N8NM: Thermatron Meets Silicon (Part II or III)

Steve N8NM has been pushing the limits of radio hybridization.  In this receiver he has 12AX7 thermatrons running alongside an Arduino and a Si5351.  Somehow I find this both very appealing and deeply disturbing.  Many of you will know what I mean. But FB Steve -- keep them coming.  Put these unique rigs on the air and strike a blow against the Yaesu-Icom-Kenwood monotony!   

Bill:

Here's a pic of a Thermatron-Meets-Silicon receiver that I've been working on.  Tubes are 12AT7 mixer, 2x6BA6 IF amps, 2x12AX7 (product detector, AGC amp and 1st AF) and 6AQ5 audio out.  An Arduino controlled Si5351 provides the LO and BFO as well as handling all of the switching, and the mixer and product detector use variations on Dr. Pullen's dual-triode circuit.  I've had this one on the air, but the hardware and software still need some, um, refinement.  And painting the panel has to wait until spring as my XYL doesn't share my affinity for paint fumes.

73 - Steve

N6ORS's Min-X Crosses the Pond on First Contact

Very cool!  Reports on new phone rigs keep coming in.  It is great to see them in their "still out on the bench" condition.  And reports of the first contacts are always exciting.  I like the MIN-X name.  This is indeed another testament to the contributions made to the radio art by our friend Farhan.   

Hello Bill,

Well I  just finished tweaking my new rig, I named it Min-X because I outright stole bits and piecesof the BITX and the Minima, thanks Ashhar. I made my first contact today and what a contact!

The contact was made with the rig as shown. The amp is a home brew FET push-pull.

I had a chat with Beth MW0VOW in South Wales! From Wisconsin to Wales on 15w PEP.
Oh, most of the rig was 'noodled' and constructed while enjoying you and Pete on the

SolderSmoke podcast.

Best 73,
Keith N6ORS

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  

TIA-Tube Hybrids from Steve N8NM (Part 1)

Last week Steve sent us a picture of his Straight Key Night rig which consisted of a homebrew thermatron transmitter and a TIA BITX as the receiver.  I asked Steve for more info on the TIA BITX. 

Bill:

Shot these right after making the first QSO using the TIA rig as the receiver.  The Arduino and '5351 are still on a breadboard, otherwise, all of the PCB modules except the filters and PA are installed on the chassis. 

The QSO was uneventful, which is a good thing!
73!
Steve

A SolderSmoke Holiday Charity Appeal -- Help Elisa help little Gonzalo!

We are going "off topic" for a moment, for a good cause.  Listeners to the podcast will have heard about my wife Elisa's strong connections to her home country, the Dominican Republic.  The new year finds Elisa trying to help a Dominican cousin who has a very sick little boy.  Details below.  All contributions large or small from the SolderSmoke community would be gratefully received.  Just click on the link to make a contribution.  And please consider forwarding this appeal to friends or relatives who might also be willing to help.

https://www.gofundme.com/porgonzalo

My name is Elisa Meara, and I am raising money for my dear cousin Eliana and  her 18 month old baby boy Gonzalo.

The week before Christmas Eliana and her husband Pedro were happily preparing to celebrate the festivities with their only child Gonzalo. This was Gonzalo's second Christmas and the first one he would be aware of.   Gonzalo wasn't feeling well and his pediatrician recommended that he be admitted to the hospital for a few days.  "Just another childhood virus" I am sure Eliana and Pedro thought.

But the morning of the day before Christmas they learned Gonzalo was very ill.  The diagnosis was leukemia.   While the world around them celebrated, they were living every parent's worst nightmare.  Baby Gonzalo needed emergency medical attention to save his life.

On Christmas Eve, trying to give their son the best chance possible, they left their home and families behind in The Dominican Republic to take him to Jackson Memorial Hospital in Miami for treatment. The morning of Christmas Day he received his first round of chemotherapy. The treatments will continue for the next six to eight months.

Needless to say,  this young and hard-working couple is devastated.  They are trying to do everything they can to help their baby boy.

While they have health insurance, the costs and expenses -especially those associated with living in a foreign city- are growing very quickly. We are hoping to help ease this tremendous heart-ache and suffering with prayers and financial support.

No contribution is too small and every little bit will help.  You can contribute here:

https://www.gofundme.com/porgonzalo

 And please consider forwarding this appeal to friends or relatives who might also be willing to help.