AGC behaviour
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Hi all,
My K3 #1263 was delivered in July with F/W MCU 2.18 DSP 1.84 and I was really enjoying the RX capabilities of the K3. Now that I have upgraded to 2.38/1.90 I believe the RX is more "restless" when listening to an "empty" space on the band. The S-meter is constantly on S5 with pre-amp ON and S3 with pre-amp OFF on the lower bands (30/40m). I have compensated that a bit by lowering the AGC threshold (from 5 to 4 now). I liked the initial F/W wrt AGC behavior better (less fatiguing to listen to). I have read in the F/W history file that changes to the AGC have been made from F/W 2.22 onwards. So I wonder if other people have the same experience. I live in an urban area so it IS noisy out here. It is just the way the K3 deals with that noisy background level. When switching to ANT2 (not connected to anything) the RX goes virtually silent. -- Enno, PF5X |
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This is what N4DSP sent me as a reaction (he is not a mailing list subscriber).
Like N4DSP and in addition to my initial posting, I have compared with my 1000MP, and although I can hear the same station on both rigs, listening with the 1000MP is just more relaxing. =========================================================================== Enno, I do not subscribe to the elecraft reflector so cannot post there. I only read the archives but I am experiencing the very same thing in regards to noise. I have a constant s4 noise level on 40 and s5 on 80 mtrs. My Yaesu FT-1000d is very very quiet with no s mtr movement on those bands and I even wrote to Tom, W8JI, about this but have not heard back from him. I am not sure what the noise was like on earlier versions but at this time it is very very noisy. If you like you can post my info I provided you. I am running the latest regular release. Keep me posted on emails to you and if you succeed in quieting the receiver. 73 john-n4dsp
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Enno -
I have very high white noise in my K3 on 75 meters when connected to the serial port computer interface. Removing this connection greatly reduces the noise. If you use HRD, LP-BRIDGE, or any control software, you can also hear a pulsing noise related to polling the K3 over the serial port. I believe this can be lessened, but have not tried as yet. Here in Florida, USA, the level of thunder storms creates a naturally high noise level in the summer, but the effects described above are clearly noticeable. I use the Elecraft KUSB as serial interface. Monty K2DLJ > > This is what N4DSP sent me as a reaction (he is not a mailing list > subscriber). > > Like N4DSP and in addition to my initial posting, I have compared with my > 1000MP, and although I can hear the same station on both rigs, listening > with the 1000MP is just more relaxing. > > =========================================================================== > > Enno, > I do not subscribe to the elecraft reflector so cannot post there. I only > read the archives but I am experiencing the very same thing in regards to > noise. I have a constant s4 noise level on 40 and s5 on 80 mtrs. My Yaesu > FT-1000d is very very quiet with no s mtr movement on those bands and I > even > wrote to Tom, W8JI, about this but have not heard back from him. > > I am not sure what the noise was like on earlier versions but at this time > it is very very noisy. > If you like you can post my info I provided you. I am running the latest > regular release. > > Keep me posted on emails to you and if you succeed in quieting the > receiver. > > 73 > john-n4dsp > > > > > Enno, PF5X wrote: >> >> Hi all, >> >> My K3 #1263 was delivered in July with F/W MCU 2.18 DSP 1.84 and I was >> really enjoying the RX capabilities of the K3. Now that I have upgraded >> to >> 2.38/1.90 I believe the RX is more "restless" when listening to an >> "empty" >> space on the band. The S-meter is constantly on S5 with pre-amp ON and S3 >> with pre-amp OFF on the lower bands (30/40m). I have compensated that a >> bit by lowering the AGC threshold (from 5 to 4 now). >> I liked the initial F/W wrt AGC behavior better (less fatiguing to listen >> to). >> >> I have read in the F/W history file that changes to the AGC have been >> made >> from F/W 2.22 onwards. So I wonder if other people have the same >> experience. >> >> I live in an urban area so it IS noisy out here. It is just the way the >> K3 >> deals with that noisy background level. >> When switching to ANT2 (not connected to anything) the RX goes virtually >> silent. >> >> -- Enno, PF5X >> > > -- > View this message in context: > http://n2.nabble.com/AGC-behaviour-tp1114728p1115079.html > Sent from the Elecraft mailing list archive at Nabble.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 _______________________________________________ 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 Enno, PF5X
With the new firmware, I found it necessary to do the S-meter calibration. This restored the previous "base" behavior.
Not sure what the state was before the calibration, whether I had done the prior calibration correctly, etc., so I can't "blame" the firmware. My guess, though, is that I'm on a learning curve, and only the latest, most informed thing I have done can be trusted, if that. Afterwards, if your noise goes from S nothing to S5 by attaching the antenna, you surely are in a noisy locaton. If so, turn off the preamp and/or use the atten to reduce the "resting" gain of your RX. After that just turn your RF gain counter clockwise until the resting noise in the RX is something you can live with. I've had to do that all summer long, as 40 and 80 meters have had nasty QRN nearly continuously. Beyond that, reducing bandwidth on CW, the K3 has been able to listen down into the noise in a way unrivaled by any other RX I've used, including the Orion. Of late for CW QSO's, once established, I center their signal, and go to 50 Hz bandwidth immediately. No reason not to, and the bandwidth drops the noise way down. If they are above the noise, tuning just barely slightly off their signal removes just enough softness in the signal to make it quite pleasant. 73, Guy. My K3 #1263 was delivered in July with F/W MCU 2.18 DSP 1.84 and I was really enjoying the RX capabilities of the K3. Now that I have upgraded to 2.38/1.90 I believe the RX is more "restless" when listening to an "empty" space on the band. The S-meter is constantly on S5 with pre-amp ON and S3 with pre-amp OFF on the lower bands (30/40m). I have compensated that a bit by lowering the AGC threshold (from 5 to 4 now). I liked the initial F/W wrt AGC behavior better (less fatiguing to listen to). I have read in the F/W history file that changes to the AGC have been made from F/W 2.22 onwards. So I wonder if other people have the same experience. I live in an urban area so it IS noisy out here. It is just the way the K3 deals with that noisy background level. When switching to ANT2 (not connected to anything) the RX goes virtually silent. -- Enno, PF5X |
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In reply to this post by MontyS
On Wed, 24 Sep 2008 07:59:36 -0400, Monty Shultes wrote:
>I have very high white noise in my K3 on 75 meters when connected to the >serial port computer interface. Removing this connection greatly reduces the >noise. If you use HRD, LP-BRIDGE, or any control software, you can also >hear a pulsing noise related to polling the K3 over the serial port. I >believe this can be lessened, but have not tried as yet. Here in Florida, >USA, the level of thunder storms creates a naturally high noise level in the >summer, but the effects described above are clearly noticeable. I use the >Elecraft KUSB as serial interface. I suspect that either the computer or the K3 are dumping RF trash onto your serial cable, which, like any antenna, is radiating it, and your 75M antenna is picking it up. I suggest that you wind the serial cable around a toroid to form a common mode choke tuned to 75M. Fair-Rite #31 is the best material to use, and a 2.4-inch o.d., 1.4-inch i.d. toroid is a convenient size. Fair-Rite #43 will work, but you'll need more turns. This size is commonly called FT-240 in the ham world. See http://audiosystemsgroup.com/RFI-Ham.pdf for tutorial information about how and why this works, as well as measured data for chokes with 1 - 14 turns around #31 and #43 toroids. Ferrite beads clamped onto the cable will NOT fix this problem on the HF bands. They WILL help on 2M. :) 73, Jim Brown K9YC _______________________________________________ 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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When I listen on ANT1 and switching to ANT2 (not connected to anything)
> I can hear pretty good signals on ANT1 on all bands! What is wrong? regards, E72X,
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In reply to this post by Jim Brown-10
In addition to the toroid, make sure the shield of the USB connector in your computer is connected to the chassis (RF ground). Many motherboards fail to ground the shield, allowing it to radiate the broadband noise generated by the high speed USB data between the computer and the USB->serial UART in the USB device. > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Jim Brown > Sent: Wednesday, September 24, 2008 12:45 PM > To: Elecraft List > Subject: Re: [Elecraft] AGC behaviour > > > On Wed, 24 Sep 2008 07:59:36 -0400, Monty Shultes wrote: > > >I have very high white noise in my K3 on 75 meters when connected to > >the > >serial port computer interface. Removing this connection > greatly reduces the > >noise. If you use HRD, LP-BRIDGE, or any control software, > you can also > >hear a pulsing noise related to polling the K3 over the > serial port. I > >believe this can be lessened, but have not tried as yet. > Here in Florida, > >USA, the level of thunder storms creates a naturally high > noise level in the > >summer, but the effects described above are clearly > noticeable. I use the > >Elecraft KUSB as serial interface. > > I suspect that either the computer or the K3 are dumping RF > trash onto your > serial cable, which, like any antenna, is radiating it, and > your 75M antenna is > picking it up. I suggest that you wind the serial cable > around a toroid to form > a common mode choke tuned to 75M. Fair-Rite #31 is the best > material to use, and > a 2.4-inch o.d., 1.4-inch i.d. toroid is a convenient size. > Fair-Rite #43 will > work, but you'll need more turns. This size is commonly > called FT-240 in the ham > world. > > See http://audiosystemsgroup.com/RFI-Ham.pdf for tutorial > information about how > and why this works, as well as measured data for chokes with > 1 - 14 turns around > #31 and #43 toroids. Ferrite beads clamped onto the cable > will NOT fix this > problem on the HF bands. They WILL help on 2M. :) > > 73, > > Jim Brown K9YC > > > _______________________________________________ > 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 Enno, PF5X
John asked me to post this additional useful info.
-- Enno ============= I wanted to report back to you on the "noise" I was encountering with my K3. I was not aware of this but changing the RX EQ settings other than default will cause excess "noise" when changing to the cw mode. When I cleared those previous settings the "noise floor" of the receiver went down. Something you may want to try at your end. 73 john-n4dsp
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