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Wednesday, December 26, 2018

Ghost Ship: Oscar 11 Tumbles Through Space



First -- Happy Boxing Day to all our UK and Commonwealth friends. 

Oscar 11 is a UK-built amateur satellite launched in 1984.   It has been dead (well, almost dead) for many years.   But when the sun shines on the solar panels, it wakes up and transmits.   I've been able to hear it and -- more usefully -- see it on my RTL-SDR  HD-SDR receive system.  My antenna is my re-born (from the Dominican Republic) three element homebrew 2 meter cubical quad (see pictures below). 

I'm sorry the video is a bit out of focus, but you can clearly see the trace of the signal from the satellite. Realize that my HD-SDR software is about 10 kHz off calibration.  You can see the Doppler shift, and you can see the signal fading in and out as the old satellite tumbles through space.  Any ideas on what the other signals seen off to the side are?  Is anyone else listening for Oscar 11?  

https://amsat-uk.org/satellites/telemetry/uosat-2-oscar-11/

https://en.wikipedia.org/wiki/UoSAT-2

http://www.dk3wn.info/p/?cat=47


UOSAT_OSCAR-11



Tuesday, December 18, 2018

All I want for Christmas is... an HT-37 L25 Choke-- 9 Henries at 135 ma


Following my own advice to prepare for Straight Key Night, I tried to fire up my venerable Hallicrafters HT-37 transmitter. It didn't work.  I quickly determined that none of the oscillators were working, so my troubleshooting focused on the power supply.  Sure enough, the choke in the low voltage power supply is open.  That's bad.  

I briefly considered giving up on this old rig.  I don't really like working with tubes anymore.  And this thing is very heavy -- a real beast.  DX-100-like in its heaviness.  It can be hazardous to your health just moving this thing around.  Opening up the case is not easy. And there are nasty voltages in there....  

But I  have had this transmitter since 1973 or 1974.  I have fixed it many times, in several countries.  I got it from a member of the Crystal Radio Club when I was a kid.   There are parts given to me by Pericles, HI8P in the Dominican Republic. I used it to transmit through Russian satellites.   That transmitter is like an old friend.  I just can't give up on it. 

So I need to replace or repair the choke.  Is there anyone out there who has a junker out in the garage or some other source of L25?   Or does anyone know of a business that could rewind the choke.  Please let me know.  I have decided to leave the rig on the bench until I get this thing fixed (it is too heavy to move multiple times!)   

It it Hallicrafters Part Number 056-300259. L25 -- 9 Henries at 135 ma.  Help! 

Saturday, December 15, 2018

SolderSmoke Podcast #208


SolderSmoke Podcast #208 is available: 

http://soldersmoke.com/soldersmoke208.mp3

15 December 2018

Pete and the California fires
Bill goes to Brooklyn
2 meter simplex
A return of the trivial electric motor
Audio from Mars
HF Conditions -- a real mixed bag

Pete looks back at 2018 -- The Year of the SSB Transceiver -- Lessons Learned

Hans Summers, the QSX and the virtues of SDR
W7ZOI's DC Receiver Retrospective
The 1972 Solar Flare and the Vietnam War

SHAMELESS COMMERCE:  Buy your gifts through the Amazon link to the upper right. 
Consider SolderSmoke the book as a gift.  Visit Pasta Pete's for cooking ideas. 

Don't Build It!   Sage -- but unexpected -- advice from Pete. 

Straight Key Night approaches. 

Book Reviews:  
--"What is Real?"  (Quantum Physics)
-- RHdb by K6LHA.

Movies
"Bohemian Rhapsody" 
"First Man" (Not yet!)

MAILBAG: 
Steve G0FUW
Ed KC8SBV 






Free Book! RHdb -- The Radio Hobbyist's Designbook by K6LHA

http://hanssummers.com/k6lha-design-book.html

Friday, December 14, 2018

Another AMAZING Homebrew Vacuum Tube (Valve)



I feel a moral obligation to put these projects on the blog every time I see one.  It just seems like the right thing to do.  Great work on the Pilotron.   Great workshop video also.  
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column