Відео

The SSB generation is done an a fixed Intermediate Frequency, in this case around 5.2MHz and dictated by the crystal filter. The 5.2MHz IF is then mixed with the VFO in a transmit mixer to the various ham bands. The output of this mixer is always bandpass filtered , then amplified up to the transmitters RF power level. Superhets have been the standard transceiver architecture since the 1950s but have been now replaced by software defined receivers and transceivers. en.m.wikipedia.org/wiki/Superheterodyne_receiver

Thank you very much, I understand everything now

Thanks Jordon. Must admit that rig hasn't been out again, getting the wire up is an effort. I planned on going 160m portable at Mt Donna Buang for the 11am coffee break, that would guarantee an all AM activation, maybe one day.

Thanks for watching!

@@Paul_VK3HN Hello Paul, I'm catching an ideas then make my own. You may glance my based on australian Codan own TX :) Wish more new for you, GL &73!

Hi Gary, I see you're a keen SST30 CW op. With only 2 watts it's real QRP. At the cycle peak and at the right time of day it's enough to make contacts! Well done on sticking with the simple CW gear, it's the true spirit of amateur radio!

Hi Nick. I find the combined design challenge of physical, electrical and RF dimensions of a radio like this to be never-ending fun. As far as size is concerned, I'm learning to use the design tools to build and populate PC boards at the factory. It's a different game to how we've always worked, and there are limitations, but if you look at the range of kits being offered now, they are almost all partially populated surface mount parts on a PCBs, so that the 'kit-building' has become soldering in a few thru-hole parts, sockets, big things, then powering it up and aligning it. That's increasingly the only financially viable way of kitting going forward. One of the consequences of this is that everything gets smaller. SP9 above is already big and clunky compared to most of today's so-called DIY or kit radios. All of that said, there will always be a place for soldering thru-hole parts onto a scrap of copper board to prorortype something. Its the absolute best way to learn. 73 Paul VK3HN.

To be honest I'm not sure, but I followed the online calculator. Try it out, and try more than one. Good luck !

Hi Pascal, good to hear from you, thanks for watching. I have an old Mizuho SSB generator board that I got from Glen VK3PE sometme back, I might use it one day. 73!

Thats common in bipolar RF amps. There are a lot of variables. Could be the transistor you are using, the change in reactance of your collector transformer over the frequency range, drive level. Easiest fix would be to use a suitable RF transistor such as MPSH10 www.minikits.com.au/MPSH10 or BFR91. You could also try a MMIC. www.minikits.com.au/rf-mmics

Thanks - it's always nice to see someone else going down the same road.

Thanks! I think you're right in recognising that any transceiver needs good analog filtering at its input, output and anywhere RF signals are mixed. Thanks for your kind comments.

Yes it's Old Skool for sure!

Tnx!

Tnx!

github.com/prt459/Arduino_si5351_VFO_Controller_Keyer

Many thanks!

Thanks. The advantage with something like this is that when it breaks it can be fixed!

Thanks for checking it out!

www.box73.de/product_info.php?products_id=919

Thanks to you Jason, and its got your si5351 library baked in!

@@Paul_VK3HN I'm curious about something, if you don't mind. I'm working on a transceiver using the same type of I2C OLED display, and it's generating a huge amount of noise in the receiver. Are you using the u8g2 library for it, or something else?

@@jasonmilldrum There is some display noise which you can hear as a low level repetitive swishing noise when the antenna is disconnected. If you socket the SSD1306 display you can test this by unplugging it at any time. In most situations it is masked by band noise once the antenna is connected. On a few occasions I have been able to hear the display noise with antenna connected, but only on a remote summit with extremely low band noise, and only early in the day before the band livens up in the afternoon. I have some basic LC filtering on the DC supply, nothing fancy. When laying out the transceiver I tried to put some space and screening between the MCU/OLED and the receiver front end. But there is no doubt that an HD7044 LCD is a better choice for a QRP field receiver, as they are perfectly quiet (there's a reason why Hans Summers has not used OLEDs in any of his kits!). But the OLED is a nice fit to the form factor of this radio's styling and case. Re the lib, I tried but abandoned the Adafruit SSD library (is this or does this drag in u8g2?) which was way too memory-hungry for an ATMega328. I found a lightweight ASCII only libary (no graphics) from Bill Greiman (github.com/greiman/SSD1306Ascii). I hand-made a new font for the S-meter and added it into the installed header. I reckon I've had more than a dozen emails from builders all over the world who are using this code in transceivers with an OLED, so it has proven reliable. Good luck with your project and thanks a heap for your library!

Thanks!

Thanks!

Not building at this time, have some other interesting challenges, but realised this nearly 3 year old video was unlisted. Hope you’re going well.

Thanks for watching.

Thanks Steve.

Thanks 👍

This video is nearly 3 years old, just noticed it was unlisted. Dual gate MOSFETs are ideal as IF stages, because they can be clamped down 50dB with gate 2 bias. The well known ones have gone, but you can still buy them... www.minikits.com.au/BF904-215

I was wondering what happened to him. Now we know

He is having a midlife renaissance.

@@Paul_VK3HN midlife renaissance ham !!

Try it and have some fun learning electronics and radio!

Thanks, this is an old video, no workshop at the moment!

Yes, it's more the nostalgia for me, and getting it going again to experience what ham radio reception sounded like back in the day. I hope you have the NE602 in 8 pin DIP, getting hard to find these days.

Good luck if you decide to build one, they make a great weekend VHF UHF antenna project.

My homebrew rigs don't have tuners so I only use resonant antennas. 😮

Thanks! It's a fairly basic little radio transceiver but it works well enough!

Thanks! Do you mean how many pulses or interrupts per turn, or how many kHz? The optical encoder generates far too many pulses per turn, so I added a line of code to increment a counter and ignore 3 of every 4 pulses. It might have been 7 of every 8 pulses. The code is on github. I cannot recall for sure and the rig is not in use at the moment, but it's tuning rate with 100 Hz increments is about the same as other commercial rigs, say 10kHz per turn.

@@Paul_VK3HN I was just wondering what encoder you used i was going to get one "100/200/360/400/500/600P/R Photoelectric Incremental Rotary Encoder" wondering if to just buy a 100p/r?

​@@klejzbigniew I used this one , they are available from lots of sources. www.minikits.com.au/ENC-360-6 I have tried a variety of mechanical encoders, all have worked.

No. The board works as shown but has some labelling errors. I could fix these and put it all on github, if you are keen and would go through with the build. I've moved on to a board half the size with a XIAO ESP32 and 5351 on board. I'm also writing new software that will include additional features such as CW decode on both Tx and Rx. This will be about another 3 to 6 months, based on current rate of progress.

Happens every day, Cycle 25 is at its peak!

It works!

Brian, thanks for your comment. The 28MHz transceiver can drive any VHF UHF transverter. If you can find a 28 to 220MHz transverter, it would work just fine. I built the 28MHz receiver/exciter and connected in a transverter from a Ukrainian supplier. You could attempt to build the transverter part but its not a beginner or intermediate project. Good luck.

Thats a super interesting homebrew project and very modern! The 20w PA should be achievable with all the switching FETs to choose from, although you will need faster ones at 14Mhz. What MCU will you use ? Will you write your own software ?

Yes for sure, going back to when these jingles and signature tunes were in use, shortwave was a competitive place where nations tried to 'catch' listeners. All swept away by internet and social media.

It's not merda

Thanks for visiting

Thanks!

I didn't try it on short indoor antennas but I don't think it would work well. Ferrite rod front end might work better on LW and MW. Yes, almost any dual gate mosfet should work.

Sure, TL598 is an updated TL494 which should work fine in this circuit. They are probably not pin compatible so you might have to make some minor changes.

@@Paul_VK3HN thanks alot i like your videos an the projects you do would you please design this with t494 since tl 494 is most available my request

​@kittony71 Time is limited at the moment, I suggest you study some TL494 SMPS circuits, read the datasheet, watch some videos and try it yourself. Doing it yourself is the best way to learn.

@@Paul_VK3HN thanks am working on it right now

Thank you 🤗