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3181
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eHam Forums / Elmers / Hydrogen power?
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on: April 19, 2008, 09:57:00 AM
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Consider a solar panel to power a hydrogen still or a new-tech solar setup with batteries and an inverter. Costs are almost all up front, but once it's running the maintenance costs are very low.
I've been considering going semi-solar but that may be a year or more down the road. My breaker panel is split so it would be very easy to run the lighting and wall outlets from solar while retaining commercial power for the HVAC equipment. That way I can miser the lighting during the winter when the days are short (if I have to) without too much overbuilding and still have heat when I need it. During the summer I'll have daylight to spare but it takes a bunch of batteries to keep an AC running.
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3182
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eHam Forums / Elmers / sight not very good
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on: April 18, 2008, 04:30:44 PM
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For Your Consideration: Regardless of the physical size of a meter movement the reading still comes down to a needle. You may not need to read the scale as the angle tells the tale, but the needle is still going to be narrow. National Semi sells 10 segment bar graph / moving dot LED driver chips like the LM3914, LM3915 and LM3916 which can be cascaded if you want 20 or 30 steps of resolution and drive an LED directly. If a person wanted clusters or strings of parallel LED's per segment the chip can drive a medium signal transistor adequate to sink the load at 20-30 mils per LED. Buy enough Green, Yellow and Red LED's and the display could be big enough to read across the street by size & color... Straight line bar, moving dot, circle or even a fan display. Be the first kid on your block to have a Fan S-Meter. The LM3914 is 10 step linear: http://www.national.com/mpf/LM/LM3914.htmlThe LM3915 is 10 step logarithmic @ 3 dB per step: http://www.national.com/mpf/LM/LM3915.htmlThe LM3916 is an electronic VU meter for audio applications: http://www.national.com/mpf/LM/LM3916.htmlNote the 8 and 16 LED low power versions mentioned on each spec sheet. Could be a plan............. 
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3183
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eHam Forums / Elmers / Need for High Stability Xtal?
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on: April 17, 2008, 10:54:31 AM
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A high stability LO is most advantageous during the first 10 minutes or so of operation. Some rigs need a little more time to settle, other a little less.
After that both the hi-stab and standard rocks will stabilize to the point where drift is not likely to be an issue.
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3184
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eHam Forums / Elmers / Will I need a beam to work Alaska & Hawaii on
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on: April 17, 2008, 10:45:07 AM
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A directional gain antenna of some sort will definitely improve your signal strength in a given direction, but no matter how much RF you pump into a band that isn't exactly open... You still won't have a path.
Sporadic E tends to run 'spotty' and generally at distances of 1,200 miles or less. Often much less. By 'spotty' I mean this: Used to run a Six meter FM net and we had an E opening one night. Local group was spread out over 30 miles or so and some could hear the DX while others couldn't. Within the span of 15 minutes the E shifted and those who were Q-Zilch came up to Q-5 and vice versa.
AK and HI are long for E but not for F layer propagation. Give it a few years and it could happen, but you'll still note some spottiness in the coverage. I've listen to stations 40-50 miles away working a contest on 20 and making Q's I couldn't hear.
Skip Zone and like that.
What a beam could do for you is to make your call the first heard and the last to fade during an opening when both ends of the circuit are in the right place at the right time.
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3185
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eHam Forums / Elmers / Can I bury regular LMR-600?
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on: April 16, 2008, 08:03:06 PM
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" Perhaps I'm touchy because I'm tired of the immediate assumption many "Elmers" make that I've done no homework before asking a question. "
Try and help a guy out...............
Perhaps your question gave no hint of any research on your part or that anything was done beyond forgetting that it was LMR-600.
Next time you're at the local handy guy store, pick up a coil of irrigation pipe in the 3/4" flavor. Buy it, bury it, shove your coax through it.
And there's your answer.
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3188
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eHam Forums / Elmers / Triplett VOM Meter Diodes Question
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on: April 13, 2008, 09:37:16 AM
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Nice overview for the advantages of a Schottky diode plus some resource links at the bottom of the page for your surfing pleasure... http://en.wikipedia.org/wiki/Schottky_diodeI checked the schematics for the Triplett 360 and 361 meters on BAMA just for grins. http://bama.edebris.com/manuals/triplett/The "three pin copper oxide rectifier module" appears to have a direct connection to the test leads only on the 3 volt scale. Anything with a PIV of 50 or greater should be more than adequate, and there's an implied usage tip in that... Start with the higher voltage scales and work your way down if there's any doubt about what you might find. I've been known to leave a meter parked on a lo-volt scale and sooner or later I'll regret it. 
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3189
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eHam Forums / Elmers / Triplett VOM Meter Diodes Question
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on: April 13, 2008, 07:03:56 AM
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Chances are the diodes are on the low voltage side of the divider so you won't need something with a super high PIV rating. For good sensitivity in the low voltage range you'd want something with a low forward voltage drop.
The originals were likely a variation on the 1N34A Germanium type, possibly matched for conduction, but unless you're into vintage parts fidelity I'd sub with something like a pair of small signal Schottky's rated at 100 PIV or greater.
If that sounds too exotic, go through the junk box for 1N914's or 1N4148's and cherry pick two with a low forward drop. Should be close enough unless you do precision audio work.
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3190
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eHam Forums / Elmers / AM Radio qrm
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on: April 12, 2008, 08:26:08 AM
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I didn't see a mention of the house being newer or older construction, but here's where I'd start: Typical setup is a 4' ground rod at the service entrance for both your phone and electrical service. Both will tie to the ground rod outside the house. Same for cable TV which may enter through a different wall. Might want to look for the ground rod(s) at the service entrance(s) and clean up the connections with some WD-40 and fine steel wool. Unscrew the clamp, put some shine back on the contact surfaces, grease them with a Molybdenum or Graphite based grease and re-assemble. Wipe some extra grease around the outside of the connection for the sake of weatherproofing. If that helps your phone setup, good. If it doesn't quite do the trick, consider adding an 8' copper plated steel ground rod to the service entrance(s). You live in a drier part of the world where a 4' rod might be marginal. End-fed longwires are very good at gathering RF and noise on the lower bands and I can speak from experience on that. I have a five gallon AM'er about three air miles away and a 50' wire coupled through a 9:1 RF autotransformer type Balun to ground will overload the front end of most General RX style receivers. An older rig with a preselector knob tends to fare better. Overload is easy to detect as you'll hear the stronger AM stations at several spots across the AM band. Assuming you have the room, consider a Doublet for your next antenna project. While the longwire is still up you might want to try a little Weird Science just for grins. Hook a 4' or shorter fluorescent light tube between the antenna wire and a reasonably good ground to see if it lights. Urban Legend says there are some yard and utility lights along East 11th street in Tulsa that burn 24/7 without the benefit of commercial power thanks to the local 50 gallon AM station in the neighborhood... If you can do that, you are definitely in a high RF environment. 
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3191
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eHam Forums / Elmers / Digital Volt Meter Problems
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on: April 10, 2008, 09:58:08 AM
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Afterthought...
It has been a while since I fixed the DMM with the blown front end. The fusible resistor I referred to was a actually a thermistor. 1k nominal at room temperature with a 50% tolerance. (!) Kinda' surprising considering it's in a DMM, but in a divider circuit the tolerance gets divided along with the voltage. In the event of severe stress the plan was for the thermistor to heat up and go to a high value thus reducing the current draw and Vout through the divider.
Clever idea, but that makes it a rare part and would have been a special order item through Fluke. Although a fixed resistor won't recover after a bit of cooling like a thermistor would, 1k is a common value and easy to replace should it blow out.
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3192
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eHam Forums / Elmers / Digital Volt Meter Problems
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on: April 09, 2008, 03:23:13 PM
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I have a hunch that at some time the flaky meter was used to measure voltage while in the ohms position... There is usually a voltage divider in the front end along with some glitch grabbers (MOV's) to protect the expensive parts. If one of the voltage divider resistors opened up it will read high. I have a Fluke 8010A that I picked up cheap thanks to a blown front end and fixed it without the help of a schematic. Didn't use it very often as I didn't trust it. About 10 years later I found the full user guide with schematic on Fluke's web site and subbed a 1k carbon resistor for the fusible jobbie Fluke had spec'd. Works fine. Volts & Ohms agree with my other meters. You may want to poke around http://support.radioshack.com/productinfo/DocumentResults.asp?sku_id=22-812&Name=Meters%20and%20Scopes&Reuse=Nto see if there's any tech info, otherwise visit http://bama.edebris.com/manuals/fluke/to see if there's something similar to yours. Same for http://us.fluke.com/usen/support/manuals/default.htmBTW: I've had excellent luck with Fluke meters and have yet to kill one... But the main meter on the work bench is an HP 3466A as it's a 4.5 digit model. The switches could use some cleaning and the internal battery doesn't hold a charge like it used to, but aside from that it's fast and easy to work with. Kinda' wish it had the Touch Hold feature of a Fluke, but for what I do it's more than adequate.
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3193
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eHam Forums / Elmers / Beginner Oscilloscope
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on: April 09, 2008, 02:53:38 PM
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A decent 60 to 100 MHz analog 'scope can be had for $150 or less and will do 90+ % of what you'll need. Newer is usually better, look for dual channel and dual time base as a practical minimum. Delayed sweep is also a nice feature, although I've yet to come across a situation where I had to have it. Same for TV sync. On most test equipment it's a good idea to shop around for the best deal on the most features, up to the point of diminishing returns. You may not need a feature tomorrow (or ever), but if and when you need it, you need it. Speaking of general advice, avoid test gear that has spent its life in the back of a service van. Some of it survives nicely, but in the Midwest those vans see scorching heat in the summer and some very cold nights in the winter. Then there is the endless bump and buzz of life on the road. You can usually tell a van baby as the case shows plenty of battle scars, bench buddies tend to have better cosmetics. As for learning how to use a 'scope, Tek is pretty good about application examples in their user guides. Here's an example of what a ~ $120 (?) 'scope can do: http://bama.edebris.com/download/tek/2213a/tektronix_2213a_op.pdfIf you want to get handy with the model spread, look here: http://bama.edebris.com/manuals/tek/In the 2xxx series, 22xx indicates a two channel 'scope, 24xx a four channel model. The higher the last two numbers, the higher the bandwidth and the feature set. Usually. Your mileage may vary. Lest you think I work sales for Textronix, nope... Philips makes some very nice 'scopes. Not as easy to come by as Tek, but there are times when you can score a better deal on a Philips 'scope 'cuz some folks think of them as an oddball. Not True. ...and you can apply the usage concepts in a Tek user manual to any 'scope of similar capability. They work about the same.
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3194
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eHam Forums / Elmers / Electronic capacitor to replace a vacuum variable
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on: April 08, 2008, 07:33:20 PM
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There are plenty of devices built for horizontal sweep service in TV's and CRT style video monitors that can handle hellacious voltage spikes, but they tend to be bipolar silicon and would need to be decoupled from the control line.
Then I wonder if you'd be ahead of the game to think in terms of relays to switch doorknob caps in and out of a stack, but the difference in cost & complexity might not be much of an advantage over a vacuum variable. Then there's the matter of avoiding a hot switch lest the contacts see too much arcing. Which means you'll be tuning by trial & error until you get the bandspread figured out.
Maybe someone here can speak from experience on this, but I'm thinking a vacuum variable or a nicely weatherproofed conventional cap is probably the path of least resistance...
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3195
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eHam Forums / Elmers / Stainless Steel Antenna Wire
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on: April 07, 2008, 11:25:51 AM
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Did some more thinkin' on this...
If the wire diameter might be an issue, and as the original post said it's coming off 'a good spool', nothing says that a person couldn't hammer two pegs in the yard and take the spool for a walk. Lay down 2, 4, 6, 8, whatever, strands then chuck the cut end to an electric drill and take it for a spin.
Thicker wire, stronger antenna, assuming there's plenty of wire to work with and no immediate plans for the rest of the spool.
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