF blanking that has been in use in analog radios for over 50 years. They do not work at all alike. The hardware blanking has advantages on some noise and was retained as one of the blanking options (marked IF). Hardware blanking, as it always has, will create extra noise from strong signals, because it is modulating the spectrum with a square transition of IF gain from on to off. The artifacts are just a matter of physics in anyone's radio. Hardware blanking is hardware blanking. The digital "blanking" (dSP in the NB menu selection) uses algorithmic methodology and does not produce these artifacts. It is a better phrase to call the dsp version "noise cancellation". Press and hold NB to bring up the NB level menu and turn IF OFF with the VFO B knob. Luckily, at my QTH I have not found a point where I need the hardware blanking. Whatever causes my 160m S9 (50uV in 50 ohms) daytime buzz (not found in two years of searching) is reduced to S6 (6uV) by the dsp blanking, but only to s7/s8 (12 to 25 uV) by hardware blanking. When the buzz is gone, ambient 160m noise at SSB bandwidths is S6. Also be sure to use as little of the ATT-nothing-PRE gain range as you can, as this ramps up the pulses as well as the wanted signal. Keeping this at a minimum allows me to use the dsp blanking. 73, Guy PS, I have my S meter set to ABS (absolute) and have done RF gain calibration, and so my S meter CAN be read in uV when AGC is on. On Tue, Feb 2, 2010 at 3:40 PM, juergen wrote: > Hi Lance > > This issue is a real problem for me. If I turn the AGC off I need too use the > noise blanker. This ruins the K3's strong signal handling performance. > Normally I dont need to use the noise blanker. However with the AGC off, > electric fence pulses are loud as hell because the pulse stretching blanker > is not on with the AGC off. > > This problem with the K3's producing noise with AGC on is real problem. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Wow, Don, the effect of setting the AGC THR is dramatic! I live in a very rural location that seems relatively free of man-made noise. With antenna connected, the K3 S-meter shows about S-5 background noise. (S-0 with no antenna!) Surprising to me, turning *down* the AGC THR to 002 (was set to 008) really quieted things down and made signals "pop" out of the noise the way you describe. (Note: NF and NB are OFF) I could hear the background noise level rise monotonically as I increased the THR setting and fall as I decreased it. With seven AGC variables to adjust -- DCY, HLD, PLS, SLP, THR, -F and -S -- setting AGC up for a given operating scenario in a given location seems like a very complex topic. Is there any way this could be reduced to a tutorial for the K3 Wiki (like K3NA's entry at http://www.zerobeat.net/mediawiki/index.php/K3_Receiver_Gain_Configurations, which addresses the "no AGC" case)? This might create a run on N-GENs... -- 73 -- Brian -- K1LI On Tue, Feb 2, 2010 at 4:50 PM, Don Wilhelm wrote: > I just thought of something that might help those confused by the AGC > Threshold setting. One other way to look at the required AGC Threshold level > is to think of it as an S-meter level If your noise is S-1 or lower (on the > K3's S-meter), you can set the Threshold to 002 or higher and all may be > well OTOH, if you have an S-7 noise level indicated, the AGC Threshold > should be set to 008 or higher. > > This is not an exact science number - the AGC Threshold menu parameter > values are not tied to the S-meter, but hopefully the relative scale can > give you an indication of which way to move the setting to avoid activating > the AGC on the ambient noise coming in on your feedline. > > As I have said before I believe the default setting of 005 is even too low > - mine normally is set at 008 even though I have a relatively quiet > location. > > 73, > Don W3FPR > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
On Tue, 02 Feb 2010 16:34:50 -0500, Don Wilhelm wrote: >BUT one *can* make that happen with incorrect settings. YES! Don has given us a LOT of great advice in his two recent posts in this thread. Let me emphasize something that I'm sure he understands, but didn't make quite it clear if you didn't read between his lines. NOISE IS PART OF THE SIGNAL THAT IS DRIVING THE AGC. IT IS ALSO PART OF THE SIGNAL THAT IS GENERATING INTERMOD, BOTH AT RF AND AT AUDIO. IT IS PART OF WHAT THE IF SELECTIVITY MUST REJECT, JUST LIKE ANOTHER STATION! CAPS ADDED FOR EMPHASIS. If the NOISE overloads the signal chain, the resulting distortion obscures the signal. It is not enough to keep the signal chain below overload on signal. We must also keep it out of overload by noise pulses. That's not easy, because much of the noise at the antenna terminal is impulsive in nature -- certainly static and stuff like fences. Bear this in mind when setting ATT, PRE, RF gain, and AGC parameters. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Hi, I wish I could set it higher than 008. I am also in a relatively quiet location but on 20m with an AGC threshold of 008 my atmospheric noise is normally above the AGC threshold. So when I want comfortable listening I back off the RF gain until the S-meter shows about S4 or so. Not a big problem, but I would prefer that the AGC threshold could go higher. Having it stored per-band, too, would be really, really nice and it makes sense. Knut - AQB2TC Don Wilhelm-4 wrote: > > I just thought of something that might help those confused by the AGC > Threshold setting. > One other way to look at the required AGC Threshold level is to think of > it as an S-meter level > If your noise is S-1 or lower (on the K3's S-meter), you can set the > Threshold to 002 or higher and all may be well > OTOH, if you have an S-7 noise level indicated, the AGC Threshold should > be set to 008 or higher. > > -- View this message in context: http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505p4504035.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
ab2tc wrote: > > > I wish I could set it higher than 008. > So do I. - Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505p4504081.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
I just thought of something that might help those confused by the AGC Threshold setting. One other way to look at the required AGC Threshold level is to think of it as an S-meter level If your noise is S-1 or lower (on the K3's S-meter), you can set the Threshold to 002 or higher and all may be well OTOH, if you have an S-7 noise level indicated, the AGC Threshold should be set to 008 or higher. This is not an exact science number - the AGC Threshold menu parameter values are not tied to the S-meter, but hopefully the relative scale can give you an indication of which way to move the setting to avoid activating the AGC on the ambient noise coming in on your feedline. As I have said before I believe the default setting of 005 is even too low - mine normally is set at 008 even though I have a relatively quiet location. 73, Don W3FPR Don Wilhelm wrote: > For ALL - a further explanation! The K3 does not make noise louder! > BUT one *can* make that happen with incorrect settings. > > The AGC Threshold must be set above the level of the noise. If that is > not done, the AGC will activate on the noise and reduce the gain of the > receiver. The result is that signals which *should* stand out above the > noise will be buried closer to the noise because their level has been > reduced by the AGC action. > Reducing the RF Gain will normally accomplish the same thing. > Since all K3s are not at the same location with the same atmospheric > noise level, the correct settings for one may not be right for another. > It all depends on the local noise, the atmospheric noise coming into > your antenna. > > I am not certain how a person can say that the atmospheric noise on his > antenna is S-2 to S-3, but the K3 S-meter reads the noise as S-5 to > S-7. I just don't understand that - what is the "standard of > comparison"? The noise is whatever it is, and the level indicated on > any one receiver will depend on the sensitivity of the receiver as well > as its S-meter response. A receiver with a better MDS *should* receive > that noise at a higher level than one with a lesser MDS. The answer is > to either add attenuation until the noise is reduced (preamp off, > Attenuator on, RF Gain backed off), or change the onset of AGC so the > noise does not trigger it - or both. Signals that are greater than the > noise will still be present and can be copied. > > 73, > Don W3FPR > > juergen wrote: > >> This problem with the K3's producing noise with AGC on is real problem. On >> my 40 meter 4 square I basically have a very low noise floor S1 -S2. With >> AGC on I am getting QRN that the K3 AGC makes thats not really at the level >> that the K3 is reporting. Yes there is QRN there, but its residual with >> occasional pops, not the S5 and S7 QRN crashes that the AGC produces. This >> is not a S meter calibration issue either. Like you my QRN level jumps up >> mysteriously. With the AGC is off this QRN is not there. I have the >> threshold set at 2. Even with the ATT on this QRN is being made much more >> apparent with the AGC on. I hope Elecraft has a fix for this because the K3 >> is unusable for me in its current form on the low bands. >> >> >> > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.733 / Virus Database: 271.1.1/2663 - Release Date: 02/02/10 > 02:35:00 > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
For ALL - a further explanation! The K3 does not make noise louder! BUT one *can* make that happen with incorrect settings. The AGC Threshold must be set above the level of the noise. If that is not done, the AGC will activate on the noise and reduce the gain of the receiver. The result is that signals which *should* stand out above the noise will be buried closer to the noise because their level has been reduced by the AGC action. Reducing the RF Gain will normally accomplish the same thing. Since all K3s are not at the same location with the same atmospheric noise level, the correct settings for one may not be right for another. It all depends on the local noise, the atmospheric noise coming into your antenna. I am not certain how a person can say that the atmospheric noise on his antenna is S-2 to S-3, but the K3 S-meter reads the noise as S-5 to S-7. I just don't understand that - what is the "standard of comparison"? The noise is whatever it is, and the level indicated on any one receiver will depend on the sensitivity of the receiver as well as its S-meter response. A receiver with a better MDS *should* receive that noise at a higher level than one with a lesser MDS. The answer is to either add attenuation until the noise is reduced (preamp off, Attenuator on, RF Gain backed off), or change the onset of AGC so the noise does not trigger it - or both. Signals that are greater than the noise will still be present and can be copied. 73, Don W3FPR juergen wrote: > This problem with the K3's producing noise with AGC on is real problem. On my > 40 meter 4 square I basically have a very low noise floor S1 -S2. With AGC > on I am getting QRN that the K3 AGC makes thats not really at the level that > the K3 is reporting. Yes there is QRN there, but its residual with > occasional pops, not the S5 and S7 QRN crashes that the AGC produces. This is > not a S meter calibration issue either. Like you my QRN level jumps up > mysteriously. With the AGC is off this QRN is not there. I have the threshold > set at 2. Even with the ATT on this QRN is being made much more apparent > with the AGC on. I hope Elecraft has a fix for this because the K3 is > unusable for me in its current form on the low bands. > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
John, If you have electric fence impulse noise, an AGC Threshold setting of 002 is too low IMHO. Try setting it higher, say at 008 and see what happens. If the noise is still a problem (with AGC ON), then try reducing the slope to 004 or even 002 - with the reduced slope, strong signals will sound louder than weak ones in your ears, which I consider a good thing - ragchewers looking for only 'armchair copy' may differ and want to use a higher slope so all signals have about the same audio level regardless of signal strength. 73, Don W3FPR juergen wrote: > Hi Lance > > This issue is a real problem for me. If I turn the AGC off I need too use the > noise blanker. This ruins the K3's strong signal handling performance. > Normally I dont need to use the noise blanker. However with the AGC off, > electric fence pulses are loud as hell because the pulse stretching blanker > is not on with the AGC off. > > This problem with the K3's producing noise with AGC on is real problem. On my > 40 meter 4 square I basically have a very low noise floor S1 -S2. With AGC > on I am getting QRN that the K3 AGC makes thats not really at the level that > the K3 is reporting. Yes there is QRN there, but its residual with > occasional pops, not the S5 and S7 QRN crashes that the AGC produces. This is > not a S meter calibration issue either. Like you my QRN level jumps up > mysteriously. With the AGC is off this QRN is not there. I have the threshold > set at 2. Even with the ATT on this QRN is being made much more apparent > with the AGC on. I hope Elecraft has a fix for this because the K3 is > unusable for me in its current form on the low bands. > > In the 160m CW contest, because of the QRN I had too use my TS850 and lowly > IC735 which seemed too cope much better in mild QRN conditions. The K3's > AGC under these conditions was making the band sound like I needed to > disconnect the antenna very soon! > > > John > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] Attenuator and RF Gain Settings
Hi Lance This issue is a real problem for me. If I turn the AGC off I need too use the noise blanker. This ruins the K3's strong signal handling performance. Normally I dont need to use the noise blanker. However with the AGC off, electric fence pulses are loud as hell because the pulse stretching blanker is not on with the AGC off. This problem with the K3's producing noise with AGC on is real problem. On my 40 meter 4 square I basically have a very low noise floor S1 -S2. With AGC on I am getting QRN that the K3 AGC makes thats not really at the level that the K3 is reporting. Yes there is QRN there, but its residual with occasional pops, not the S5 and S7 QRN crashes that the AGC produces. This is not a S meter calibration issue either. Like you my QRN level jumps up mysteriously. With the AGC is off this QRN is not there. I have the threshold set at 2. Even with the ATT on this QRN is being made much more apparent with the AGC on. I hope Elecraft has a fix for this because the K3 is unusable for me in its current form on the low bands. In the 160m CW contest, because of the QRN I had too use my TS850 and lowly IC735 which seemed too cope much better in mild QRN conditions. The K3's AGC under these conditions was making the band sound like I needed to disconnect the antenna very soon! John This is a very interesting thread. I am seeing a similar RF gain/AGC issue on my K3 (I posted a description of this effect on 1/31). While I have also defaulted to presetting the AFG and use the RF gain to control receiver performance, I have noticed issues with the AGC on the K3 that make it behave differently than other radios that I have tried. The K3 has both hardware and DSP/firmware AGC. Strong signals (over S9) cause the AGC to behave normally but weak signals (DSP/firmware) behave oddly with an apparent, and I say apparent, noise issue. Audio quality of weak signals with the AGC on also seems to be slightly compromised as compared to operation with the AGC off. Perhaps weak signal performance of the K3 with AGC on needs some DSP/firmware modification. In the meantime, I am using the rig in a similar fashion as Barry and other have described. Lance, NR7N __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Since Barry posted his settings some time ago,I have been using them every day on SSB or CW,always with the ATT ON and the preamp OFF and the RFG set around 12 o'clock and I can tell that the weak stations sounds crystal clear as the strong ones,I can't hear any bad audio os minimun distorsion at all,I normally has the 2.8 Khz roofer and the SHIFT set at 1.2 and flat audio at the RX EQ.My band noise under these settings is very low always. AD4C "For a refined ham it is compulsory to own a k3" --- On Tue, 2/2/10, Don Wilhelm wrote: From: Don Wilhelm Subject: Re: [Elecraft] Attenuator and RF Gain Settings To: "Lance Wilson" Cc: elecraft@mailman.qth.net Date: Tuesday, February 2, 2010, 3:10 PM Lance, CW or SSB? Similar conditions do not exist here on SSB. I can't say anything about CW performance right now. Right now, I am listening to a net on 80 meter SSB with both strong and weak signals in the mix. The Preamp is off and ATT is on - and the RF Gain is backed off to about 2 o'clock. The RF Gain position was determined by listening with no signals and reduced until the atmospheric noise was not bothersome. All signals are quite clear, including the weak ones. My AGC settings are THR = 008 and I have moved the SLP up to 004 for listening to a net - I normally run it at 002 which makes a greater difference in audio volume between strong and weak signals. With those settings at this particular time, it is almost (but not quite) like having squelch on when there is no signal present. 73, Don W3FPR Lance Wilson wrote: > This is a very interesting thread. I am seeing a similar RF gain/AGC issue on > my K3 (I posted a description of this effect on 1/31). While I have also > defaulted to presetting the AFG and use the RF gain to control receiver > performance, I have noticed issues with the AGC on the K3 that make it > behave differently than other radios that I have tried. The K3 has both > hardware and DSP/firmware AGC. > > Strong signals (over S9) cause the AGC to behave normally but weak signals > (DSP/firmware) behave oddly with an apparent, and I say apparent, noise > issue. Audio quality of weak signals with the AGC on also seems to be > slightly compromised as compared to operation with the AGC off. > > Perhaps weak signal performance of the K3 with AGC on needs some > DSP/firmware modification. In the meantime, I am using the rig in a similar > fashion as Barry and other have described. > > Lance, NR7N > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Don, I am only using the S-meter as a relative indicator. I actually don't care too much about the absolute reading. My main concern is that the K3 has both DSP and hardware AGC and I am speculating that the interaction between the two may not be quite right. The signal to noise relationship (not receiver SNR) behaves a bit peculiarly to me. Lance, NR7N -- View this message in context: http://n2.nabble.com/KAT3-antenna-tuner-tp4490403p4501769.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Lance, Both the AF Gain setting and the AGC on/off condition will modify the S-meter response. As a result, comparing S-meter readings with AGC on vs. off is not a valid comparison. All I can say is that "yes" the S-meter reading will change. Some combination of that behavior is present on each receiver I have ever owned or operated. Each one is different. How the S-meter changes with each condition depends on where the particular receiver picks off the S-meter signal. 73, Don W3FPR Lance Wilson wrote: > Don, > > Given how you have set up your K3 I am in agreement with the performance > you've noted. I'm experimenting on 20M, RF gain full on, preamp and att off. > I am also listening under SSB conditions. I have the RF gain fully on only > to experiment with the AGC. > > Here is an example, with the AGC off my noise level on the S-meter is S2 to > S3. With the AGC on it is S6 to S7 with no signal present. If I listen to a > S8 signal with the AGC on my noise level is still S6. With AGC off that same > signal is S7 with a noise level again of S2 to S3. This is not normal AGC > behavior and perhaps there are some issues between the DSP and hardware AGC. > Changing AGC parameters has no effect on what I am seeing. > > Lance, NR7N > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Don, Given how you have set up your K3 I am in agreement with the performance you've noted. I'm experimenting on 20M, RF gain full on, preamp and att off. I am also listening under SSB conditions. I have the RF gain fully on only to experiment with the AGC. Here is an example, with the AGC off my noise level on the S-meter is S2 to S3. With the AGC on it is S6 to S7 with no signal present. If I listen to a S8 signal with the AGC on my noise level is still S6. With AGC off that same signal is S7 with a noise level again of S2 to S3. This is not normal AGC behavior and perhaps there are some issues between the DSP and hardware AGC. Changing AGC parameters has no effect on what I am seeing. Lance, NR7N -- View this message in context: http://n2.nabble.com/KAT3-antenna-tuner-tp4490403p4501486.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Lance and All, I don't think this is so much an "issue" (as in rig specific) as it is a fact of life. In other words, this technique works with just about any receiver. While each rig I own has somewhat different characteristics, they all benefit from not over-relying on AGC and RF gain. A long time ago I sort of stumbled onto the fact that running the RF gain relatively low was a good thing. I've been more reticent to disengage my AGC because I use headphones a lot, and there always seems to be someone out there who will suddenly pop up on a frequency running mucho power! However, I did go through the process as described by Barry, N1EU, and it does work extremely well. Furthermore, I tried it on a couple of other rigs, and got the same beneficial result. It was an improvement over my more simplistic process of just running both gain controls at minimum, or at least running the RF gain at minimum. I rarely use the pre-amp, and now I'm experimenting with the attenuator. Obviously I've been underutilizing this tool. Anyway, I'm enjoying the comments in this thread, and hopefully learning something! Dave W7AQK - Original Message - From: "Lance Wilson" To: Sent: Tuesday, February 02, 2010 7:42 AM Subject: Re: [Elecraft] Attenuator and RF Gain Settings > > This is a very interesting thread. I am seeing a similar RF gain/AGC issue > on > my K3 (I posted a description of this effect on 1/31). While I have also > defaulted to presetting the AFG and use the RF gain to control receiver > performance, I have noticed issues with the AGC on the K3 that make it > behave differently than other radios that I have tried. The K3 has both > hardware and DSP/firmware AGC. > > Strong signals (over S9) cause the AGC to behave normally but weak signals > (DSP/firmware) behave oddly with an apparent, and I say apparent, noise > issue. Audio quality of weak signals with the AGC on also seems to be > slightly compromised as compared to operation with the AGC off. > > Perhaps weak signal performance of the K3 with AGC on needs some > DSP/firmware modification. In the meantime, I am using the rig in a > similar > fashion as Barry and other have described. > > Lance, NR7N > -- > View this message in context: > http://n2.nabble.com/KAT3-antenna-tuner-tp4490403p4501164.html > Sent from the [K3] mailing list archive at Nabble.com. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
Lance, CW or SSB? Similar conditions do not exist here on SSB. I can't say anything about CW performance right now. Right now, I am listening to a net on 80 meter SSB with both strong and weak signals in the mix. The Preamp is off and ATT is on - and the RF Gain is backed off to about 2 o'clock. The RF Gain position was determined by listening with no signals and reduced until the atmospheric noise was not bothersome. All signals are quite clear, including the weak ones. My AGC settings are THR = 008 and I have moved the SLP up to 004 for listening to a net - I normally run it at 002 which makes a greater difference in audio volume between strong and weak signals. With those settings at this particular time, it is almost (but not quite) like having squelch on when there is no signal present. 73, Don W3FPR Lance Wilson wrote: > This is a very interesting thread. I am seeing a similar RF gain/AGC issue on > my K3 (I posted a description of this effect on 1/31). While I have also > defaulted to presetting the AFG and use the RF gain to control receiver > performance, I have noticed issues with the AGC on the K3 that make it > behave differently than other radios that I have tried. The K3 has both > hardware and DSP/firmware AGC. > > Strong signals (over S9) cause the AGC to behave normally but weak signals > (DSP/firmware) behave oddly with an apparent, and I say apparent, noise > issue. Audio quality of weak signals with the AGC on also seems to be > slightly compromised as compared to operation with the AGC off. > > Perhaps weak signal performance of the K3 with AGC on needs some > DSP/firmware modification. In the meantime, I am using the rig in a similar > fashion as Barry and other have described. > > Lance, NR7N > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
This is a very interesting thread. I am seeing a similar RF gain/AGC issue on my K3 (I posted a description of this effect on 1/31). While I have also defaulted to presetting the AFG and use the RF gain to control receiver performance, I have noticed issues with the AGC on the K3 that make it behave differently than other radios that I have tried. The K3 has both hardware and DSP/firmware AGC. Strong signals (over S9) cause the AGC to behave normally but weak signals (DSP/firmware) behave oddly with an apparent, and I say apparent, noise issue. Audio quality of weak signals with the AGC on also seems to be slightly compromised as compared to operation with the AGC off. Perhaps weak signal performance of the K3 with AGC on needs some DSP/firmware modification. In the meantime, I am using the rig in a similar fashion as Barry and other have described. Lance, NR7N -- View this message in context: http://n2.nabble.com/KAT3-antenna-tuner-tp4490403p4501164.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
My experience jibes well with Jim's. Gain throttling is imperative to get more than mediocre results using the K3: http://n1eu.com/K3/K3_agcgain.htm 73, Barry N1EU Jim Brown-10 wrote: > > On Sun, 31 Jan 2010 14:23:33 -0500, Brian Machesney wrote: > >>For the first time, I turned on the K3's ATT and found that I was even >>better able to separate callers, particularly when trying to pick out >>relatively weaker EU signals from stronger NA signals responding to my CQ. > > Those of us with lots of grey hair learned 50 years ago that the most > important control on our receiver was the RF Gain. They didn't come with > attenuators or preamps in those days, but we also learned to switch them > to > a shorter antenna when they got overloaded. > > With a modern radio, on bands below 20M, the ATTenuator should almost > always be ON and the PREamp should almost always be OFF for the greatest > ability to separate weak signals from strong ones. On 20M you can usually > turn off the ATTenuator, but you may not need the preamp until you go to > higher bands. > > Another hint -- to pull really weak ones out from between strong signals, > turn down the RF gain to the point where you are just hearing the weak > one. > During the 160M contest this weekend, preamp was off, ATT was on, and my > RF > gains were at about 2'o'clock. > > 73, > Jim K9YC > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > -- View this message in context: http://n2.nabble.com/KAT3-antenna-tuner-tp4490403p4500970.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Attenuator and RF Gain Settings
I am 61 years old and more than 40 as a ham and always since I started on hamradio with the tube type receivers has used the volumen control almost to the maximun and then control the signal with the RF gain control,no matter which radio you will be using,this is the best way to cut down band noise and close freq QRM,,without a doubt the K3 is the highest performer in the market and doing this it will work even better,I have never used my preamp,not even on 10M,the K3 has enough sensitivity not to use it,on 40 and 80M I always have my ATT engaged and I am able to pull any weak dx station no matter how weak it is and even with a strong one at 2Khz away my freq. My two cents. AD4C "For a refined ham it is compulsory to own a k3" --- On Sun, 1/31/10, Jim Brown wrote: From: Jim Brown Subject: [Elecraft] Attenuator and RF Gain Settings To: "elecraft@mailman.qth.net" Date: Sunday, January 31, 2010, 10:09 PM On Sun, 31 Jan 2010 14:23:33 -0500, Brian Machesney wrote: >For the first time, I turned on the K3's ATT and found that I was even >better able to separate callers, particularly when trying to pick out >relatively weaker EU signals from stronger NA signals responding to my CQ. Those of us with lots of grey hair learned 50 years ago that the most important control on our receiver was the RF Gain. They didn't come with attenuators or preamps in those days, but we also learned to switch them to a shorter antenna when they got overloaded. With a modern radio, on bands below 20M, the ATTenuator should almost always be ON and the PREamp should almost always be OFF for the greatest ability to separate weak signals from strong ones. On 20M you can usually turn off the ATTenuator, but you may not need the preamp until you go to higher bands. Another hint -- to pull really weak ones out from between strong signals, turn down the RF gain to the point where you are just hearing the weak one. During the 160M contest this weekend, preamp was off, ATT was on, and my RF gains were at about 2'o'clock. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] Attenuator and RF Gain Settings
On Sun, 31 Jan 2010 14:23:33 -0500, Brian Machesney wrote: >For the first time, I turned on the K3's ATT and found that I was even >better able to separate callers, particularly when trying to pick out >relatively weaker EU signals from stronger NA signals responding to my CQ. Those of us with lots of grey hair learned 50 years ago that the most important control on our receiver was the RF Gain. They didn't come with attenuators or preamps in those days, but we also learned to switch them to a shorter antenna when they got overloaded. With a modern radio, on bands below 20M, the ATTenuator should almost always be ON and the PREamp should almost always be OFF for the greatest ability to separate weak signals from strong ones. On 20M you can usually turn off the ATTenuator, but you may not need the preamp until you go to higher bands. Another hint -- to pull really weak ones out from between strong signals, turn down the RF gain to the point where you are just hearing the weak one. During the 160M contest this weekend, preamp was off, ATT was on, and my RF gains were at about 2'o'clock. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
