Re: [Elecraft] New Elecraft Product: K-Pod Control Panel for K3S and K3 Transceivers
Hi Wayne Will the K-pod work with the K3-0? 73, Mike, W3IP From: Wayne Burdick To: Elecraft Reflector Cc: "elecraft...@yahoogroups.com" ; "elecr...@yahoogroups.com" Sent: Wednesday, April 13, 2016 11:04 PM Subject: [Elecraft] New Elecraft Product: K-Pod Control Panel for K3S and K3 Transceivers Hi all, We've had many requests for a small control panel (or pod) as an extension to the K3 and K3S transceivers. We finally got around to it! Our new K-Pod is a very compact unit, featuring a precision tuning knob, VFO A/B/offset rocker switch, and 8 programmable tactile-feedback switches. Switch feedback is provided by activation messages on the radio's LCD, as well as the pod's own 4 indicator LEDs and audio tone generator. This multi-modal information can help maximize operating efficiency and reduce fatigue during extended operating periods. Typically the K-Pod would be placed next to a computer keyboard, allowing the operator to quickly QSY, clear RIT, enter diversity mode, change menu settings, etc., without that long stretch to reach the radio's front panel. But the K-Pod's flexible interface goes beyond substitution of the radio's knobs and switches. In effect, you can design your own customized controls for the radio. Each of the 8 programmable switches has tap and hold functions. When a switch function is used, it activates one of up to 16 user-defined command sequences that are actually stored in the radio itself, as macros. A single macro can accomplish many tasks at once, such as setting up custom splits, configuring the receiver or subreceiver for specific situations, sending transmit messages at differing code speeds, etc. Macros can be easily created or edited using K3 Utility, which runs on PC, Mac, or Linux platforms. The K-Pod has the following features: * high-quality weighted, soft-touch tuning knob--same as used on the K3S * same 400-count, ball-bearing optical encoder used in the K3 and K3S * adjustable knob friction * 3-position rocker switch to assign the knob to VFO A, VFO B, or RIT/XIT * 8 programmable function switches, each with tap/hold functions * simple switch programming using K3 Utility (many examples in K-Pod manual) * four user-definable LEDs (three of them show knob assignment by default) * audio tone generator for switch feedback (can be easily turned off) * USB port for firmware loading and future equipment/computer control applications * simple connection to K3 or K3S--uses the 6-pin RJ-style jack beneath the front panel * flexible power source: rear 12-V jack on the radio, DC barrel jack, USB port, or even through the 6-pin data cable, with minor radio modification (the latter method results in a single cable to the K-Pod for data and power) * 3 utility outputs for miscellaneous equipment control applications (outputs provide a low resistance to ground when turned on, usable with relays, etc.) The K-Pod's all-steel enclosure weighs a full pound for excellent stability, yet measures only about 3.5 x 3 x 1 inches. A highly stable folding tilt stand is included to angle the panel for optimal access. There's also a 2-hole RAM mount pattern on the bottom for easy attachment to any surface. For photos and further information, please visit our K-Pod web page: http://www.elecraft.com/k-pod/k-pod.htm 73, Wayne, N6KR Eric, WA6HHQ __ 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 m.cre...@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
Re: [Elecraft] Transverter XV144 way off frequency
Bob My observation is that the K3 reference oscillator is much more stable (moves just a few Hz max) than any of the XV transverters even if equipped with ovens. I would instead use the LeoBodnar Mini to replace the local oscillator in the XV144. The process is identical for the XV222. Comments below assume an otherwise properly adjusted and operating XV144, and that you are handy with a soldering iron or a hot air rework station. First, before you start, measure the DC voltage at TP1 on the XV144 with a voltmeter. Write it down. Be gentle unsoldering parts from the PCB. The traces and pads are fragile. Remove U2 - the regulator for the crystal oscillator. Remove the oven if one is installed (no need to create more heat). Remove C15. Repurpose the back panel "Aux" BNC connector and run RG174 (or similar cable) from the connector to the vicinity of C15. Connect the coax center conductor to one end of a small 1000 pF disc ceramic capacitor (value not critical) - short leads! The other end of the 1000 pF capacitor goes into the now empty hole previously occupied by C15 that is closest to Q2 with minimum lead length. Ground the coax at both ends. Done. The other oscillator components can remain in place. Set the LB Mini to 11600 Hz and the output drive to "8 mA". Connect the LB Mini output to the "Aux" connector. Check the DC voltage level at TP1. If the voltage is the same or higher than the original reading, you are done. If it is less than before, increase the LB Mini output to the "16 mA" setting. Measure the DC voltage level at TP1 again. Repeat if necessary. This step makes sure you have sufficient drive level to the mixer. My XV transverters are in close proximity to a computer and router, plus several (now shielded) ethernet cables, USB cables and a couple of serial cables. There were many weak birdies observed when tuning across the band. Lots of ferrites helped a little. There are internet articles by Jim, K9YC who discusses why the birdies appear (see his comments and drawings about the "Pin 1" problem), and Bruce, NT4RT, who shows what he did to (among other things) improve the grounding on his XV432. Many of his comments are applicable to the XV144. Adding in the LB Mini may increase the number of birdies present in the receiver output unless additional steps are taken. It may also help reduce birdies to run the LB Mini off of a linear lab power supply at 4.5 volts (cut off the computer side connector of a USB cable, use the +5 and ground wires in the cable to connect to the supply). YMMV 73, Mike, W3IP From: Don Wilhelm To: Bob KD7YZ ; K3 List Sent: Friday, May 17, 2019 3:24 PM Subject: Re: [Elecraft] Transverter XV144 way off frequency Bob, I skipped Dayton this year. It is true that there is no stock means of syncing the XV144 to an external standard. A few owners have said they were successful with replacing the crystal with a circuit that is synced to an external standard, but I now nothing of that implementation. Perhaps someone who has done it will speak up. How is JP9 jumpered in your XV144. For maximum stability, the jumper should be between pins 4 and 5 (no other jumpers). With that setting, the crystal oven will be powered as long as 12 volts is applied to your XV144 - don't turn the power supply off! Let the oven warm things up for at least a half hour (longer if possible) and then calibrate. It should stay close on frequency. 73, Don W3FPR On 5/17/2019 3:06 PM, Bob KD7YZ wrote: > My K3 has an external "Leo Bodnar" reference [REF * CAL] . Thus the K3 > is accurate for my EME and MSK144/FT8 adventures on 2m. > > Except: I discovered that the XV144 is not synced with anything. > The K3 Menu/Config DOES allow for "XV1 OFS", and knob turning, to set in > a "Calibration" value. > > As I do not have the luxury of a bench of accurate test and calibration > equipment, I am unable to get the XV1 to get and remain near to accracy. > > Some friends told me they "Thought" that the XV144, external > Transverter, does have the option for an external GPS REFLOCK as the K3 has. > > Calls to Elecraft revealed, other than friendly people, that there is no > way they know to REFLOCK the XV144 .. > > So List people, figuring I do not want to calibrate every day, how are > you users of XV144 keeping your other friends from naggin you every day > and every time you call CQ on MSK144 ?? > > > Hoping Don, W3FPR, will have some time after hectic daily Dayton > HamFest schedule to answer too. > > > -- > 73 > Bob KD7YZ > AMSAT LM #901 > > __ > 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] K3/K3S with KXV3B Feature request
Wayne/Eric I'd like to use a lower net gain (on receive) transverter with a K3/K3S.The transverter IF frequency is 28 MHz. Would it be possible to selectively enable Preamp 2 of the KXV3B during transverteroperation? Moving the transverter receive line to "Rx ant. in" andselecting Preamp 2 should result in improved sensitivity (with related changein dynamic range). Thanks 73, Mike, W3IP __ 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 - Transverter IF frequencies outside the ham bands
I am contemplating building a 2 meter transverter based on a very low noise commercial100 MHz crystal oscillator that would result in a IF frequency of 44 MHz. Can the KXV3 et al be coerced into emitting 0 dBm outside the ham bands and the front panel display the transverter tuned RF frequency? The subject K3 does have the KBPF3 installed. Thanks 73, Mike, W3IP __ 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] K4 Question
Once any FT8 passband is digitized, filtered, and decimated in a K4, there should be no need to ever apply AGC - just pass the bits over to WSJT. The decimated bit stream may exceed 16 bits, so the WSJT input processor would have to be modified to accept the additional dynamic range. On Tuesday, June 23, 2020, 9:12:47 PM EDT, Adrian wrote: On 24/6/20 11:02 am, Jim Brown wrote: > On 6/23/2020 4:53 PM, Adrian wrote: >> An excessive strength FT8 signal is easy to remove with notch. > > Yes, BUT -- the notch introduces phase shift, which can degrade > decoding. K1JT recommends running the IF wide and letting WSJT-X > separate signals. Ok on that, My experience is that it allowed decode of my target RX., I did use narrow notch. > > I DO strongly differ with the advice in the WSJT-X manual for setting > levels. Instead, I recommend setting audio gains so that the green bar > indicating audio level as close as possible to the top without it > turning red on when strong signals are present. I find Slow AGC works > well for me, because both the strongest signals AND my local noise > vary widely. Yes I do that all possible gain and AGC turned off on low band use, with green as high as 80dB with no red seen , for good weak signal decode. Using low width roofing/dsp filtering around the signal boosts it to great extent, using width/shift to focus. __ 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] K4 TERM mode
Or will a K3/0 be able to control a K4? 73, Mike, W3IP On Friday, June 26, 2020, 7:53:37 PM EDT, Fred Jensen wrote: Hope this isn't redundant ... anyone know if the K4 will control a K3 in the RRC 1258 K3 Twins mode? 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County __ 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 m.cre...@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
Re: [Elecraft] XV222 RX is Dead, Need Advice
Mark You can check the performance of your XV222 receiver amplifiers with only a common voltmeter. Take off the top cover of the transverter, check the voltage between TP2 and ground (should be between 200 to 275 millivolts). That measures part of the source voltage of Q3, the first receiver amplifier. Find R16 (a 120 ohm resistor) and measure the voltage to ground on each side of the resistor. One side should be 12 volts, the other should be about 5 volts. That measures the series dropping resistor for U1, the second receiver amplifier. R16 will normally be very warm to the touch. If those measurements are correct, the problem is most likely elsewhere. You can check the condition of the local oscillator by measuring the voltage between TP1 and ground. It should be between 1.0 and 1.5 volts. The part and test point locations are shown in the Transverter Owners Manual, page A-4, available on the Elecraft web site. Good luck! 73, Mike, W3IP On Thursday, September 17, 2020, 8:58:35 PM EDT, k2qo wrote: During the recent September VHF contest I could only hear the absolute strongest local stations on the XV222/K3 in my rover. It worked FB in June. My XV432 worked just OK as usual. Stations told me I was the loudest signal on the 222 band so the TX side is fine. I put it on the bench and connected my Elecraft N-Gen. When turned on I could barely detect an increase in noise. Tried the same on my XV432 and it went from S0/1 to a solid S9. I'm guessing that I somehow blew up U1 (an ERA6) and/or Q3 (an ATF 34143). I don't have a good scope, RF generator, or RF voltmeter but kinda think replacing both will fix my XV. A bad relay is an option too. Thoughts? I'd like to fix it to have for a spare as I plan on moving non-BigE transverters for 222 and 432. 73, Mark K2QO NF2RS/R for the September VHF -- Sent from: http://elecraft.365791.n2.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 m.cre...@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
Re: [Elecraft] HI CUR on 40
Dave So where is the optimum place to place the ferrites for this antenna if you have a problem like Alan described? Does the near field extend roughly to half the stacking distance of that antenna (i.e. 6 feet or so), making that the best place for the ferrites? Does a mostly vertical coax passing through the near field of a horizontally polarized antenna (i.e. an antenna side mounted to a tower) need ferrites? Do you need to decouple ALL of the rest of your coaxes and control lines at the lower near field edge of that antenna (or at some other point)? I have heard that argument (decouple everything) made to improve performance of inverted L antennas on 160 meters located near a tower. 73, Mike, W3IP On Saturday, October 31, 2020, 10:04:48 AM EDT, David Olean wrote: Hello Alan That was my antenna design. It has a teflon coax 1/2 wave balun that kills RF on the shield side of the coax, but there is not much you can do about near field energy getting picked up by the outside of the coax due to radiation. It is best to tape the coax down snugly along the boom and masting etc. Still, it does not hurt to add more RF chokes to any antenna! It is pretty easy for RF energy to get impressed on the outside of the coax in any typical installation. The balun at the antenna only keeps the energy from the coax center conductor from going to the outside of the coax at the feedpoint. The way I check for decoupling effectiveness is to match the antenna really well, and then run your hand along the outside of the feedline near the feed. While looking at the screen of a network analyzer, you can see little perturbations in the return loss 20 or 30 dB down if there is RF leaking to the outside of the feedline. This is a qualitative test and you can estimate the bandwidth of the decoupling network. You will see larger return loss change amounts away from the resonant frequency of the decoupling element. This won't apply to ferrites, as they can be broadband, but with a quarter wave choke, or similar, you can definitely see the effect. 73 Dave K1WHS On 10/31/2020 5:39 AM, N3ALN wrote: > Hum, I was getting this HI CUR error only with my Directive Systems 6 Meter > antenna (DS50-5) that has a 1:1 SWR I hope they know antenna design? Maybe > not? The toroids fixed my issue. I just love how some of the forum or so > judgmental, it is a only a freaking hobby, chill. > > > > -- > Sent from: http://elecraft.365791.n2.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 k1...@metrocast.net __ 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 m.cre...@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] KPA1500 replacement devices
Anyone have an educated guess whether the ART1K6xx or ART2K0xx devices would be a drop in replacement for the currently used device in the KPA1500? Most of the interesting specs are within 10% of the current device, the open loop gain may be a dB or two higher (if the data sheets are really comparing apples to apples). The main attraction of the ART1K6 and ART2K0 devices is the higher peak voltage handling capability - 177 or 200 volts vice 135 volts for the current device. Maybe a higher peak voltage capability will keep the amplifier out of the repair shop due to external events like arcing baluns or antennas flexing in the wind. The package styles are identical, the ART devices are in stock from a few of your favorite distributors, similar price to the current device, maybe the quiescent bias voltage would have to be tweaked a bit... 73, Mike, W3IP - __ 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] KPA1500 replacement devices
Hi Hal I see the Rds difference. Wouldn't the higher Rds be compensated by the better Rth (thermal resistance from junction to case) spec in the ART devices? 73, Mike, W3IP On Tuesday, November 1, 2022 at 03:15:09 PM EDT, Dynolab wrote: While the higher voltage ratings of the ART1K6 or ART2K0 series looks very attractive, it is extremely important to remember that heat is the number one killer of LDMOS RF power FETs! That being said, take a look at the specifications of the ART1K6 and ART2K0 and note that the Rds(on) drain-source on-state resistance of these devices is significantly higher than that of the devices presently being used in the KPA1500. And this higher Rds(on) would result in higher drain-source saturation voltage when the amplifier is running near its limits which would in turn result in higher heat dissipation. It is therefore possible that the ART1K6 or ART2K0 devices may be less reliable than the devices currently being used in the KPA1500. 73, Hal W7YNC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of M Cresap via Elecraft Sent: Tuesday, November 01, 2022 10:21 AM To: Elecraft@mailman.qth.net Subject: [Elecraft] KPA1500 replacement devices Anyone have an educated guess whether the ART1K6xx or ART2K0xx devices would be a drop in replacement for the currently used device in the KPA1500? Most of the interesting specs are within 10% of the current device, the open loop gain may be a dB or two higher (if the data sheets are really comparing apples to apples). The main attraction of the ART1K6 and ART2K0 devices is the higher peak voltage handling capability - 177 or 200 volts vice 135 volts for the current device. Maybe a higher peak voltage capability will keep the amplifier out of the repair shop due to external events like arcing baluns or antennas flexing in the wind. The package styles are identical, the ART devices are in stock from a few of your favorite distributors, similar price to the current device, maybe the quiescent bias voltage would have to be tweaked a bit... 73, Mike, W3IP - __ 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 dyno...@comcast.net __ 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] KPA1500 replacement devices
Hi Hal I like the water cooling! I debated about using water cooling on a W6PQL 2 meter amp I built several years ago, ended up with an oversize heat sink instead. Since the KPA1500 power supply probably can't safely be adjusted to 65 volts to best accommodate the ART2K0, the ART1K6 is likely the better choice since it is expecting 50 volt on the drain. An interesting experiment. Thanks for your perspective 73, Mike, W3IP On Wednesday, November 2, 2022 at 01:13:46 AM EDT, Dynolab wrote: Hi Mike, Agreed, the ART series does have lower Rth but I would still worry that it may not be low enough to make up for the increased saturation voltage and loss of efficiency due to a drain to drain impedance that has been optimized for a Vdd of 50Vdc. However, I may be overly timid as I have a graveyard of LDMOS devices that did not survive air-cooled amplifiers. I have since gone to water-cooling and don’t have to deal with the heat problems anymore. (See Attached) 73, Hal W7YNC From: M Cresap [mailto:m.cre...@yahoo.com] Sent: Tuesday, November 01, 2022 3:21 PM To: Dynolab; Elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA1500 replacement devices Hi Hal I see the Rds difference. Wouldn't the higher Rds be compensated by the better Rth (thermal resistance from junction to case) spec in the ART devices? 73, Mike, W3IP On Tuesday, November 1, 2022 at 03:15:09 PM EDT, Dynolab wrote: While the higher voltage ratings of the ART1K6 or ART2K0 series looks very attractive, it is extremely important to remember that heat is the number one killer of LDMOS RF power FETs! That being said, take a look at the specifications of the ART1K6 and ART2K0 and note that the Rds(on) drain-source on-state resistance of these devices is significantly higher than that of the devices presently being used in the KPA1500. And this higher Rds(on) would result in higher drain-source saturation voltage when the amplifier is running near its limits which would in turn result in higher heat dissipation. It is therefore possible that the ART1K6 or ART2K0 devices may be less reliable than the devices currently being used in the KPA1500. 73, Hal W7YNC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of M Cresap via Elecraft Sent: Tuesday, November 01, 2022 10:21 AM To: Elecraft@mailman.qth.net Subject: [Elecraft] KPA1500 replacement devices Anyone have an educated guess whether the ART1K6xx or ART2K0xx devices would be a drop in replacement for the currently used device in the KPA1500? Most of the interesting specs are within 10% of the current device, the open loop gain may be a dB or two higher (if the data sheets are really comparing apples to apples). The main attraction of the ART1K6 and ART2K0 devices is the higher peak voltage handling capability - 177 or 200 volts vice 135 volts for the current device. Maybe a higher peak voltage capability will keep the amplifier out of the repair shop due to external events like arcing baluns or antennas flexing in the wind. The package styles are identical, the ART devices are in stock from a few of your favorite distributors, similar price to the current device, maybe the quiescent bias voltage would have to be tweaked a bit... 73, Mike, W3IP - __ 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 dyno...@comcast.net __ 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 Power-hunting on FT8
I have been running tests on K3s and K4s to understand the conditions needed to transmit clean FT8 signals. I have previously shared some of my findings with Pete N4ZR and a couple of other folks. Their feedback has been very valuable. Joe Taylor, K1JT has shown the spectral purity of the FT4 and FT8 protocols (using WSJT-X version 2.1 and later) to be very clean to 80 dB below the peak signal. See https://wsjt.sourceforge.io/FT4_FT8_QEX.pdf (Figure 3 and related discussion on pages 9 and 10) and https://www.w2zq.com/wsjt-x-innards-explained-by-joe-taylor-k1jt/ (slide entitled Spectra: RTTY, FT8, FT4). If the WSJT-X operating instructions are followed (use operating mode "Fake-It" or "Split"), there is exactly one clean signal to be transmitted as discussed in the exchanges in this thread https://groups.io/g/Elecraft-K4/message/25371 I have been endeavoring to ensure that ALL of the FT4 and FT8 spectra purity shown by Joe Taylor can be replicated by my K3 and K4D in the Data A mode - and that the recipe for a clean spectra can be shared with others. Clean FT8 spectra is badly needed, especially in metro areas at 10 meters and above, where many poor quality FT8 signals abound and wipe out many of the weaker stations that other stations are trying to receive. Yes, there are suggestions that folks in the same area all transmit at the same time, and many people try it, but in practice, not everyone is on-board with that suggestion. But, there are also stations on the air that transmit very clean FT8 signals every day, so it can be done! I shared with Pete that neither my K3 or K4 transmitted the cleanest possible FT8 signal using either analog or USB digital inputs and the conventional setup instructions that have been often repeated on this reflector (i.e. set the audio level so there are 4/5 bars of ALC showing). After I beefed up my DC power cable (it is now 2 feet of #10 wire between the K3 and the power supply), I found that setting the Line In level to the point just before the 1st ALC bar lights up (i.e. Line In = 2 in my case) results in a very clean FT8 signal. As Pete reported, there is a slow increase of RF power output level for 10-20 seconds as the ALC circuit compensates for the lower input level, but apparently the ALC loop remains open, hence the clean signal. For my K4, the FT8 signal is clean with no more than 2 bars of ALC. To be clear, the spurious responses I have seen with ALC set to 5 bars has NO measurable IMD responses. There is only the one strong signal present, the spurious signals being discussed here are all less than 50 or 60 dB below the intended carrier level. My goal is to reduce all the spurious responses to 80 dB below the intended carrier level. The discussion that Pete, N4ZR started several days ago got many responses that could be grouped into three categories: 1. "The manufacturer says use 5 bars of ALC, end of story". I don't buy that at all. I have yet to see any manufacturer's DATA on the relationship between their transmit ALC levels (or any other metric) and the in-band spectral purity of an FT8 like signal beyond "meets FCC spurious signal requirements". 2. "I must be mistaken, my equipment is overloaded, etc". In years past, that would have been a fair criticism, it would have taken hundreds of thousands of $$ worth of calibrated test equipment to prove whether anyone's receiver was overloaded or not. With today's high end receivers (the K4 being one of them), the overload point in every gain state is well known (notably confirmed and publicized by NC0I, Rob Sherwood), and overloaded signals trigger a visible alarm on the radio. The K4 (and I assume other high end receivers with similar architecture) has a repeatable performance (amplitude stability) in showing signal levels to the dB on a panadapter. To me, external monitors and external display programs (like Win4K4) help to visualize and collect data better than trying to read the data off the radio's relatively small screen. 3. "Don't use my data, have someone near you with a high end receiver /panadapteror a good spectrum analyzer (and who knows how to use it) look at your signal". I agree, that is a very sound approach. On 6 meters, a station 10-20 miles away, and near line of sight should provide a good signal strength for analysis by a high end receiver/panadapter. It is also possible for any transmitter that more than one problems exists, beyond the ALC issue. Other potential problems include poor power supply regulation, excessive DC voltage drop on transmit, ground loops, or a defective phase locked loop. Those problems should be fixed before changes to the ALC response is attempted. The K3 accepts both analog and digital inputs for Data In, with multiple generations of I/O boards. I have not tested all of these combinations! Ground loops in particular can be challenging to clean up. I used a Signalhound SA-44B spectrum analyzer and a
Re: [Elecraft] K3 Power-hunting on FT8
Hi Dave, Joe, and Jim The GMSK to AM distortion across any 50 Hz bandwidth of a K3 filter would seem to be minor. With an FT8 symbol rate of 6.25 symbols per second, would that not create some relatively weak 6.25 Hz sidebands plus a bit of mush around those lines due to the pseudorandom nature of the bit patterns? That could increase the overall bandwidth by maybe 18 Hz above the nominal FT8 signal bandwidth. The narrowest resolution bandwidth I have been using is 10 Hz, which is too wide to pick up that level of detail. There is an equalization tool in WSJT-X that is supposed to equalize phase and amplitude filter distortions inside the radio for improved decoding. I haven't played with that feature, but it looks like it could provide degraded results if it collects data at one passband tuning setting, then tries to decode signals after the operator changes the PBT. Bob has reminded me that ALC related measurements should be done with a fresh Tx Cal using the DC voltage/voltage drop that exists today in my shack. I recently changed the DC power wiring to 2 feet of #10 wire between the K4 and the power supply, just like what I did for my K3. I plan on doing that Tx cal tomorrow, will rerun the K4 measurements and let you know what I see. 73, Mike, W3IP On Sunday, July 23, 2023 at 11:59:58 AM EDT, Dave (NK7Z) wrote: Hello Mike, Thanks for sharing your data!! Help me understand something you said... Are you saying that at 2 bars, (for your K4), all spurious signals, are at least 80 dB down from carrier, while at 5 bars, all spurious signals are running around 50 or 60 dB down from carrier? 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist, RFI ARRL Asst. Director, NW Division, Technical Resources On 7/23/23 07:23, M Cresap via Elecraft wrote: > For my K4, the FT8 signal is clean with no more than 2 bars of ALC. > To be clear, the spurious responses I have seen with ALC set to 5 bars has NO > measurable IMD responses. There is only the one strong signal present, the > spurious signals being discussed here are all less than 50 or 60 dB below the > intended carrier level. My goal is to reduce all the spurious responses to 80 > dB below the intended carrier level. __ 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 m.cre...@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
Re: [Elecraft] K3 Resistor Values
Chris The value is stated on the schematic for the K3S RF board, downloadable from the Elecraft website at https://ftp.elecraft.com/K3S/Manuals%20Downloads/E740323%20K3s%20Schematic%20Files.pdf A quick PDF search on R81 will take you to 3 different parts labeled R81 in the schematic. Pick the one on the "K3 RF Board, sheet 3 of 4". 73, Mike, W3IP On Wednesday, November 15, 2023 at 08:31:18 AM EST, sem...@semaos.plus.com wrote: Can anyone tell me where I can get the values of Resistor R81 on the K3S RF Board please? TIA Chris G0TZZ __ 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 m.cre...@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
