SolderSmoke Daily News -- Ham Radio Blog

Saturday, February 28, 2015

F6AWY's Beautiful, Colorful, Wooden Box Transceiver

I was beginning to fear that I might be the only radio amateur in the world operating a wooden-box SSB transceiver. But no! Patrick F6AWY built this MAGNIFICENT rig. Wow, I really like this one. Note the Heathkit S-meter and main tuning knob (I suspect an HW-?? carcass lies somewhere nearby). Note the colorful analog dial and speaker cover, and the classy lime-colored Dymo tape knob labels. This is really an amazing and inspirational piece of work.

The construction details are all here:
http://www.araccma.com/le-tranceiver-en-bois-de-f6awy-p820968
Yes, it is in French, but even if you can't get Google or Google Chrome to translate it (and that should be possible) you can see what he did through the great pictures and schematic diagrams.

Congratulations Patrick!

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Thursday, February 26, 2015

Video on W4OP's Progressive Receiver (Solid State Drake 2-B)

This is so great. I saw pictures of Dale's receiver a few years ago, but somehow missed the video. I am the proud owner of a W4OP-built Barebones Superhet. And, of course, of a Drake 2B (mine has tubes!)

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

A Really Cool Idea: Use your BFO as your Arduino DDS Clock


(21)  If you add a microprocessor chip to augment some of the BITX 

functions, it might be advisable to use the 10 MHZ BFO signal to clock 

your uP.  This could help avoid unwanted 'birdies' from the uP oscillator 

getting into your BITX circuitry.
From a nice list of BITX mods: 

http://kambing.ui.ac.id/onnopurbo/orari-diklat/teknik/homebrew/bitx20/modifications/LIST%20(9-24-04).txt

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

N6ORS's Long-Delayed SSB Rig

We've heard of a few of these "long-delayed" projects. My own 38 year pause in the Herring Aid Five receiver project comes to mind. I like Keith's idea of a "homebrewers home frequency" but I strongly suspect it would be a very lonely place! Thanks for sending us the pictures of your rig Keith.

Bill:

This project started out about 20 years ago as
a 2 meter FM handheld, then sat in boxes for decades.
Thanks to you and Pete and your podcasts keeping
me company, it morphed into a homebrew 2 meter SSB
rig. It saw 'firstlight' last weekend. Of course
I had to operate it without the covers but I made
a short QSO, about 1 mile across town with the wife (kg6oeo).
Homebrewers should pick a "Homebrew home frequency" on
various bands to facilitate homebrew to homebrew contacts.

73,

Keith N6ORS

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Wednesday, February 25, 2015

N0YUD's Mighty Mite (complete with harmonics)

Bill N0YUD built this really nice Michigan Mighty Mite. I like the wood base (with little feet!). And the classic black 35 mm film container. And the Vero board. Fancy connectors too! Nicely done Bill.

Bill has also wisely left space for a low pass filter. As you can see in his 'scope picture below, the MMM produces a lot of harmonics. With a low pass filter, that mess will turn into a beautiful sine wave. We'll be talking about harmonics and low pass filters in the next podcast.

Feb 20 at 3:31 PM

Hi Bill and Pete,

I just completed my Michigan Mighty Mite and am proud to announce it seems to be generating about 1 watt of what appears to be extremely harmonically challenged RF. I was worried about the ugly signal on my scope until I saw another screen shot on the blog page that looked almost exactly the same as mine.

What a fun project and lots to learn with just 7, or in my case 8, parts (I had to stack a couple of 56ohm resistors). I utilized those small pc board sockets for the coil and crystal so I can easily change bands and also left room for a low pass filter....

I am still struggling with the tank coil theory and impedance... Impedance matching is a very murky area for me!

I am looking forward to building the low pass filter. By the way, I checked for third and fifth harmonics and could not hear anything on my receiver. There's another question, why does this circuit generate odd harmonics? Fun stuff, this learning game!

I love the Podcast! Thank you for your efforts and keep them coming.

'73

Bill McMillan

N0YUD

Tuesday, February 24, 2015

TR on Homebrewing

"It is not the critic who counts; not the ham who points out how the homebrewer stumbles, or where the builder of rigs could have built them better. The credit belongs to the ham who is actually at the workbench, whose hands are scarred by solder and metal and glue; who strives valiantly; who errs, whose amp oscillates again and again, because there is no effort without error and shortcoming; but who does actually strive to build his rigs; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid operators who neither know victory nor defeat.”

Monday, February 23, 2015

Parasitic Anguish on 40 then... Homebrew Transceiver Heard by Homebrew Receiver (with a PTO!)

Oh man, I was struggling yesterday. I guess I had been lulled into a false sense of security by the phenomenal ease with which I had put my BITX 17 on the air, then added a 120 watt amplifier, all without any sign of the dreaded feedback and parasitic oscillations that had plagued almost all of my previous projects. So when I decided to add the low pass filter and the switching/relay arrangements needed to use the amplifier with my BITX 20/40 rig, I kind of expected a similar trouble-free experience.

WRONG! And you know what? I think guys on 40 and 20 are a bit less forgiving and collegial than the folks on 17. As I struggled to exorcise the transceiver, I'd make some changes then hopefully go out onto the airwaves and call CQ, looking for a signal report. Well, I got them. Many were not accompanied by call signs. I'd be in contact with someone who was trying to help, and -- as we were trying to figure out what it might be -- we'd be bombarded with harsh, sometimes angry, anonymous commentary: "YOU'RE 20 kcs WIDE!" "Are you on AM?" "You have a CARRIER!" One fellow scornfully told me "That little QRP rig of yours is not ready for prime time." Ouch. (I didn't realize we were on prime time. Isn't this AMATEUR radio?)

Others would answer my CQ by announcing that I was "on the wrong frequency." Others would respond (off frequency) and tell me I was distorted -- I'd ask them to tune me in, then they would say, "Oh yea, you are OK -- you were just on the wrong frequency." Some of these guys seemed to be under the impression that there are "channels" on 40 meters. It was a real disheartening mess.

Then came the saving grace. I got the e-mails that appear below. WOW! My faith in ham radio was renewed! In the 18 months that I've been running the BITX rigs, I've never once worked another station using a homebrew rig. But Rick and I were 3/4 of the way there yesterday. And he was using a direct conversion receiver of his own design, with a PTO in an enclosure made from "flattened out tin-plated food tins." Fantastic! It was as if the radio gods had arranged all this to pull me out of the depths of parasitic despair! Thanks Rick! A video of his receiver picking up my BITX 20/40 appears above.

Pete and I will talk about the actual troubleshooting in the next podcast. I am HOPING to have it fixed by then. I may have to sacrifice some chickens to Papa Legba."

................

Bill,

I'm a long-time SolderSmoke podcast listener, and today one of my ham radio dreams came true.

I was listening to 40 meters today on my homebrew direct conversion receiver, and I heard your call. At first I didn't believe it was you, but there you were.

At first I just sat there dumbfounded, just listening, but soon realized that I should make a video of this "rare DX" (rare DX for me hi hi), and post it on YouTube for you to review.

My apologies for the low audio in the video. I was using my iPhone and its inboard mic leaves a lot to be desired, but the best audio of you is at 0:13, 0:50, and again at 2:12 into the video.

Heard you on 7.16 MHz, Sunday 2-22-2015 at 10:15 a.m. local east-coast time (15:15 UTC).

I'm located in Manchester Maryland (North - Central Maryland). My homebrew 40 meter rig is a PTO tuned direct conversion receiver with all discrete components. My antenna is a simple wire dipole about 6 feet above the ground just outside by workroom window.

Below are links to the YouTube video of your QSO , and the schematic the DSB transceiver that you were received on. The rig is one that I designed, based on the published works of many home-brewers from the web. I call it the Lakeside 40 (in homage to Peter Parker's Beach 40 transceiver).

So far I only completed the receiver section, and hope to complete the transmitter sometime this summer so I can use the rig at Lake Marburg (at Codorus State Park in PA), thus the "Lakeside" in the rig's name.

http://youtu.be/emsKg5n5-0c

http://www.remmepark.com/circuit6040/lakeside40.gif

73
Rick - N3FJZ

Bill,

Yes, what a coincidence with the PTO! That's the same WA6OTP PTO design
I based my PTO on.

I created a webpage tonight(very much a work in progress) so you can see
the details of how I constructed my PTO in the Lakeside 40, as well as
my rendition of a BITX 20. Click the [Permeability Tuned Oscillator], or
[My rendition of a Bitx 20] links on the left of the page.

The webpage is here:
[http://www.remmepark.com/circuit6040/index.html]

The ground plane for the Manhattan construction (and RF tight enclosure
for the PTO) are made from flattened out tin plated food cans, and the
coil-form for the PTO is cut from Masonite wall panel material with my
scroll saw.

Don't get discouraged from the less than enthusiastic response from the
others about your signal, pay them no mind; I'm sure they simply didn't
realize the significance of what it represented. To me, your signal was
the most perfect signal I have ever heard. It was perfect because I
know (from your pod-casts, and my attempts at homebrew) what it took for
it to be produced. Its existence, and the fact that I successfully
received it on my little homebrew rig too, represents the fundamental
core foundation of Amateur radio; experimentation, building equipment
with your own hands from scratch, expanding ones knowledge in the radio
art, and most important, having fun and enjoying the excitement that
comes from using gear that *you* built.

I cannot put into words how significant hearing your signal was for me
today - thank you! My biggest regret is that I didn't have a means of
transmitting yet on 40 meters, and my Bitx 20 is not ready yet,
perhaps in the future we can have homebrew to homebrew QSO's
where we can fine-tune our designs and tweak things (however we'll have
go above 7.175 MHz, or 14.225 MHz since I only hold a General ticket at
the moment).

Rick
N3FJZ.

PTO another view.

Rick's PTO

Sunday, February 22, 2015

Analog FOREVER! Menus are For Restaurants! Hardware Defined Radio! Chris's PTO

Beautiful! A Permeability Tuned Oscillator. No need for a fancy variable capacitor -- that brass screw moving into and out of the coil varies the inductance and the frequency. Collins style.

Feb 20 at 6:58 PM

I also wanted to send you a shot of what today's project has been. It's WA6OTP's PTO.
I bought the plastic tube/screw/bracket from Jim and I provided the rest.
This is a 40 meter PTO that covers the entire 40 meter band.
A little Q dope secured the windings.
Chris
KD4PBJ

WA6OTP has a very nice PTO kit:

http://www.wa6otp.com/pto.htm

And a lot more good radio info here:

http://www.wa6otp.com/radio.html

Friday, February 20, 2015

Italy, Spain, Gibraltar, a Flight to Prague, and How the Mighty Mite Really Works

Gab IZ1KSW is a true Knack-afflicted member of the International Brotherhood of Electronic Wizards: He is an Italian homebrewer who lives in Spain and works in Gibraltar. At the end of this e-mail exchange he has a great story about reading "SolderSmoke -- The Book" on a flight to Prague with his Greek girlfriend. It reminded me a bit of the problems I've had with fellow passengers while reading "Hot Iron" on the Washington DC train system.

A blog post about Gab's version of the Mighty Mite is here: http://soldersmoke.blogspot.com/2015/02/iz1ksws-italian-mighty-mite-video.html
His desire to REALLY understand the circuit is, I think, admirable. I know that my quick explanation of how the Mighty Mite circuit works isn't complete, and I'm sure that others will jump in with more details.

........................

Hi guys,

I write to you because I'm a bit lost.

Ok, the MMM is oscillating, brilliant!

Now I'd like to understand why it's working and how it's working.

I've been sitting on the workbench with the schematics in front of me and I found some resources on the internet, I've understood the concept of feedback loop but what really make me scratching my head is that I cannot match the MMM schematic with anyone of the typical oscillator design I found (Pierce, Colpitts, Hartley).

I've read online that it can be considered as a Pierce oscillator but from what I've found online I cannot find the purpose of the tapped coil. Maybe you can point me in the right direction before my GF starts complaining about the pile of schematics I'm accumulating in the living room!

Also, if you have any books to recommend, I'll be happy to go "back to the books"

Thank you and 73

Gab - IZ1KSW

.................

OK Gab. I've been meaning to do this. This little circuit needs some explanation. I'll take a shot:

Start by thinking of this circuit as an amplifier. The 27 ohm resistor from the emitter to ground (negative terminal) puts a limit on how much current will flow.

The 10K resistor from the base to the positive terminal puts a positive voltage on the base and biases it so that current will flow through the transistor.

Now the fun begins! It is an amplifier, but it has no input signal! The input signal is the output signal -- it is like a dog chasing his tail!

The crystal is very important. It is the main frequency determining element, and it is the conduit for the feedback that gets this thing oscillating. It is a piece of quartz. If you put a voltage across it, it will begin vibrating (physically) at a specific frequency. As it physically vibrates, it also creates electrical vibrations.

So, when you turn this thing on, noise in the circuit will put a bit of charge on the crystal. It will begin to ring, much like a musical tuning fork. The electrical vibrations from the crystal will go to the base. They will be amplified by the transistor and will emerge (stronger) from the collector. From the collector, they go to the 3.579 MHz tuned circuit formed by the big coil and the variable capacitor.

The coil wound on the film box serves several purposes. The portion of the coil between the positive terminal and the collector carries the 12V DC to the collector of the transistor. It also carries the amplified 3.579 MHz signal coming from the collector. This signal goes through the lower portion of the coil and causes the coil and the capacitor to resonate. The signal at the top of the tuned circuit peaks when the tuned circuit is tuned to.... 3.579 MHz.

The capacitor/coil tuned circuit (with the tapped coil) are set up so that the right amount of energy is fed back from the output to the input, and that this energy is fed back in the proper phase relationship to the signal at the input. Think of a child's swing at a park: To keep the swing oscillating, you have to push at the right moment (frequency and phase) and with the right amount of energy.

The little capacitor across the battery is to prevent "key clicks." The output coil on the main coil takes some of the energy and sends it to the antenna while converting the impedance of the antenna to a suitable "load" for the transistor.

Whew, how did I do? Lots of electronics and physics in those 7 parts!

73 Bill

................

Hi Guys,

Bills explanation is absolutely perfect –but there is some additional Math in the woodworks known as the Barkhausen criteria where kB = 1

see this http://link.springer.com/article/10.1007/s10470-008-9250-1#page-1

73’s

Pete N6QW

...............

Well, what can I say Bill? Grazie mille!!

I keep thinking that you would have been a great teacher, you have the rare ability to explain complicated concepts using simple words.

Yesterday I finished reading your book SolderSmoke GAWE (yes, you deserve an acronym too) and there have been several "eureka" moments while I was reading it. It gave me a lot of motivation to go in depth and understand what's going on in a circuit down to the physics of the components. I got the Kindle version but I'll order the paper version too, I love the hand make schematic and they're not very readable in the electronic version, plus I believe that a book about radio home brewing must be in the old fashioned paper version don't you think?

There's a funny story about the book. Few days ago I was on a flight to Prague with my YL, I was reading the book and zooming on the schematics to see them better, I was really into it and I didn't notice that the guy sitting on the seat next to me started to look at the kindle nervously, he probably though I was an bomb home brewer HI! So I decided to pass the Kindle to Angeliki so that she could read her books. She's Greek and she started reading a Greek book, written with the Greek alphabet which looks quite weird if you don't know it. At that point probably the guy thought to be sitting in the middle of some exotic terrorist... it was funny.

Wow... as most of the Italians do, I talked too much! Thanks again both for the big effort you make spreading the tribal knowledge with the podcast, the ARCI LBS articles and the books.

Siete fantastici!

IZ1KSW - Gab

Monday, February 16, 2015

SolderSmoke Podcast #172: Pete's New Rig, Bill's BITX 2040,Crystals, MMM, SNA jr.,Portable SDR, KX3!, W7ZOI at a 'fest, BANDSWEEP!

Pete and Ben's LBS Receiver

SolderSmoke Podcast #172 is available

http://soldersmoke.com/soldersmoke172.mp3

16 February 2015

Bench Reports:
Pete under the gun to finish SSB transceiver project. NEW VIDEO:
http://youtu.be/hbLXW0sHTFo
Bill fixes his BITX 2040 Oscillator (Bandsweep!)
Next: LP filter for 120 watt amp.
Bill's 13 dollar Chinese freq counter (Blue! With anti-wobble tape!)
Bill's next rig: Chipped to the Max, DDS, SBL-1s, plug in filters!
Radio Shack going under and JAN no longer making crystals.
Mighty Mite Project: Let's get them DONE!
An easy way to get Q or ESR measurements on crystals?
SI5351 as a crystal substitute.
DuWayne's Scalar Network Analyzer lights up the internet!
The Portable SDR rig -- Pete almost goes to the dumpster!
Report from the cutting edge: Pete's new Elecraft KX3.
MAILBAG: Meeting W7ZOI and WA7MLH at a hamfest.
Instant Messaging with Farhan

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Sunday, February 15, 2015

World Radio Day! Article with Farhan

The Hindu did a nice article on World Radio Day. They wisely featured someone with a true case of The Knack, someone with a strong emotional connection to radio and radios: our friend Farhan.

http://www.thehindu.com/features/metroplus/thank-you-for-the-radio/article6886601.ece

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Saturday, February 14, 2015

This Kid has THE KNACK TO THE MAX! And is in the International Brotherhood of Electronic Wizards! (VIDEO)

Oh man, we've all been there in one form or another. The struggle, the frustration, then, THE TRIUMPH! I love when his mother drops the plate.
Thanks to John KC0BMF

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20