You get the ideaīottom Line: DO NOT OMIT THE TRANSFORMERS! That is a 6:1 transformation and a close match would be 10 Turns and 4 Turns. OK you now find Z in/out of the filter is 250 Ohms. Again two separate windings or a solenoid winding.
This can be done with a 6 turn and 19 turn winding. I suggested that the Z in/out is 200 Ohms (fairly typical) but suppose it is 150 Ohms. The solenoid winding makes things a bit "fool proof" as you don't need to worry about the phasing of the windings. The bottom end (nearest the 4 turn tap) is connected to ground, the 4 Turn tap to the homebrew filter and the 11 turn end winding to the NE602. Use #26 enameled wire.īTW optionally the filter matching transformer could be solenoid wound where you make a single winding on the FT-37-43 core of 11 turns and then tap the winding at 4 turns.
If you wind 11 Turns (1500 Ohms side ) on a FT-37-43 core and over that wind 4 turns (200 Ohm Side) you get 121/16 = 7.56 : 1 - close enough for government work. For those of you whom are not uBitx or EMRFD illuminati, the home brew filters are in the range of 200 Ohms so a 1500 Ohm to 200 Ohm match is 7.5 to 1. If by some strange quirk of fate you are using a homebrew crystal filter then the filter matching transformers ARE CRITICAL as this set of transformers set the pass band ripple and leaving them out could materially impact signal distortion on transmit. Regrettably when I reviewed the publication schematic on of #178, I missed not seeing the matching transformers. Later in the write up of this project this was documented as being required. This match is from 1500 Ohms to 500 ohms. Internal to the IF module are another set of matching transformers to match the NE602's to the Crystal Filter. These match 50 Ohms from other modules to the 1500 Ohm In / Out of the NE602's. There are matching transformers on the input / output of the IF Module. In the SPRAT #178 Article on, the Block Diagram shows four matching transformers. ( Watch the Sudden Transceiver in actual QSO's) Fast Forward - the Sudden PSK receiver is now a Sudden Transceiver! Here it is in all its glory. Thus, I knew it was possible to make such conversions.
Aade ssb crystal filter design full#
I have a history with such an undertaking, as I turned a Wes Hayward W7ZOI, high performance receiver project as described in Solid State Design for the Radio Amateur, pp 104-105, into a full fledged 20M SSB Transceiver. My first thoughts – why couldn't’t this be made into an SSB transceiver? It had two active devices, one being a 2N3819 arranged as an RF amplifier and the 2nd a NE602 arranged as a Product Detector. While perusing a 2013 issue (#156) of the GQRP publication called SPRAT, I noted a clever project called the Sudden PSK receiver authored by Steve, g0fuw. The Sudden Scratch Built SSB Transceiver ~ 2018.