Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 13 Nov 2010 21:09:40 -0600
On 11/13/2010 8:31 PM, Rick - NJ0IP / DJ0IP wrote: Jerry, we all prefer a link coupler tuner. Unfortunately there are no commercial units available anymore, at least not in the amateur radio market.
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 14 Nov 2010 11:48:55 -0600
Sometimes we want to FORCE that voltage balance, sometimes we just want to limit feed line shield current on the outside of the line. A home built tuner need not have the secondary capacitors or coil
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 14 Nov 2010 12:52:35 -0600
On 11/14/2010 12:15 PM, Don Jones wrote: I think a "very fine hair" is being split here. When this "hair" is measured in dB units instead of linear units the loses become insignificant. While yes the
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 14 Nov 2010 13:11:42 -0600
Its really difficult to have a wire antenna that is truly balanced. One end nearly always has a different exposure to dielectric and grounded objects than the other leading to differing capacitance t
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 14 Nov 2010 18:22:37 -0600
There are two causes of feedline radiation/reception -- common mode current and conductor spacing. A common mode choke AT THE FEEDPOINT can essentially kill the radiation due to common mode current u
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 14 Nov 2010 18:24:27 -0600
I must challenge you again on that statement - it simply isn't true of a 1:1 Current Balun at the output of a tuner. The core flux of that Balun - and therefore its loss - is determined by the CM sig
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Mon, 15 Nov 2010 15:43:08 -0600
Most analog meters are linear. But they can be made with nonlinear results, like the movement for a thermocouple ammeter has varying pole piece gaps to vary the sensitivity as the armature moves. Gen
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Tue, 16 Nov 2010 15:07:28 -0600
Overnight I came up with a concept for a single band Link coupled tuner made entirely of small coax like RG-6 or RG-58 that could be so simple and low cost to construct that the user could build one
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 10:57:10 -0600
The thread is probably 1-1/8"-18 and there probably is a ring from a multi pin military connector that will fit. Look at Amphenol series 97 shell size 18 (MIL-C-5015 style). You could start with a 97
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 11:09:20 -0600
But it doesn't mention the Bird Coplanar connector at all. 73, Jerry, K0CQ http://www.mwjournal.com/BGDownload/RF%20Connector%20Guide.pdf This link gives a little history and might be helpful too. Do
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 11:32:27 -0600
Not by the picture. 73, Jerry, K0CQ There is a good chance the connector is a Type C. Carl KM1H -- Original Message -- From: "Bill Mellema"<mellema@qis.net> To:<boatanchors@mailman.qth.net>; "Discuss
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 11:34:03 -0600
It is definitely NOT a type C. Type C is the same size as type N but is a bayonet instead of threaded connector (a maxi BNC, so to speak). Type C is my absolute favorite coax connector. It would appe
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 11:35:00 -0600
Bird would have that, for a price. Maybe RF parts. On 11/17/2010 11:23 AM, Don Jones wrote: Yes I know that - I can read too. Just a historical evolution of the market. I am currently trying to find
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 17 Nov 2010 11:46:51 -0600
Google search failed me. But my vintage Amphenol catalog in the file drawer A to B showed on page 25 that 82-325 is an HN connector. It has bigger parts all around and a different interface from N or
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 10:00:09 -0600
The critical features of that Airpax breaker are its current rating and the fact it has no extra time delay. That its the fastest available. Hence pure magnetic, no hydraulic or thermal time delay. A
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 11:34:41 -0600
Mostly vintage radios with the four pin power connector. Up through Omni VI at least. Omni VII and Orion manuals that I have downloaded talk about voltage transients from generators and alternators,
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 11:34:49 -0600
ATC. I checked my box. 73, Jerry, K0CQ On 11/21/2010 10:28 AM, Bill Harris wrote: Morning Jerry: Would you pl;ease confirm Buss MTC-16. Unable to locate it on their web site. TFYT BillHarris/w7kxb
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 14:04:30 -0600
While buying the parts from TT. But you might find the same parts from Mouser or Digi-Key for less. A good rebuild would probably need semiconductors and electrolytic capacitors. 73, Jerry, K0CQ I am
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 14:08:01 -0600
True. I think there's no RF alignment when replacing the finals in a broad band PA, but there would be a need to set the idling bias for best linearity. Without the PA protection of circuit breaker,
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 21 Nov 2010 19:06:09 -0600
1) How I know if RF from my Omni VII was causing problems with my Astron RS-35M linear type power supply ? Would it show up as an anomalous readout on one or both meters? Probably as a voltage change