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Main MHST Module Board Layout

 


Starting at the 12 O'clock position we have the Band Pass Filter and the Orange wire at the top connects to one of the amplifier steering relays. On receive this leaf actually is connected to the output side of one of the steerable relays. On transmit the orange wire is now connected to the input side of the steerable RF amp.


As we move around the clock the splitter is connected to the BPF. This splitter consists of 8 Bifilar wound turns on a FT-37-43 core. The end of one winding connects to the start of the 2nd winding which in combination connects to the band pass filter and the two free ends are connected so that one lead goes to the input of one ADE-1 and the other end to the 2nd ADE-1 input. These two windings are bridged with a 100 Ohm resistor. Why you ask the resistor well that is a good question whose answer likely involves elements like providing a constant load and balancing signal levels.

At the five o'clock position is our sideband inversion relay which is not needed if you check the block in QUISK. At 7 o'clock is the two stereo jacks for I/Q input and output. At nine o'clock we have the two 600:600 Ohm modem transformers. These units cost about $6 each. However, you can buy 10 Pieces from Amazon for $10 and they work perfect. Finally, we have at 10 o'clock the Quadrature LO which is run through 10K pots so that the LO level is exactly the same for each ADE-1. (The Blue squares in the photo.) 



The output from each ADE-1 is run through a 100uFd cap and that input goes the modem transformers. The Modem coupling is to reduce any noise pickup -- a small incremental improvement.

The only power needed to this board is voltage to the J310 amp which is powered on at all times and power to engage the three board mounted relays which is only needed on transmit. Two of the relays steer the J310 amp and the third relay (lower right-hand corner) is part of the T/R operation and directs the antenna to the steerable amp. 

Them that know can make it go. 

If things are this bad in less than 60 days wait until year three. Consumer spending is down and the real impact of all of the terminations is yet to be fully felt. But hey when you are a billionaire, no impact to you.  


73's
Pete N6QW

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