Re: FW: [Elecraft] K1 Battery Question
Hi Dan: As I wrote the reply, I was thinking that 40% duty cycle was way too high, because, as you say, there's lots of dead time even while transmitting, but I figured the example would show John how to go about estimating the life of his battery using his own guesses. There are lots of unknowns involved. I have no idea what power setting he uses, how efficient the K1 transmitter is, his SWR, etc. My K2 draws anywhere from 1.5-2.4 Amps at 5 Watts into a dummy load, depending on the band. Another thing not factored in is the 4.0 Amp Hr battery rating assumes a 20 hour discharge. A 1 Amp load would finish off the battery in less than 4 hours. Battery temperature is also a factor, but not so much in the Summer. In my case, I'm sure I'd be asleep well before the battery died. Thanks for the clarification. I should think twice before I hit the send key. This group's too smart! 73's John AA0VE Dan Barker wrote: Actually, the 40% Tx duty is only 50% key down (there's spaces betewwn the elements). So, you use .2 for the Tx factor. .8 Ir + .2 It = .24 or 16 hours. Now, after you work the 9 hours, you might fall over and hit your head on the key, and then the CW duty cycle goes to 100%. But the Tx duty cycle would go to 100% also, and you'd be off the air sooner. Not that it matters much as you are napping on the keyg. Dan / WG4S / K2 #2456 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
[Elecraft] loops
I love loops. They're quiet, have lots of capture area, wide bandwidth, and when big enough, don't have the big horizontal spikes that collinears or other horizontal wire antennas have. But here's my question: Does anybody know whether the stup on Radio Works's superloop is open or closed? Methinks it's probably open, but I bet somebody out there knows for sure. Merlin, W3ICT, proud owner of K2100 2631 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
[Elecraft] Batteryt Life
I have posted how to calculate battery life here before. John gave a pretty good reply, but there are a couple of other points that should be made. 1. A lead acid battery is rated assuming the current is drawn at the 20 hour rate. If you draw more current than this, you will get less capacity from the battery. At the 10 hour rate, the capacity is diminished by about 10%, at the 5 hour rate it is diminished by 25%, and at the 1 hour rate it is diminished by 40%. 2. It is difficult to fully charge a lead-acid battery by trickle charging it at a constant voltage. Trickle charging at a constant voltage will only restore about 85% of the battery's capacity. To do better than this you need to use one of the smart chargers or triple mode charges such as those based on the Unitrode (now TI?) 3906. If you do not realize this you can get substantially less life from the battery than you anticipate. My K-1 draws about 70 mA on receive with the headphones and volume set for comfortable listening in the field. The transmitter draws about 1.1 A on transmit. With half of the time spent listening, and half of the time spent transmitting with a 40% duty cycle I get an average current draw of 0.276 A. If you constant voltage charged the battery, you will have a 20 hour capacity of 3.4 AH. At a current draw of 276 mA, I am pulling current out of the battery at a 12 hour rate. Since this is greater than the 20 hour rate our capacity will be diminished by about 10%. Reducing the capacity by this amount leaves 3.06 AH capacity. Dividing by the average current draw, 0.276 A, we get 11 hours capacity. Of course, in actual operation the average current draw can vary quite a bit, usually on the down side (we forgot to include bathroom time and emergency antenna repairs in the above calculations) so it is best to only use these numbers as a guide and not to really expect to get that last hour or half hour out of the battery. I hope that this helps. - Dr. Megacycle KK6MC/5 __ James R. Duffey KK6MC/5 Cedar Crest NM 87008 DM65 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
[Elecraft] Featherweight Yagi Design Questions
My summer project besides upgrading my K2-100 with the latest modes and maybe DSP, I'm thinking about the possibilities of building a 3-element, 20-meter monoband yagi with the design emphasis on light weight to enable use of a 40-ft steel, telescoping, TV-type mast and rotor which I can afford and not raise and building permit issues. This idea inspired by PA3HBB article about such a yagi in the July 2001 QST. The availability of relatively cheap (under $10 USD) 20-ft telescoping fishing poles for elements and composite tubing for booms make this design seem plausible. The QST design involves attaching #12 solid copper wire to the fishing poles to construct the elements. Can anyone tell me if the elements can be practically shortened if the wire was spiral wound around the pole elements instead of laid straight. How can one calculate the effect of a spiral winding and predict the shortened length? Would such a spiral design denigrate gain, or SWR bandwidth performance to the point it would not be advisable? Also, would matching antenna to feedline (RG-8) using an off-center driven element approach to match impedance be a practical solution? If not, what might be the best method to reduce weight? Any comments or recommendations on the best element spacing parameter to ensure 1.5 SWR from CW to SSB segments of 20 meters. I see .2 wavelength even and off-set element spacing designs in the literature. Can anyone recommend one or the other approaches? ( I understand that off set elements will induce a higher wind torque load on a rotor unless compensated for. Any other considerations such as element or boom guys? Thanks for any advice you may have to give--it will be appreciated. Jack Jack H. Shrawder, KT6JS K2 3256 Success is the only option. --Dave Borges, DC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
[Elecraft] field operating tip: paperless logging in a pinch
Suppose you're operating in the field, or mobile, and don't have a log book or writing instrument. You then snag a new state or country and want to remember the call, etc. What to do? This happened to me today while walking around with my KX1. I worked AA5AE in New Mexico using 1.5 watts and a 4-foot whip--a new state for my pedestrian-mobile effort. Not trusting my memory (for the time, call, QTH, name, and RST), I used one of the KX1's two CW message buffers to log the QSO. On arriving home, I played back the buffer (in P=0 playback mode) and logged the QSO. 73, Wayne N6KR --- http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
[Elecraft] PLL linearization
Hi Gary, PLL linearization is completed in this morning after removing and re-soldering PLL reference oscillator temperature compensation PCB and U4. When I do the PLL range test pressing BAND- then BAND+ the voltage at pin 1 of U6 were 5.1mV and 7.67V (OK). RFC15 show 8.2 Ohms of resistance which is (OK). Pin 16 of U4 is 4.95V (OK). VFO works on all bands and passes the VCO voltage tests on R30 at the min and max frequencies shown in the manual. CAL PLL worked with the counter probe inserted in TP1. T5 is OK I adjust L34 selecting CW mod and FL4 with the weak birdie near 7.0MHz. Voltage from U5 outpin pin 7 change slowly when I tuned the VFO (OK). I have checked SCK, SDO and DAC2CS connections which are OK. It seams that everything are OK know. I have three other questions at this moment: 1) Receiver works but the signals are very weak. XG1 1uV and 50uV signal heard but S-Meter did not show S9 in 50uV. S-meter calibration done before. When I connect N-gen no noise heard. Is this normal at this step. 2) I red 3.75 volt on U10 pin 14 and pin 1 of RP6. Is this OK. 3) Where I have keep P7 jumper on INT or EXT? I think I can start assembly, Part II. Thank Gary, Wayne for your immediate respons. 73' Ruchan Ozatay, TA2AH ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
