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Sunday, February 24, 2019

An Update on Jac's Homebrew Receiver

About four years ago we posted a report on the FB homebrew receiver of Jac KA1WI     Here is the original report:

As most of us do, Jac has continued to work on his creation.  He sent me an update:


Basically I have finished it, from a tentatively working model to a more definitive set. For example there are three IF filters, LSB, USB and CW switched by relays grounding the un-used filters.  The AGC was optimized for a good sound. So was the multistage audio circuit, avoiding unnecessary filtering which in my opinion masks the sound of some very good sounding transmissions, not to mention the terrible ones.

The front end works very well, with a SBL-1 DBM terminated with a low noise 2N5109. You notice it when a strong signal is nearly covering the weaker one you are listening to and it remains readable without loosing strength! No many receivers can do that, either because poor front end, noisy LO or bad AGC or all of the three. Not with this receiver!  

The BP filter bank is not my design but removed from a German receiver from the early 1970’s I had to align it to specs and it works pretty well, although I would have preferred  to use a tunable pre-selector. I am planning another set with three IF 9mHz filters which will include a pre-selector for optimum image rejection. I hope. 

In general I am happy with the set, despite the birdies of the DDS, most of them well under the level of most received signals. I wsh I could build a simple PLL to clean up the DSS LO signal. It is worth exploring issue as I see new VCO designs are available. I could try at least one ham band for starters, a PLL covering 350 kHz locked to the DDS,  instead of 2-30 mHz covering, should be feasible. 

Have more videos of the set I will send to you. 

73s de Sac


Note how well you can hear the band's noise floor when the antenna is reconnected in the third video.  

Saturday, February 23, 2019

The Shortwave Radio Audio Archive

Dig out those old tapes and make a contribution to the archive. Lots of good stuff in there.  The Sandinista recording from 1979 was quite something.  Radio Moscow's Mailbag brought back Cold War memories.    Check it out: 


Thursday, February 21, 2019

Wednesday, February 20, 2019

Shortwave Radiogram

On 18 Feb 2019 I talked to Kim KD9XB on 40 meter SSB.  Kim -- who is retired from the Voice of America -- told me about a really interesting retirement broadcast project of his. "Shortwave Radiogram" uses a variety of amateur digital modes to transmit what are essentially text and image bulletins.  The really cool part is that Kim uses commercial shortwave broadcast transmitters to get his programs out. He uses transmitters in the U.S. and in Europe.   Listeners around the world tune in via shortwave (sometimes through WEB-SDR receivers) and then use FLDIGI or similar software to read the messages. You can see one of the radiograms being received in the video above.  There are more like it on YouTube.

Kim's site has more information, including his broadcast schedule on his web site:

All of this reminded me of our old idea about putting the SolderSmoke podcast on a commercial shortwave transmitter.  I have my eye on the Bulgarian station... Stay tuned.  

Thanks Kim! 

Monday, February 18, 2019

RE-RUNS OF VINTAGE SIDEBAND NET -- To fill those lonely hours between SolderSmoke podcasts...

I really enjoy listening to these guys, and I suspect SolderSmoke listeners will too.  Like the SolderSmoke podcast, it is the perfect thing to have playing in the shack while you are working on something.  

Mike N9MS has recorded and placed online many of the net's sessions, some going back to 2015.  FB OM.  We thank you.  Please keep doing this.  

Back issues are available at the site below.  Just put the letter V in the search box and click.  The back issues will then appear. 

My message to the group: 


I have now listened to the mp3 recordings of three of your Saturday morning sessions.  They are really great.  I tried to listen via the airwaves, but I am too far east.  To whoever is recording and posting these sessions:  please keep up the good work!  These recordings allow the FB ham spirit of the net to reach a GLOBAL audience. Please make the older sessions available -- many of us only recently learned of the net and would like to listen to earlier episodes. If server space is a problem, maybe I could help.  Let me know. I don't know if you realize it, but you guys are producing a very cool podcast every Saturday morning.  

My buddy Steve N8NM tried to check in with his S line last weekend but you guys couldn't hear him.  I'm sure he will try to somehow get more fire in the wire.  Please be listening for Steve. 

As for myself, I find myself plotting the use of one of those WEB-SDR sites to check-in.  But I fear the wrath of the brotherhood.  

73  Bill N2CQR  

Sunday, February 17, 2019

SSTV from SPAAAAACE! International Space Station Sends Images

The crew on the space station have been transmitting SSTV images.   This morning I threw together a receiving system:  I used my four element refrigerator tubing quad feeding the an RTL-SDR Dongle with HD-SDR software in the computer.  For the SSTV decoding I downloaded a program from Japan: MMSSTV (very nice).  To get the signal from HD-SDRto MMSSTV I just plugged a cheap little electret computer mic into the computer and taped it to the speaker.  

At 0838 local today ISS flew almost directly over me.   I aimed the quad south-west, and almost as soon as it was above the horizon very strong signals started pouring in.  They produced the first picture (above).  

ISS went silent as it passed over head. I swung the quad to the north-east hoping to catch another image as the station moved away.  That is the second image (below). You can see that I was losing the signal about halfway through.  

The distortion in the video image may be the result of me manually adjusting the receiver for Doppler shift. 

Here is a little video of the action in the shack during the first half of the pass. 

Here is the RTL-SDR Dongle Receiver in an Altoids Box: 

Here is that the programs looked like on the screen -- HDSDR on top, MMSS on the bottom:  

Here is what the orbital pass looked like. ISS was East of New Zealand when I took this picture.  ISS came up over the Eastern Pacific and Mexico before passing over N2CQR.  This display comes from the excellent Heavens Above web site:  

Tuesday, February 12, 2019

Listen to our Podcast while wearing a beret!

This is the official headgear of the Color-Burst Liberation Army. 

For a mere 16 dollars, you can wear the kind of beret worn by Pete Juliano, N6QW. 

Here at SolderSmoke, we are all about style, panache, savoirfair,  je ne se qua... 

If you send us a picture of yourself wearing a beret while either operating or building a rig,  you will win FOR FREE a one year subscription to the SolderSmoke on-line podcast.  ACT NOW!  Please tell them that SolderSmoke sent you. 

Saturday, February 9, 2019

Thursday, February 7, 2019

Indie Documentary: Apollo 11

Thanks to Bob Scott for the alert on this.  This new Indie film promises to be even better than the recent "First Man" movie (which was somewhat disappointing, with too much focus on family drama).   Armstrong looks so young in this trailer. 

Sunday, February 3, 2019

The Wizard of Wimbledon M0JGH: "Always Listen to Pete!"

Dear Bill and Pete,

Sincere apologies for my chronic lack of correspondence but life has proven exceedingly eventful of late. As a long-standing member of our international brotherhood I am aware of a reoccurring, often subliminal, theme: “Always listen to Pete!”. What follows is a cautionary tale of one humble ham following the sage advice offered to him during Soldersmoke 186’s Mailbag…

You might recall the report of my Christmas 2015 escapades from rural Italy, making homebrew CW contact with friends operating GB2RN aboard HMS Belfast, whilst trying to fend-off curious locals from tampering with the wire I’d strung through their trees. Throughout these shenanigans my remarkably-understanding girlfriend was nearby minding her own business (albeit with a certain degree of eye-rolling).

The following year we returned to the same summit above Frascati. Before setting off I advised her that, being a generous chap, there were now two miniature radios in my coat pocket: one for each of us to enjoy. She was politely thrilled by the prospect... but still faithfully assisted with antenna rigging. 

Once operational I insisted that we should try her radio first and, following Pete’s advice from SS186, I slipped the tiny red box out of my jacket pocket and knelt down on one knee... (Fear not, Pete, other sage opinions were consulted in the matter first too!).

Remarkably, she said yes! And, exceedingly generously, I was allowed me to make a few contacts too... after all, we had gone to the trouble of lugging it from London and setting up the antenna. Owing to poor telephone reception the first person to learn of our wonderful news was an unsuspecting DL on 40m CW.

We are now happily married so I’m pleased to report that, unsurprisingly, the SolderSmoke tribal knowledge offered to me back in 2016 appears to have been spot on. To return the favour here is my own life lesson to take from the story:

Should one ever need to conceal a surprise gift from a loved one, a radio shack is a cavernous world which even the most curious spouse is unlikely to dare explore.

Furthermore, if one “has previous” (as British policemen say) for smuggling tiny boxes of radio wizardry away on holiday, what better cover could there be for the unsuspected transportation of an engagement ring? 

The power of QRP knows no bounds...

All the very best for 2019 and thanks again for the life-changing advice.


Editor's note:   In case you don't remember SS186, Pete's advice -- upon hearing of the ham radio tolerance of Jonathan's then-girlfriend -- strongly advised him to "marry that woman!" 

Saturday, February 2, 2019

Friday, February 1, 2019

UK Wartime Radio -- The Secret Listeners

We had this video on the blog before, but it was seven years ago, so it it time for a re-run.  


Thanks to Graham GW8RAK for reminding us of this. 

Listening to it again, I was struck by the claim that the nationality of the operator could be discerned purely by his or her CW sending style.  Is there really an Italian accent in Morse Code? 

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