Showing posts with label DSB. Show all posts

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.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

SolderSmoke Podcast #168 Software Inefficiencies! DSB Blues! Schematic Errors! QRO Confessions!

SolderSmoke Podcast #168 is available. 
22 November 2014 

http://soldersmoke.com/soldersmoke168.mp3
The benefits of software inefficiency.
Don't throw a wet blanket on computer baby steps.
DDS-ing Pete's old boatanchors and Bill's BITX. 
Bill's DSB amplifier woes: a JBOT unfairly scorned.
Getting ready for solar-powered beach DSB.  
Michigan Mighty Mite Crystal Offer -- FREE ROCKS!
Tribal knowledge: Beware of mistakes in published schematics!
QRO update: Working Japan on 17 meters. 
Happy Thanksgiving! 

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

N2CQR WINS ARRL SWEEPSTAKES! AGAIN! (video)



We did it AGAIN!   Winners in the Homebrew Double-Sideband QRP Northern Virginia Category!  Sweet!  I can't wait to pick up the trophy!   

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

F6FEO's BITX 20 (and DSB Rig)


This morning I was looking at F6FEO's wonderful web site (Frank, KM4AXA is building the 28 Mhz DSB rig from Michel's site) .  The drawings have a nice JF1OZL feel to them.


Check out Michel's site.  Just hit the translate button if you have trouble with the French language:
http://f6feo.homebuilder.free.fr/index.html

Merci Michel! 



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

DSB Transceiver with Only 3 Transistors


Wow.  Looks like something Peter Parker would really like.  This one was sent to me by Stephen, G7VFY.  It comes from Japan:
http://www.cqpub.co.jp/hanbai/books/15/15061/15061_p.180-181.pdf

From this book:-

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

SolderSmoke Podcast #156 -- Special Echolink Interview

 
Podcast #156 is available: 
http://soldersmoke.com/soldersmoke156.mp3

Special hour-long interview with Peter Parker, VK3YE
-- Early experiences with radio
-- CW
-- DSB Gear
-- Simple gear, and gear that is TOO simple
-- VXOs, Super VXOs and Ceramic Resonators
-- Building receivers
-- Chips vs. Discrete
-- Making the leap to SSB
-- The Knob-less wonder and the BITX
-- No need for a sophisticated workshop
-- Advice for new phone QRPers


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

Thoughts on DSB PSK-31



To QRP-L: 

I have a JUMA TRX-1 cw and dsb transceiver. It seems to me that if I transmit an psk signal there would be two signals generated, one on usb and another on lsb. Is this correct? It does not seem like a good thing to do to me.
Thoughts?
73 Larry WB4HLX

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

Larry: 

I've been experimenting with DSB PSK for the last few weeks.  Sure, you are using twice the needed bandwidth,  but in this mode that means you are using only an additional 31 HERTZ! That's not a lot.  Also, if (as I am) you are using a Direct Conversion receiver, in your waterfall you will also be looking at two sets of frequencies -- those going about 2 kHz above center AND 2kHz below.  This helps you avoid causing interference:  If the frequency looks clear on your screen, you can be reasonably sure you won't be bothering anyone with your extra sideband.

This is similar to the AM question: there too you are using additional spectrum.  But it is allowed.

Doug DeMaw and other esteemed technical gurus have promoted DSB as a useful mode that -- through its relative circuit simplicity -- encourages the building of homebrew gear.  DeMaw wisely advised against using high power when running DSB.

I've been having fun with PSK DSB.  I've had many contacts.  I'm running less than one watt to a dipole.   One curious thing that I've noticed:  PSK seems to be sideband independent:  When I tune in a PSK signal on my FLDIGI waterfall, the software will decode it even if I have the FLDIGI set for LSB or USB. 

You might also want to try JT-65.

Good luck. 

Glad to hear that I'm not alone.           Center             Glad to hear that I'm not alone.

73   Bill N2CQR
http://soldersmoke.blogspot.com

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

Homebrew Adventures with JT65


My six dollar DDS board hasn't arrived yet, so this weekend I worked on the re-build of the 30 meter Direct Conversion/DSB transmitter that I built in Rome (originally for WSPR use).  I was hoping to use this rig to make at least a few PSK-31 contacts.   But I started seeing these strange looking sigs in the waterfall.  I found out they are JT65 (JT for Joe Taylor).  So I downloaded the program JT65-HF.  I got the receiver going very quickly (it is a 40675 dual gate MOSFET followed by the audio amplifier out of Roger Hayward's Ugly Weekender RX).  The transmitter is just a two diode singly balanced modulator followed by the RF chain from Peter Parker's Beach 40 Rig.   QSOs seem imminent.


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