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341. Re: [TenTec] "Low Note" 221 250Hz Filter Problem (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Sun, 04 Mar 2007 12:12:56 -0600
That sounds like way too large a capacitor for trimming a crystal to frequency, and too important to be missing. Unless there is some other coupling a missing series capacitor ought to increase the i
/archives//html/TenTec/2007-03/msg00041.html (8,723 bytes)

342. Re: [TenTec] "Low Note" 221 250Hz Filter Problem (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Sun, 04 Mar 2007 13:57:07 -0600
Looks right 10 plus 2 trailing zeroes. If the value is critical (and at RF 1000 pf is not usually a critical value, more for coupling or bypassing), it will change value for a while as it cools from
/archives//html/TenTec/2007-03/msg00047.html (9,497 bytes)

343. Re: [TenTec] RF loss in antenna tuner (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Sun, 04 Mar 2007 14:00:09 -0600
I prefer a center fed wire to the vertical or inverted L. It cuts down on RF received from the shack computer and the home TV set. I've run several Field Days with a bare 8' whip on the top of my lit
/archives//html/TenTec/2007-03/msg00048.html (9,368 bytes)

344. Re: [TenTec] emergency back up power (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Sun, 04 Mar 2007 22:48:31 -0600
Old batteries are no bargain. I haven't detected that golf course batteries are changed before they fail completely. 6 volt batteries in series sometimes benefit from an "equalizing" charge where you
/archives//html/TenTec/2007-03/msg00059.html (9,436 bytes)

345. Re: [TenTec] emergency back up power (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Mon, 05 Mar 2007 18:49:12 -0600
At a cost of anywhere up to 50% of the battery's power from the inefficiency of the inverter and the linear Tentec power supply. Sometimes it is more effective in the long run to let the radio strugg
/archives//html/TenTec/2007-03/msg00079.html (9,559 bytes)

346. Re: [TenTec] emergency back up power (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Mon, 05 Mar 2007 20:15:56 -0600
An 85% efficient switching supply with that inverter gets you 72% overall. Nearly 30% losses. A common linear supply isn't that efficient with the unregulated voltage over 20 volts. At best 65% effic
/archives//html/TenTec/2007-03/msg00086.html (10,950 bytes)

347. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 15:24:21 -0600
I've used 2N5302 for a bit more voltage head room. Dissipation is likely limited by the power supply heat sink. Be sure to apply a minimum amount of heat sink grease to the replacement transistor and
/archives//html/TenTec/2007-03/msg00121.html (9,252 bytes)

348. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 16:59:37 -0600
That depends on circuit details. The Darlington will have a great deal more current gain but at the cost of at least twice the base to emitter voltage when forward biased. And it will have quite a bi
/archives//html/TenTec/2007-03/msg00126.html (10,695 bytes)

349. Re: [TenTec] emergency back up power (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 19:47:28 -0600
Most modern wire connections for sizes larger than 10 or 12 are made of tin plated aluminum, so the use of aluminum wire works well with them. Today receptacles and wall switches can be had designed
/archives//html/TenTec/2007-03/msg00143.html (9,267 bytes)

350. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 19:50:34 -0600
There may be more efficient and economical techniques. Such as low drop regulators using MOSFETs or going to switching supplies. Wouldn't moving 100 watts average from a pass transistor require more
/archives//html/TenTec/2007-03/msg00144.html (10,155 bytes)

351. Re: [TenTec] TenTec Digest, Vol 51, Issue 8 (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 19:56:58 -0600
Hmm, the wall warts for my scanners put out 12 volts DC. Laptops can be run from 12 volts with reasonably priced 12 to 18 volt step up supplies. Desktop computers could be run from 12 volts, though t
/archives//html/TenTec/2007-03/msg00145.html (8,769 bytes)

352. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 20:28:08 -0600
The pass transistor failing is the desired reason for tripping the crowbar. Often the crowbar is sensitive to RF, sometimes the regulator is sensitive to RF. One time I built out a regulator with a c
/archives//html/TenTec/2007-03/msg00146.html (14,074 bytes)

353. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Tue, 06 Mar 2007 20:30:55 -0600
So today in Iowa that heat sink could be cooled to 15 F but on a warm summer day in Houston, the dew point might be 95 F so you would have to include a dew point sensor to pick the cooling point, or
/archives//html/TenTec/2007-03/msg00147.html (11,523 bytes)

354. Re: [TenTec] Noise reduction of roofing filter? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Wed, 07 Mar 2007 10:52:50 -0600
Probably not. The filter tends to integrate the pulse and reduce the bandwidth at the expense of stretching it out in time. The narrower and the sharper cornered the filter frequency response, the wo
/archives//html/TenTec/2007-03/msg00159.html (9,451 bytes)

355. Re: [TenTec] emergency power via generator (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Wed, 07 Mar 2007 13:45:02 -0600
The water heater is the killer. Likely 4 KW. Fortunately unless its very poorly insulated and the family insists on long showers, it can hold half a day or a day without power. An insulating jacket i
/archives//html/TenTec/2007-03/msg00168.html (9,319 bytes)

356. Re: [TenTec] Noise reduction of roofing filter? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Wed, 07 Mar 2007 13:49:23 -0600
And it cuts down on how much the peaks of the noise spikes overload stages. The more you narrow the band going into the DSP, the more you handicap its noise reduction algorithms. -- 73, Jerry, K0CQ,
/archives//html/TenTec/2007-03/msg00169.html (9,977 bytes)

357. Re: [TenTec] emergency power via generator (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Wed, 07 Mar 2007 13:58:05 -0600
Not true. But the propane tank must be large enough. Too small a tank won't have enough vapor at low ambient temperatures. My 5 KW Onan needs at least a pair of 100 pound tanks. They typical house 50
/archives//html/TenTec/2007-03/msg00170.html (9,658 bytes)

358. Re: [TenTec] Emergency Power via Generator - Natural Gas (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Thu, 08 Mar 2007 10:59:34 -0600
Pickups, cars, tractors, and buses use a different fuel system than the small generator. They can't carry a large enough tank to get the evaporation from the environment, so run on liquid. That liqui
/archives//html/TenTec/2007-03/msg00208.html (10,251 bytes)

359. Re: [TenTec] Omni VI+ Intermittent Power Amp? (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Sun, 11 Mar 2007 18:35:49 -0600
Check the voltage on the wiper of the power adjust pot. That last move makes me think its the pot. 73, Jerry, K0CQ _______________________________________________ TenTec mailing list TenTec@contestin
/archives//html/TenTec/2007-03/msg00276.html (10,160 bytes)

360. Re: [TenTec] Orion 1QRP (score: 1)
Author: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Date: Mon, 12 Mar 2007 17:46:24 -0600
Battery to the microphone terminals? I suppose it would reduce the audio, it shouldn't change the tube bias to reduce the gain, and wouldn't even do anything on CW. Perhaps you are remembering wrong
/archives//html/TenTec/2007-03/msg00289.html (8,941 bytes)

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