Re: [Elecraft] K3 - 6m Internal Birdie
Tom Lizak, K1TL, wrote: > I have been having a problem with a 6m internal birdie around 50.096 ... I > did the "birdie removal tool" thingee but seems to put a small "void" in that > area when I did it. Hi Tom, The SIG RMV method can, in some cases, introduce a small dip in audio response at that specific frequency. The way the K3 owner's manual describes it is: "You may hear a slight tuning artifact as you tune in and out of the affected VFO segment." (See CONFIG:SIG RMV description.) This is an unavoidable side effect of how SIG RMV works. SIG RMV allows you to apply a small shift to both the first and second local oscillators, which can shift the birdie completely out of the passband while shifting the crystal filter passband only a small amount (and keeping the VFO accurate). But if the target signal happens to be close to the edge of the crystal filter passband, even a small shift could attenuate that point in the tuning range by a few dB. Generally, this is preferable to hearing the birdie. How successful SIG RMV is depends entirely on whether the birdie results from the first LO's fundamental, or from a harmonic. If it's due to a harmonic, which is usually the case, SIG RVM can be very effective. For example, shifting the LO 100 Hz would shift the birdie 1000 Hz in the case of a product involving the 10th harmonic of the LO. If the birdie you're removing is due to the fundamental of the LO, you may be forced to move it farther, creating a greater chance of an audible tuning artifact. Unfortunately there's no way to completely eliminate birdies in a high-dynamic-range superhet receiver. When we designed the new synth, we spent a lot of time tuning through the ham bands, slowly, at multiple bandwidths. We selected divider values (etc.) for the new synth such that ham-band birdies were "virtually" (but not entirely) eliminated. 6 meters is especially difficult because both the target band and its image band are both 4 MHz wide. Nonetheless, I think we did a pretty good job of minimizing birdies here. There are other things you can do about birdies if a small residual artifact is an issue. In CW mode you might try using CW reverse instead of CW normal. Or you can use a different crystal filter with a different offset. In SSB mode you can turn on the notch filter. But before taking any of these more drastic steps, I would also check the orientation of the coax cables associated with the synthesizer(s). Sometimes just moving a cable a bit can greatly attenuate one problematic birdie. Let me know if you have any further questions about this. 73, Wayne N6KR __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 - 6m Internal Birdie
Hi Tom, It's been a few years since I did birdie hunting on my K3 because most of them turned out not to be birdies but signals originating from my wireless router in a different room. So step 1 is to pull the power cord out of your router and see if the problem goes away. If it does buy a different router. Step 2 is to remove your antenna cable and make sure the birdie does not decrease in strength. If it does then it's probably a signal coming in on your antenna and not something generated inside the K3. After confirming that it is internally generated, step 3 is to remove the K3 top cover and listen to the birdie while you move the various coax cables inside the K3 around. If you find a position that eliminates the noise, tape the cable in place with some painters tape. 73, Mike K2MK k1tl wrote > Hi all, > > I have been having a problem with a 6m internal birdie around 50.096 which > is fairly strong and interferes with any signal(s) around that frequency. > I > did the "birdie removal tool" thingee but seems to put a small "void" in > that area when I did it. > > Have any of you K3 owners have a similar problem? > > I'm wondering if it may be a cabling issue with the SYNTH boards cable > routing. I just installed two new SYNTH boards and all seems working fine. > > 73 > Tom/K1TL... -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-6m-Internal-Birdie-tp7601081p7601089.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K3 - 6m Internal Birdie
I have the new synth boards, and do not have that birdie. Do you have the P3? Are all your interconnect cables between the various pieces of equipment of quality cable? From: Tom Lizak To: elecraft@mailman.qth.net Sent: Wednesday, April 8, 2015 9:02 AM Subject: [Elecraft] K3 - 6m Internal Birdie Hi all, I have been having a problem with a 6m internal birdie around 50.096 which is fairly strong and interferes with any signal(s) around that frequency. I did the "birdie removal tool" thingee but seems to put a small "void" in that area when I did it. Have any of you K3 owners have a similar problem? I'm wondering if it may be a cabling issue with the SYNTH boards cable routing. I just installed two new SYNTH boards and all seems working fine. 73 Tom/K1TL... __ 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 Message delivered to hlyin...@yahoo.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 Message delivered to arch...@mail-archive.com
[Elecraft] K3 - 6m Internal Birdie
Hi all, I have been having a problem with a 6m internal birdie around 50.096 which is fairly strong and interferes with any signal(s) around that frequency. I did the "birdie removal tool" thingee but seems to put a small "void" in that area when I did it. Have any of you K3 owners have a similar problem? I'm wondering if it may be a cabling issue with the SYNTH boards cable routing. I just installed two new SYNTH boards and all seems working fine. 73 Tom/K1TL... __ 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 Message delivered to arch...@mail-archive.com
