Has AA1TJ Joined the FMLA?

I have learned that esteemed homebrewer Michael Rainey, AA1TJ, recently whipped up a 56 MHz, quarter-wave, helical coaxial resonator (BTW: the spoon is also homebrew).  Hmm, 56 Mhz.  Or perhaps we should say MegaCYCLES?  Michael claims this device is for a low phase- noise VFO, but I find the frequency selection highly suspicious.   The last time I heard of that frequency it had to do with an underground group set up by the late (or not so late) Frank Jones.  
Here is all the info on Frank's Five Meter Liberation Army.  

http://www.sunflower.com/~brainbol/frank/

A man of the '30s awakens one night in the '90s (episode 13) with a new mission: recapture 56-60 mc. He forms a Five Meter Liberation Army from his mobile home in a Barrio trailer park run by Tom Joad of Steinback's Grapes of Wrath (episode 9), and soon draws a decidedly uncolorful bodyguard (episode 7). A six foot tall half Mexican stockbroker named for Ayn Rand makes him rich and a demonic white ferret and a half-siamese cat become his familiars. (episodes 10 and 9). The leader of all this, called only "Frank," settles down in the narrator's basement to be joined by Maj. Armstrong (episode 8), Hiram Maxim (episode 23) and one-time pals Carl and Jerry from the 1950s Popular Electronics (episode 25). His huge 1940s sedan, with contemporary plates, is immune from police (episode 13 et seq) and his breadboarded electronic creations recall those distant days when a ham built his own rig and could "fix a radio." Of course all this is crazy. No one builds anything anymore and the other things Frank stands for, like self- reliance, tolerance and a generally Boy Scout viewpoint are simply out of step. Frank knows that too (episode 20), but he does not care. If you're standing in the middle of the road and see a big brown Frazer coming at you, you better jump - one way or the other.

VIVA EL FMLA!  VIVA!


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

Narrow Band FM on 160 Meters? Using SSB phasing rigs?

On the G-QRP mailing list our British cousins are discussing the use of Narrow Band FM on Top Band.   160 meters has long been used for day-time local "chin wags" in the UK.   Noise, of course, is a factor to consider on 160.  FM would take care of the noise problem.

I was wondering if this would be legal in the USA. This is the kind of question that seems to provoke passionate, sometimes angry reactions.   I think the answer depends on the resulting bandwidth of the signal. 

There was an interesting discussion of this here:

http://www.eham.net/ehamforum/smf/index.php?action=printpage;topic=65481.0

Especially intriguing to me was Tom's comment about the link between Narrow Band FM and the early SSB phasing rigs.   I hadn't heard about that:

---

Title: RE: Narrow Band FM is it legal below 30 MHZ.
Post by: N5EG on January 22, 2010, 11:10:43 AM

---

Hi Tim,

Yes - NBFM is legal. This is actually a hold over from long ago equipment. Back in the olden days phasing SSB exciters could also be adjusted to produce NBFM.

It's a little different than modern FM, in that the signal looks just like an AM signal, except the phase of one of the sidebands is 180 degrees reversed compared to the AM equivalent (doesn't matter which sideband). This gives an angle-modulated signal with +/- 45 degrees phase variation, but also 3 dB of amplitude variation.

While we don't normally like amplitude variation on an FM signal, it has the effect of preventing the generation of the higher order sidebands that true FM produces. A receiver than has a limiter stage doesn't care that much.

The result is that the old phasing exciters could produce this different kind of Narrow Band FM (probably the true meaning of NBFM long ago) that had the same channel width as AM, and a modulation index that's well below 1. Such a signal is compliant with current FCC regulations on HF bands.

-- Tom, N5EG

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!

73 

IZ1KSW - Gab

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

"From Crystal Sets to Sideband" -- Homebrew Wisdom from Frank, K0IYE (Free Book)

Get Frank's book here (FREE!) http://www.qsl.net/k0iye/

I've had Frank's book on the blog many times over the years, but it is a book that merits repeated mention.   It is filled with great advice and homebrew wisdom.  I found myself looking at it again recently, and at Frank's QRZ.com page.  I came across lots of wisdom that I may have missed in earlier visits.  For example:  

From the QRZ page: 

My version of ham radio is 100% scratch built equipment. I buy nothing manufactured for ham radio except log books...My rig is based mostly on the 1986 ARRL handbook. Modern designs in today's QEX and Handbooks are usually full of mysterious ICs. In my opinion, they don't qualify as homebrewing. 

From his book (Chapter 15): 

I was fascinated by ham radio, but I didn’t learn much about how sideband worked. I had the impression that sideband was MODULATION FOR MILLIONAIRES and too complicated to homebrew. The 1957 ARRL handbook’s opaque descriptions of “phase shifters” and “balanced modulators” only confirmed my opinion.

If you are like me, you will have a devil of a time getting your SSB drivers to produce intelligible speech without hissing and noise problems. All I can tell you is to keep your brain mulling over your difficulties. Shield and filter your prototype until the darn thing works. Keep careful notes so you don't make the same mistakes twice. Persistence will win in the end. 

My sideband transmitters are still in the experimental category. You will find that it takes a great deal of tweaking and fussing to get SSB tuned so it sounds good and doesn’t radiate on unplanned frequencies. You won’t believe how many diseases your SSB transmitter will create for you to conquer! Sideband is not a project for impatient people. 

Foreword: 

We homebrewers are nearly extinct, but there are still hundreds of us scattered around the world, some are even in the USA. Yes, there ARE American homebuilders! We’re rare, but thanks to the QRP hobby, the number is growing. Even if we homebrewers don't change the world, I guarantee you will enjoy learning radio technology and building your own equipment.  

Get Frank's book here (FREE!) http://www.qsl.net/k0iye/
THANKS FRANK!      Send Frank a thank you note:  Frwharris@live.com 

  

N6ORS and "Satan's Digital Radio"

Hey Bill,

I just finished testing the new rig.  Better sit down for this......
Its an SDR (Satan's Digital Radio). Actually its an estension of an
earlier experiment You might remember the 'Franken SDR". The Franken sdr

worked so well I thought I would make a companion for it and built a QSE 

(quadrature sampling exciter) and an amplifier chain to go with it. The rig
used G3PLX's fantastic SDRTX software for the transmit and DB0JBJ's
wonderful HDSDR software for receiving. The original idea was to make
a small rig for Digital comms, but I decided to add a Mic for voice, also
there is a 'Hardware" audio Phaser already in the building stages 

(you can calm down now).

A few specs. The RX is fantastic , -135 noise floor and the audio is
so clean that it copies wspr signals to -33db. The transmit is 

12 watts and the phasing audio sounds so nice that my wife says 

"thats your terrible voice exactly."So if you catch me on Sunday night

 and i dont sound 'yellowee' enough and you justdont like that 

no-crystal-filter sound just say  "Hey , Dont phase me bro"

See Ya on the bands,
73
Keith N6ORS

South African Homebrew: ZS4L's "Griffin" 40 Meter SSB Transceiver

 

That's William, now ZL4L, and his homebrew 40 meter SSB transceiver.  He has given the rig a wonderful name from Greek mythology:  The Griffin (see below).  I talked to William this morning on 10 meter SSB.  I mentioned my homebrew rig and to my surprise (this doesn't happen much) he asked for more info.  Then he told me about his own homebrew creation, The Griffin.  FB William! 

-------------------

From William's QRZ.com page (https://www.qrz.com/db/ZS4L):  

I have always wanted to build a homebrew transceiver-and recently I completed my pride and joy-a 40m SSB/MCW transceiver-I call it the ZS5WC "Griffin"..

"Griffin"..-well --if you know greek mythology you will find that it defeated much greater adversaries in battle.(to cut a long story short..)
The parallel I am getting at is..Big commercial rigs can be taken on by a rig constructed at home-and with great success!.
Sure, it does not have the bells and whistles of a 1000mp-but the TX audio is good, the RX is great , and the SMILE factor-even with all the little quirks is off the scale!..
Basically it is a single conversion superhet-4 tuned BPF stages,ATT, Gain control stage ahead of 1st Rec. Mixer/Bal. mod (NE612) , Xtal 10mhz homebrew filter,2 transistor feedback amp, second gain control stage,2nd mixer/BFO (NE612)-On TX to PA board-4 transistor pre-amp, IRF510 mosfet PA, LPF and RX /TX relay. ON RX to TL072 audio pre-amp, Spits to AGC/S-meter amp-(741 and BC107's) and audio amp TBA820m.
ALC is done on AGC board as well with BC107 back to back to AGC bc107.
The S-meter drive is developed in the emitter leg of the AGC BC107-simple series pot to calibrate-no zero pot is required..(Works great!)
There is a volt control PCB too, with RX/TX switching.
On the main PCB there is a phase shift osc. for MCW and sidetone. Alc is adjustable from front panel from 1/2 watt to 5 watt.Rit is included in the Hartley osc. circuit and readout is done with a pic and two line LCD disp.(from AADE.com..)
Freq. drift from warm is 200Hz down in frequency then swings round and stabilises close to start freq.
Rit is good for around 5Khz swing.
Amp keying is available on the back panel, as well as an aux. 12 supply-(To run a homebrew noise squasher and amp..)

https://www.qrz.com/db/ZS4L

Some Inspiring Phasing Philosophy from KK7B

KK7B holding his original Mini-R2

Rick Campbell KK7B concludes Chapter 9 of "Experimental Methods in RF Design" with these inspiring words:

"An amateur who has built up a phasing receiver, looked at the I and Q channels on a dual trace oscilloscope, and tweaked the phase and amplitude adjustments while listening to an opposite sideband signal drop into the noise acquires a depth of understanding far beyond that of most wireless graduate students and many of their professors. The best part is that understanding of phasing systems comes from experimenting with simple circuits and thinking -- the tinkering comes first -- then the understanding. In this area the amateur with his simple workbench; primitive test equipment; and time to contemplate, has a profound advantage over the engineering student with a computerized bench and exam next week, and the professional engineer with a million-dollar lab and a technician to run it."

N2CQR Frankenstein R2 showing I and Q audio outputs

(No exam next week for me!)