Re: [Elecraft] K2: Filter and BFO Settings for RTTY
Don, Thanks for the response and info. The wording in the Operating Manual made me think that the same values are used for RTTY as for SSB, my mistake. I used Spectogram (surprisingly easy) and have everything working nicely now. On the digital transmission heat issue. The rig is ok on 1-2 minute digital transmissions (e.g., 1-2 minutes of PSK at 30 watts). It'll warm up a bit, although nothing uncomfortable, and the internal fan can handle it. The problem is longer transmissions. For example, I do a lot of file sending for EmComm simulations and those transmissions can run 5-10 minutes at a time. The area above the power transistors gets very uncomfortable on a long transmission like that and people notice drift in my transmissions. For now I've got a desk fan pointed at the rig when doing longer transmissions and that's keeping the rig cool and stable. I'll find myself a muffin fan or smaller desk fan at the next hamfest. Jon KB1QBZ __ 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] K2: Filter and BFO Settings for RTTY
Jon, Look to computer shops for fans from defunct computers - often you can get them for free. Put a resistor in series to reduce the fan speed (and noise), and place the fan over the PA transistor area of the heat sink. The fan should pull air away from the heat sink for the most effective cooling. 73, Don W3FPR On 10/2/2010 8:54 PM, Jon Perelstein wrote: Don, Thanks for the response and info. The wording in the Operating Manual made me think that the same values are used for RTTY as for SSB, my mistake. I used Spectogram (surprisingly easy) and have everything working nicely now. On the digital transmission heat issue. The rig is ok on 1-2 minute digital transmissions (e.g., 1-2 minutes of PSK at 30 watts). It'll warm up a bit, although nothing uncomfortable, and the internal fan can handle it. The problem is longer transmissions. For example, I do a lot of file sending for EmComm simulations and those transmissions can run 5-10 minutes at a time. The area above the power transistors gets very uncomfortable on a long transmission like that and people notice drift in my transmissions. For now I've got a desk fan pointed at the rig when doing longer transmissions and that's keeping the rig cool and stable. I'll find myself a muffin fan or smaller desk fan at the next hamfest. Jon KB1QBZ __ 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] K2: Filter and BFO Settings for RTTY
jperelst wrote: For now I've got a desk fan pointed at the rig when doing longer transmissions and that's keeping the rig cool and stable. I'll find myself a muffin fan or smaller desk fan at the next hamfest. Jon, You might want to check out Tom Hammond's web site at www.n0ss.net. Click on the Elecraft K2 related files, then scroll down to the Auxillary fan for the K2. Might be something that would work for you. 73, George, NC5G, K2-2217 __ 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://elecraft.365791.n2.nabble.com/K2-Heat-On-Digital-Modes-tp5572168p5595458.html Sent from the [K2] 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] K2: Filter and BFO Settings for RTTY
I'm having a problem with the BFO settings for RTTY. The outputs on the different filters are centered at significantly different places in the waterfall. For R-Reverse, they're as follows: Filter WidthCenter on Waterfall --- --- FL12.5 KHz1.1 KHz FL21.3 KHz2.0 KHz FL30.6 KHz1.6 KHz FL40.3 KHz1.1 KHz Thus, a station centered at 1.0 KHz on my waterfall when using FL1 is not visible in the waterfall when using FL2 or FL3, but is again visible when using FL4. My understanding from the main K2 manual is that R-Normal is LSB, and R-Reverse is USB. Based on that, I used the KSB2 LSB BFO settings for R-Normal and the KSB2 USB BFO settings for R-Reverse. The settings for R-Reverse were: Filter Width BFO --- - FL1Op1 4916.3 FL21.40 4916.1 FL30.70 4915.5 FL40.20 4914.7 These R-Reverse BFO settings are the same as I have set with USB. By comparison, for USB, using the same BFO settings, I get all four filters centered at about 1.1 KHz. A station at 1.0 KHz on my waterfall is visible on FL1, FL2, FL3, and FL4. I took the measurements with a straight stereo cable from the headphone out to the line in on my computer. I also re-did them with a SignaLink USB and got the same results. Similarly, I tried both fldigi and DM-780 as my software and got the same results. What am I doing wrong? I didn't find anything in either the K2 Operating Guide or the KSB2 Operating Guide for any BFO calibrations related to the RTTY mode. By the way, I re-did the KPA-100 bias adjustment on my rig and it was pretty close to correct to begin with. I did notice that the K2 Operating Guide recommends against transmitting at more than 10w for more than 1-2 minutes at a time for continuous duty cycle RTTY/data modes. As always, thanks for your help, Jon KB1QBZ __ 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] K2: Filter and BFO Settings for RTTY
Jon, The default BFO frequencies for the RTTY filter set will not be optimum for your K2, you will have to optimize them the same as you must do for SSB and CW if you are to achieve decent filters. A note of interest - due to the varactors that were supplied with K2s over the past year, the wide (greater than 1.00) filter widths are much greater than that indicated by the K2 display. The cure is to use Spectrogram (or other audio spectrum analyzer) to measure the actual width of the filters for SSB and possibly for RTTY. I suggest you use Spectrogram to set the filters. RTTY is not much different than either the SSB or the CW filters. See part 3 of the K2 Dial Calibration article on my website www.w3fpr.com for information about using Spectrogram for filter alignment. Set FL1 to the OP1 filter since the OP1 filter will be always be used for transmit. Set the BFOs for FL1 the same as you have for SSB - yes, RTTY should be the same as LSB and RTTYr should be the same as USB. The low frequency -3dB corner of the filter passband should ce located at 300 Hz. That will provide you with a full width filter for use with most PSK31 applications. I usually set FL2 at a 1.00 kHz bandwidth, FL3 at 0.70, and FL4 at 0.40. You may vary those if you prefer different widths. Whatever your chosen widths, set the BFOs for those filters to center on 1000 Hz. Use Spectrogram to see the filter passband and where it is positioned. Those settings will give you narrow filters for PSK31 when there are strong signals nearby and good narrow filters for RTTY (set the RTTY application to use 915 Hz as the mark frequency). When using the narrow filters, tune the desired signal to the vicinity of 1000 Hz on the waterfall display using the K2 VFO. If you have the KDSP2 installed, you must change the DSP RTTY filter AF2 through AF4 center frequencies to center on 1000 Hz to agree with the IF filter frequencies. Leave the AF1 setting at LO PASS. On the RTTY power question, that recommendation you referenced is for the base K2 without the KPA100. With the KPA100, you can operate continuously at 35 watts, or for 1 to 2 minute periods at 70 watts with no harm. 73, Don W3FPR On 10/1/2010 11:20 PM, Jon Perelstein wrote: I'm having a problem with the BFO settings for RTTY. The outputs on the different filters are centered at significantly different places in the waterfall. For R-Reverse, they're as follows: Filter WidthCenter on Waterfall --- --- FL12.5 KHz1.1 KHz FL21.3 KHz2.0 KHz FL30.6 KHz1.6 KHz FL40.3 KHz1.1 KHz Thus, a station centered at 1.0 KHz on my waterfall when using FL1 is not visible in the waterfall when using FL2 or FL3, but is again visible when using FL4. My understanding from the main K2 manual is that R-Normal is LSB, and R-Reverse is USB. Based on that, I used the KSB2 LSB BFO settings for R-Normal and the KSB2 USB BFO settings for R-Reverse. The settings for R-Reverse were: Filter Width BFO --- - FL1Op1 4916.3 FL21.40 4916.1 FL30.70 4915.5 FL40.20 4914.7 These R-Reverse BFO settings are the same as I have set with USB. By comparison, for USB, using the same BFO settings, I get all four filters centered at about 1.1 KHz. A station at 1.0 KHz on my waterfall is visible on FL1, FL2, FL3, and FL4. I took the measurements with a straight stereo cable from the headphone out to the line in on my computer. I also re-did them with a SignaLink USB and got the same results. Similarly, I tried both fldigi and DM-780 as my software and got the same results. What am I doing wrong? I didn't find anything in either the K2 Operating Guide or the KSB2 Operating Guide for any BFO calibrations related to the RTTY mode. By the way, I re-did the KPA-100 bias adjustment on my rig and it was pretty close to correct to begin with. I did notice that the K2 Operating Guide recommends against transmitting at more than 10w for more than 1-2 minutes at a time for continuous duty cycle RTTY/data modes. As always, thanks for your help, Jon KB1QBZ __ 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
