N8NM's SR-16 Hallicrafters Tribute RIg

Bill,  Pete:

The rig is loosely based on the Hallicrafters SR-160 transceiver, since I'm using a RD16HHF1 in the final RF, I'm calling it the SR-16.   It's a tri-band rig covering 80, 40 and 20m.  Architectually, it's similar to Pete's JBOM, which is partially coincidental (thanks for sharing the article, Pete!)  The heart of the rig is the W7ZOI hybrid-cascode IF, a really slick circuit that really makes the rig a joy to use. 

Frequency generation is handled by the ubiquitous Arduino/Si5351 combo and a sketch based on Tom, AK2B's "Multi Function VFO", to which I added functions for selecting the appropriate bandpass and IF filters, generating CW, RIT, and dual VFOs (with split functionality), the state of which is saved in EEPROM when the rig is powered-down.

The rig's just about finished - I've got the remaining parts ordered and hope to have it on-the-air soon.

73! - Steve N8NM

DARK SIDE TO THE MAX: WA7HRG's Android Tablet SDR (with a question)

Jim's experience with the Android tablet SDR was very similar to mine.  But he used a "Ham It Up" up converter ahead of the RTL-SDR while I used an RTL-SDR modified for direct sampling of HF.  I built a pre-amp/pre-selector stage for mine.   On my Android Tablet (50 bucks via Amazon) I found the touch screen to be kind of clunky -- it was hard to get the receive passband lined up with the incoming signal. The touch screen was not nearly as smooth as the one on my IPhone.   A Bluetooth mouse solved that problem.  

Like Jim, I am using SDRtouch from the GooglePlay.  I'll have to follow his lead and try Droid RTTY and PSK.

My reaction to the completed project was also similar to Jim's: He writes that this is, "The first and last of my SDR adventures.  This is just not the same as scratch building!"  Indeed, it is not.  But still, for very little money you end up with a pretty impressive receive capability, and you get some valuable insight into an intriguing method of receiving radio signals.  And you don't have to mess with Linux!

I have a question for the SDR gurus:  With direct sampling, we are  just running an ADC at RF.  So we no longer need an I-Q front end to take care of the image problem we had when we were running soundcard-based SDRs, right?  But I sometimes I hear that even with direct sampling systems, there is a digital generation of I and Q signals.  Why would you need I and Q if you are just digitizing the incoming passband, multiplexing it,  and sending it to the software?

Hi Guys

OK, so I am a little (A LOT) behind you guys in my bench work.  Several unfinished projects are waiting in the wings.  But I thought I would also dabble in Software Defines Radios.  Thought I would go the Raspberry Pi route as Pete did.  Then I woke up and sided with Bill.  I don’t want to learn Linux!!

For about the same price as a Pi-3 and a 7” screen I bought one of Bills Android tablets and I found on eBay an estate sale that had a bag of NuElec parts.  The RTL dongle, a Ham it Up vs. 3, and several cables, all unused.   Last but not least I bought an Android ‘On the Go’ USB cable adapter.
I removed the LED and UV diode for the remote to drop the current some. Then tapped some power off the USB connector and ran it out to the Ham it Up.  A few holes and some double sided carpet tape and ‘Bobs Your Uncle”.   I added an enable switch to the up converter for the noise source but still waiting for the SMA connector to come in.  Then I’ll see what that can do as a poor man’s spectrum analyzer for filter design.

I found several interesting apps on GooglePlay.  Besides the SDRTouch program I downloaded Droid PSK and RTTY.  Also the RFCorb client that allows you to connect to hundreds of remote stations around the world.  That I may have to spend some time exploring but not really part of this build.
The Up Converter fired right up and after tuning around some I jumped to 14.070, the PSK hot spot. The tablet truly does multitask.  I left SDRTouch running and opened Droid PSK.  A waterfall full of signals jumped up and I was easily copying stations on the East coast and Canada.

All this running on the USB power from the tablet!  How cool is that.  After about 45 minutes or so the battery was about half.  The only problem that I may have to address is that the tablet and/or the Ham it Up gets pretty warm and my carpet tape lets go and things fall apart.  HA.  Haven’t ran it long enough yet to see what else the heat might effect.

So that was fun and I will be playing with it some more.  I have coffee on Mondays with some ham buddy’s.  When I showed them the PopCorn radio they jibbed about it not being battery powered. 

Well Monday is coming!!  HA

Jim WA7HRG

FB IBEW HB DC CW de UAE: A65DC's International Homebrew Rig

Good evening!

After my JOO moment, Bill put me in contact with Pete Eaton, who suggested that I would have a look at the schematics for K4GC 40m CW Transceiver.

And I did, It was just perfect for me, low part count, lots of things done in software!!! Perfect Bryan!

http://www.k4gc.com/40mdirectconversionxcvr061516.html

I started off the build and both Bryan and Pete supported me along the way, thank you! 

So here we have it:

The design slowly deviated further and further from the original, but I think I learned quite a lot by starting to make it “my own”.

The Arduino was changed to an UNO, yeah they are clunky and big, but I was not shooting for a pocket-size anyway… and they do have a proper USB port.

The RF-path is now switched by a relay straight after the filter, when the relay is relaxed the antenna is connected to the mixer, when I touch a paddle it connects to the TX circuit.

I have a short hang time from the last key input and it goes back to RX, VOX Delay I guess.

I completed the 700Hz bandpass filter, boy! this makes it a much nicer rig to work CW, I originally I skipped this filter for no good reason? That is the board standing up in the picture.

The TX circuit is a two stage, the first stage is a replica of VK3YE beach40 amplifier circuit, that also uses DB139. The second stage is a spin of the EMRFD Page 2.38 IRF511 Amp.

I have cranked it up to 17w, but it gets too hot too fast, as you can see I don’t have any proper cooling yet, I need to redo this board and plan for the heatsink a bit better.. it is now set around 10w, still getting hot, "599 TU 73”.

To be honest my CW does not go much further anyway, but I guess with this radio now completed I have one more reason to get my speed up.

 I use for convenience both CLK0 and CLK1, when I go into TX I switch off CLK0 and do the keying on CLK1, both transmitter stages are powered up the whole time (until I stop keying as described above)

As the 700Hz filter worked so superb, I decided that I wanted to introduce “modes” to the rig, I can now switch the audio either thru the filters (CW) or straight to the AF amp (AM).

I do enjoy listening around, and we have a lot of AM stations on offer in my region.

I kept the smart RX mute transistor circuit and when I ask the Arduino to change mode, it will mute the receiver quickly, pull the relay and then un-mute again, no ear pain from the loud relay click. (I am happy with that detail).

The 2 line display became a four line, and I can change Tuning Rate, RIT, Key Speed and Mode by using only the encoder and the one button built into the encoder.

The front panel sports, on off, Headphones, Paddle and volume, the display and the big knob.

Power connector and USB Port on the side. I did complete the CAT control changes while working on this radio, it now uses the classic Kenwood interface e.g. TS480. (A lot fewer questions from the PC to answer.)

The CAT control works very nice while using N1MM, it works a lot less nice using CQRLog, I guess it has to do with the number of times the software in the PC is asking about things from the radio.

I will look into logic to only worry about incoming serial requests if I have not answered for some time, and never answer while in TX…

By pressing the VFO button a small arrow appears next to TR, if I push again it moves the arrow down to RIT and so on.

if I turn the knob with the arrow standing in front of e.g. KEY it will increase or decrease the KEY speed, when I press again, it will return to frequency control.

Oh, another detail (that I am happy with) while the arrow is in front of the KEY, you can fiddle with the paddle with out transmitting.. practical for testing the speed.

So this is a K4GC transceiver with bits and pieces from VK3YE and bits from the A65DC laboratory in Dubai, truly international.

To trim things in I scheduled a QSO with a local ham here, and things worked very nice, later the same night I made my first “DX” contact with RM2D!!! Moscow!!

What are the odds that a Swedish guy living in the UAE makes the first contact to another Swedish ham who lives in Russia!

73,

Martin A65DC

Homebrew Canoe (video) (beautiful)

I post this because it is nice to occasionally look up from our soldering irons and take a look at what other people are building.  This video is really beautiful.   

Channelized! BITX 60 with the Five Channels (with video)

Here's an update on my BITX 60 project.  The modified module is in the lower box.  An Arduino Uno and an Si5351 (this one with unreleased smoke) is in the Heath QF-1 box on the top.  I am using an Arduino sketch written by Don ND6T. It spits out the needed 17 MHz LO freq needed for each of the five 60 meter channels. You can scroll through the channels by just holding down the rotary switch interrupt button.

There is a move afoot to liberate from channelization about 15 kHz of the 60 meter band. When that happens, I'm ready to go -- I'll just reconnect the rotary encoder for the Si5351 and load some new code.  I suspect that by the time that happens, Don will have modified his code so that the 15kHz "tunable" segment will be integrated into the current program and will appear as one of the options as you scroll through the choices. 

For reasons that most readers will understand, I have resisted channelization for many years.  But here I am, channelized on 60.  It is not so bad.  I'm having fun listening to a new band, using a modified BITX, an Arduino, a bit of Heathkit and code from a fellow ham.   

BITX 60 (with three short videos)

Inspired by Don ND6T, I decided to put a BITX40 Module on the 60 Meter band.  All you really have to do is modify the bandpass filter.  Don showed us how to do this by simply adding three 100pf caps.  I was going to order SMD caps, but this just didn't seem right -- I found three of the old "with wires" kind and easily soldered them into position.  The bandpass shifted as Don had promised.

You also have to change the VFO freq.  You need it to be in the 17.3 MHz range. Don has a nifty program for the Raduino that also works with the Si5351/Ardunio Uno combo that I use.  It keeps you on the five channels currently authorized on 60. Unfortunately I managed to let the smoke out of yet another innocent Si5351 breakout board.  Amazon and Lady Ada are sending me another one, but in the meantime I pressed into service an old AD9850 DDS. I had a little trouble getting the 17MHz signal through the BITX's VFO 4 MHz VFO system, but I eventually figured it out. (More on this later.)  

The receiver is working nicely.  I like the relaxed 60 meter conversations. 

For Pi Day (3.14) - Looking Back on 5 years of Raspberry Pi Tinkering

Not by me, thank God! No, the five years of Rasp Pi maso-tinkering were done by Thorin Klowsowski.  His report appears here:

http://lifehacker.com/what-i-ve-learned-from-tinkering-with-the-raspberry-pi-1793236686

In the second and third paragraph, he confirmed all my suspicions:

The Raspberry Pi is far, far away from being as user friendly as a PC or Mac. That’s a feature, not a bug... Before hobbyists latched onto the Raspberry Pi, it was a computer for learning how to code targeted mainly at kids. Since then, the appeal has broadened, but it’s still impossible for a project to “just work” out of the box. You will have to tweak something, dig into the command line, or spend a few hours buried in an obscure internet forum to find solutions to problems that only you seem to be having. You will slam your head against the wall, yell a little, and throw your Raspberry Pi at least once for every project you attempt to make.

I told you so. 

KC1FSZ's Peppermint Bark BITX: Aeronautical Mobile for his FIRST QSO. TRGHS.

Bill and Pete:

Can’t say enough good things about your podcast - thanks for all that you do.  I’m a fairly new ham and have been trying to go the home-brew route as much as possible.  

I bought a BITX40 module (pre Raduino vintage) and added my own VFO board using the usual parts.  Actually, I’m using a Teensy 3.2 instead of an Arduino because it is a faster part and has a lot of DSP functions built into it that I’m using for digital mode stuff.   But it’s the same basic idea.  

My BITX40 is not as photogenic as some of the others, but I sent a picture below. This is the “biscuit tin” variety.  It’s was funny actually: a co-worker of mine stopped by my office around Christmas to give me a gift and pulled out of his bag a very nice box of “peppermint bark” candies with a ribbon around it.  The VERY FIRST thing that crossed my mind the instant I saw the gift was …. BITX40 ENCLOSURE!  He must have been pleased to see the huge smile that came across my face. :-)   I’ve been bitten by the bug for sure.  

My first three HF QSOs (ever) where on the BITX and were all very interesting:

• First real QSO of my life was with KE4TJB “air-born mobile” off Delaware.  He is a commercial pilot flying for JetBlue and apparently has time to work QRP stations during flights??  I wonder who was flying the plane?
• Then I was scanning around this morning and caught K4HW making last calls for check-ins on a net running on 7242 out of North Carolina.  I decided to give it a shot, having never joined an HF net and I was recognized!  As the first round got going I realized I had joined a Jehovah’s Witnesses net.  They were very friendly and the net control stopped to help my get my frequency calibrated before they continued with the scripture passage for the week.
• Later this morning I reached K3KLC in Maryland who had the high-end SDR rig with the waterfall/panadaptor/etc.  Remembering comments that you guys have made about these types of folks on 40m, I was very concerned.  But this guy turned out to be very helpful and sent me some screen shots showing what my signal looks like.  

Thanks again, and 73s,

Bruce MacKinnon

KC1FSZ

Wellesley, MA

https://www.qrz.com/db/KC1FSZ

WA8WDQ Builds OZ1JHM's Arduino CW Decoder (Video)

Bill, Pete:
I wanted to update you on my DC receiver progress.  While I'm still operationally proficient in CW, many of my friends are not.  So I thought it would be fun to add a CW decoder to my DC receiver. 

In my research for a solution, I ran across a sweet decoder I thought might be of interest to the SolderSmoke listeners.  OZ1JHM developed a totally software based decoder for Arduino that uses the Goertzel Algorithm.  This algorithm performs similarly to a Fast Fourier Transform but only for tone decoding at specific frequencies.  This limitation keeps the code small and fast making it perfect for microcontrollers like the Arduino. 

I was able to hack Hjalmar's code into mine and the result is CW decoder functionality in the receiver with no additional hardware!  But, the Arduino Uno's performance is limited so I need to dynamically switch between receiver VFO/control code and the CW decoder in order to preserve real-time performance.  This is only my first pass so perhaps I will find a way to optimize the code to more fully integrate the two.  I currently switch back and forth based on whether the VFO knob has been rotated or is idle.  This at least gives the illusion of real-time integration but makes it harder to tune in a signal for the decoder. 

Now that the Arduino Zero is available, I've been considering moving that direction to dramatically improve available horsepower.  This isn't the first time I've run out of gas with the Uno.  Now it's time to start working on a transmitter module for the radio :).  You know, even though I have an operational K3, I find myself reaching for this radio first.  Something magical about using something you've created :).  But hey, preaching to the choir!

Be sure to check out Hjalmar's site (http://www.skovholm.com   and 

http://skovholm.com/cwdecoder) for details on his design and a video demo.

Brad  WA8WDQ

WU2D's Wonderful Video on Retro-QRP

(Link to video appears below.)

Stephen G7VFY sent me the link to Mike WU2D's Retro-QRP video.  In the last month spoken to Mike at least twice on 40 and 75 meter AM.  Stephen was responding to a post I did about a 1958 18 milliwatt solid state QRP rig.

Mike's video is really wonderful.  I've never been into military surplus, but this video made me think I might want an ARC-5. The rig Mike builds and tests is very similar to our beloved Michigan Mighty Mite. His description of the build and the testing procedures he used will be of great interest to those who've built the MMM rigs.  And he made some contacts.  Finally, there is a cameo appearance by Paris Hilton.  And she is holding a HOT transistor!  Wow!  

Mike has a real talent for making these kinds of videos. Thanks a lot Mike -- see you on 40.  And thanks Stephen (Stephen has sent us so much great stuff over the years, including a fantastic box of British valves.)   Pete:  See how nice it is to get back to QRP?

Here's Mike's YouTube Channel. I love the intro:
https://www.youtube.com/channel/UCN7RQv_qmzhzuJV1HhJ4OEA

Beyond Al Fresco: Boxed Up In Style with AB1YK's Very Cool BITX Box

Mike AB1YK is doing some excellent work boxing up the BITX. 
Check out his article on the Nashua Area Radio Club Blog:
http://n1fd.org/2017/02/28/my-ssb-bitx-40-build-from-vu2ese/

Here is a picture of Mike's case:

These enclosures might become available for purchase soon...

SolderSmoke Podcast 194 - Approaching the Digital-Analog Singularity

SolderSmoke 194 is available (scroll down for link)
March 4, 2017

BIG NEWS:   uBITX from Farhan

BENCH REPORTS
Pete: Recycling Old Boards
Working on Arduinos and advanced displays

Bill: SDR Adventures and Misadventures.
RTL-SDR is fun.  Built HB front end.  
HDSDR under Windows is fun and easy.
Thought about Raspi3, 7 inch touch screen, Linux, software YUCK.  
Followed advice of Ken G4IIB and got a 50 buck tablet with Google Play. 

Who needs tiny OLEDs?  Use a 7 inch tablet as your display!

Building a Ceramic Resonator for the HRO  455 kc filter
The value of doing something different. 
Boxed up my NE602 OLED rig. 
OLED noise and ACTIVE decoupling.
NE602 and MOSFET tips

LEXICON:  
OTD   Obsessive Tinkering Disorder  G6LBQ
"A Thing of Beauty"  
Source of Tombstoning term:  Don ND6T.
Ken G4IIB’s extremely smooth audio.

ON THE AIR:
On AM on 75 and 40.  Fun.  Old Military Radio Net and "The Lonely Guy Net" on 75 Saturday morning.
Good old 17 meters. Open at mid-day
HB2HB on 40 with W0PWE.
Listening on 60

Hambrew magazines disappeared, but are back now.
EMRFD Classic Edition available
New Posts to BITX HACKS

MAILBAG:
Gloves follow-up. Not a good idea.
VK3YE’s QRP by the Bay event  and a new book!
Colin M1BUU achieves Mountaingoat status
Martin A65DC JoO MMM in the UAE
Tom NY2RF Editorial with mention of JoO!
Lots of Al Fresco rigs: W8LM BITX on a board, Brad WA8WDQ DC RX, KA4KXX Al Fresco OZ DSB
ON6UU DSB from Spain via Belguim
Hugh ZL1UEM SMALL Si5351 OLED
Cookie Tin rigs VK2EMU’s Biscuit Tin DC RX,  WA7HRG’s Popcorn rig
VK4FFAB FB LTSPICE intro
Ken G4IIB’s BITX adventure (with VERY smooth audio.  How smooth? We can’t say.)
VU2XE’s BITX with a CAD box
G0ETP’s shockingly beautiful SDR receiver
Alan W2AEW on the mend with broken ankle.  His videos are a treasure trove of tribal knowledge.

http://soldersmoke.com/soldersmoke194.mp3