Simpleceiver ~ Part 13

Second Generation Simpleceiver

This post is to let you hear how the Second Generation of the Simpleceiver sounds in operation. What I have done is to mate the front end of the 1st generation Simpleceiver consisting of the RF Amp Stage, homebrew Double Balanced Mixer, Post Mixer Amp and three pole Crystal Filter. Using this part it was "haywired" to the new J310 Product Detector, J310 BFO and the NE5534 + LM380 Audio Amp. Ahead of the 1st generation board sandwiched in between the RF Amp and the homebrew DBM, I installed the new Band Pass Filter. Take a listen how quiet it is between stations.

I did make a modification of the interface between the J310 BFO and the J310's that are connected in Cascode. On Gate #2, I have added a 22K resistor to ground and connecting the two modules is a 100 NF cap. A revised schematic is shown below as well as the plot of the output. These changes were made to accomplish two things: 1) the BFO loading is improved and the BFO now reliably oscillates every time the power is applied and 2) the overall gain of the Product Detector is improved. I found a condition that you need to tweak the BFO trimmer cap so that the signal was placed properly on the slope of the 3 pole Crystal Filter. But once you powered the circuit down there were cases where upon application of power the BFO Oscillator would not oscillate. This now has been cured.

Special Note: In the hardware configuration a Broad Band Matching Transformer is connected to Gate #1. The primary is 3 Turns and the secondary is 20 Turns on a FT-37-43 Ferrite Core. The 3 Turn winding is the input and the 20 Turn winding is connected directly to Gate #1. If we do the math the Z in is 50 Ohms and the input to Gate #1 is forced to 2.2K. 2.2K/50 = 1:44. The match is based on the turns ratio squared. 3^2 =9 and 20^2 = 400. 400/9 = 44.44. This this is a close match.

73's

Pete N6QW

January 26, 2024. A simple CW Transceiver/Transmitter

Cruise through the lower part of the ham bands bands and what do you hear? Well, FT-8 and CW. Often you will not hear any SSB stations yet go to the lower part of the bands, and it is a cacophony (I love that word) of bad sounding signals and some high-speed keying. Fast is not so much of the issue as is bad, run together and jerky keying. But none the less our hobby started there. So, you could crank down your ICOM 7300 and watch the waterfall on CW or you could homebrew a radio. Actually, to do CW right you need more thought up front than you do with a SSB transceiver. Often, I will state that a CW Transceiver is much more difficult to build than a simple SSB rig. I published two articles in QRP Quarterly on CW transceivers and all I got was a yawn so maybe history will repeat itself. Yawn! 30M CW Transceiver with RIT! Of interest is that the LO is a Varactor tuned LC oscillator using a NE602. Look closely at the RIT circuit which is only activated on ...

March 31, 2024. Happy Easter to those who celebrate this day.

What a great day to Binge on Chocolate and experience the pain of that filling that has been leaking. I would be in that category with the leaking filling(s) had I not just spent an amount equivalent to one of the fancy new uptown appliance box transceivers on two filling repairs. Well at least I can binge on the Chocolate bunnies without fear of pain. Regrettably everything appears to have jumped in price including the price of parts. Well not so much the parts as the shipping costs. That notably is seen in the eBay treasures. I spotted a nice heathkit DX-20 for about $50 and the shipping was $65. Likely it is a twofer with part being a way to in effect charge a higher price by inflating the shipping and in part by increased shipping costs. Shipping with insurance across the US was about $150 for this jewel and that was three years ago. 6AM on the Left Coast ~ 20M Easter Sunday! My only hope is the cost of Chocolate Bunnies remains steady although a pound of See's Candies f...

August 30, 2024. A PNP 20M SSB Transceiver

Shown below is the Block Diagram for the 20M PNP SSB Transceiver steered in the Transmit Mode . The components shown in the dotted block are relay steered so that the block module is single pass and amplifies in a single direction. The Block diagram show steered in Transmit. Essentially the steering process works so that the IF Module input follows the Balanced Modulator on Transmit and then the input side follows the Receive Mixer on Receive. All done with some relays and a bit of RG174U coax. For those who count things in detail, this block diagram is not unlike what was used for the PSSST Transceiver which can be found on my website . Yes, a warmed over P3ST only using PNP devices. TYGNYBNT. 73's Pete N6QW

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