Hooking up Rigblaster to rear pins of Spectra ?

n0top · Post by **n0top** » Thu Aug 10, 2006 12:57 pm

Hello all, Name hr is John Verser de N0TOP.
I was wondering if I hookup a Rigblaster to rear pins of my Spectra ?
TX/RX, RX Audio, TX Audio and Ground. I my Spectra on 2 meters and
would like to send some SSTV.
Any ideas ? I dont want to change that Great Motorola mic.
Thanks you all...
John.

Will · Post by **Will** » Thu Aug 10, 2006 1:13 pm

"Rigblaster" ????

wb0qqk · Post by **wb0qqk** » Thu Aug 10, 2006 1:27 pm

http://www.westmountainradio.com/RIGblaster.htm

KB5AKO · Post by **KB5AKO** » Thu Aug 10, 2006 9:21 pm

John,

This is a quote from Will in a previous post with a different topic:
(Hope you don't mind Will)

"On the TX audio input, AKA mic, use a 2.2 to 5uF cap, the + side to the Spectra as the Spectra has mic bias 9 volts here.

The RX out is the discriminator and it goes thru an opamp, so it needs a coupling cap of 1uF, again + to the radio assuming that the controller has a medium to high impeadance input.

The PTT is alogic input and a ground here keys the Spectra.

Audio output, Speaker leads, can be terminated using a 8 to 25 ohm resistor, and the volume turned down as required. 25 ohm 2 watt resistor works good."

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Look at the schematic for the Rigblaster to see if they have already incorporated the coupling components in the design.

The pinouts for the Spectra are here:

http://www.batlabs.com/spectra.html

The Spectra is not designed for this mode of operation. Be sure to decrease power output and utilize forced cooling.

Victor, KB5AKO

Will · Post by **Will** » Fri Aug 11, 2006 1:05 am

I did some checking on the RigBlaster and have these connections:

Spectra Accy jack 15 pin
Mic ground Pin 8

Mic low Pin 15

PTT Pin 13

The RigBlaster TX audio has an audio isolation transformer, and the required coupling capacitor, so no extra parts are needed for this part. Infact you do not even need the RigBlaster, just a 1:1 coupling transformer, resistors and a cap for the mic, a 9 pin DB connector and a reed relay for the PTT.

Audio out to your sound card is another problem. The RX does not go into the RigBlaster box. The 6 volts DC on the speaker lines will do dammage to sound card inputs, so ISOLATION is needed.

One way: Use a 600 to 600 ohm audio coupling transformer ( sometimes called a telephone coupling transformer).
One winding, lets say the primary would go to the speaker leads on the Spectra.
The Secondary winding would go the the sound card thru an attenuator or voltage divider..
Something like 330 ohm resistor from the secondary Hi to a second 330 resistor and the other end of the second resistor goes to the secondary Low side and the shield of the audio input of the sound card. The middle junction of the two resistors goes to the hi side of the sound card LINE IN. This gives a 2:1 attenuation.

If you have to use the Sound card Mic input, some software can not use the LIN IN, the resistor attenuator/devider would need a 560 ohm resistor and a 47 ohm resistor on the ground/shield side giving about 10:1 attenuation.

You still have the problem with any volume change on the Spectra changes the input to the sound card.

I hope I have not confused anyone!!!!!