Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 29 Jan 2011 20:39:59 -0600
"Cheap" and "clamp on ammeter" don't come in the same package for DC. .07 volts on the base of a silicon bipolar transistor won't turn it on, .7 may turn it on too much. I find nothing in the manual
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 29 Jan 2011 23:50:16 -0600
I have bought cables with that end on them from Tentec in past years. It wasn't possible from Yaesu, though their gear uses them too. 73, Jerry, K0CQ Stephen AD7TD Thanks guys! Anybody happen to have
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 30 Jan 2011 00:28:05 -0600
Most class C bipolar transistors have no bias at all. Especially VHF FM and CB "linears." CB linears for AM depended on the carrier for forward biasing but were dirty besides being outside FCC regula
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 30 Jan 2011 23:44:53 -0600
Yup you are right, I didn't look at all the bias circuit connections. So my technique would be: on receive, turn the driver and PA bias pots to zero. Turn down the RX audio (to minimize the supply cu
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Tue, 30 Nov 2010 23:20:04 -0600
Sure if there's no lightning protector grounding that coax, which there wouldn't be if you set up for that purpose. You could use house wiring ground, metal water pipes, and metal heating and cooling
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 01 Dec 2010 09:12:33 -0600
The frame of the PTO is cut from a bit of aluminum channel and the inside is not exactly perpendicular to the shaft, but that's how the out race is supported at an angle to the shaft, not quite squar
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 02 Dec 2010 10:07:22 -0600
The ground rod will work, but it will introduce more resistance to the antenna feed than radials. It will tend to make the matching easier, but the efficiency poorer. The hazard with a ground rod is
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 02 Dec 2010 16:24:01 -0600
As I understand it, the Corsair or Corsair II with the external VFO can do things it takes two receivers in the Orion to accomplish, and that could be done with a DDS external VFO as well using the o
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 02 Dec 2010 16:51:04 -0600
Been there, done that. Back in 1970 I moved to a rented house in the country on a farm. I knew there was a wire from the house to the garage to power lights in the garage and with a three way switch
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 02 Dec 2010 16:55:08 -0600
More likely selected crystals because the ladder filter often needs slightly different frequencies to get the desired response curve. The crystal maker may have marked them the same, while Tentec sor
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 02 Dec 2010 23:45:43 -0600
Your problem reminded me of an amp I fixed remotely for a ham in this county. In the 425, K7 and the fried resistor are a soft start circuit that slows the turn on capacitor charging current surge an
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 08:16:56 -0600
Precisely, and the bandwidth of that match with the ground rod will be much wider than with a radial system. 10 ohms is a very good ground rod, and one driven into basement fill is likely to be consi
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 13:31:51 -0600
But the burned up surge limiting resistor points the poor voltage regulation of both supplies to the soft start relay not taking it out of the circuit. If the soft start relay was doing its job, the
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 15:21:57 -0600
On 12/3/2010 3:04 PM, Jim Brown wrote: On 12/3/2010 12:37 PM, CSM(r) Gary Huber wrote: But I was trying to find out if anyone had used the WD7S HV-2 board for the 3CX800A7s..... the HV-2 board has be
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 15:41:48 -0600
On 12/3/2010 3:26 PM, Ron Castro wrote: There was an article from a ham in Texas on the internet on modifying the 425 for 3CPX800's but I can't find it. I recall it required an entire new supply, inc
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 17:05:47 -0600
The low long wire is a Beverage and the termination is for RF. It works down to DC as does the antenna though it looses its directivity when it gets short in wavelengths. Overall its rotten at receiv
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 19:03:56 -0600
Rotten based on recovered signal strength. A low efficiency antenna that can require a low noise preamp because the typical HF receiver has relatively poor sensitivity due to the normal level of atmo
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Fri, 03 Dec 2010 20:02:33 -0600
Target is 5 ohms but it often takes two three or more rods to achieve 5 ohms unless in a salt marsh swamp. Fresh water swamp land doesn't do as well. A 20 ohm ground is more typical. 73, Jerry, K0CQ
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sat, 04 Dec 2010 07:57:05 -0600
I have always been leery of running an antenna which needed a terminating resistor for transmitting, but I have used Beverages for nearly half my ham life (almost a quarter century) and I know that t
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Sun, 05 Dec 2010 12:54:17 -0600
On 12/3/2010 10:10 PM, Stuart Rohre wrote: Some terminated antennas such as the terminated Beverage are operating as a high impedance traveling wave antenna, and thus a resistor to even lossy ground