Tubes – Page 11 – SolderSmoke Daily News

Regen Receivers in Cuba

Hola amigo Bill:

I was able to pick up the podcast with excellent audio quality.
It is quite true that regenerative receivers are very much in use
even today… for example many if not all of the automobile RF
keys opening and closing the cars doors rely on a superregenerative
receiver circuit !!!

The radio that you copied at the blog works very well indeed
but it would be good idea to include a 5 kilo ohms volume
control…. Very easy to do indeed.

But let me tell you that my favorite regenerative receivers are
the classic ones, using vacuum tubes, and operating them
at voltages not higher than 50 volts… As a matter of fact many
tubes work very well at the 24 volts DC voltage level.
Using the classic Hartley circuit , there is no need for a hard to
find throttle capacitor required by the Armstrong circuit, because
the regeneration control works very well by using a potentiometer
to change the screen grid voltage of the detector.

I agree that using an RF stage ahead of the detector is always
a very good idea…. In my tubes regenerative I use a triode connected
6AK5 clone…. as a grounded grid stage….another 6AK5 clone ( the
6ZHE1P Russian tube ) is the detector and I use another 6AK5 clone
as the first audio amplifier then feeding an audio output pentode
all provided from a very simple basic 70 volts DC power supply.
BTW, using regulated DC on the filaments of the detector stage,
although a luxury by my standards is very helpful to reduce
hum …. 7805 regulator recycled from a bad motherboard, with
one 1N4007 from broken Compact Fluorescent Lightbulb inserted
in series with the regulator ground pin, produces a nice 5.7 volts
regulated DC that with a brand new tube is more than enough… with old
6ZHE1P recycled from Russian TV sets, you add another 1N4007 to obtain
6.4 volts regulated DC….

As said in the podcast, it is very important to do a very good
mechanical engineering job, place the main and bandspread tuning capacitors
away from the front panel, use isolated shafts between the capacitors
and the dial mechanism and make the front panel of a a thick steel
plate if possible.

There is a Dutch Cascode Regenerative radio that several Cuban radio
amateurs have built… it was designed with the amateur bands in mind so
the information about the tuning coils and capacitors lets you
obtain a very excellent bandspread on the ham bands.
I can send you that circuit that uses very common 12AT7-ECC81
and Russian equivalent double triodes.

Keep up the good work amigo and always tell us when the next
podcast is available. BTW it lasted for almost an hour !!!

73 and DX

Your amigo en La Habana, Cuba
Arnie Coro
CO2KK
Host of Dxers Unlimited radio hobby program
Radio Havana Cuba

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Some Inspiration on Receiver Building

As a result of all the recent toob talk with Pete Juliano I’ve been going to work with old copies of Electric Radio in my backpack. Yesterday, somewhere in the tunnel under the Potomac River, I read these inspiring words from master receiver builder Bob Dennison, W2HBE (SK):

“Part of the fun in the radio building hobby is tearing up a set after a short period of use so its parts can be used again in a bigger and better set. Another order is sent to Allied Radio for an audio transformer, an RF choke, a vernier dial and some of those exquisitely beautiful Hammarlund variable condensers. Oh what a joy it is! You just haven’t lived until you’ve built a whole series of progressively more exotic receivers. Give it a try!” (ER, March 1993)

SolderSmoke Podcast #164 Ancient Tribal Knowledge: Tube and Tube-like Radios

SolderSmoke Podcast #164 is available:

August 16, 2014

http://soldersmoke.com/soldersmoke164.mp3

ANCIENT TRIBAL KNOWLEDGE — TUBE AND TUBE-LIKE RADIOS

Workbench Updates:
— Pete’s Arduino Keyer Project
— Bill Builds (and LIKES!) a REGENERATIVE RECEIVER
— The Joys of Regen Shortwave Listening
— Grayson Evan’s Tube (Thermatron) Book
— Book review: “The Joy of X” (It’s about math).
— Shameless Commerce: A Plug for Bill’s Book
— Pete discusses tube projects
— Making your own enclosures from Home Depot flashing
— Amplitude Modulation
— Compactrons, Nuvistors and other unusual tubes
— BANDSWEEP: Radio Havana on Bill’s new regen

Bill’s Mate for the Mighty Midget Receiver
3 6U8 Tubes on a Benton Harbor Lunch Box Chassis

Nuvistor 2 meter down converter

Video: Regenerative Receiver Project!!!

Pete Juliano and Grayson Evans are luring me back into the world of tubes and (gasp!) regen receivers.

Part III with Pete Juliano this Saturday

It looks like Pete Juliano, N6QW, and I will be able to do Part III of our discussion of homebrew SSB gear this Saturday. We might start out with ladder filters. Other possible topics include construction practices (shielding, decoupling, the handling of heat, etc), junk-box practices, essential test gear and, time permitting, tube (or, as Grayson would say, “thermatron”) gear. Speaking of which, here are some pictures that Pete sent me of a 20 meter CW rig he is working on.

“Here is a 20 Meter station that I recently got working and hope to have it on the air soon. The Rx is something I cobbled together and it does have a Crystal filter. The Tx is an amalgamation of several Handbook radios – one feature it uses a bandpass tuning network from the oscillator to the final. The screen voltage has a separate regulator. Each unit size is 4 inches high, 4 inches wide and 8 inches long. There is still some work needed for the control and TR.”

Clocks, CRTs, HV supplies: Eric has The Knack!

Nice interview by Jeri Ellsworth. This fellow definitely seems to have the Knack. At the end of the video he shows a high voltage supply that he is WEARING AROUND HIS NECK!

Here’s Eric’s site: http://tubetime.us/

Thermitron (Tube, Valve) Op-Amps

It is kind of appealing. I like it better than the 741. This one you can take apart and see how it works. Thanks Rogier!

Thermitron (Tube, Valve) Op-Amps

It is kind of appealing. I like it better than the 741. This one you can take apart and see how it works. Thanks Rogier!

Tour of WLW 500,000 Watt Transmitter (video)

Well, you know that you are really in the high power big leagues when your transmitter requires a cooling pond, and you have to put on welding goggles before you examine your tubes! I especially liked the bit about how they built the transmitter BUILDING from the packing materials used to ship the transmitter (my operating desk is made from a box used to ship my HT-37!).

This is all really amazing. They built this thing less than ten years after the initial launch of commercial broadcast radio in the U.S.

Thanks a lot to Randy for doing this video and to the guys who gave the really excellent tour.

My apologies to the QRP purists who I know will have been deeply disturbed by this presentation.

Grayson’s New Book

Our friend Grayson’s book about hollow-state radio is now available. It looks like a great addition to the radio art. Available from Lulu:

http://www.lulu.com/shop/grayson-evans/hollow-state-design/paperback/product-20987562.html

Knack Story: Ryan’s Rig

Bill,

… [I know] a young ham locally who suffers terribly from the
affliction of the “knack”. Ryan, KJ6HBY, is 17, and an Extra class,
who earned his DXCC in a year. He is a great builder, starting out
building his first antenna a couple years ago by breaking apart an old
washing machine motor and unwinding it for the wire. Along the way he
has restored various rigs, i.e. HR10, S-38, IC707, etc and built a
BTX17 (17 meter version of the BTX20). Enclosed is a couple photos of
his latest creations. First, he hand carved a wood morse code key. It
actually feels and works well. Now he has build a single tube xmtr,
and after fussing with it, is pumping out 4 watts. Both of the kid’s
folks are hams as well as his sister. I had an opportunity to visit
his shack the other day. It’s a teenage ham’s dream and a mother’s
nightmare. Racks floor to ceiling with radios! If anybody has the
knack, Ryan does. Makes me think there is a future, we can sleep well
tonight.
73
Mike Herr
WA6ARA
DM-15dp
Home of The QRP Ranch

My Mate for the Mighty Midget

Al, W1UX, asked for a picture of the receiver that I used to listen to his dulcet tones this morning. Here you go Al. Here is an article on the project:

http://www.gadgeteer.us/erart.htm

Above is the Mighty Midget RX paired up with a DX-60 and a VF-1 (circa 1998)

Mighty Midget RX on a Key Chain

The key chain device will soon be carried to 1200 feet by our new rocket.

Eddy’s “Salvage Super”

I had our friend Grayson (in Turkey) in mind when I put Eddy’s messages about this “thermitron” receiver on the blog.

Here’s my version of the famed “Mate for the Mighty Midget”: http://www.gadgeteer.us/erart.htm

Hi Bill,

Many thanks for the FB note…

Well, I think my buddy VE3CSK is 99% “hooked” on the notion of making an MFTMM receiver for himself—and that’s a good thing. That rascal of a rig is pretty much fool-proof, & the design sure does lend itself to no end of enhancements / improvements / changes / mods! I should know: with my set-up here I added AVC, and extra IF stage, an extra stage of AF, more pre-selection, etc. etc. etc.

As for selectivity, I simply incorporated regeneration in the 2nd IF stage: with judicious tweaking of the BFO, one can achieve a near single-signal selectivity effect that is GLORIOUS on CW. I guess one can make these things as complicated—or as simple!—as we might chose to do, yet further proof of the flexibility of this receiver.

I’ve taken some jpegs of my set-up here, and am attaching them herewith for your perusal. I like the notion of using these rigs on 80- and 40-meter AM, too—but am presently somewhat “distracted” with the task of re-inking my main tuning dial for my 1929-style superhet.

I think my next step in my MFTMM receiver here will be the addition of an internal 125 VDC power supply—most likely will mount the components inside, on one of the vertical sides (still LOTSA room there!). I have a FB Hammond power transformer that’d be perfect for the job, & I won’t have to connect / dis-connect / re-connect its current out board power supply (that I use with other peripherals, too—a REAL pain by times).

~73~ de Eddy VE3CUI – VE3XZ

Mates for Mighty Midgets

Hi Bill,

Gosh, we haven’t exchanged e-mails for—literally–-years now…! You may recall me from those heady days of yore when we both worked on / built / modified / boast of our respective MFTMM receivers…

A good friend of mine—Bill, VE3CSK—is in the process of collecting parts for an HB receiver, & I’ve been trying to sell him on the idea of an MFTMM: I keep telling him it’s an excellent “foundation” receiver, & that it’ll prove to be much more than a toy, or pleasant diversion, if he leaves enough room on the chassis & the front panel for future mods. I think I may be finally winning him over: he’s asked me for the references to the rig, & has placed an order for a National-brand slide rule dial with a fellow Stateside!

Do you still have your receiver, Bill…? If so, do you have any nuggets of info that might be worth sharing re. it, that I could pass onto Bill…?

I’ve since built yet another superhet here—in keeping with my interest in 1929-ish radios, I built this thing, & have been having a ball ever since: http://www.superhets.info/page9.html

This rascal can REALLY play—but it’s a LOT larger than my MFTMM rig!

~73!~ de Eddy VE3CUI – VE3XZ

————————————-
Hello Eddy! Great to hear from you. I like you FB page on the Super Hets. Beautiful.

Yes, I still have my MMRX. Haven’t used it for a while, but I am thinking of putting it back in operation — I am now getting active on 75 and 40 AM, and it would be fun to use this RX.

Here is an idea: The 455 kc filter crystals are now un-obtanium. But I’m thinking that we could substitute some 455 kc ceramic filters, which are readily available.

I like the receiver. A lot. So far it is my only real tube HB project. Encourage your friend to give it a go!

Keep me posted! 73 Bill

Valve line-up of British Homebrew Rig

A number of electro-archeologists out there have asked about the valves found in the old British homebrew rig I presented yesterday. Here you go:

Mic amp: ECC83

What I think is the modulator: EL84

Suspected oscillator: M8162 also marked as 12AT7 WA UJ

What looks like the driver: EL85

Final: QQVC3.10

I’ll try to determine the resonant frequency of the tuned circuits.

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GE Ham News — All of Them! (1946-1963)

Walter, AJ4UM, alerted us to this. Here’s yet another treasure trove of ham radio literature. I’m going to have to retire just to make time to read all the stuff that is coming on line!
http://n4trb.com/AmateurRadio/GE_HamNews/ge_ham_news.htm

Evil Mad Scientist Builds a Heathkit

You guys will get a kick out of this: An old unbuilt Heathkit is discovered, and is then put together by “Evil Mad Scientist.” EMS obviously loves electronics, but is clearly of the digital/IC generation: “The tubes are gorgeous! Their exteriors are glass with electrodes extending from the bottom!” Wow.

The Evil Mad Sci guy fears that the solder provided by Heath will have “gone bad over time” and says that he will use “more modern solder.” Hold your horses Frankenstein! Don’t you dare put that Heathkit together with lead-free solder! That could tear a hole in the fabric of space time! Also, I dunno about the idea of putting all the components on the lugs and rotary switch terminals first, with all the soldering coming later. The boys at Benton Harbor wouldn’t have liked that. And you might want to gradually bring the voltage up on that big electrolytic cap up using a variac. Which brings to mind some needed advice: BE CAREFUL! You have moved out of the realm of 12 V DC. That old Heathkit could zap you good!

http://www.evilmadscientist.com/article.php/heathkit-part1

Thanks to Mike Butts for alerting us to this.

Fat Tubes-day!

I couldn’t resist using that title. Stephen from the UK sent me this link to Jeff Duntemann’s site about Compactron tubes. Many possibilities here. I think I have a 6T9 in my junk box. These are kind of like tube versions of ICs, but with the advantage of being understandable.

http://www.junkbox.com/electronics/CompactronTubesIndex.shtml

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More Homebrew Tubes — This Time from Poland

That’s a homebrew triode built in an apartment workshop by the intrepid Polish radio wizard Aleksander Zawada. The last line in the blog post really got to me:

“All is needed now is to solder a socket to the base of the triode, and use it to make (for example) a regenerative radio receiver!”

Check it out: http://lekernel.net/blog/2011/09/prywatna-wytwornia-lamp-where-diy-meets-vacuum-electron-devices/

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