Category: DSB

A Direct Conversion iPhone!

Well, really a DC receiver in an iPhone box.

I think the Apple iPhone boxes have great potential as project enclosures. They are cardboard, but they are very rigid and solid. I decided to use them for a Direct Conversion receiver project I’ve had in mind.

This is a 40 meter DC receiver. No chips. Ceramic resonator VXO tuned by a varactor diode. 9V battery as the power source. Ear buds as the transducer. Passive, two diode, singly balanced detector. It sounds great — so great that I may have to add a gain control.

The nice fit is no coincidence — I cut the board so it would fit in the iPhone box.

Take a look at that top cover. It is all, well, empty. I could put another board in there, right? Maybe a balanced modulator, a mic amp and an RF amplifier. Then this thing would be a Double Sideband transceiver. We could even make use of the little microphone that comes with most of the ear buds.
I’m thinking that this might be the kind of project that people would like to take on this winter. Build the VXO first. Then the AF amp. Then the product detector and front end. At that point you’ve built a receiver. For extra credit you could go on to the transmitter. No need to use Apple boxes (but they are cool…) I will try to get the schematic done soon. My nephew John Henry will test the prototype.


Another LM373 Rig – Pete Is Not Alone!

More DSB, from Belgium and Spain

Frank ON6UU writes:
Hello Soldermelters,
Maybe some interesting news for you as there are some new kits at hand from EA3GCY (http://www.ea3gcy.com)
I’ve made the MFT-40 DSB without any problem, all parts were provided with the kit, only things to buy were a microphone connector, a speaker and an antenna plug. The box was taken from my attic and was a VGA-selector in his previous life.
Kit came together in a few evenings, I followed the very well written manual, all was well pointed out, which resulted in a working kit. After aligning the kit I could start making qso’s. The microphone was made from a piece of tube, a simple switch and a electret microphone, it doesn’t look pretty but the microphone works.
Rx-Tx 7.066 – 7.133 (With DDS the complete 7MHz band)
Pwr : some 3W peak.
Double Side Band
Made some You-tube films about it.
Easy to make, no SMD, easy alignment without necessity of expensive material. Fine for someone who never made a transceiver, hence the name…My First Transceiver, MFT. As soon as the weather permits I will take the TRX out in the field and activate a SOTA with it.
Now working on the MFT-20 DSB. I’m hoping for an 80mtr version to come available too. 🙂
All info is on Javier’s site. (http://www.ea3gcy.com)
72, 73
Keep the solder melting !!
ON6UU




Walter KA4KXX’s “Al Fresco” Oz DSB rig with VFO Mod

A while back we ran a post about the MDT 40 DSB rig out of Australia. Walter KA4KXX liked the design so much that he built his own version and, with it, made his first homebrew phone contacts. I always say that DSB is a great way to break into the world of microphones. Walter is obviously on the right path — not only did he come up with a nice Al Fresco DSB rig, but he modified the VFO to get additional coverage and to incorporate a frequency counter. FB Walter!

Walter KA4KXX writes:

 Since I earned my Ham Radio license in about 1979, I have always operated only on CW since I like to build all my own equipment, but recently at the SolderSmoke website I discovered the MDT 40 Meter DSB Transceiver, and decided this was the design I had always been looking for to finally build and operate on phone.

 After I made my first phone contact after only 5 minutes of trying, just a few weeks ago, I was so excited I sent an email thanking designer Leon of ozqrp.com.

Then I modified the VFO further to cover the entire 40 meter USA General Class License phone band, which is 7.175 – 7.300, in two overlapping steps. I also added a 5K fine frequency adjustment, used a more friendly 1SV149 Varactor diode which I purchased on EBay at very low cost, and also added a high impedance buffer (found at the website listed below) to the VFO to drive a frequency counter.

http://www.arising.com.au/people/Holland/Ralph/buffer/highimpedanceprobe.htm

 I was able to implement these modifications very easily since I always make my own un-crowded state-by-stage Manhattan style circuit boards and build first on a breadboard.
So far I am very pleased with the results.

Walter KA4KXX


Another Great DSB rig from New Zealand

So many great Double Sideband projects come from Down Under. There are the various versions of the famed ZL2BMI rig. And Peter Parker VK3YE has long been the acknowledged guru of DSB. In fact, Peter sent me an enthusiastic e-mail about the new ZL DSB rig pictured above — his e-mail arrived before the message (below) from the intrepid builder. I detect a bit of the “Tucker Tin” influence in this rig. (But perhaps this one is more Tupper than Tucker!) Charlie’s work has graced out blog posts before: http://soldersmoke.blogspot.com/search?q=zl2ctm
Be sure to check out his video: https://youtu.be/JsAuWGkyvmE (and below).
Hi Bill.
You asked recently on the podcast for listeners to let you know what they had on their work bench. Well I’ve been working on a tramping (hiking) radio, which is now complete. It’s a DSB 5W rig designed for 80, 40 and 20m, as well as our New Zealand mountain safety radio system. I designed everything in LTSpice as was suggested by Pete, N6QW. That was great, as I could ‘desolder’ components with the mouse and instantly see what impact it had on the output. An amazing tool that’s free! I highly recommend it.
Once again I’ve used upside down strip board for each stage, which are tacked down onto an un-etched copper board (earth plane). That seems to work really well for me.
The rig uses an Arduino mini driving a small OLED screen and a Si5351 DDS. The Si5351 is going straight into a SBL-1, which seems to work fine too. The AF strip is a 2N3904 before a LM386, which has enough drive to run a speaker. The TX amplifier is a three stage one with shielding between each stage. It’s made up of two 2N2222A stages followed by a BD139. That in turn is followed by three simple filters, one each for 80, 40 and 20m.
All-in-all it works really well. I’ve uploaded a quick video at https://youtu.be/JsAuWGkyvmE
The next project will be a proper SSB rig using a crystal filter salvaged from an old Codan 7727. Like this one, it will use an Arduino and a Si5351.
Finally, I am certainly no expert in homebrew, but I hope my ‘dabbling’ will help inspire others to pick up the soldering iron and give it a go. If I can do it, then anybody can! There is certainly a great sense of achievement to operate a rig you built yourself.
Regards, and thanks to you and Pete for all your inspiration.
73’s
Charlie
ZL2CTM

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!

HB2HB QSO with N6ORS — MIN-X to BITX

That’s Keith N6ORS’s MIN-X transceiver. Keith explains that it has circuitry from the BITX, the Minima and even from the ZL2BMI DSB rig. We featured the MIN-X before, when it was still outside the box:
http://soldersmoke.blogspot.com/2016/01/n6orss-min-x-crosses-pond-on-first.html

I was on twenty today with my BITX, finishing up a rather disheartening contact with a fellow who told me that he is a “checkbook operator.” I was trying to encourage this fellow to build something simple — perhaps a Michigan Mighty Mite? He told me that he might give it a try, but only 16 years from now, after he retires. It was like a case of the Anti-Knack! Then Keith N6ORS saved the day by calling in with his beautiful MIN-X HOMEBREW transceiver. We had a nice talk — Keith mentioned the beauty of Pete’s “Blue Rig.” That’s HB2HB (phone) QSO #5 for me. Thanks Keith!

Bill,
That was great fun!
I was just tuning around and heard you mentioned the Michigan Mighty Mite
so I stopped to listen and realized it was you!
Well here was my chance for a homebrew to homebrew with ‘the man’ himself.
I wanted to record it but missed the chance.
Here is the Min-x boxed up. the case is made from thrown away computer cases.
It runs about 70watts on 160,80 and 40 meters and about 35watts on 20 meters.
I promise to write it up, maybe even draw a schematic. hihi.
73,
Keith N6ORS

Here’ a short clip of the MINX in action:

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


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

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.


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

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

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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.

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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.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our 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.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our 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!

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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:-

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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

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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 N2CQRhttp://soldersmoke.blogspot.com

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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.

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