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  • Category: Electronics
  • Founded: Jul 10, 2005
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Messages 20 - 51 of 1821   Oldest  |  < Older  |  Newer >  |  Newest
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20 krolradio Offline Send Email Aug 1, 2005
7:10 pm
... since ... thick. ... purpose. ... informed ... I was able to receive a MC1590 from Charles sometime ago.I built the (fig 5 ferrite antenna with built in...
21 charleswenzel Offline Send Email Aug 2, 2005
3:06 am
Ha! I just looked at the schematic and I didn't even use the AGC function. Oh well. Anyway, it looks like an LM733 (MC1733) should give about the same...
22 lauriecam2002 Offline Send Email Aug 16, 2005
8:23 pm
Boltek makes lightning detectors http://www.boltek.com/stracker.htm which work pretty well. My question is how do they manage to get an LF/MF direction finding...
23 charleswenzel Offline Send Email Aug 16, 2005
11:40 pm
I don't really know what is inside but to get direction info from such a small space makes me suspect that higher frequencies are used. Maybe there are three...
24 charleswenzel Offline Send Email Aug 17, 2005
6:15 am
Now that I think about it, it doesn't seem likely that they are resolving phase in that small of a space; the delay is just too short. I still like the VHF...
25 Laurie Camion
lauriecam2002 Offline Send Email
Aug 17, 2005
4:27 pm
There are prof VHF lightning systems, used with the LF systems, but while I can see getting some directivity in that sized space in the GHz range, but I'd have...
26 charleswenzel Offline Send Email Aug 17, 2005
9:18 pm
I agree. It is hard to imagine reflectors and directivity at VHF in that small space but it is equally hard to imagine resolving the direction ambiguity at LF,...
27 mike
naptha89 Offline Send Email
Aug 31, 2005
12:13 am
http://www.lightningsafety.com/nlsi_lhm/detectors.html From the above site. Boltek Stormtracker in the Low Frequency Range 100-700 KHZ?; ... sense ... an...
28 ahmed73500273 Offline Send Email Sep 1, 2005
10:00 pm
Hi Charles! I want to design 20W VHF power amp. for my FM TX because I found an already designed one at a website, but I couldn't found the required values of...
29 Laurie Camion
lauriecam2002 Offline Send Email
Sep 1, 2005
11:24 pm
A good source for ham project parts is Dan's Small Parts http://www.danssmallpartsandkits.net/ ahmed73500273 <ahmed73500273@...> wrote: Hi Charles! I...
30 charleswenzel Offline Send Email Sep 2, 2005
1:25 am
I bet I couldn't find those trimmers in my "big" town, either! Those are pretty big values and a small trimmer is likely to not be very stable or able to...
31 lamboguy Offline Send Email Sep 27, 2005
2:13 pm
Hi Folks, I'm playing around with building a small frequency generator that I could use in the field to check/drive speakers. I took a measurement last night...
32 charleswenzel Offline Send Email Sep 28, 2005
9:20 pm
What DC voltage does your frequency generator require? Or, how much audio power do you need and what is the speaker impedance? Could you step the 7.5 volts...
33 lamboguy Offline Send Email Sep 29, 2005
12:55 am
Hi Charles, Well...I don't have a frequency generator, so I'd have to build that too. I've been using an old Yamaha TX802 (FM synth) but I don't want to lug...
34 charleswenzel Offline Send Email Sep 29, 2005
3:44 pm
I'm guessing that the 1.5 amp draw was at 12 volts which is 18 watts. Some of that is lost to inefficiency so lets pretend that 14 watts reaches the load....
35 lamboguy Offline Send Email Sep 29, 2005
5:28 pm
Squarewave would be perfect. It's not rocket science, it's just jolting the thing at different frequencies, and I think those 4 batteries could pull that off...
36 lamboguy Offline Send Email Sep 29, 2005
5:38 pm
I didn't realize these batteries are available up to 11v/3400ma! http://www.shulmanaviation.com/E-Tec.html That's got to have a good sock to it. Maybe use 2 of...
37 charleswenzel Offline Send Email Sep 29, 2005
6:08 pm
Don't confuse mAh with mA. mAh is the product of mA and hours but it doesn't mean that the battery can only supply that much current. It simply tells you how...
38 lamboguy Offline Send Email Sep 30, 2005
5:13 am
Hi Charles, Thanks, I'll dig into it tomorrow... Yes, I didn't realize mAh was hours! But if I can only get 1 minute of performance, that's good enough for...
39 Laurie Camion
lauriecam2002 Offline Send Email
Sep 30, 2005
5:24 pm
You really like the idea of paralleling batteries? charleswenzel <charles@...> wrote: I'm guessing that the 1.5 amp draw was at 12 volts which is 18...
40 charleswenzel Offline Send Email Sep 30, 2005
6:28 pm
No, but it isn't necessary for that current drain. The 1100 mAh lithiums are bound to have an acceptable discharge rate of several amps. I don't like putting...
41 lamboguy Offline Send Email Oct 8, 2005
1:58 pm
Ok, I'm back. :) Keeping in mind that I'm really bad at this, here is a "draft" of the modified circuit: http://www.400gt.com/technical/misc/circuit2.jpg I...
42 lamboguy Offline Send Email Oct 8, 2005
2:02 pm
Hummm...already I see a problem. There's no way +12v will go straight to the speaker. oops. But anyway, maybe you can point out what I need to change to get...
43 charleswenzel Offline Send Email Oct 9, 2005
3:38 am
You have the speaker wrong. Connect the top of the speaker to the negative side of the 1000uF capacitor and not to +12. Connect the bottom of the speaker to...
46 c_b_kauai Offline Send Email Oct 9, 2005
5:17 pm
I have invented a new energy source whereby heat is converted directly into electrical power. The heat is absorbed from background air or water that is of...
47 lamboguy Offline Send Email Oct 10, 2005
5:51 pm
Thanks Charles, it's starting to make sense. I think next step is for me to breadboard it. I have a feeling some of those resistors will need to be power ...
48 charleswenzel Offline Send Email Oct 10, 2005
6:05 pm
The 3.3 ohms will dissipate some power at full volume. A couple of 2 to 5 watt resistors should be fine. ... <charles@w...> ... 1000uF ... the...
49 lamboguy Offline Send Email Oct 16, 2005
4:13 am
Hi Charles, I finally got around to building the circuit: http://www.playerviolin.com/misc/speaker_driver/speaker_driver.htm Unfortunately, nothing much...
50 charleswenzel Offline Send Email Oct 17, 2005
2:52 pm
You might want to add a resistor in series with the frequency pot, maybe a 100k or so. Also, some of those prototyping boards split the power strips right in...
51 charleswenzel Offline Send Email Oct 17, 2005
4:12 pm
I did use a '4069 instead of a '4049 but I don't know why that would matter. I'll try to build it in the next day or so to see if I have a problem....
Messages 20 - 51 of 1821   Oldest  |  < Older  |  Newer >  |  Newest
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