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Two More Modules for MHST: The BPF and the Steered J310 Amplifier

Last night at 8:17PM we had a 3.9 Magnitude " shake, rattle and roll" event and Bill Haley and the Comets were nowhere in sight. About 10 miles from my QTH.

Happy St. Patrick's Day!

The ever-skeptical ham wants to see the plots and the circuits. Today we will look first at the all-important Band Pass Filter. (This gives pause that maybe every ham has Thomas as a first name.)

Credit goes to VU2ESE for the BPF used in the Bitx40 and the 1st item is just a lift from that project starting with the plot and then the circuit. The 50 Ohms resistance is for simulation purposes and not installed when placed in the circuit.

 

Now that is a flat Band Pass!

 

This uses standard values!

  

 
We next turn our attention to the J310 Steerable Amp stage that is used as the Rx RF Amp on receive and the Tx Pre-Driver on transmit. This circuit is for 40M and provides 10dB of Gain. We must add the steerable relays so that is in essence the direction of amplification is steered for incoming on Receive to outgoing of Transmit.
 




While the steerable concept is shown above for the P3ST the two SPDT relays control the direction of how the amp works. On transmit the switched connection input is connected to the BPF and the output side goes to the follow-on RF stages. On receive the R contact is connected to the antenna via the TR and the output side goes to the Band Pass Filter. I am looking to make this a single BFR106 stage as it would involve less parts. The 13.3K resistance shown on the schematic is actually a 10k pot wired as a variable resistor in series with a 3.3k 5% fixed resistance. This gives a range of gain adjustment.

A source for the J310's, BFR106 and the ADE-1's all mounted on small circuit boards is from Todd K7TFC . Scroll down to the very bottom of the webpage to find these components!

Them that know can make it go!

Going shopping for vittles today but must stop 1st at the bank to get a home loan so I can afford to buy groceries this week. It is really sad where we are headed -- and some have the audacity to call this on the road to great prosperity. BS as only a few will prosper, and they are already billionaires. What about the rest of us?

73's
Pete N6QW

 

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