[TenTec] Heil ProSet adapter with Orion -- hum

[Warren J. Walsh]

On Thu, 24 Jun 2004 15:50:18 +0000, Rob Atkinson, K5UJ wrote:

 >If the Orion uses balanced input, then why do they label pins 1 and 2 as 
Mic (1) and gnd (2)? And the PTT switch uses >PTT (3) and gnd (2). It 
appears to be an unbalanced input, and handling of the "gnd" connection is 
what we've been >discussing. I'm saying all of this without having looked 
at the schematics, just the pinout of the mic connector in >the manual and 
the accompanying diagrams. 73, Duane



I am looking at the schematics, I unzipped the schematics using the zip 
file directory structure. Looking in directory A08 at schematic file 
81913.pdf I see that the Orion is an UNBALANCED microphone input.  Pin 1 
goes to a coax connector using RG174 to pass the input to an Analog Devices 
SSM2166 part which is a preamp with variable compression and noise 
gating.  It is AC coupled to the devices POSITIVE input pin. This part is 
located on schematic file 81971_9.pdf located in the A07 directory.  Pin 2 
is SIGNAL GROUND, NOT Chassis ground.  Pin 3 is PTT and Pin 4 is 8VDC.  Pin 
1 is decoupled to SIGNAL GROUND with a .01uF cap and Pin 3 is also 
decoupled to SIGNAL GROUND with a .01uF cap.   I built my own Heil adapters 
using cable with 2 wires and a shield, I attached the shield to the 4 pin 
connectors SHELL.  I used the Orion in the June VHF contest as the 28MHz IF 
for our 6M station, we ran 1000W on 6M, and had NO RF in the audio problems 
at all.

73
Warren Walsh - K2BM


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