Meet the PSSST!
Pete's Simple Seven SSB Transceiver
(PSSST)
[A Plug for Jameco Electronics and My Story]
Documented QSO
The PSSST ~ You know when we want to get someone's attention we go "PSSST". Well it also is an acronym abbreviation for "Pete's Simple Seven SSB Transceiver!" Did I get your attention?
I have posted videos of how the receiver portion sounds on crowded bands and hopefully you have been impressed. I was!
My work involved NO bilateral circuits, NO TIA amps, it has not been published QEX and there are no Facebook groups and neither are there any group.io lurkers to make snarky comments. The band of choice is 20 Meters
The best part there are only 7 transistors in the whole rig. Five of the transistors are 2N2222A's along with one 2N2219A and one IRF510. The power output is 4 watts and I have a confirmed "1st contact" (DX no less to Canada @ 1200 miles). [I now have a RD006HHF1 in the mix versus the IRF510 and have made a half dozen contacts using the PSSST.]
What sets this rig apart from other topologies is the how it is works. There are two circuit modules that are relay steered to have different signal paths depending on whether in Receive or in Transmit.
The 1st module consists of two 2N2222A's and a 9 MHz Crystal Filter. The input and output are steered between two ADE-1's. On one end the ADE-1 is either the Balanced Modulator or the Product Detector.
In receive the IF Module output is connected to the ADE-1 in the Product Detector Mode. But on Transmit the input of the IF Module is now connected to the same ADE-1 which now is the Balanced Modulator.
A relay on the 1st ADE-1 connects to the Audio Amp on Receive and to the Microphone Amp on Transmit. In case you are counting all this is done with three SPDT communication relays.
Shifting to the 2nd ADE-1 on Receive it is the Receiver Mixer and on Transmit it is the Transmit Mixer. At all times the 2nd ADE-1 is connected to the Band Pass Filter. However, the 2nd ADE-1 is either connected to the input side of the IF Module on Receive, or to the output side of the IF Module on Transmit.
Noteworthy the BFO and LO are always connected to only one ADE-1 and are not switched.
The second "steerable" circuit module is a single 2N2222A that acts as the Receiver RF Amplifier on Receive and as the Transmit Pre-Driver on Transmit.
Stop! Up to this point only FOUR 2N2222A's are used in Receive (Audio Pre-amp, IF Module and the Rx RF Amp) and FOUR 2n2222A's on Transmit (Microphone Amp, IF Module, and TX Pre-Driver). I would call that Minimalist!
The Audio Amp uses a 2N2222A driving an LM380N-8 for more than room filling volume. The Microphone Amp uses a single 2N2222A. A good deal of time was spent optimizing (LT Spice) the Microphone amp to have lots of low frequency gain, so the sound has lots of "presence". This same circuit is the audio pre-amp.
Note to those who don't read the print. What connects the Pre-Amp to the LM-380N-8 is the 10K Pot. Read Carefully that R6-R8 are there only for simulation and are replaced with the 10K Pot. Having R6-R8 gives the three plots to simulate a Pot. I have to say this because undoubtedly I will get two emails that say "I don't understand the schematic". Friend learn how to read!
USE ONLY THE TO-18 VERSION OF THE 2N2222A. Because they are being driven hard -- they run hot!
A lot of effort was spent with circuit simulation and hidden in the blocks are optimized amplifiers and extensive use of circuit matching. I am particularly impressed with the 2N2222A over the 2N3904 for this application as it current limitation is 500 ma (versus 200 ma for the 2n3904) and it can be fitted with a heat sink.
Now there are those who will go to Google and tell me immediately that the 2N3904 total device dissipation is 625 mw versus the 2N2222A at 500 mw. But it is hard to put one of those cool top hat heat sinks on a 2N3904!
Keep in mind NO BITX, NO TIA and NO QEX. This is not a kit but holds the promise of a minimalist rig goal that sounds really good. I am encouraged by the Pout (4 Watts) on 20 M and think with a different filter (like 10.7 MHz from Spectrum Comms. UK) this can be transported fairly easily to 17M.
I need to dig out my digital adapter and run this up on FT-8 and WSPR --just to quantify how good the hearing part is.
The those who never have built anything; but act as if they know everything about anything must be suffering terribly. Aside from a few block diagrams they have nothing to pounce on with the intent to denigrate.
In time I will be publishing (note I said publish) detailed circuit, information, LT Spice simulations, and lots of photographs of the fabricated modules. But for right now I am just delighting at having been successful with the PSSST.
A ham yesterday got an email about his homebrew rig from a lurker. The email contained factual errors and it was obvious the person sending the email lacked technical skills and yet spoke with such authority. Thus, before you send me one of those emails, I have the hardware and the data. You now also have the video of a QSO.
It is like the ham who commented on a you tube video I made on the HW-101. He said if he owned one, he would never do what I did. Well friend if you owned one, you would do what I did. The bottom line -- if you haven't built the PSSST -- you can't possibly know!
73's
Pete N6QW