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Battery charging question??
On Sun, 12 May 2013 20:36:26 -0400, "Ralph Mowery"
wrote: I was thinking there was a mobile antenna system that you mounted two antennas and had a switch box that phased them for differant directions. Don't believe it worked too well as the antennas were usually too close together. Chuckle. That's because the co-phasing harness combiner would produce a giant null in the fore and aft directions. The box had a 3 position switch, that selected antenna 1, 2, or both. The problem was that there was no way to use a real Wilkinson splitter with the switch, so the both position was simply both antennas in parallel. That didn't work. The the base station 'scanner' antenna was devoloped using 3 verticals in a triangle patern several feet apart. Seemed to work ok for what it was. It's still being sold and it actually works fairly well. It's just a VHF/UHF version of an HF "fan" antenna, where each band has its own dipole. Well, for the scanner antenna, a monopole. The stranger looking the antenna, the better is works (and sells). During that period of time, I think Antenna Specialists' made up much of the CB antenna sales. Yep. I wasn't involved in antenna design at the time, but I did meet with some of the designers. The RF part of the design was minimal. The aesthetics, cosmetics, packaging, and sales pitch were the major considerations. Only double the power,, many of the ones I knew ran 50 to 100 watts in the mobiles back in the 70's. It started with doubling the power, again for good reason caused by the power divider. Radios had such features on the schematic as "Don't short this resistor or you will transmit at illegal power levels". That would usually get the typical 23 channel CB up to about 12 watts in. Linears came later. Incidentally, in about 1979, I worked on a marine 2-30MHz HF SSB transmitter. The 150 watt power amplifier was my design. Sales of "replacement" power amplifiers were rather high until management found out what the dealers were doing with them. Oh well. During those years you could sell almost anything to the CB. Much like for the last number of years you can sell to the audio/hifi people. Best scam I know of is the wire going from the hifi to the wall socket. For about $ 120 you get 6 to 8 feet of 'special wire' Even if it was special that would not account for the wire going from the outlet to the breaker box and then to th epole transformer.. Got $10,000? http://www.amazon.com/Denon-AKDL1-Dedicated-Link-Cable/dp/B000I1X6PM There probably should be a law against this, but on the other hand, the purchase of such an overpriced cable is probably its own punishment. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Battery charging question??
On 5/11/2013 8:42 PM, tom wrote:
On 5/11/2013 8:34 PM, tom wrote: Best buys on AGM batteries is to look for 3 to 5 year old ones being rotated out from data centers that demand high reliablity. They are usually rated for at least a 20 year life. And are 0 maintenance to boot. tom K0TAR And finding the used ones isn't hard. I found the 133AH on craigs list. Be sure to buy identical types. My 2 are not the same AH rating but are from the same line by the same manufacturer. tom K0TAR mcalhoun asked me a question via email. I replied but my response was rejected - Delay reason: SMTP error from remote mailer after RCPT : host mail.xxxx.zzzz [ipv4 address]: 451 4.7.1 Greylisting in action, please come back later Sorry, your end is unnecessarily paranoid. Mine is selectively paranoid. You should get one of those. :) tom K0TAR |
Battery charging question??
I am noticing a lot of fuel lines up here in Ontario are failing because of
the newly introduced or mandated or shoved down our throats Alcohol or Ethenol they are putting 15% in the fuels. One dealer around here actually doubled that amount and was caught and fined now is paying for everyone's fuel lines, gaskets, seals that were eaten by the ethenol they mix in the fuels. We are seeing this happen around here and boat owners and chainsaw owners etc etc are squacking. Thanks for all the great advice on batteries gents, I appreciate it all and thank you. "Jeff Liebermann" wrote in message ... On Sun, 12 May 2013 16:34:53 -0400, "Ralph Mowery" wrote: "Jeff Liebermann" wrote in message . .. Yes, I know. A clean workbench is a sign of a sick mind. http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html It's currently not quite as messy, but it's close. Looks like you have an antenna harness for phasing 2 meter antennas. I guess you mean the Wilkinson power divider/splitter in the lower left. It's not for phasing antennas, but for combining the signals from two receive only 1090MHz antennas for ADS-B reception. The lines are 3/4 electrical wavelengths long RG-6a/u because I couldn't find any small diameter 75 ohm coax. That was a prototype I just threw together to see if I really needed the 100 ohm resistor for receive only. With low gain antennas, it's not needed. For high gain, where impedance matching is more important, it's needed. Is the chain saw apart to put the co-phased antennas on ? hihi.. The chain saw has nothing to do with RF, unless you include using the trees as supports for various HF antennas. In this case, the only thing wrong with the saw was that the fuel line split and started leaking. In order to replace a simple fuel line, I had to tear down the saw completely. I used the occasion to also clean out the accumulated crud, clean the carb, replace various filters, clean the carbon out of the exhaust port, and do the usual tuneup. Right now, the bench has two weed whackers torn apart. Since I took them apart about 2 weeks ago, I don't remember which parts belong to which engine. This should be interesting... -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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