A Paraset and the Heathkit SG-6 Signal Generator (Video)

Mike WU2D put out this nice video (above) about whether or not he should part out his Heath SG-6 signal generator, using the parts in a Paraset construction project.  I faced a similar question years ago: 

https://soldersmoke.blogspot.com/search?q=SG-6

I just solid stated the SG-6.  I was influenced by Farhan and the drinking straws that he picked up with his kids at a McDonalds in Hyderabad. 

As with the QF-1, I say to Mike: GO FOR IT OM!  You need those parts for other projects.  Don't feel bad about the SG-6.  But keep that switched coil assembly -- it is quite useful. 

A Promising Start for the SG-6 Solid State Conversion

We have kind of half a holiday today -- I have the day off, but the kids went to school.  I made use of the additional shack time to test the feasibility Farhan-izing my old, not-so-beloved Heathkit SG-6 signal generator.  I did a quick Manhattan build of the oscillator section from Farhan's sig generator (link in yesterday's post).  Using an idea from an old 73 Magazine article on a similar project (thanks Clint!), I smashed the tube (appropriate, don't you think?) and connected (using the glass stump!) Farhan's oscillator directly to the pins that lead to the switchable coils and the variable cap of the SG-6.    I just wanted to see if it would oscillate, and see if there was a big change in SG-6 dial calibration.  

Wow, it worked great!  It oscillates very nicely on all but the upper frequency band setting (20-50 MHz).   I feel confident that I'll get it to oscillate at least up to 30 MHz.   Next I'll build Farhan's buffer and amplifier stages.   The SG-6 had a switchable attenuator -- I want to include that feature in the solid state version.  I'll have to give some thought to the audio modulation feature (nice for aligning AM receivers). 

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Solid State Conversion for a Heath SG-6 Signal Generator?

I've recently become acutely aware of the shortcomings of my signal generator. 
It is a Heathkit SG-6.  It is really old.  It has a selenium rectifier in it. It has one of those old mic connectors on it for the output.  The output is very low.  But I like the cabinet and there is a nice switchable coil/variable capacitor LC circuit in there (see above).  

In 2008 in Hyderabad, India Farhan went to McDonalds with his kids and went home with some straws.  Soon the straws are chopped up and turned into coil forms for a signal source:  http://www.phonestack.com/farhan/siggen.html

So here is my idea:  de-tube the SG-6.  Turn the selenium over to the HAZMAT authorities.  Save the coils and the cap and most of what George Dobbs would call "the socketry."  Use an MPF-102 for the oscillator, then make use of the buffer and feedback amp from Farhan's soda straw circuit. 

What do you guys think? 

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SolderSmoke Podcast #148

SolderSmoke Podcast #148 is available:
http://soldersmoke.com/soldersmoke148.mp3
December 30, 2012

SPONSORED BY usedradiomall.com

-- Hurricane Follow-up
-- Subliminal Mind Control to Encourage Homebrewing (beep-beep)
-- The Shortcomings of the All American Five Receiver
-- Solid-Stating a Heath SG-6 (with Farhan's circuit)
-- VK3YE's Beach DSB Rig
-- Tek 'scope connection to frequency counter
-- Mod to W7ZOI/W7PUA power meter
-- JBOTing my 20 meter DSB Rig -- A Tale of Woe
-- LU1AR "The Most Interesting Ham in the World"
-- Billy's Raspberry Pi
-- Latest QST, SPRAT, Hot Iron
-- Videos: Landfillharmonica,  Knack in Sierra Leone
-- Santa delivered a Soldering Station
-- MAILBAG

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

Test Gear/Workbench Maintenance

I mentioned in the last podcast that I was going to take a break from construction projects and spend a little time fixing up tools, test gear, and the work bench. First up was my old soldering gun. I bought this thing almost 40 years ago! It is pretty beat up, but I managed to patch it up and it now works fine. Even the original light bulb works.

I use this little AADE L/C meter a lot, but was having trouble getting parts across the test terminals. So I soldered alligator clips onto one of the parts connectors that came with the device. Makes testing easier.

Just a little audio oscillator. Puts out .2 volts at 713 Hz. Useful for testing the phone rigs.

I picked up this little Lafayette power supply at a hamfest and found it quite useful. But then I managed to knock the needle off the meter while fooling around with trivial electric motor. Any ideas on where I could get a replacement meter movement, or on what value I should use?

Here is a wave meter that I picked up at the Kemptom Park rally in London. Apparently at one point all UK radio amateurs were required to have one of these devices. I'm tempted to chop it up for parts. That variable cap with the reduction drive looks promising. And could that meter solve my problem with the power supply (above). If anyone can think of a reason to keep this as a wavemeter, please let me know.

Further proof of my extreme retro-ness. This is what I use as a signal generator. A Heathkit SG-6. Older than me!

This is my scope. HAMEG. Supposed to be good to 10 MHz but of course I can use it at higher freqs (which I do). I need to upgrade. Any suggestions?

A very useful little square wave generator.

I need to make more use of this noise bridge. Lots of potential here.

Obviously a London purchase. Very useful little AF sig generator from the UK's equivalent of Radio Shack. My only complaint: No auto-off. I forget to turn it off and run down the two 9 V batteries.

Long time listeners will remember this device. This is the one in which I soldered in the chip upside down. It works fine on th 5 Hz to 100 MHz range. Dead on the 4 - 600 MHz position.

I bought this power supply at the Kempton Rally, then converted it into a current limited supply using a chip and a circuit provided by Tony, G4WIF. My daughter Maria helped paint the cabinet. Lots of soul in this little machine.

Just three meters. The middle (analog one) is still very useful, and has considerable sentimental value for me -- my wife got if for me when we were back in the Dominican Republic.
My version of the W7ZOI power meter. Mike, KL7R, and I built versions of this device back in 2004 or so.
This is Cappuccio. He joins me in the shack most mornings. I'm not really a dog person, but I'm growing fond of him, even though he occasionally eats resistors and capacitors.

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