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Friday, January 4, 2019

Jan's Slovakian Si5351 VFO




Jan in Slovakia put together a very comprehensive web page on his Si5351 VFO project.  Check it out: 

https://janoc.rd-h.com/archives/649

Thanks Jans! 

Thursday, January 3, 2019

Please Listen for Dave AA7EE's New "Boris Beacon"




https://aa7ee.wordpress.com/2019/01/03/putting-the-hifer-brs-boris-beacon-on-the-air-finally/

From Dave's blog: 

The beacon sends the letters “BRS” at 10wpm, with a break of 3 or 4 seconds between the end of one transmission and the beginning of the next, with a mighty power to the dipole of about 1mW. The frequency is a nominal 13556.9KHz (13.5569MHz), which varies either way by a few tens of Hz, depending on the outside ambient temperature. I will be overjoyed if anyone, anywhere hears it! There is no battery, so it transmits during daylight hours only. It comes on about half an hour after local sunrise, and goes off about half an hour before local sunset. I’ll update this with more accurate information, as I observe the on and off times over the next few days.
---------------
AA7EE is in Oakland California.  His cat is named SPRAT.  Please send him a report (and if possible a recording) if you hear his beacon. 



New Rock Video By Astrophysicist and Queen lead-guitarist Dr. Brian May


We don't carry many music videos on this blog, but this one definitely belongs here.  We've mentioned Brian May several times:  Lead guitarist in the rock group Queen.  PhD Astrophysicist. 

I didn't know that he went to work as a full member of the New Horizons (Pluto and beyond) mission.  

The video is definitely for us -- it features a lot of antennas.   And it includes the computer-generated voice of Stephen Hawkings.  

Read more about Brian's careers and about his latest adventure here: 

https://www.space.com/42875-brian-may-new-horizons-song-ultima-thule-flyby.html

New Horizons principal investigator Alan Stern poses with astrophysicist and Queen lead guitarist Brian May on Dec. 31, 2018 at Johns Hopkins' Applied Physics Laboratory in Maryland just before New Horizons flew by Ultima Thule.
New Horizons principal investigator Alan Stern poses with astrophysicist and Queen lead guitarist Brian May on Dec. 31, 2018 at Johns Hopkins' Applied Physics Laboratory in Maryland just before New Horizons flew by Ultima Thule.
Credit: NASA/Bill Ingalls

Tuesday, January 1, 2019

HNY (Happy New Year), SKN (Straight Key Night) 2019, and an HT-37 with "presence" -- even on CW


I got the HT-37 working just a few days before the New Year's Eve/New Year's Day Straight Key Night event.  Looking at my older blog posts, I now see that the problems first surfaced in LAST YEAR's SKN.  Wow, it took me a long time to get to that problem. But I'm glad I fixed it in time for SKN.  

For SKN I used the VU3XVR straight key from India that Farhan gave to me.   See the picture above.  

I started out on 80 meters on New Year's eve.  I rarely operate on that band -- I thought it would be a good change of pace. Here is who I contacted on 80 CW: 

In the warm-up period before the official start of SKN I worked John KU4AF.  John was running a homebrew tube transmitter and a REGEN receiver.  Respect, my friends.  RESPECT! 

N9EP Ed near Chicago was on a K3. 

VE9XX Don was on a KX3. 

NJ8D Tom in Ohio. 

K4IA, Buck, down the road in Fredricksburg Va.  Buck was running a Drake TR4C with a Begali key.  FB Buck.  He mentioned that he had had a Drake 2B -- he said he regrets selling it.  Indeed. 

VE9WW Bill in Moncton NB.  On a straight key. 

AA8MI Gene (gosh, that name really sings in CW -- try it!) in Ohio.  Gene was running 5 watts from a K3.  This added a needed QRP element to the festivities.  Thanks Gene. 

AI4SV Jack in Rockville Md. OH MY GOD!   NOW I REALIZE WHO THIS WAS!  Jack!  Jack of Antanarivo Madagsascar!  And now I understand what he said to me.  He said in CW that my HT-37 has "Lots of presence." Huh?  What?  I couldn't figure out what he was talking about, but now I realize that he was joking about all our discussions mocking the poor audiophiles.  Well, thanks Jack. I'm glad the rig has presence, EVEN ON CW!  THIS QSO GETS MY VOTE FOR BEST SKN QSO. 

I also listened for a while to W3GMS.  His signal had a lot of character and personality.  He was telling the other fellow that he suspected this was the result of a soft voltage regulator tube in his DX-60.  I think he was also using a Drake 2-B.  I didn't get a chance to talk to Howard, but I'm sure it would have been fun. 

 On New Year's morning I switched bands.  First to 40 where I worked Greg NM2L near Atlanta. He said he fingers and wrist were out of condition, but I told him his fist was FB. 

Then I went to 20 CW where I worked a bit of DX.  First David F8CRS then Bert F6HKA.  The contact with Bert reminded me of the charms of DX contacts using CW. "VY GM DR OM."  It was nice.  

N7AQQ Mike in Montana.  

So it was a good SKN for me. Working the French stations reminded me of the allure of listening to CW coming in from far away, and from a foreign culture.   And it was great to hear from AI4SV that my HT-37 has "presence" even on CW. 

73 and HNY to all. 

Sunday, December 30, 2018

HT-37 Choke Failure -- Why did this happen? What is your diagnosis?


Look, it has been 60 years, so I'm not looking for my money back or anything, but having just repaired the LV power supply choke on my very venerable Hallicrafters HT-37, I started thinking about how and why it failed. 

Clues: 

-- I found it with four of the windings broken, with the eight broken leads kind of sticking out of the winding wrap. 

-- The four broken leads were on the outside of the winding (thank God!) an were at the part of the winding closest to the chassis and the back of the cabinet.  (See picture below.) 

-- There was evidence of burning on at least two of the leads. 

-- The choke is located in the extreme back corner of the chassis, near the back of the cabinet. 

-- The paper and cellophane wrapping around the windings was a bit deteriorated.  

So,  what is your diagnosis?   What happened to cause the choke to go open? 


Saturday, December 29, 2018

KC1FSZ's Peppermint III Homebrew BITX with Mods


Hi Guys:

I had some time over the holiday to finish off my second scratch-built rig.  I am very thankful that I got the work done on these projects before I read Pete's "Don't Build It" diatribe.  That would have been very demoralizing. :-)

Scratch build #2 (called Peppermint III) is still fundamentally BITX although I've made changes this time around.   I've switched to ADE-1 mixers with LO ports driven by adjustable gain buffers (ala N6QW LBS).  I've noticed that performance can be improved a lot if you can buffer/tweak the LO levels of the VFO and BFO (particularly carrier suppression on TX).  I did W7ZOI TIAs in the IF chain.  I've also taken the shielding/layout of the finals more seriously and have been able to dial up the power a lot (I did the KB1GMX thing with cutting off the drain pin on the IRF510 and using the tab).  The software is also greatly improved and now supports LSB/USB modes as well as software-driven PTT control for RTTY/FT8 and the hooks for my poor man's panadaptor.  I've been working lots of stations on QRO.

Total build time was about three months (half the time of #1) and the layout came out much smaller than before.  I made a trip over to Williams/Sonoma after Christmas and picked up the 2018 edition of the Peppermint Bark candy tin on discount and I think I can make it all fit.  More to follow ...

Happy New Year and 73s,

Bruce KC1FSZ




Friday, December 28, 2018

HT-37 FIXED -- Thanks for all the support

Don't worry-- I covered it with tape
This week I found myself with some unexpected free-time, courtesy of the government shutdown.   And of course, my thoughts turned to the HT-37.  I started thinking about the open choke in the power supply.  Four wires were sticking out of one side, four sticking out of the other.   Figuring out which went to which would have driven me nuts.   But it occurred to me that I could just wrap the four one on both sides together, and then just connect them with a piece of wire (see above).  I'd end up sacrificing three windings, but that shouldn't matter.  

It worked.   My AADE L/C meter won't measure up into the full Henry range, but  the choke was no longer open and the resistance looked right (about 230 ohms). 

I put it into the HT-37.   It works.  I had a long rag chew with AE2EE --  a guy who really knows his boatanchors.  He said it sounded great.  This contact was like icing on the cake.  TRGHS.  

Thanks to everyone who wrote in with offers of parts or suggestions on how to acquire a suitable replacement.  

Special thanks to Steve Murphy, N8NM who removed the LV choke from a junker HT-37and mailed it to me JUST AS I WAS LEARNING THAT THIS REPAIR WOULD WORK.  I feel bad about putting Steve to the trouble. I blame the shut-down.  Idle hands are the devil's workshop. And that broken HT-37 was bothering me. 

This was a very satisfying repair.  It was great fun to put the old rig back on the air.  And I did it without injuring myself.  Straight Key Night is right around the corner. 

Terminal strip for newer caps.  Repaired choke went to the two ends of the strip. 


Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column