Tuesday, January 29, 2008 Zulu
TR4C Leds from N9OO

I ordered a pair of blue LEDs in #47 bulb bases from Don N9OO. He makes them by hand, and they arrived in a couple of days. They look great! Here's a quick snap.
- posted by Leigh @ 01:18 z 0 comments
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Sunday, January 20, 2008 Zulu
2 Farad Capacitor

I bought a 2F capacitor from Fry's on sale. It's not a nano-carbon or aerogel cap, I think, just a really big electrolytic. It was listed as "2.0 FARAD DIGITAL CAPACITOR . Digital LED Voltage Meter CA170 #5477179 $29.99." The capacitor wouldn't hold a charge very long, and the voltmeter (the "digital" part) didn't work. Reverse polarity made an LED glow and a beep from the attached sounder, but nothing from the 7-segment display. I took it back and got another one, but it was the same. So I removed the DVM and the capacitor holds a charge pretty well.

The DVM has an "EM78P156ELPJ-G" 18-pin DIP, which appears to be an Elan OTP 8-bit microprocessor, a variation of this one. There's a 4Mhz crystal, and a scope shows no crystal activity; the oscillator is in the uP. The 7805 TO-220 shows 5V. I suspect the uP, even if it weren't programmed, would oscillate OK so there must be some other problem.

That's probably why they were on sale. A web search on "CAPI70" or "CAP170" shows nothing, nor does "DP Audio" (on the box) or "Divine Electronics" (on the can).

Update: In the intervening years, I've received a number of great comments and email messages on this post. One comment pointed out that the voltmeter needs to be powered explicitly. Craig AE6RR contacted me and said that he's tested that comment, and indeed that's the case. Here's what he said:

I tried connecting the + terminal to the small screw on the top that appears to just hold the plastic cover on and yes the relay clicks, the display lights and the voltmeter works. Maybe you are supposed to connect it to ignition switched voltage to avoid running your battery down? The package claims "relay included" but the manual doesn't say anything about it or the voltmeter. Also, the 1K resistor supplied is too high of a resistance to charge the capacitor due to the current draw of the voltmeter circuit. It will never get to 12V.

- posted by Leigh @ 20:34 z 4 comments
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Sunday, January 13, 2008 Zulu
I heard CX4ACH San in Montevideo, Uruguay. I was running 5W from my K3 and SteppIR on 14.071.684 PSK31. San was using 30W to an Icom 775 DSP and a KLM 6el.


- posted by Leigh @ 00:40 z 0 comments
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I heard PP5TG Walfredo in Blumenau, Brazil. I was running 5W from my K3 and SteppIR on 14.071.836 PSK31


- posted by Leigh @ 00:25 z 0 comments
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Saturday, January 12, 2008 Zulu
I worked J39BS in Granada in the PSK Fest with 5W and K3 to the SteppIR 3el Yagi on 14.073.


- posted by Leigh @ 22:30 z 0 comments
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Sunday, January 06, 2008 Zulu
W5VZF in MS on 40m RTTY


- posted by Leigh @ 03:33 z 0 comments
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I worked WA1FCN in Alabama on 7.092.8 with 20W for 599 AL.


- posted by Leigh @ 02:32 z 0 comments
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W6YX in RTTY Roundup
The weather was bad here so I cranked down my tower, but there was a break in the clouds so I hooked up my K3 to the low loop and tried RTTY with the K3's built-in RTTY. I didn't trust sending with the key in real time so I re-programmed the M1 and M2 to send the reports, ending with prosign IM which cuts the carrier. I worked W6YX on 7.080 with 10W but the timing might be a little off since it seemed it took a second for the OM to respond. Perhaps the IM cuts the carrier too quickly. I sent 599 CA and received 599 CA.


- posted by Leigh @ 02:02 z 0 comments
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Friday, January 04, 2008 Zulu
First Sunspot of Solar Cycle 24
The buzz is that a sunspot signaled the start of Solar Cycle 24, but the truth is a bit more complex: there is indeed a high latitude sunspot with the Cycle 24 magnetic polarity, an improvement over the December 13, 2007 not-a-sunspot, but but that doesn't mean that Cycle 24 has started; it's just one of the signs. I haven't seen news about the disappearance of the coronal hole, for example. Cycle 23 is still ramping down, and reportedly will continue to cause activity. The folks over at SolarCyle24.com have some ideas...
- posted by Leigh @ 23:34 z 0 comments
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