Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 30 Dec 2010 23:13:22 -0600
Searching the internet has proven useless. All the modern links say it was used by the German military during WW2, but it never says when it began to be called NVIS. I saw a couple references to Pat
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 09:52:58 -0600
Best I can tell from his index, the most recent previous discussion of the medium haul range antenna was in 1975 but was discussed several times earlier, just the term nvis wasn't used. One of those
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 11:23:04 -0600
I'll have to look at that. I don't remember QEX existing in the 50s. In my collection issue #38 is April 1985 in newsletter format and issue #86 is April 1989, four years later. 48 issues in four yea
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 12:25:43 -0600
I found a mention in 1998 QST that refered to an article in World Radio from 1955 that described NVIS, but I bet it didn't CALL it NVIS. The concept was well known, just wasn't called NVIS until much
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 15:06:37 -0600
On 12/31/2010 2:28 PM, Bwana Bob wrote: We called it "short skip", during my misspent youth. From my Novice days in 1966 to the present, I don't think I've ever had an antenna higher than about 25 fe
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 15:39:48 -0600
Yup the technique was known, it just wasn't called "NVIS." Its not the technique we are hunting, its who adopted and claimed to have invented that name. 73, Jerry, K0CQ FYI wb2vuf's comments remind m
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 31 Dec 2010 17:20:24 -0600
Not sure if it helps much, but NQ6Z was obviously on the same quest. In one posting, he claimed that the earliest reference to the term he had found was a 1972 Fort Monmouth report: http://www.amrad.
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 06 Nov 2010 10:20:12 -0600
Might be a sign of running higher line voltage than it was designed for. Or that the design didn't quite include enough heat sink area. The fan is a good help. You might try lowering the line voltage
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 07 Nov 2010 17:23:49 -0600
Yes, but it ought to be done gently and it ought to be spaced 4 to 6 inches from everything, especially metals. It should be twisted so both conductor approach objects evenly. Not a rapid spiral but
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Mon, 08 Nov 2010 12:30:14 -0600
There are lengths that tune easier, depending on the feed point and feed line length. A center fed wire tune easiest when near a half wave long. An end fed wire tunes easiest when about a quarter wav
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Mon, 08 Nov 2010 23:14:03 -0600
Many low priced aluminum electrolytics have a lot more series resistance than a quality tantalum. Many I fail fresh from the distributor when I check them for power factor, the capacitance bridge's m
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Tue, 09 Nov 2010 03:20:30 -0600
Trouble with introducing a balun is that sometimes ladder line is used to allow a wide tuning range and so there can be a wild set of impedances and SWR on the ladder line that the balun can't handle
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Tue, 09 Nov 2010 12:40:11 -0600
But Steve, the original post suggesting the balun specifically said 1:4 impedance ratio to transform open line impedances to a better match in coax where the coax is also far more tolerant to bends a
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 10 Nov 2010 19:39:09 -0600
Hardware AGC pumping. Full RF gain and no attenuation invites it. A good post filter audio AGC to compensate should have cured it but that concept doesn't seem to have reached the DSP receiver. The s
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 11 Nov 2010 12:30:39 -0600
From the on line Corsair II manual, pin 1 is audio, pin 2 is ground, pin 3 is PTT and pin 4 is +v for electret power. So white goes to 1, 2 gets shield, I'm not sure about black and red. But with a m
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 12 Nov 2010 18:27:25 -0600
Prime suspects. Check the voltage IN the radio under load. It probably needs 13.8 volts for full power. 73, Jerry, K0CQ A friend of mine in DL has trouble with his Orion I. The output power is now at
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 12 Nov 2010 20:41:33 -0600
But power poles I contend are not the long term solution because they depend on plastic that tends to release pressure for contact pressure. Collins rules would not have allowed using them. 73, Jerry
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 13 Nov 2010 18:23:18 -0600
On 11/13/2010 11:21 AM, Jim Brown wrote: On 11/12/2010 4:22 PM, Stuart Rohre wrote: Most external baluns are of heavier construction and therefore lower loss potentially, than built in baluns common
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 13 Nov 2010 20:43:13 -0600
There is NONE. The output coil is balanced to ground, as are the capacitors, which in my link coupled tuner can be switched from parallel for high impedance loads to series for low impedance loads. T