VK3HN: SOTA, HB, SSB, and QRP FB!

Peter VK3YE sent me the link to this amazing site.  Wow, Paul VK3HN does great work, both with the homebrew rigs and in describing his work on them.  Check it out: 

https://vk3hn.wordpress.com/2016/10/25/summit-prowler-one-a-homebrew-7mhz-ssb-qrp-transceiver-for-sota/

Great stuff.  Thanks Peter!  Thanks Paul!

From the DSB-SSB Pier In Melbourne, Australia: SolderSmoke Book Reviewed by VK3YE

It is a real honor to have my book reviewed by DSB guru Peter Parker VK3YE, and to have him do the review from the iconic "DSB-SSB" pier in Melbourne, Australia.  Check out the video (above). Thanks Peter.

The Joy of Analog Oscillation -- A Character-Building Experience

Gentlemen,

I'm a younger ham, just 26, and I've just experienced what I think you call Joy Of Oscillation as I completed my first L-C VFO. What fun!

I'm working on Peter Parker VK3YE's Beach 40 Double-Sideband transceiver, and while my natural proclivity is toward the SI5351 and it's brethren, I figured it would be character-building to actually put together an analog VFO for once.

After much tweaking of the feedback capacitor in the oscillator, and massaging the tank inductors, and conking out an additional buffer stage to drive the diode-ring mixer at the appropriate level, and gluing Manhattan pads on top of Island pads.... I say, without reservation, that this was great radio fun! And isn't that what it's all about?

(Now it only it didn't drift so much... so I guess it's not quite complete yet)

Just wanted to share, love the podcast and the blog, I learn something new each episode.

All the Best,

Jeff, KK9JEF

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

Great stuff Jeff.  Character building indeed!    As for the drift, try this:

-- Replace the toroid in the oscillator circuit with a coil wound on a non-metallic core.  I use a cardboard tube from a coat hanger.

-- Make sure the capacitors in the oscillator and even in the buffer are NP0 caps (they don't change in value as they heat).

-- Try to run the oscillator stage at reduced voltage.  Six volts is better than nine.

--  After you solder, always let the device cool down for several hours (or even overnight) before you evaluate it.  Heat from the soldering iron will be dissipating and changing the freq for a LONG time.

Above all, IGNORE the inevitable recommendation from Pete Juliano that you forget about all this nonsense and just go with an Si5351.

Please keep us posted on your progress. 

73  Bill   N2CQR

Oz QRP2QRP From Mt. Bullfight, Pyramid Hill, and Melbourne's Chelsea Pier

Paul VK3HN has obviously made an admirable effort here, and a visit to his very nice blog shows that he has a lot of true homebrew gear available.  We hope that he will haul some of that HB stuff up the mountain, perhaps to find Peter Parker operating from the Melbourne pier with a Beach-40.  As I type this I am listening to VK3IO on 40 meters, coming in nicely on my Barebones Superhet (kit version).

Dear Bill and Pete,

I would like to claim an entry in the SolderSmoke Homebrew To Homebrew
(HB2HB) log. Here's the story. On Sunday 24th April 2016 I drove two
and a half hours north east of Melbourne into the edge of the Great
Australian Dividing Range, to climb two summits, for the fun of
operating my 40 meter SSB QRP (5 watt) rig in a beautiful, RF-quiet
setting, and to activate two Summits Of The Air (SOTA) peaks.

My first summit was Mount Bullfight
(http://www.sotawatch.org/summits.php?summit=VK3/VN-002), in the
Rubicon Ranges, at 1,490 meters ASL not high by American or European
standards but a good heart-racing climb through thick Australian bush.
After a successful activation with good signal reports into Tasmania
(VK7), around Victoria (VK3) and New South Wales (VK2), I descended,
and drove about 2 miles up the valley to an adjacent SOTA summit,
Pyramid Hill (1,314 meters) where the activation also went well. Just
as I was finishing up with the chasers, Peter Parker VK3YE called me,
operating portable from his beloved Chelsea Pier, and we had a very
pleasant beach-to-summit ragchew QSO. The RF path is about 62 miles.

Peter was running his MDT double sideband rig, with 2 watts. I was
using my MST400, with 5 watts SSB. Both rigs are kit radios from OzQrp
(http://www.ozqrp.com/). Both are assembled by hams -- I built my
MST400 18 months ago and Peter was using the MDT rig that OzQrp
founder Leon, VK2DOB designed, built and kitted, the one he sent to
Peter for a YouTube review. So it was built by a ham, just not by
Peter.

Now, I know that there may be some, possibly even you Bill, who may
question the legitimacy of my claim on a coveted HB2HB log entry in
this particular case. I can assure you that we did experience the Joy
of QRP/P operation, Peter basking in the late afternoon Australian sun
on a beach and I on the mountain top. And to further add authenticity
to my HB2HB claim we discussed QRP, aerial experiments, and 'whats on
your bench' topics for a full 20 minutes.

However, I would not want to risk disturbing the wrath of the Radio
Gods with a dubious claim.

I admit that neither radio was scratch-built, on copper board
ugly-style, or had the form of a wild birds-nest of separate modules
and interconnections, with parts loosely screwed onto an Italian
chopping board or a discarded lump of wood. Indeed, neither can it be
claimed that both operators built their rigs. So I will take a
rejection of my request with acceptance and dignity, acknowledging
that you are duty-bound to maintain the highest of standards, and that
entry into the SolderSmoke HB2HB log is not to be granted without
proper consideration.

I do understand that you may feel that accepting this QSO could set a
dangerous precedent and risk opening the flood gates to a tsunami of
dubious HB2HB QSO claims from hams using minimal assembly rigs, like
some of the Elecrafts. Who knows, some individuals might even be
tempted to claim HB2HB QSOs from VHF FM hand-helds after managing to
screw on the rubber-ducky antenna. Even unboxing a shiny new
Yae-com-Wood is, to some, a form of 'handiwork'.

Bill, the decision is yours. Peter VK3YE and I look forward to your
decision. Judge wisely.

73 from down under, Paul VK3HN, with agreement to this claim from Peter VK3YE.

Details of this day of activations are on my blog at:https://vk3hn.wordpress.com/

Peter's MDT review is at:  https://www.youtube.com/watch?v=2OtZeFkb1xw

Soldersmoke Podcast #186 Is Available -- April 1 Rap Up, Pi Talk from Pete, Collins and Raspberries, Bill's Analog RX, Visits and Hamfests, MAILBAG

SolderSmoke podcast #186 is available:

http://soldersmoke.com/soldersmoke186.mp3

-- April 1 WireWrapRap Rap-up.  Feedback from participants.

-- Bench Reports:

   - Pete talks about his Raspberry Pi SDR DSP rig.  

   - Bill talks about on his Mate for the Mighty Midget Receiver and his R2 Frankenstein.

-- A story from Pete's youth: Cruising the "Miracle Mile" with a Heathkit "Ten-er."

-- Why do we need more RF amplification (in receivers) on 20 than on 40?

-- Have you ever tuned the BFO freq in a superhet by the "sound of the noise?"  

-- A visit to Washington by Jonathan W0OX and family.

-- Bill goes to Winterfest Hamfest with Armand WA1UQO

-- Pete on the importance of balance (in life).

-- Great interviews on QSO Today: Peter Parker, Grayson Evans, and Ashhar Farhan.

-- MAILBAG:

- Paul Darlington M0XPD has a new book about life, travel, and the Dayton Hamvention.

- Michael AA1TJ QRV with a tuning fork at its 2,000th harmonic.

- Jonathan M0JGH living dangerously with homebrew QRP in Italy.

- Ben KC9DLM JoO with MMM

- Stefan DL1DF needs 3.579 MHz rock "with mojo." We have it for you OM.

The music for SolderSmoke 186 was written and performed (the bass lines) by Pete's son Tim.  Thanks Tim!

Pete also suggested that we have some rap lyrics for this music, so renaissance man that he is,  he composed some words. We are still looking for a performer.  

Yo we solder no more – its wire wrap and cables

The cables connect to the small  black box

hold on to your pants and pull up your socks

A cable goes here and a cable goes there

Turn on the switch and its Shazam all software

 

A Great Knack Story: Peter Parker Interviewed on "QSO TODAY" by 4Z1UG

I really liked Eric's interview with the Peter "The Wizard of Melbourne Beach" Parker aka VK3YE. What a great Knack story!  There he was, trolling the garbage dumps of Western Australia, looking for discarded electronics.  Using the LO of one broadcast receiver to demodulate SSB signals coming in on another... Great stuff!  Check it out:

http://www.qsotoday.com/podcasts/vk3ye

A Phasing Receiver from Montenegro (Video)

Thanks to Peter Parker VK3YE for alerting us to this beautiful receiver from Bore 4O6Z in Montenegro.  This may be our first ever report on a Montenegrin rig.  And it is a thing of beauty. Bore says it is based on a phasing circuit by homebrew legend V. Polyakov, RA3AAA.

Here is 4O6Z up on the tower:

Dead Chickens and Fake Transistors in Medellin Colombia: HK4DEI's Micro 40 DSB Rig

Daniel HK4DEI wrote to report that page 149 of the SolderSmoke book was providing some solace and comfort as he struggled to get his version of Peter Parker's Micro 40 Double Sideband rig going.  He was having problems with the amplifier.   He was almost at the point of sacrificing chickens to Papa Legba.  I wished him luck and told him to hang in there. 

Elisa saw my e-mail to Daniel and complained that I hadn't given him the solution to his amplifier woes.  I tried to explain to her that there are sometimes things in this universe that are just UNKNOWABLE.  C.F. Rockey W9SCH (who alerted us in SPRAT 22 to the chicken sacrifice option) spoke of transistors that exhibit "quantum mechanical necromancy."  Rockey explained that when this happens, "The transistor simply turns up its toes and dies. Not even an Atomic Physicist can tell you why!"  

But Daniel persisted.  And he won the battle:

Hey Bill

Did you kill some chickens already? If you did, THANK YOU!  If you don't, then please enjoy a nice sancocho de gallina for me.

But seriously... guess what?

FAKE TRANSISTORS!!!!

I knew I couldn't be screwing everything up so badly and VK3YE's circuit couldn't be so wrong.

I was getting nuts trying to understand why it wasn't working, changing a single inductor could fry the final instantly or not getting any power out at all (?) also my final BD139 was getting extremely hot, and many of them died with no apparent reason (Page 149!!!!).

I ordered a "good" deal of BD139's and BD140's combo for an incredible low price from [A WEB SITE], I've ordered many *apparently good components from that site with no problems so far... mainly resistors and capacitors. Having tried everything to get my circuit working and after some quick online search about fake transistors from china my suspicions grew considerably and I remembered some -other- BD139's I had ordered from Amazon some time ago.

I proceeded to solder the new transistors in place in my PA and Bingo! No more heating of the final and about the expected 0.5W out from my first DSB homebrew rig. I quickly reported to a fellow homebrewer in a local net and the report was amazing! 59 +10, the final transistor was comfortably warm to the touch and my mind could finally rest... lesson learned! What an electromagnetic achievement!

Just wanted to share my success Bill and thank you again for you book and you kind response.

Please say hi to Elisa and the Cristalinhos from a fellow Latin friend.

Clear Skies.

73/72 from Colombia!

Daniel

HK4DEI

ZL2CTM's New Zealand Double Sideband Success

New Zealand and Australia seem to produce an amazingly high percentage of the world's double sideband transceivers.  Charlie ZL2CTM adds to the count.  He took inspiration and circuitry from DSB  hams in both countries and produced this beautiful DSB transceiver.  It is obviously -- as Charlie notes -- chock full of soul.  I definitely identify with his comment about "taming some kind of  electro-mechanical machine" and also, of course, with his remark about the feelings that come with putting a homebrew rig on the air.  So follow the advice of Charlie!  Build a DSB rig and put it on the air!  Make this your ham radio resolution for 2016!  Give it a go!    

Hi Bill:

I have been following you and Pete Juliano for many years now, and thought I would send you a photo of my 40m homebrew rig that I finished yesterday. Hopefully, it will help encourage others to melt some solder and make their own rigs. The rig is based on ideas and designs from Eric Sears ZL2BMI, Peter Parker Vk3YE and of course Pete N6QW. The aim is to make the final version relatively compact so I can take it tramping/hiking here in New Zealand.

The VFO is an AD9850 being controlled by an Arduino Pro Mini. The output is amplified to provide sufficient drive for the balanced modulator. I was using a nice 1” OLED screen to show the frequency, but that generated a huge amount of noise, so I changed to a LCD. Changing frequency is simply a matter of moving the curser left and right then using the up and down buttons to change the number. Very quick and easy. I was contemplating a rotary encoder, but I find those always seem to skip and jump every now and then. Must be the way I use them...   

The balanced modulator is a 4148 diode ring. I do have some SBL-1s lying around, but I thought I’d go with the discrete diode ring for something different. I’m using a standard electret mic and a simple single stage amp. The switch above that switches between phone and CW.

The PA is two stages; the first a 2N3053 and the second a BD139. At this stage it puts out just over 1W into a 50ohm load. I might look to add another stage and get that up to 3-5W.

The audio amp is a simple LM386. I am not running it hard out as per the datasheet as it generates quite a bit of high frequency hiss in that configuration.

Unlike Pete, I don’t have access to a milling machine to make squares to mount the components on. Instead, I use vero/strip board upside down and solder directly to the strips. This works really well for me on HF. I cut tracks with the twist of a small drill bit.

Last night I made two contacts with the rig. The farthest was 527km according to some well known mapping software. Both reports said the audio was ‘very nice’, which was great to hear. The receiver worked surprisingly well too, and I managed to hear stations in Europe.

As for user controls, you will notice that the pots, switches and plugs are all over the place. I did that to keep leads short. I like it as i feel like I am taming some kind of electro-mechanical machine to generate and receive RF.

Anyway, this little rig has a ton of soul in it and is really fun to use. There is something different about making a contact with a rig you built. I really encourage everyone to give it a go!

The next iteration will be a SDR using a Teensy. Rheslip over at Open Emitter has done some great work with that.

73s

 Charlie

ZL2CTM  

New Rig: The FRANKENSTEIN Phasing Receiver

Here is my latest project.  I call it The Frankenstein because of the two BNC connectors that come off the side of the DDS oscillator box -- they look to me like the bolts on Frankenstein's neck. The square waves from the DDS LO also seemed to evoke Frank's bolts. There may be other similarities.  We'll see.

Here is the idea:  Phasing,  Direct Conversion, Image Rejecting receiver based largely on the R2 design by Rick Campbell KK7B  as presented in the January 1993 QST.

I'm using an AD9850 with an M0XPD Kanga board and an Arduino to generate the quadrature LO signals (you can see the square waves on the 'scope in the background).  I'm using the software of Richard AD7C;  this, combined with the divide-by-4 scheme on the Kanga board,  puts the upper limit of reception at 7.3 MHz.  That's OK for now. 

When I first fired up my AD9850 box I was dismayed to find that the square wave quadrature output was no longer there.  I was about to give up and get anther shield board, but this kind of surrender bothered me.  So I started troubleshooting and isolated the problem to the /4 chips. My soldering of the surface mount chips was, well, a bit dodgy, so I changed to a tiny soldering tip and reheated all those tiny little pads.  Hooray!  I fixed it. 

The receiver will be built mostly on a PC board that Pete made for me back when he was trying to convince me to build a fourth BITX receiver.  I am pleased to put the board to use.   See below.

Yesterday I soldered on the two SBL-1 mixers that will form the heart of this receiver.   I realized that the very robust quadrature square waves from the Kanga board might be robust enough to fry the sensitive little SBL-1s.  Sure enough, I measured about 17 dbm coming out of the Kanga board.   I threw together two roughly 10 db resistive pads.  These should prevent the SBL-1s from releasing their smoke.     

I hope this receiver will be four receivers in one:

1) Standard DC receiver.

2) Binaural Receiver!  Groovy, stereo CW that floats around in your head,  man! 

3) I-Q receiver that can be fed into the sound card of the computer for DSP, panoramic display, etc.   I promise not use it to find fault with the signals of homebrew SSB rigs.

4) SSB image rejecting receiver for easy, Direct Conversion SSB listening without the burden of having to listen to the other side of zero beat. 

There is already a lot of soul in this new machine:  Kanga board with the design my Paul M0XPD, PC board made on Pete's $250,000 CNC machine, and all of it on an actual breadboard (from Italy, I think).  

Rick Campbell and Peter Parker have commented on the allure of phasing rigs.  There is something very attractive about them.  There is a cleverness in the way this design exploits the phase relationships between sidebands to allow us to null out the unwanted side of zero beat.  It took me a while to really understand how this is done -- once I understood it, I really wanted to build a rig that would make use of this principle.    

VK3YE's HB Superhet: Simplicity+Serendipity = Elegance

Simplicity + Serendipity = Elegance.  Indeed it does.   I would also point out that Peter's rig contains an admirable dose of ugliness (in the positive sense).  Thanks Peter!

HB2HB! N3FJZ-N2CQR Si5351 and BITX TIAs on Both Sides, with Some LBS and Peter Parker Circuitry Too!

In those dark days of February 2015, when all the members of the SDR ESSB Panoramic Spectral Police were on my case over some imperfections in my 40 meter homebrew SSB signal, Rick, N3FJZ came to my rescue by sending me a great YouTube video of his reception of my new rig.  Rick was using a wonderful homebrew Direct Conversion receiver with a really cool PTO.   Here is my blog post on Rick and his receiver:

http://soldersmoke.blogspot.com/2015/02/parasitic-anguish-on-40-then-homebrew.html

Then, yesterday, I received this e-mail:

Bill, Pete,

I want to share my excitement with you.

After 32 years as a ham, I finally had my first ever HF QSO on October
16, 2015, and on a homebrew rig no less!  Oh the Joy of Emission!It was on 7.242MHz, 8:00 a.m. eastern on the "Woodpecker net".
- Rig was based on the Bitx, using ZIA bidirectional amps.
- 20 Watts into a 80 meter full-wave loop up at 20 feet.
- 600 ohm homebrew open wire ladder line.
- Balanced antenna coupler inspired by the Annecke and Johnson matchbox
units.
- and most importantly, the Arduino controller software and use of the
Nokia display were derived and inspired from Pete's "Let's Build
Something" code presented on his website, and the carrier
oscillator(BFO) & L.O. are generated by an Adafruit SI5351 clock
generator board.  Thank you Pete.

See my N3FJZ look-up on QRZ.com for photos of my homebrew rig. I have
also put links to the SolderSmoke blog and to Pete's web page and blog.

I just want to tell you both that your podcasts, websites, circuit
diagrams and stories were a huge part of my success.  They were the
inspiration I needed on many dark days when my amplifiers would
oscillate, and my oscillators would simply smoke.  At times I thought I
would never get on the air, but an hour listening to SolderSmoke podcast
would give me the drive venture on.  Thank you!

***VERY IMPORTANT!!!!

Bill, during my first QSO, I was getting 5x8 and 5x9 signal reports
(with 20 watts!)from North Carolina, up-state New York, Michigan, and
Indiana, and I know we are only about 50 miles apart (I'm in north
central Maryland), so I believe we could probably achieve a successful
HB2HB contact if you want to try.

If you want to, and have the time, you could join me on the Woodpecker
net any Friday, Saturday or Sunday on 40 meters 7.242MHz 8:00 a.m.
eastern, or we could set-up a prearranged contact on a General class 40
meter frequency of your choosing.  Let me know - making an HB2HB
contact with you would mean the world to me.

Pete, I also extend this invitation to you as well, but with only 20
watts on my end, it may be a stretch, but we could try.

Thank you both again for the joy you have given me with your pod-casts.
73
Rick - N3FJZ

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

Rick and I got together on 7.288 MHz yesterday evening.  It was a really amazing QSO.  Rick made a video of it (see above) and I recorded the audio on my side.  My old tape recorder didn't do Rick's signal justice -- it sounded better than this.  But here is the full QSO:

http://soldersmoke.com/N3FJZN2CQR.mp3

Be sure to listen closely at around 21 minutes when Rick describes a software feature that allows him to switch -- with the touch of a button -- from high side VFO to low side VFO.  The BFO frequency also changes to account for the resulting sideband inversion.  Very cool.

Rick's Digital Board

Ricks Rig as it was during our QSO

 

Crystal Filter

Rick's Dual HEXFET Power Amplifier

 

Check out the N3FJZ QRZ.com page for more info. 

 

CONGRATULATIONS TO RICK!  



SolderSmoke Podcast #181 Of Dongles and DX-100s -- SDR vs. HDR, Music & Art, 2B, HB2HB, Noise, The Martian, VK3YE's New Book

Two RTL SDR Dongles in front of a DX-100 Transmitter

SolderSmoke Podcast #181 is available:

http://soldersmoke.com/soldersmoke181.mp3

17 October 2015

-- Our audience IGNORES Pete's guitar intro!
-- Pete on QSO Today Podcast.
-- Part 97, The Radio Art and International Goodwill.
BENCH REPORTS:
-- Pete connects his new beam to the KX3.
-- Pete puts the Bell-thorn on 20.
-- Simple-ceiver update.
-- Pete's new drum machine: http://makezine.com/2015/10/15/learn-electronics-worlds-oldest-drum-machine/
-- Bill fights noise in the DIGI-TIA.
-- Bill fights power-line noise (and wins!).
-- Drake 2B, skirts, reduction drives, and tuning rates.
-- Warming up (with!) the DX-100.

-- N2CQR -- N6QW  First Ever HB2HB QSO.

-- On 40 AM with an HT-37
-- Listening to Chinese CubeSats.
-- SDR Dongle as a bandwidth checker.

-- SDR and the Future of Homebrew Radio.

-- Bryan's LBS Receiver.
-- Dean's First Ever QSO with his HB rig.

-- 32 Mighty Mites Completed

-- The Martian -- Did Mark Watney REALLY have the Knack?

-- MAILBAG:
Peter Parker's New Book
Sparks from Ron Sparks
Armand's 1Watter
Rogier's  pyro machine
BIG boxes from Tim KI6BGE
Mikele's ZIA and N6QW rig collection
SPRAT 141 and SPRAT 164

Peter Parker's New QRP Book

The wizard of Melbourne Beach, Peter Parker VK3YE, has written a book about QRP.    Check it out here.  

Peter is a true QRP guru. His Beach 40 transceiver is shaking the ether from locations around the world.  I am really glad that he put that Melbourne dock on the cover.  That dock has been the test site for many of Peter's amazing creations.  The railing has supported many great antennas.   So many wonderful YouTube videos have been recorded there.  There really should be a plaque or something... 

Peter's book is available as an e-book from Amazon.   Details on how you can get it are here"
http://home.alphalink.com.au/~parkerp/miniqrp.htm

Thanks Peter for this important addition to the QRP literature.

VK3ZZ's Magnificent Rigs

 

Oh man is that beautiful or what?   Thanks to Peter Parker for the alert.   This is yet another reminder that Australia remains a bastion of homebrew enthusiasm and expertise. 

 

This is the work of Ross, VK3ZZ.   Read more about this rig, and the other creations of this Electronic Wizard (including an impressive AM rack), here:

 

http://www.qrz.com/DB/VK3ZZ

 

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

Peter Parker Reviews a DSB Kit and Presents Cool Mods (3 Videos). Also: Why DC Receivers Don't Work with DSB sigs. (It doesn't seem fair!)

I found Peter's recording of the DSB signal being received by a DC receiver to be very interesting.  We've long been warned about the very ironic incompatibility of DSB rigs and DC receivers. 

In "W1FB's Design Notebook," Doug DeMaw wrote (p 171):  It is important to be aware that two DSSC (DSB) transmitters and two DC receivers in a single communication channel are unsatisfactory.  Either one is suitable, however, when used with a station that is equipped for SSB transmissions or reception. The lack of compatibility between two DSSC (DSB) transmitters and two DC receivers results from the transmitter producing both USB and LSB energy while the DC receiver responds to or copies both sidebands at the same time."     Bummer.

In essence, we've been warned that the simple DSB/DC rigs we've put on the air cannot communicate satisfactorily with similar rigs.  We are, it seems, doomed to only speak with SSB/Superhet rigs.

The later portion of Peter's second video allows us to hear just what happens when we try to listen to a DSB signal with a DC receiver:  It sounds, well, unsatisfactory.   I was trying to figure out why.  Here are some ideas:

Simplify things by assuming we are transmitting only a single audio tone of 1000 Hz through our DSB transmitter.  The rig's VFO  is at 7100 kHz.  The 1 kHz tone results in signals at 7101 and 7099 kHz.  Along comes somebody with a Direct Conversion receiver. If he were able to put (and keep) his receiver oscillator on EXACTLY 7100 kHz,  he would end up (by taking the difference products from the product detector) with  a 1 kHz tone resulting from the 7099 kHz signal AND a 1 kHz tone from the 7100 kHz signal.  But there would be phase differences between these two signals, so you would end up with a less than pure 1kHz tone. (Did I get that right?)  And if -- as is likely -- your local oscillator is a bit off frequency you'd get a real mess.  If for example the local oscillator was at 7100.1 kHz, you'd have tones at   900 Hz (7100.1 - 7101) and 1.1 kHz (7100.1 - 7099).      Yuck.  

You might think you could just use the local oscillator in your DC receiver to replace the carrier in the DC receiver, turning it into an AM signal, then use an envelope detector as you would with any AM signal.  But not so fast!  For this to work your local oscillator would have to be not only at the same frequency as the original carrier, but also in the same phase.  That is hard to do. (Hard, but possible -- that is what they do with synchronous detectors using phase locked loops.)

I think you can actually hear many of the DC-DSB problems as Peter tries to tune in the DSB signal of VK7HKN using the DC receiver in the MDT transceiver.  It is indeed unsatisfactory.    But don't worry.  It is highly unlikely that when using a DSB rig you will encounter another DSB rig.  I speak from experience on this.  Pity.



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

Another Great Rig (and Video) from Peter Parker VK3YE

Peter Parker has a double dose of The Knack:  Not only is he a great rig builder, but he is also a very skilled teacher.  His videos provide really excellent descriptions of how he selects, designs, and modifies the stages that make up his magnificent rigs.  You can learn a lot from these videos.  Thanks Peter.  

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

Finally! An Award for QRP DSB! VK3YE's 40-40 Award

Brilliant!   Great stuff!  Lots of fun! 
Another great idea from Peter Parker, VK3YE.

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

VK3MO's 20 Element Monobander for 20 Meters!

 

Ian VK3MO was booming in from Australia this morning. No wonder: he has a 5 over 5 over 5 over 5 array on a rotatable tower.  He can get a 3 degree takeoff angle with this antenna and I think I heard him say that he is working on another so that he can get a one degree takeoff angle. He was also using a using a Collins 30L1 linear.  Lots of soul in that old machine!

 

At one point in our QSO, I turned off my .12 kW amplifier.  He said I was still 58-59 with 3-4 watts. 

 

And Ian is a homebrewer!   He has built a number of transceivers and has another one in the works.  I told him about the BITX and he printed out Farhan's article (to read later).   He tells me that he has heard Peter Parker, VK3YE, on the air. 

 

In this QSO, Ian was using a modern commercial rig, but wouldn't it be great if we could get him to connect a homebrew sideband rig to that big antenna.  Go for it Ian!

More on Ian's antenna here: http://vk6ysf.com/vk3mo_visit.htm


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 Thatched Roof, Some Palm Trees, A Dipole, and a Homebrew Rig

 

Look at the drawing above.  That is the banner logo of Rod Newkirk's column in QST magazine.  For many years Rod regaled us with exciting reports on the activities of intrepid foreign radio amateurs, transmitting from exotic locations using ingeniously devised homebrew radio equipment.  Look at the picture on the left side.  See the palm trees?  See the thatched roof shack with the dipole antenna?  Well, that's pretty close to what it was like for me out on the Samana Peninsula in the Dominican Republic last month. 

I set up the station under the thatched roof in this picture:

The red pins mark the spot:

Here I am, tuning the rig while looking across Bahia Rincon: 

The rig was my Azores-built, oft-modified, NE602-based, ceramic resonator DSB transceiver with a recently added India-designed BITX IRF510 RF amplifier chain.  A little article I wrote about the ceramic resonator VXO was featured in SPRAT 127.  My antenna was a half wave dipole strung up in the thatched roof. Power came from 10 AA Batteries.  So this was the Double A, Double Sideband, Dipole DX-pedition.   

I had given some thought to building an SSB rig for this trip, but because of the efforts of Peter Parker, VK3YE, I felt compelled to take a DOUBLE Sideband rig with me to the beach. 

Here is an old (2006) video on the rig.  The power amplifier has been significantly modified: 




Here is some more information on the rig, including a schematic for the receiver and the SPRAT article on the Variable Ceramic Oscillator:

http://www.gadgeteer.us/PORTABLE.html
 
Here is the log book for my contacts.   

17 DECEMBER 2014

W1JPR PAUL MT. DESERT ISLAND MAINE

8P6AE (BARBADOS) COULD BARELY HEAR ME, BUT GOOD QSO

18 DECEMBER 2014

N4USA DAVE IN FLOYD, VA. FAIRS NET. (KK4WW.COM)

KE4UGF DON ALSO FAIRS, NICE GUYS. FUN CONTACTS!

KA4ROG ROGER NORTH OF ORLANDO

19 DECEMBER 2014

WB2HPV GUIDO TALKING TO ITALIANS EVERY MORNING FROM WAYNE NJ.  HE HAD TROUBLE HEARING ME.   

CONDITIONS SEEMED POOR, BUT I WAS HEARING AUSTRALIAN STATIONS

W8GEO GEORGE IN THE INTERCON NET.  HEARD ME.  ALSO ON INTERCON: KA4AOQ AND 6Y5MP (JAMAICA) ALSO HEARD ME.

N4PD PAUL

W3JXY/4 NAT IN KEY WEST

N1FM TOM, NORTH OF MIAMI SOLID QSO.

KM4MA PAUL IN ORLANDO WITH MARITIME MOBILE NET.

20 DECEMBER 2014

NA2LF LLOYD IN NY

WB8YWR JIM IN DALLAS 

KM4MA.

W1AW/3 IN MARYLAND (TOOK ME A WHILE TO GET HIM)

21 DECEMBER 2014   NICE 4 WAY SPANISH LANGUAGE QSO:

KI4PZE MIGUEL

CO8OT JUAN IN SANTIAGO DE CUBA

WA4RME RAFA IN CHARLESTON S.C.

C08KB MARCO IN CUBA

Here is a short video showing the station and the location.  Note the little birds (Golondrinas or Swallows) flying by.  They nest in the thatched roof.   They often got confused and flew inside the house.  Billy and Maria rescued many of them.  Whales breed in this bay in January and February.  There are also  manatees.  It is really a beautiful place. 

There were obviously other attractions (!) so I didn't spend a lot of time on the radio -- just a half hour or so every now and then.  But it was really very satisfying to carry this little homebrew device with me, set it up in this amazing place, and use it to send my voice across mountains and hundreds of miles of ocean.   I built this rig in the Azores and have used it in the UK, France, Italy and the Dominican Republic.  It contains circuits devised by members of the British QRP club and by my friend Farhan in India.  The ceramic resonator circuit is something I cooked up on my own.  The microphone is from my old Sony Walkman and the pen that serves as its support is from that wonderful magazine "Electric Radio."  In short, there is a lot of soul in this little machine.  And it was a lot of fun to take it to the beach.  

Thanks to Elisa for finding us this wonderful place.  And to Rod Newkirk and QST for the DX inspiration. 


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