Simpleceiver~ Part 25

Temporarily QRT @ N6QW

Due a family medical emergency there will not be much coming out of the pipeline from N6QW for a short period of time. However there has been enough information presented to proceed with the transmitter portion. You would only need to add a pre-driver and driver stage plus the final amp and the low pass filter and you are there.

Here are some circuits to consider for the final pieces of the transmitter portion. These are proven circuits having been used in the 2009 Tri-bander, the JABOM and the KWM-4. I strongly recommend NOT using the IRF510 as is the favorite of the BITX crowd but instead put a real RF device in the final amp. For those who want to pick apart the pre-driver/driver check EMRFD for an explanation and specifications of the circuit. The RF Final is my own design and the LPF you can simulate in LT Spice. You will need to fit in a TR Relay and the final integration wiring. If at this point you are not capable of doing that then I suggest you do some Internet research on how this is done. I just do not have the time right now to provide that information.

Good Luck and I hope this temporary cessation is in fact temporary. That said the objective has been to share my experience and knowledge of how to scratch build a radio. The over documentation in this project was so that the project didn't end up like so many kits --solder all the resistors first and then .. Hopefully I have provided information on the functions of the circuits and how with tools like LT Spice it is possible for you the homebrewer to make changes. I know how to do it -- the important point is that you know how.

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

Pay More and Get Less. Flash the Cash!

Search This Blog