Showing posts from 2020

New Technology for 2020 ~ You almost can't keep up and here is #48...

Updated Photos of the #48 ~ 9-29-2020
I have made a half dozen contacts just this afternoon including two DX contacts into South America. Got a High quality audio presence report from a station in Florida. So once again the Plessey Amps (all three sets) and the homebrew Crystal Filter rule the airwaves.

Work remaining: installing the back plate and finalize the power wiring and antenna connections. This is a winner! 
The next two photos were taken before I installed the TR relays and LPF board.

SSB Transceiver #48 ~ 20 Meters.[ The repackaging continues...

For those who still might be members of QRPARCI and have QRP Quarterly publications going back to 2011 you would find I penned an article on a 20 Meter Shirt Pocket QRP SSB Transceiver. 
I am no longer a member of QRPARCI nor get QQ so I am woefully unaware if any other innovative projects such as the Shirt Pocket Transceiver that are being published. I do know  that one of my other projects was recently republished. 
Regrettably I was not…

New Technology for 2020 ~ A Return To Crystal Sets...

Crystal Sets, Is That What You Said?In the 1950's living outside of Pittsburgh I was fortunate to have some very high powered AM radio stations close by namely KDKA. This early pioneering radio station had a 50KW transmitter and was "Clear Channel". Bottom line a simple crystal set with a modest antenna could hear KDKA. I had a crystal set and an exposed bed spring antenna provided many hours of enjoyment. No Crystal set was complete without a pair of Brush headphones. I am a side sleeper and to this day one of my ears (the one one the side facing down)  is slightly bent from an earphone constantly pressing on that  ear.
It was an an amazing time for me as I did not have a kit crystal set but one that I actually homebrewed myself. So it is today that there are many new radios, totally driven by technology, that are like those crystal sets of old. 
Sparse on hardware but driven by software. There is a "hot on fire" new SDR radio that is enjoying viral trending st…

New Technology for 2020 ~ Moving beyond the MC1496 Direct Conversion Receiver

The MC1496 SSB Transceiver ~ #479/21/2020 Added Schematics and Layouts

I had 40673's! This shows J310's as a substitute

It all started with SolderSmoke Podcast #224 and the comment from N2CQR about a transceiver project from Paul, VK3HN. It seems Paul found an assembly at a Radio Rally (hamfest) that was a project in SSDRA pp203-205. This assembly was an IF amp stage (2 X 40673 and Crystal Filter) and a Transmit mixer Stage comprised of the Motorola MC1496 DBM. VK3HN took that assembly and added bits and pieces to create

New Technology for 2020 ~ A FREE TKT ( Tribal Knowledge Tip)

How to Handle More Than One Band!

[Arduino Code Snippet ADDED to this post]
So you have just homebrewed a new QRP transceiver and it doesn't matter if it is SSB or CW and as a bonus have included two bands. Now the problem how to switch all the needed circuits so that with a simple DPDT Toggle switch -- the magic happens!
But let us back up in the sewer so we get the full aroma. Switching bands entails several actions including switching the LO range (I am presuming a digital LO) as well as the Band Pass and Low Pass Filters. One half of our DPDT can be dedicated to the Arduino Input for band change while the other half of the switch can "Power On" sets of relays to select the one of two bands.

Above is a two band LPF with the yellow core being the 20 Meter Section and the red core the 40 Meter Section. The two black relays are SPDT. and the Yellow relay is a DPDT.
By my wiring convention I made it so the NC contacts on the DPST are connected to the 40M Section and the NO to …

New Technology for 2020 ~ Some exciting happenings in the greater ham community

The Direct Conversion Receiver -- MoreSeptember 7, 2020 ~ GQRP Club Virtual Convention -- some thoughts.
The Covid19 dramatically has changed all of our lives and yet technology has jumped in to take up where normalcy left off. The GQRP Club Virtual Convention is a sterling example of how through the use of Zoom, hams around the world were able to participate in the two day event. High marks for the team that put the event together.
I liken GQRP Convention Central to Mission Control in Houston, much like when the first space ship headed to the Moon. As a presenter I was really concerned how well this would work -- about 5 seconds into my presentation and it was clear -- it was going to work seamlessly --and it did. I think the message is clear when perhaps normalcy returns, future conventions will take form as a hybrid with personal and well as virtual attendance.
But the GQRP club is more than just the annual convention as it is an organization with a publication that fosters low power …

New Technology for 2020 ~ A Direct Conversion Receiver You Can Build

Some Arduino Code as used with the Left Coast Loafer CW Transmitter.//Turn ON:     si5351.clock_enable(SI5351_CLK1, 1); //Turn OFF:   si5351.clock_enable(SI5351_CLK1, 0);
/*OK you missed it -- the "1" turns it on and the "0" turns it off.)
So my code senses if Pin 4 is LOW and if so then turn ON the CLK1. If it is not LOW then turn it OFF. This is the standard If Else regime. You also have to blank out the frequency in the else part of the code. Here is the code*/
 void CheckCW() {

                 digitalRead(4);                  if(digitalRead(4) == LOW){                  si5351.clock_enable(SI5351_CLK1, 1);

                 si5351.set_freq( rx1 - 700, 0, SI5351_CLK1);

si5351.clock_enable(SI5351_CLK1, 0);

I plan on a MOX operation where you flip a switch and that turns on CLK1 and at the same time does the TR. There is embedded code to produce a pulsed 1kHz Tone for tune up. 

No reason with a little code rework that this 988Hz Tone would be the …