Re: [Elecraft] Dave Clark Microphone
As others have mentioned, the M-7A electret's output will be too high for good performance on the K2 (400mV RMS ±6dB into 150 ohm load @ 1kHz for 114dB SPL input), so you'll need to pad it down. And you'll need a series 1uF capacitor (again, as others have mentioned). Jim, W6JVE, uses an aviation headset on the K2 with the Radio Shack 1000:8 ohm transformer: http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-02/msg00306.html If you don't care about keeping the Clark headset in stock form, you can replace the M-7A element with the three-dollar Radio Shack electret element that will work with the DC voltage and expected mic output level at the K2's mic jack. http://www.ac6rm.net/mailarchive/html/elecraft-list/2004-01/msg00197.html Please let us know how it works out. ___ 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] Dave Clark Microphone
Here's the explo and schematic for the H10-13.4 ... http://www.davidclark.com/PDFFiles/PL19515P-39.pdf 73, Ken Rice K3VV Coopersburg, 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] Preventing Li-Ion fires - a summary
Every half-decent laptop since 1997 has Li-Ion batteries, often an eight-cell pack of 18560 (185 x 60 mm) cylindrical cells. Every cell phone I have ever opened up has a single Li-Ion cell in it. Li-Ion fires are extraordinarily rare, considering the millions of Li-Ion packs in the field. When portable, I run my K1 and K2 off Li-Ion packs, but I DON'T put Li-Ion packs inside radios. Here's a picture of a couple of my homebrew Li-Ion packs. http://world.std.com/~rice/ham/projects/K1-GO-KIT/battery-packs.html There are only a few ways to torch a Lithium Ion battery: 1. Charging at too high a rate. Prevent this by using a manufacturer- recommended charger and a protective PCB (see below). 2. Continuing to charge a battery that is fully charged. 3. Discharging at too high a rate. 4. Using a battery that has grossly imbalanced charges across its constituent cells, resulting in a self-charge (from the charged cells to the undercharged cell) that exceeds that cell's charge rating. 5. Self-discharge at too high a rate owing to internal conduction paths (partial shorts) that result from damage (dings) or manufacturer's defects. Internal shorts are alleged to have caused the handful of laptop fires that resulted in over a million recalls in recent months. You can avoid #1, #2, #3, and #4 by using both: 1. A slow-blow fuse mounted CLOSE to the battery pack, and rated at less than half the manufacturer's maximum discharge rate. 2. A PCB that (1) limits charge rate (2) limits discharge rate and (3) balances the charge across each cell in the pack. You can avoid most of #5 (damage-induced internal shorts) by mounting your pack inside a sturdy, padded container with a rational connector scheme that prevents (1) shorted leads and (2) dings to a cell that cause problem #5, above. There's NOTHING you can do about manufacturer-induced internal shorts, but there have been only a handful of such cases in the last ten years. It's not entirely clear to me that there has been even a single case of this problem. Protective PCBs and battery packs with pre-installed PCBs are available in various pack configurations here: http://www.batteryspace.com/ Here's an example of a PCB for a 11.1 volt pack. http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2779 Disclaimer: I have bought batteries and PCBs from batteryspace.com for several years, but otherwise I have no relationship with the company. In particular, I don't accept discounts from their review-for-discount program which is said to offer discounts even for negative reviews. Homebrewing Li-Ion packs is easy if you take the precautions set out above. You DO have to be careful when designing Li-Ion packs. Hope this is helpful. 73, Ken Rice K3VV Coopersburg, 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] A K1/Pelican portable station
There have been a couple of inquiries lately about using Pelican cases to pack Elecraft transceivers for travel. So I put up a couple of pages on my Elecraft K1/Pelican portable station on the web this morning. http://world.std.com/~rice/ham/projects/K1-GO-KIT/ I'm using a new HTML template, so please let me know if you have problems getting the page to work. 73 Ken Rice Coopersburg, 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
Re: [Elecraft] suggestions for a paddle?
If you're willing to pay more than $100 for a paddle, it's hard to beat a Begali Simplex at $150-$170 depending on details. If you get the Simplex, spend the extra $15 for gold contacts, IMO. They are a permanent solution to contact problems. Being a single-paddle guy, having cut my teeth on the Vibrokeyer, I have the simplex mono. It's better than the Vibrokeyer in that once it's adjusted it STAYS adjusted. It's easy to set the Simplex for reliable operation with the barest perceptible movement of the paddles. It's the only key I like better than my old 1960s Vibrokeyer. I make fewer errors on the Simplex Mono than on any other key that I've used. My only regret is that I waited so long to get one. Just one aging gomer's opinion. 73, Ken K3VV Coopersburg, 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
Re: [Elecraft] Integrated paddles for K1?
Hi Mike, I have been quite satisfied with the tilt stand and Paddlette paddle. I take both with me for portable operation. Mounted to the tilt stand, the Paddlette has good to very good feel, especially when you consider the compromises required to keep its weight down. It never comes off its magnetic mounting base from the stresses applied while keying, but I knock it off occasionally reaching for the log or something similar. It pops right back on. IMO, the magnet strength is adequate for this type of operation. I have also used a Paddlette Jeep-mobile for two years without any problems. It has seen some pretty rough service without breaking or even losing its settings. The Paddlette-supplied magnet is not strong enough to hold it in place while off-roading, so I stuck to the steering column with Velcro. 73, Ken K3VV Coopersburg, 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] Calibrating wattmeters and HF voltmeters. (Was KAT2 power calibration)
Hi Don and everyone. It does seem that calibrating a wattmeter is a hard thing to do if you don't have an office at NIST! When I care about accuracy, I measure RF voltage with the Elecraft DL1 and hope for the best. Suppose you have a good DC standard, such as Don's or Joe Geller's designs. Is there anyway to bootstrap accurate RF voltage measurements from accurate DC measurements? It's true that measuring power at +/- 20% is plenty good if what we care about is signal strength on the other end of a QSO. Still, it would be useful and satisfying to be able to measure RF voltages more accurately when doing experiments. Thanks and 73, Ken K3VV ___ 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] Re: OT: How do you measure common mode current?
Hi Steve, Question: How do you go about detecting common mode current on the outside braid of your co-axial cable and then measuring or quantifying the amount thereof? You need a shield current meter. They're easy enough to build: http://w8ji.com/building_a_current_meter.htm And cheap enough to buy: http://www.mfjenterprises.com/products.php?prodid=MFJ-853 http://www.mfjenterprises.com/products.php?prodid=MFJ-854 I have an MFJ-853 that works as advertised, and it's a usefull device. Standard disclaimer applies.. 73, Ken Rice K3VV Coopersburg, 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] Sand/scrape mechanical connection points on EC2 case?
Dear Elecrafters, Do I need to sand or scrape the points where the EC2 panels join together so that the whole case forms a continuous Faraday cage? This seems to be done in the K2's case, but the EC2 case doesn't have the bare metal masked areas seen on the K2 case. What do you think? Thanks and 73, Ken Rice K3VV Coopersburg, 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] KPA voltage checks out of range -- problem?.
Builder Fil Fuma and I are seeing some out-of-range voltages on a newly built KPA100. All measurements are DCV in receive mode. Some voltages were drifting slowly. What should we check next? Thanks for looking at this. (Voltages are below.) 73 Ken Rice K3VV Q8 E 0.0 Q8 B - 1.4 (fluctuating) Q8 C 7.7 D1 A 39 D1 C 176 D2 A 110 D2 C43 D3 A29 D3 C 112 D4 A 44 D4 C 29 D5 A 21 D5 C 44 D6 A 13.5 D6 C 21 D7 A - 29.7 D7 C - 10.7 D8 A - 12.1 D8 C 0 ___ 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] KPA question: Gap at "S" area of heatsink pedestal
Good friend and builder Fil Fuma is working on a KPA100/KAT100/EC2 build. He sent the following question to post to the list. Thanks to everyone for taking a look at it. "Looking at figure 28 on page 35 of the KPA100 manual, it shows the machined heat sink. http://world.std.com/~rice/figure_28.GIF There is raised section on the heatsink called the "pedestal". It is shown in detail in figure 35 on page 40. On the pedestal there are two machined standoffs labeled "S". One of these standoffs is near Q2 and Q3. I call this "S2". The other standoff is near Q1. I call it "S1" http://world.std.com/~rice/figure_35.GIF Careful measurements show that the board is not warped. When the circuit board is attached to the heatsink without the thermal pads, there is no gap between the circuit board and standoff S1. However, there is a gap of 0.013" between standoff S2 and the circuit board. This is because the height of the standoffs over the pedestal is 0.085" and Q3 (and Q4) are 0.098" thick. Is this gap supposed to be there? If not, does its existence pose a problem -- what should I do about it?" Thanks again! 73, Ken Rice, K3VV for Fil Fuma ___ 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
