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Friday, September 30, 2016

Listen to Keith Ranger G0KJK on "QSO Today"


http://www.qsotoday.com/podcasts/g0kjk

Wow Eric,

I just listened to all of the Keith Ranger interview and was struck by the eerie parallels between YOUR 24 September podcast and OUR 24 September SolderSmoke podcast:

-- Both shows discussed the involvement of Anglican clergy in the hobby.

-- Both discussed the joys of simple QRP gear.

-- George Dobbs G3RJV came up in both.

-- BOTH featured discussion of the BD139 transistor (!!!)

-- Both discussed the use of ceramic resonators in ham circuits.

Great minds think alike!

I really enjoyed your interview with Keith. I have enjoyed reading in SPRAT about his projects -- years ago I built his MB4 receiver. I listened while I worked on my homebrew receiver. It was the ideal accompaniment. I also like the stickers on his transmitter.

Please pass this on to Keith if you can.
Thanks and 73 Bill

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

I also liked Keith's comments on the joys and perils of amateur electronic engineering. 




Thursday, September 29, 2016

Video: Sweeping a Filter with a FeelTech Signal Generator and a Rigol Oscilloscope



This short video shows how I used my new FeelTech Signal Generator (90 bucks shipped from China) and my trusty Rigol oscilloscope to display the passband of the filter in my Armand HROish receiver.  Feedback on this test procedure would be appreciated.

Wednesday, September 28, 2016

K1RID's 6L6 CW Transmitter from QST: "Barracks Bag VFO"

A new old thermatron device is coming to life on the kitchen table of K1RID.  Don't spill the coffee on that thing Ed.

Tuesday, September 27, 2016

Blowing the Dust Off of KW4KD's Homebrew Station from the 1970s

KW4KD CW TRANSMITTER
I got on 40 meter SSB over the weekend and spoke to Jim KW4KD.   He was on a modern commercial rig, but then he told me he had some homebrew gear on his shelf...  Wow, it is magnificent.  A complete CW station (with homebrew keyer) AND an SSB rig. I immediately launched a campaign to get Jim to fire that gear up and to provide opportunities for more HB2HB contacts.   Here is his description of the equipment:


Hi Bill,

It was a blast to get to chat with you too.
Just listening to the audio on this end, I can tell you’ve put a lot of time and effort into getting what you have there up and running.
Never once touched the dial on this end. So your radio gets a A+ for stability too.
Read your Bio on QRZ and sounds like you’ve been a few places, and seen a few things, and that unto itself would make a great contact . But for me, the fact that you are out there building, and I ‘m getting to hear the fruits of your efforts, is ham radio at its best.
 
Attached are pictures of the gear that made up my station back in the 70’s.
FWIW: At that time my call was WB4YQC.
(But for the record, these shots were taken today.)
In those days I had two setups (Both on 40 mtrs).
A CW station, using separate Xmtr & Rcvr, And a SSB xcvr.
By themselves the CW xmtr ran 8 to 10 watts, and the SSB unit probably hit 5 Watts peak (on a good day).

Like you, I had a separate linear. But in my case I used a pair of 6DQ5’s (TV Sweep tubes) that would run about 180 watts input, (Nothing Solid State, that I could afford, could make that kind of power back in then). The linear is still here, but stashed away in a closet somewhere, so not shown in today’s set of pictures.

As an Add-On for the SSB unit, I built a Frequency Counter, and used it as a digital dial.
The counter is unique in that it supports two inputs (one for the VFO, and the other for the Xtal BFO). In the 2 input mode, the counter is an UP/Down counter.
The Xcvr’s BFO runs at 9Mhz, while the VFO runs at ~2Mhz. So the counter counts up on one pass, and then down on the 2nd. At the end of the 2nd pass, it updates the Display with the final tally. (i.e, the effective TX/RX freq)

The cases for the Xmtr & Xcvr were designed by me, but were built by a friend who had access to a metal brake. Internally none of the units are especially pretty, as the were always works in progress.

I’ll have to dust off the linear. Its been at least 40 yrs since its seen AC.. Not sure what kind of shape the electrolytics are in.

Probably need to apply power slowly. I’ll see if I can round up an Autotransformer.

As far as posting on your blog, if you think it will encourage others, I’d be flattered if you did;
However, before anybody asks, (assuming that they might) there’re no schematics. Everything was built from sketches made on envelopes and napkins, which have long since disappeared. And even if they did exist, not sure today that you’d be able to find some of the ICs & transistors that the units use.

Again, it was my pleasure to catch you on the band today, & look forward to getting to hear you again.

73  Jim (KW4KD)


KW4KD CW TRANSMITTER WITH HB KEYER

40 Meter CW receiver on Left

40 meter SSB transceiver with freq counter


Saturday, September 24, 2016

SolderSmoke Podcast #190: Pilgrims, Junkbox rigs, BANDSWEEP, Matching xformers, On the Air with HB, MAILBAG



SolderSmoke Podcast #190 is available:

http://soldersmoke.com/soldersmoke190.mp3

Pilgrims' Progress:  Inspiring words from G3RJV

BENCH REPORTS on JUNKBOX RIGS:

Pete describes his beautiful 40 meter blue transceiver (video above)

Bill describes his "Armand HROish" receiver

BANDSWEEP!

Bill needs small (yellow slug) 455 kc transformers.

We need a good user-friendly 40673 SPICE model.

SEND US YOUR BENCH REPORTS!

The BD139 transistor

Ferrite Core Matching Transformers

QSO Reports:  Getting on the air with HB rigs

Bill's new FeelTech Signal Generator

MAILBAG




Friday, September 23, 2016

QRPp Back Issues (and some new ones too!)


Here's an index: 

http://www.k7qo.net/qrpp_toc_de_k7qo.pdf

And here are lot of the back issues:

http://www.ncqrpp.org/

And I see there are August and September 2016 editions available in the Files section (KI6DS)  of the qrp-tech Yahoo group.  Did I see articles there from Steve "Snort Rosin" Smith?

Sunday, September 18, 2016

My New Chinese Signal Generator



More amazing low-cost test gear from China.  Elisa gave me this device on the occasion of my completing another solar orbit.  Amazing capability for less than $90.  The video above gives you a good sense of what this thing can do.

I have already had success with the freq generator function.  The frequency counter also works great.  The sweep function looks very useful for filter checking.  And the ability to generate square waves at different phase relationships will be very useful in phasing receiver and transmitter projects.  

This little box should help me eliminate a lot of clutter on the work bench.  And it looks good next to the Rigol 'scope.  

Mine came from Amazon:

https://www.amazon.com/gp/product/B01A8S4TZK/ref=oh_aui_detailpage_o00_s02?ie=UTF8&psc=1

They come with a variety of different brand names:  I ordered a Jinwen but got a FeelTech.  They are obviously the same device.

Be sure to begin your Amazon shopping on the Amazon search link on the SolderSmoke blog (upper right).

Thursday, September 15, 2016

QRP Wisdom from George Dobbs, G3RJV



This video makes me want to destroy my amplifier...

Saturday, September 10, 2016

Alan Wolke Talks 'scopes on "The Workbench" Podcast


George KJ6VU is a long-time supporter of the SolderSmoke podcast.  He has recently teamed up with another ham and launched a podcast called "The Workbench."  This morning I listened to Part I of their interview with the legendary Alan Wolke W2AEW.   It was great.  As I was listening to Alan I was soldering together a crystal filter for my new receiver, and using my RIGOL 'scope to check the results.  

I liked Alan's description of how they made images of 'scope patterns in the days before the advent of Digital Storage Scopes (Polaroid!).  I also liked Alan's scorn for those who use the "Auto" switch on the 'scopes.  The host's reaction to Alan's description of a $300,000 Tektronix 'scope was also fun: "For that price I want to be able to drive a car into it and put a swing set behind it!"  Indeed.

Recommended listening:   
http://hamradio360.com/index.php/2016/08/30/ham-radio-workbench-5-oscilloscopes-part-1/

Friday, September 9, 2016

Oz JOO : An Australian Mighty Mite with 3D Printing


Hi Bill & Pete,

I have the JOO - joy of oscillation! The transistor is a 2N3053 with a clip on heat sink, but I don't think that I really need it. Output power +22dBm or 160mW. When I tested it on a Comms test set  at work, I found that the harmonics were about 12dB to 15dB down and I stopped looking at the 10th harmonic. Not good.

Fitting the 80m low pass filter (salvaged from another project) brought the harmonics more than 50dB down.

The coil former is a 31mm diameter and 3D printed by one of the guys at work. The material is PET - the material they make soft drink bottles from. After we printed it, I put it in a microwave oven with a glass of water. 30 seconds and the water got warm and the coil former stayed cool.

I haven't had a contact yet, but maybe in the next few weeks.

The next project is an 80m CW transmitter based upon the Goodfeller transmitter from QST 1946. It requires a inductor in the pi coupler, 1.5 inch diameter, 32 turns at 20 tip; but where to get one of those these days - wind your own.

I got the guy at work to also 3D print me a coil former with a spiral thread around the outside with a 20tpi pitch for the wire to lay in. Some hot glue and the coil is ready.

Now that I have finished all 189 episodes and two specials, my days are empty. Please make some more.

73 de Peter VK2EMU


Hi Peter (great name BTW),
 
Congratulations –really liked your build – top drawer! 3D printer access WOW – now if I could only get my 3rd son (Mechanical Engineer) to build me one of those machines.
 
The 3D made coil form is perfect for a VFO and follows the principles set down by Doug DeMaw W1FB (SK) about keeping the coil supported at both ends and away from metal. Bill needs a coil like that to mate with his HRO dial mechanism –and follows something old (dial) something new (coil).
 
73’s
Pete N6QW

Wednesday, September 7, 2016

ZL2BMI @ AA7EE -- Possibly the Most Beautiful DSB Rig Ever Built

Dave AA7EE has a very cool blog post on his version of the famed ZL2BMI DSB transceiver (seen above).  As usual, Dave puts most of us to shame with his excellent non-ugly construction and enviable in-focus macrophotography.

Check it out:
https://aa7ee.wordpress.com/2012/07/29/half-of-the-zl2bmi-dsb-transceiver-a-simple-80m-direct-conversion-receiver/

I especially liked Dave's discussion of how and why .1 uF caps are used in the coupling and bypass network between the two chips.

Of course, the only thing I don't like about this rig is the, well, the chips.  Can we persuade Dave to build the earlier discrete component version of this rig?

Be sure to read the many comments on Dave's post.   Our friend Rogier comments on the beauty of it all.  Edgardo LU1AR (the Argentine wizard with the gyrocopter) chimes in.  And we see  feedback from Eric Sears ZL2BMI himself.  FB. 

VIVA DSB! 


Sunday, September 4, 2016

First Signals from the "Armand HROish" Receiver


I've been kind of busy lately with other things, but I have managed to squeeze in a few minutes most days to work on my latest receiver project.  I call it the Armand HROish receiver.  Armand WA1UQO sent me the big National HRO-style dial and gear box, and he was there at the Manassas hamfest when I bought the dual variable cap that now serves in the front end pre-selector.

I went with a 455 kHz IF.   The idea is to have a receiver that tunes from around 6.5 MHz to around 8 MHz so I can do some shortwave listening AND listen to 40 meters.

So far the filter consists of three IF cans (one small transistor can and two larger tube-type cans).  The small transistor can was given to me by Michael Rainey AA1TJ - thanks Mike. Doug DeMaw suggested this use of IF transformers in his "Design Notebook."

At the front end I have a tunable dual tuned circuit filter followed by a 40673 amp. 

The mixer is an SBL-1.

1st and 2nd IF amps are a 23 db 50 ohm termination insensitive amplifiers.

I have a second SBL-1 that will be the product detector, but I haven't built the BFO yet.  So today I hooked up two 1N34A diodes in voltage double config and -- with a bit of AF amplification, got the receiver inhaling with a diode detector.   I could pick up Radio Canada.  Then I heard SSB sigs on 40.  With no BFO, I decided to put my sig gen on 455 kHz and just wrap the lead around the IF cans.  It worked -- I could listen to SSB and CW sigs.  Very satisfying. 

Still to do:
-- BFO and product detector.
-- Work on AF amp.
-- Get my CM-455 crystal mechanical amp in there with some relays around it so I can switch from narrow to broad via the front panel.

Lots of soul in this receiver:  All parts either 1) came out of the junkbox, 2) were gifts from friends, or 3) were recent hamfest purchases.  The HRO dial from Armand and the IF can from AA1TJ.  The 455 kHz filter idea came from Doug DeMaw, the VFO circuit from SSDRA.  The VFO base is from Whole Foods and the whole thing is built on a kitchen cutting board. It includes a 40673 and germanium diodes. The VFO amps are in Altoid tins.  It will, when finished, go into a big metal box given  to me by Tim KI6BGE and shipped east by Pete Juliano.  And when I was working on the 1st mixer, I accidentally pricked my finger and a drop of N2CQR blood went onto the breadboard.  Of course, I left it there.   SOUL!

The Radio Gods are apparently pleased:  In the first hour or so of listening, I was rewarded for my efforts when I managed to hear Tim WA1HLR on 40 AM describe his troubleshooting of an old piece of gear.  TRGHS.  


Wednesday, August 31, 2016

A Signal for SETI? HD 164595


That's the Russian radio-telescope that picked up what was thought to be a possible signal from an extraterrestrial civilization.   This article from the SETI Institute has some interesting tech info on antennas and power levels.  Definitely not QRP!


Monday, August 29, 2016

Update on the PA3GSV M4MMRX -- And a Mystery



Note the establishment of a new acronym (M4MMRX) for Lew McCoy's Mate for the Mighty Midget receiver.  We  have needed this acronym for a long time, and SolderSmoke HQ is proud to have come up with it.  We do our part my friends.

Jan has made more progress on his amazing Dutch M4MMRX and has produced a short video showing the receiver in action with SSB and CW signals. 

Here is a bit of intriguing homebrew mystery:  Jan has gone to a LOT of trouble to create that semi-circular opening in the center of the front panel.  He even cut a corresponding semi-circular hole in the sewer pipe cap that serves as the large wheel in his amazing homebrew reduction drive.  But he won't tell us what he plans to do with that space.  So I ask you, dear SolderSmoke readers:  What is that space for?  Why the see-through panel and sewer-pipe cap?  What is Jan's plan? 

From Jan:

Hi Bill,
 The rattle is gone, so I made a little video of the MMMRX in ssb and cw mode.

In the text, a ch327 and a ch45 crystal is mentioned, but I can’t get this to work.
The ch45 has a 453.6 kHz fundamental, for ch327 can’t find one.
The ch327 is a FT-243 one, tested several, but no fundamental somewhere around 455 kHz.
For ssb there is a ch45 and a ch46 crystal in, which should provide a bandwidth of about 2kHz.
(Still not totally in the clear how this should work with the very narrow resonance response of the crystals.
One should expect two peaks and nothing in the middle?)
For cw I found two ch45 crystals about 130 Hz difference in frequency, which seems to work well.

Still need to correct the 40m oscillator coil, then move on to finishing the receiver.
This is my first home brew tube superhet.
The project isn’t finished yet, but it sure is fun to build, and learned a lot during the process.

73  Jan

Sunday, August 28, 2016

40673 LTSpice Model?

Does anyone have an LTSpice Model for the venerable 40673?  Or for a similar MOSFET?  I'm hoping to find something that I can easily plug into LTSpice. 

Friday, August 26, 2016

The NAA VLF Station (NOT QRP!) and Brad's Receiver

NAA Towers -- Arlington Va. 1913

Brad WA8WDQ wrote to us about a VLF (24 kHz) his receiver project (see below).  This led to some Googling about the VLF station NAA.  Wow, there is some important radio history associated with that call sign.   The station's original location was just a few miles from I where I live now.  From Wikipedia  (https://en.wikipedia.org/wiki/VLF_Transmitter_Cutler):

The station began operations in 1913 as a radio telegraphy station call sign NAA in Arlington, Virginia, at a facility next to Fort Myer. Although its broadcasts occasionally included band concerts and speeches, it was most famous for its nightly time signals. The three towers known then as "The Three Sisters" stood 600 feet, 450 feet and 200 feet (183, 137, and 61 m) above the ground. The site was referred to as "Radio", Virginia. The towers were the second largest man-made structure in the world behind only the Eiffel Tower. The word "Radio" was first used instead of "Wireless," in the name of this Naval Communications facility. The First Trans-Atlantic voice communication was made between this station and the Eiffel Tower in 1915. The Nation set its clocks by the signal and listened for its broadcast weather reports. The Towers were dismantled in 1941 as a menace to aircraft approaching the new Washington National Airport. The towers stand today at United States Naval Academy in Maryland, on the edge of the Chesapeake Bay. 

Be sure to read about the de-icing system for the antenna.  It uses more power than the actual transmitter!

From Brad:

Bill, Pete,
Here's the current status of the 24 KHz NAA SID receiver.  All the major sub-assemblies are mounted in the chassis and power is hooked up.  For convenience, I've been using the PowerWerx USBbuddy switching DC-DC converter to supply +5V power to the Raspberry Pi from the +12V input.  I've found them extremely RF quiet, clean and stable; capable of supplying 3A though this project will only need about 1.5A @ +5V.  At this point, I'm just waiting for Adafruit to send the A/D chip I'll wire up to the Pi on that empty protoboard just under the meter.  Speaking of the meter, it's not really needed as the Pi records and broadcasts over Wi-Fi the received signal level.  However, I like my projects to have some sort of physical human interface so I added the signal level meter and an LED for SID event alarms :).

As previously mentioned, my bench test of the receiver using my signal generator was successful.  Once everything is wired, I'll do an actual on-air signal test receiving NAA.

Brad  WA8WDQ


Monday, August 22, 2016

Radio New Zealand Booming in on 7245 AM

The day is off to a good start here at SolderSmoke HQ, with Radio New Zealand booming in on my homebrew Mate for the Mighty Midget receiver.  I was listening from around 0900 to 1030 UTC on 7245 kHz. Once again we see that The Radio Gods favor homebrew receivers. Gray line propagation also played a role.  

Above we see a technician at work at RNZ in 1945.  More historic photos here:
http://www.pcc.govt.nz/About-Porirua/Porirua-s-heritage/Porirua-s-suburbs/Titahi-Bay/Historic-site--Radio-New-Zealand-Transmission-Station

Sunday, August 21, 2016

First Signals from the PA3GSV Mighty Midget Mate



Obviously the Radio Gods (Spirits in the Sky) approve of Jan's work.  How could they not?  I can now see why he took the trouble to cut that hole in the sewer pipe cap that forms the large wheel on his homebrew reduction drive.  But what are we going to see through that center hole Jan?  What will the frequency readout be like?  
----------------------
Hi  Bill,

Just finished the last stage of the Mighty Midget MK2.
There are first signals!
The first one I heard was a broadcast station, believe it or not, the song that was on was “Spirit in the Sky” ..
All stages were built, tested and as far as possible, adjusted separately.
It was built from back to front, so the RF amplifier was last.
I added an ECL82 for more audio, the first thought of only using an EL84 didn’t bring enough.
The triode of the ECL82 as a pre-amp, the pentode as final.
Furthermore ECF82’s were used instead of the 6U8, they’re more widely available over here.
The Miller coils are hard to come by, so the 300 uH coils are homebrew.
Also used a grid detector instead of the two germanium diodes.
The triode of V1 originally intended for audio was used for this.
Made the BFO adjustable as well, still remember the screwdriver sticking out of the coil on your side... 
 
Happily there was not much troubleshooting needed.
The 80m coil was only 5 kHz off, the 40m coil 300 kHz (to low in frequency), still have to fix that.
Initially the receiver worked reasonably well without adjusting, but C1 quit at some point.
After some investigation, the problem was a dirty wiper contact on the rotor.
An ultrasonic bath fixed the problem, so no looking out for a replacement there. (hope it stays that way)
 
After adjusting, sensitivity is around -114dBm (0,4 uV) / 10 dB S/N!  (with the FT241 crystals in place, and careful tuning of the controls)
Really not bad for this small receiver, Lew McCoy was right, it really is a Mighty Midget.
I wanted to make some video’s, but over here there’s a terrible S9 rattle from 160 to 15 meters.
Every now and then it appears out of nowhere, and disappears the same way.
As soon as it is gone, I’ll make some video’s.
I made one video though, just after completing the receiver.
 
 
Reception on CW and SSB sounds really well, but unfortunately didn’t record that.
The receiver is not finished yet.
Next to the 40m coil,  S-meter has to be tried, and there’s still some work on the cabinet and front panel.
 
More to follow.
   
73  Jan
PA3GSV
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column