Category Archives: RF

Analog Electronics RF Tindie Tools and Test Equipment

Just in! and the start on a VSWR bridge

I’ve been working on little bits over the last week or two, nothing notable but filling up my notebook with plenty of “lessons-learned”. For instance I decided I’m no good as estimating how many uH my home-made inductors are. I purchased a BK Precision 879B LCR meter to confirm that fact. A side-bonus was I went through all my caps and could test my home-brew ESR meter vs. the ESR meter built into the 879B and I now have a fair amount of capacitors that are going to the garbage. No more saving scrapped caps for me. I was working on an oscillator the other day.. well I winged the inductor.. not a wiggle out of the oscillator when finished, that’s what finally made me break down and buy the meter..

A crystal oscillator.. that doesn't oscillate
A crystal oscillator.. that doesn’t oscillate

Today I sat down at the bench and I started working on a project I have had on the board for a while (it’s a surprise); for this piece I made a 50 Ohm VSWR interface; then I threw it into a test jig and checked it out. It actually worked pretty solid. I got some 1 watt SMD resistors off an eBay purchased of some 49.9 ohm 0805 SMD resistors I ordered. The guy just randomly threw in 10 1-watt 49.9 ohm resistors… nice guy. I tested it up to 500MHz but after that I had a bit of noise measuring reverse power.. that’s okay though for me. Interestingly I found with my SA I have a pretty solid local noise source at 90.9, some local station I’m sure.  If you’re interested in making your own check out this guy’s website. He has a basic schematic of a bridge that is functionally equivalent to mine it seems. (a bridge with 3 resistors.. not a brain buster).

 

A little home made VSWR bridge for an upcoming project..
A little home made VSWR bridge for an upcoming project..

So after some success I decided it was time to get to mail. Yesterday I got a packages from the @tymkrs and Jason at AtomSoftTech.

Jason stuffed a box with some goodies I ordered and extras (thanks Jason!) The two most notable items of the bunch is the breadboard PIC buddy and the ESP8266 breakout board. The ESP board was flawless, but after use of BB PIC buddy I have ideas for v2. Now let me make it clear I saw this design before it went to the fab and I missed stuff that seems now obvious.. totally my bad.

Is it functional? Yep.. What would I recommend for changes?

Make the power side a little longer and have the USB jack coming in on the side.. if the PICKit2 is plugged in you can’t use the USB connector. Also while the PIC Kit 2 works okay I think pushing it a 1/2 inch away from the RJ12 jack for the ICD would make the insertion a little more solid. Nice product though.. this is certainly a new breadboard-fav. Jason is selling these for too cheap on Tindie. Get it before he gets smart and raises his price 🙂

The BB PIC Buddy and ESP8266 breakout board
The BB PIC Buddy and ESP8266 breakout board

There are some other items from AST as well but I’ll mention them later on. I had purchased two items from the @tymkrs ; the new Analog Shift Kit and the new SMD LM386 audio amplifier “Amplify Me”. The Amplify Me board works as expected, I checked out the PDIP version of this some time back ago, I’m not going to hunt for the post though, it’s a LM386 audio amp, kind of a no-brainer. I though of one change for future versions of this product that might have been a little more user friendly. It’d be nice if they made the product just a few more tenths of inches wide and brought that PCB 3.5mm jack out away and further back (back in reference to the photo below). I would make the jack so that it was level with a panel if you mounted the potentiometer into a panel. I don’t think it would add too much to board coast but it wold make this much easier to integrate into projects. As it is though, the potentiometer doesn’t have to be soldered into the board (it doesn’t come soldered) so it would be easier enough to work around. I still find it shocking to get a battery included in an order! It’s the little things @tymkrs!

Updated @tymkrs SMD LM386 Amplify Me
Updated @tymkrs SMD LM386 Amplify Me

No time to get to the Analog Shift kit today, I’ll save that for the future.

I have a lot more Analog bits I’m working on in the near future; I hope to get some of them mentioned here.

C Microcontrollers RF

PIC talks UART on RF – 434 MHz | 0xEE.net

PIC talks UART on RF – 434 MHz | 0xEE.net.

A cross post of the latest 0xEE.net article on using cheap RF modules with PIC Microcontrollers streaming serial using parity.

Analog Electronics Radio RF

Amidon Toriod Experimenter Kits

I have been pushing myself to build some IF filters. I’ve never built a front end of a radio; VCO, mixer, filters.. none of it. I started by buying the Amidon Toroid Experimenters kit #2 and #3 as many of the ARRL handbook samples use Amidon part numbers. I ended up switching to another book to do all my research though; “Secrets of RF Design”. Let me let you in on the secret.. it’s a lot of reading, not all of it stimulating. I also bought the “Island Cutter” from QRPme which is probably one of my favorite purchases of the year… armed with that I started building circuits.

If you’re working about purchasing the Amidon Experimenter Kits.. well I have no regrets. It gave me a good selection of options and even some larger one’s I don’t know when I will use but maybe for a switching supply project or something. I ordered a few other small pieces I knew I’d need more than 4 of just to have them on hand.

Amidon Toroid Kits

I really enjoy the circuits around varactor diodes. I’m building an analog front end but for stability I might just end up wwitching to DDS later on but for now for the VCO is a tank circuit. Next step is the mixer..

Varactor Tank Circuit Fun

 

I probably should still be working on other things, I have a pile of “to-do”s but I needed a little inspiration to keep me at the bench after all this summer fun. My last summer outing is a 7 day backpacking trip in the northern cascades packrafting! That’ll be some seriously needed unplug time. So stay tuned… I ordered about ~$500 worth of electronics for all my up-coming fun.. looking forward to digging into it. I still need to buy an LCR meter, I’ve never owned one and it would be nice to know my inductors is/are “in the ball field” when I wind something using the tables… I can do the math but I think it’d still be nice for a confirmation before I start soldering and making measurements.