RE: [Elecraft] Hearing CW - Fundamental Keying Waveform?
Hi Bob, >As long as we are discussing hearing cw I'd like to ask a question that has >been bothering me for many years. I am very sensitive to chirp, and that is >not what I am referring to. When I listen to a good cw signal in the range >of about 20-35 wpm I heard the dots and dashes as at slightly different >frequencies. This may simply be some sort of psychological quirk unique to >me. I am not even sure "slightly different frequencies" or tones is correct >way to describe it. Realizing that I am not listening to a sinusoidal tone >but sequences of short and long symbols and that long strings of dots will >have wider sidebands than long strings of dashes, I wonder if this is >relevant in any way. Most likely it is some sort of personal quirk. But I >wonder if anyone on this reflector by any chance notices anything similar or >has an explanation? Let's say the dots are 40 msec long - that's 12.5 dots per second. The fundamental frequency is 12.5 Hz of course, with all the odd harmonics (37.5, 62.5 ...) So if you tune to hear this as 600 Hz, your actually hearing 600Hz+12.5Hz, 600Hz-12.5Hz, and 600Hz+37.5Hz, 600Hz-37.5Hz and so on depending on keying waveshape and receiver filter setting. So, dashes must then be 120 msec long, but with only 40 msec space between. That comes out to 6.25Hz. So what you hear is 600Hz+6.25Hz, 600Hz-6.25Hz, and the odd harmonics 600Hz+18.75, 600Hz-18.75, and so on, and certain even harmonics, since this isn't really a square wave. How much power is in each harmonic depends on the waveshape But - let's say your hearing or filter settings don't have a perfect flat response around 600 Hz. To exagerate, lets just cut off everything below 600 Hz. You might then hear dashes as 606.25 Hz, and dots as 612.5 Hz. That's a difference of 1% or so, and about 17 percent of the difference between two notes on a piano. The effect would get bigger as you move the center frequency down. You would be able to hear the change. 73, Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] N-Gen Output
Hi Stewart and Kevin Calculation for white noise are a bit tricky - here goes: The power output is specified as Excess Noise Ratio. This is how much more power the N-gen produces compared to a 50 ohm resistor at a temperature of 290 Kelvin. How much power that is depends on bandwidth. If you double the bandwidth, you get twice as much noise power. The equation is Pn=kTB. So, at 2300 Hz bandwidth, at 290 K, we get 1.38x10(-23)*2300*290=9.2x10(-18) watts out of a 50 ohm resistor. Since we're 35 dB above that, we've got a power out of 9.2x10(-18)x3162=2.9x10(-14) watts. Since this is a 50 ohm source, voltage output is only about 1.2 micro volts. Of course, this is in RMS. Now, the oscilloscope bandwidth is going to be much larger, let's say 50 MHz. So the noise bandwidth increase by 5000/2300, which in dB is 43 dB. So voltage will look higher on the scope, by the square root of that, or about 137 microvolts. Again, this is RMS, but not like for a sine wave. You should often see peak values up around 0.4 millivolts in a very random fashion. Might be a bit hard to catch unless you have a delayed sweep circuit and a fast sweep rate. Michael, AB9GV >Hi Kevin, > >If your calculations are right ( and I have not checked them) then 56 uV would >be very difficult, if not impossible to see on the average oscilloscope. > >On most oscilloscopes the maximum Y axis sensitivity is 1 to 5mV/cm, so you >are >trying to measure something approx 100 times smaller. > >73 >Stewart G3RXQ > Hi guys, > > I have built the Elecraft Noise Generator. The specs say that the noise > output is 35 dB. > > Am I correct in assuming that 0 dB corresponds to 1 microvolt, so that > an output of 35 dB corresponds roughly to 56 microvolts? > > If this is so, it would explain why I can not see the output on my > oscilloscope. > > Many thanks in advance, and 73 > > Kevin > VK3DAP / ZL2DAP ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 led diffuser
Hello Arie My K2 was a few serial numbers before yours. The layers in my kit were: The LCD: Polarizer (remove this and it is ruined) Glass Liquid Crystal stuff Glass substrate with lots of pins Transflective Layer (looks a bit like metal foil - don't mess with it) The Back Light: Thin milky film half stuck to clear plastic diffuser, kind of wrinkled Clear plastic diffuser with LEDs stuck to it Thick white material (not attached well, but it is important to leave it on there) I tried to straighten out the milky film but it only got worse, so I decided to leave it off. My guess is that it might help even out the light if you leave it on, but I didn't want to look at the wrinkles forever. I figure it was in there to prevent scratches - but I could be wrong. I wonder how many encountered this? Michael, AB9GV >I'm building K2 # 3612 . Question about the led diffuser. >The back side has a thick foil. The front side is much more thinner, a milky >thin foil which is a bit loose from the glass. >Is it right to leave the thin foil on there, or should it be taken off. I'm >not sure. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 intermittent CW fault - help!
Bob, is the Mic plugged in when this happens? /DOT-PTT is wired to the Mic input, and perhaps picks up RF if the shield ground on J2 Mic isn't working. Michael AB9GV --Hi All, -- I have an intermittent problem with CW on my K2 (ser 5309). ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] Trouble with K2
Hello Luc As a quick test, don't adjust C22 or L30, just verify the tests on page 60 and 61 of manual F still give reasonable values: Do the PLL Reference Oscillator Range Test to make sure the PLL still works. Do the VCO Test to make sure the VCO still works. If both of those are working, make sure that the Table 6-1 VCO Voltage Readings haven't changed much. A poor solder joint in the Phase Lock Circuits might be the problem. The K2 is pretty tough, it isn't likely to get killed by a near by transmitter. Michael AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] PLL Ref. Osc. Fixed
With normal component values, and 7.8 V on 8A, you will get 3.72 V max at U2B pin 5, so you've done everything right. Even with 8.0 V on 8A, you shouldn't get more than 3.82 V at U2B pin 5 with RF gain set full clockwise. (The manual calls for 3.8 Volts there, not 3.9) --I did find one other thing that doesn't seem quite right. I'm having --some trouble with the AGC circuit, and adjusting R1 on the control --board. It says to adjust R1 to see about 3.9 volts on pin 5 of U2, --but I can't get any more than 3.7 volts. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] Silly arrestor question
I see that a coaxial line arrestor has a gas discharge tube between the center conductor and the coaxial shield. The other stuff, inductors, resistors, capacitors are important, but not interesting during a lightning strike. All of this stuff is in a thick conductive box. This may sound like a dumb question, but think about it. How does the lightning get out? The walls are several skin depths thick. There seems to be a ground lug on the outside of the box. That would take care of current on the outside of the coaxial cable well enough. Wouldn't the voltage and current running between the center conductor and shield have to reflect back up the coax, and then come back down the outside of the cable to get to the ground lead? Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 - Rsspy sound on CW
Hi Jerry, Sometimes RFC15 broken, causing problems at some frequencies for the PLL. Michael, AB9GV >I got a report of it sounding very raspy, so I monitored it with another >rig and sure enough the CW sound horrible and raspy is a good word for it.. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 Anomaly
--- and so, if you want the problem to go away, move the control just a touch to get it away from the switch point. On the other hand, if you want the value to pop up from time to time, move the control to the switch point. Of course, that's like dropping a penny on edge, it never sticks when you want it too. Michael AB9GV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ron D'Eau Claire Sent: Monday, November 28, 2005 11:21 PM To: 'Tom Hammond'; [EMAIL PROTECTED]; 'Chuck Gehring'; Elecraft@mailman.qth.net Subject: RE: [Elecraft] K2 Anomaly A few years ago that anomaly got a lot discussion along with the one in which the code speed will suddenly pop up on the display. IIRC, the most likely cause was that one of the DAC's that monitor the controls and reports any change was right near a switch point, so very minor variations on voltages or even just tiny changes in the response when it is polled for data will sometimes cause it to report an change in the value by one increment. Of course, the K2 is designed to display the change whenever something like the power or keyer speed is changed, so it pops up on the LCD for a moment. Ron AC7AC -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Hammond Sent: Monday, November 28, 2005 8:37 PM To: [EMAIL PROTECTED]; Chuck Gehring; Elecraft@mailman.qth.net Subject: RE: [Elecraft] K2 Anomaly >It is not confined to your K2, it does it on mine too - SN 00020 with >all the latest upgrades and most recent firmware. I too cannot find >any way to duplicate it with certainty, and it is not really bothersome >- just surprising when it happens. I guess it is just one of those >'interesting' artifacts of the K2 firmware processing. I've always figgered it was due to my having brushed one of the knobs with my finger as I 'thumbed' the VFO knob around while tuning. Tom N0SS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
RE: [Elecraft] AA lithium batteries & K2...
Hi Bill, The battery is only good for 2 watt hours. So six of them does 12 watt hours. If you pull 10 amps at 12 volts for 1 hour, that is 120 watt hours, so the battery will last for 1/10 of an hour. That's 6 minutes of talk time. A couple of things go wrong though - the voltage will drop to 3 x 3.25 volts = 9.75 at 5 A per cell, which is too low I think, but 4 in series will make 16.3 volts open circuit, which is too high I think. 73, AB9GV >This has me examining how to Pelicanize my portable setup. >Maybe I will go with the k2/100 kat100. I loose only the battery, which >these little Tadiran Batteries could supply at SMALL SPACE cost.(for qrp op >only). >bill >> 5-A continuous discharge would feed my ATS-3 very well ;) I could put >> 6 of them is series-parallel to work for quite a spell. >> ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 L33 (BFO) - aesthetics & adhesives
That's what I did. Polyimide (Kapton) tape looks very nice there. It looks like surplussales sells the stuff. 73, de AB9GV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mike Markowski Sent: Friday, April 01, 2005 11:15 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K2 L33 (BFO) - aesthetics & adhesives On Fri 01-Apr-05 at 1152 EST, Mike Markowski wrote: > [...] must put tape over the prewound L33 toroid to prevent it from > contacting the chassis. [...] On second thought, I'll put the tape on the chassis itself! :-P Mike AB3AP Avondale, PA ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
RE: [Elecraft] CW tone
Hi Ian, As far as I can tell, the rasp/buzz issue related to power supplies has to do with magnetic fields coupling into L30 on the right side bottom of the K2. This messes up the VFO frequency, so it should also mess up SSB transmit and receive both. Is it possible that you have a problem with the side tone? Hold down SPOT - if that sounds raspy the problem is with the side tone. If the side tone is clean, flip the K2 on its side. If the rasp/buzz changes a lot, its a magnetic field from somewhere. Look for a "wall wart", a fluorescent ballast, or some kind of unfiltered DC line close to the K2. Also, look at the ~7 MHz birdie tone using spectrogram. A 60 Hz magnetic field will cause the 600 Hz tone to have side bands at 60 Hz intervals due to the FM modulation of the VFO. (The structure might be a little funny looking because of 60 Hz harmonics on the magnetic field.) 73 and Good Luck, Masleid, AB9GV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ian J Maude Sent: Friday, February 11, 2005 8:23 AM To: elecraft Subject: [Elecraft] CW tone Hi all, I have seen this so many times but have been bitten by it. I have just started to get back on the key and my tone is awful. Raspy and buzzy. The tone on Tune is fine. SSB is great. I have moved the PSU well away (Revex 30A, Regular PSU) and even tried using one even further away, easily 5 feet and about 3 feet above it (Farnell Switch Mode). I have the same problem with both. I have removed the PA and tried but still the same. Ideas would be appreciated. Many thanks Ian -- Ian Maude G0VGS Morecambe Lancs UK | [EMAIL PROTECTED] Sysop of GB7MBC, the Morecambe Bay Cluster Running Linux and DXSpider | K2 #4044 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 IF Amp Alignment and AGC Threshold
Hello Chuck, I also never saw much change on the DMM, but the L34 peak was close to the top. Later, I used the Spectrogram program. The peak still didn't change much, but the background noise spectrum does change. Much of the high frequency noise goes away as the slug is turned down, so I know that the setting should not be too near the top. I haven't figured out a good way to center the band pass around the signal though, because the audio from the low side of the IF filter bandwidth gets lost in the low frequency audio cut off frequency. >Second: The IF Amplifier Alignment, outlines a procedure to tune >the VFO to 7.000 MHz then with the L34 slug turned down 1 1/2 turns >from the top of the can, adjust the L34 for signal peak. I hear a >tone at 6,998 MHz and the audible tone is pretty solid for a full one >and half turns in either direction on the L34. I hooked up a DMM to >the headphone output and the voltage appears to peak at the top of >the L34 can. Comments? 73 de AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 Q7 Collector To GND Resistance Reading
Hi Gary, Yes, you are also looking at the 12 volt line. Only 1.7 ohms is too low. Look at your meter. Is the "positive" lead at Q7 - if not you could be "turning on" D12 on the 12 volt feed. That's a reverse polarity protection diode. Also, the resistance readings don't come out right if your ohm-meter puts out too much voltage. The meter should not make enough voltage to "turn on" semiconductor junctions. If you really only have 1.7 ohms on the 12 volt line something is likely to smoke. >In running the final Resistance Checks on p. 71 of the K2 manual, I only >get 1.7 ohms at the Q7 collector. The manual says I should get >500 ohms. GL de AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 #4472 new builder question on 4 mhz alighment
Hi Jerry, >What do I adjust ? If i adjust C22 nothing changes. C22 and the 4 MHz oscillator is used when you calibrate the K2. First you set C22 using CAL FCTR, then you run CAL PLL and CAL FIL so that the MCU can learn about the BFO and PLL reference oscillator settings by "comparing" those to the 4 MHz oscillator. The rest of the time, C22 and the 4 MHz oscillator is not used as a reference oscillator, so nothing happens when you change C22. You can set C22 using CAL FCTR, but you have to run CAL PLL and/or CAL FIL again in order to make any change in tuning. 73, Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
FW: [Elecraft] K2 - SN4511 Diffuser Question
Hello Malcolm, >I am a bit confused with LCD backlight diffuser. >It has a really nasty looking thin film on top which appears to be protective >only then below it another matt white >thin film which appears to be attached at LED ends of the diffuser only. >Looking at the instructions it appears to say that I should not remove any of >these. >Help please. Do I remove the top one which looks awful, both or none? My LCD diffuser had 4 layers. The back side was thin as paper and was white. Next was a thick, water clear, plastic sheet, same thickness as printed circuit board material. Next was a thin, soft, white diffusing layer that was only attached at the LED ends of the plastic plate. Next was a really crummy thin film, like you'd wrap a sandwich in for lunch. This was buckled up in places, and looked like it might show up in the display. I tried to make it be flat, but that made it worse. The way the thing is supposed to work is light bounces around in the clear plastic plate. Some scatters off of the back side white layer and shines through the front. Some gets caught by the front white layer and also shines through the front. The idea is to pipe the light around in the clear plate so that it spreads out evenly, and then lets some of the light leak out the front by scattering from the top and bottom films. So, don't damage or remove the bottom (backside) white film. Don't damage or remove the top (frontside) matt white film. I don't think the crummy, slightly cloudy looking film that protects the top matt white film should be there, but I could be wrong. I took mine off. My display looks just fine, but I can see a little extra brightness at the left and right edges from the LEDs. 73 and GL, Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] Hum Coupling
Hello Allen, >My guess is that magnetic fields from power transformers are either 1) being >picked up by L30, or 2) that the magnetic fields are going through the cores >of L30 and/or T5, and modulating the effective permeabilities of these >cores. This will cause a modulation of inductance, and thus a modulation of >the VFO frequency. The magnetic field is picked up by L30. >To work best, the magnetic shield should completely surround the susceptible >parts. Putting the shield on only one side seems to make things worse. >Here's a possibility for experimenting with K2 susceptibility: Try using one >of those bulk tape erasers near it. They put out huge 60Hz fields. [Just >don't get it near your credit/bank cards!] Of course, keep it away from the latching relays. I used a tape head demagnetizer. Placing the probe near the base of L30 causes a vast huge amount of FM. Don't try this unless you cut the current way down. Looking on the scope, FM modulation is at 60 Hz, not 120 Hz, so we're not modulating the permeability, we seem to be inducing a 60 Hz voltage onto L30/T5 which is modulating the varacters. What I don't understand is this: I figure L30 has perhaps 14 turns, and 2.3 ohms winding resistance. I figure that the effective aperture is 1 cm squared. I figure that the winding resistance of T5 is 0.05 ohms, so a 1 gauss vertical 60 Hz field will induce 37 micro volts on T5. That should cause 0.3 Hz FM modulation on 80 meters. No one should notice that? BTW, I calculated 2.3 ohms from the Q, sensitivity at T5 goes way up if L30 has less resistance. I know that the cup and core used in L30 will focus any external field through the winding, but I don't know how to calculate how much. It would be nice if someone could put an L30 (TOKO T1005Z 4.7 uH) into a Helholtz coil and get the numbers on it (uV/gauss at 60Hz, winding resistance). 73, Michael ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] Opinions please...
Hello Julius > Ok, I want to build a balun. It should be able to > handle 200 Watts RF (safety factor built into this > number), 80 thru 30 Meters (160M would be nice) and be > efficient. Well, I'm guessing here, but I think you'll need to use ferrite to keep the inductance reasonable. You also want to keep the B field low so it doesn't get hot or non linear. Let's shoot for 200 gauss peak. If you were running 200 watts into 50 ohms, you'd need 100 volts on the line, but that would be into a matched load. Into a doublet lets say we have a 10:1 VSWR, so we'll see 1000 volts at the balun. How many turns? Lets try 10. Frequency, 1.8 MHz. Using Fair-Rite's formula, we'll need 6.26 cm squared core area. If you use FT-100-43 I think you'd need to stack them up until you have a 1" diameter by 5" long tube. I might be way off though. 73, de Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 CAL PLL
Hi David, >I'm looking for (links to or) a fuller explanation of what happens in this >process: number of points, interpolation, etc. To find out on your own, you could try this: 1. Get a stable CW signal source. 2. Get the spectrogram program. 3. Setup spectrogram for very high resolution. 4. Using CW mode, display the tone from the source in spectrogram. 5. Copy down the VFO setting and the tone frequency per spectrogram. 6. Change the K2 VFO setting by 10 Hz (don't change the signal). 7. Do steps 5 and 6 until the tone is at the edge of the CW filter bandwidth. 8a. Note the frequency per spectrogram 8b. Change the CW signal source frequency to get the same tone as in 4. 8c. Take the difference and write it down. 9. Do step 7(loop 5-6) and 8 until the signal is outside the RF filter bandwidth. 10. Plot the points as an X Y graph. This will look like a saw tooth. If you add back the differences recorded in step 8c you can fix up the curve to get a ramp and see each interpolation point. Step 8b causes an error that accumulates, but over any short range you can see how the K2 is setting the VFO. A better procedure could be done with an old fashioned crystal calibrator, but I think you'll get a feel for how the K2 works after looping through steps 5-8 a few times. 73 de Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] Parts for compact loop antenna - toroid help
Hi Daniel >I'm just posting this so that someone can tell me ... NO - DON'T DO THAT - or - >DO THIS. OK, use FT 43 material. You want to make a broadband transformer. You want tight coupling, but you need the right turns ratio. If the small loop has a radiation plus loss resistance around 1 ohm, you need a 1:7 turn ratio to match 50 ohms. You want the shunt reactance of this 7 turn coil to be much more than 50 ohms. FT 43 can do that. If you run 8 watts, you need 20 volts on 7 turns. An FT-50-43 core will run about 138 gauss at 3.5 MHz to do this. Use a bigger core to reduce loss, handle more power, and have enough room for the windings. 73, de Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] J.T.O.A
Hello Kenneth, > I have been asked to put up a station for the local BSA troop to observe > Ham Radio on Saturday October 16th. I'm going to be running barefoot out of park in Dyer, Indiana. It might work? Last year I was listening from the Camp Betz. I could hear JOTA SSB stations on 40 and 20 meters from across the country with no problem (the antenna wire tossed up in a tree, and the ground wire running off into the woods somewhere). I didn't hear anyone at the JOTA calling frequencies, but there were scouts up and down the band from there. Figure that JOTA is set up so the scouts can talk on the radio. Only a few scouts know CW, so I wouldn't expect much there. This year I've built the SSB adapter for that reason, but I don't know if it works. You might want to try near 7.270 MHz, I think that's the 40 meter calling frequency for JOTA in the USA. 73, Michael, AB9GV (Scoutmaster, Troup 510) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 Alignment
Hi Fred, > I have a calibrated service monitor. Don's page has what you need to know. Since you have a service monitor, there may be a shortcut. The service monitor needs to be within 1 part per million. I don't know if CAL FCTR has changed in the latest firmware, but this used to work: To set C22 with an accurate service monitor: Let the K2 warm up. Start CAL FCTR. Set the service monitor to 28100 KHz. Attach to the frequency probe. (Connect the shield from the monitor to one of the ground points on the K2.) Increase output from the monitor to get a reasonably stable count on the K2. I needed about 1 Volt. Set C22 so that you read 28099.95 on the K2. The display may switch between 28099.95 and 28099.96. That's all there is to it. This creates a small offset to the 4 MHz oscillator that is needed for some reason. You have to do CAL PLL and CAL FIL with the bottom cover in place, and the stand the way you want it when you operate, and you have to do it before to much time goes by, since the setting on C22 is temperature sensitive. 73, de Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 Front Panel
Hello Steve, --I am at the point of adding the capacitors, Q3 , P1, RP3 , R13 and the --MYSTERY Rbias 10K resistor that I am having trouble locating. Can anyone --explain to me what this part looks like. It should look just like R16. You are better off not finding it. The correct value for Rbias depends on the microphone that you are actually going to use. For instance, the MH2 microphone from Elecraft includes a 5.6K resistor that will be used as Rbias for the MH2, as well as parts and instructions for setting up the microphone configuration. 73 de Michael, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
RE: [Elecraft] K2 transmit rapid drift on 10 meters
Hi Bill --Everything sounded great on 80, 40, 20, and 15 meters, but on 10 --meters, yuk. --... there was a very bad frequency drift on key --down that never seemed to stop. Take a look at the Table 6-1 VCO Voltage Readings for your K2. It may be that you are close to the voltage limit. I think that the VFO has to shift by the BFO offset frequency on key down. It must do this very quickly so that there is no chirp. If the VFO is barely hanging in there, if may do some strange things. 73, AB9GV ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
