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Sunday, June 25, 2017

Mod to Correct DESIGN ERROR in Heath HW-8

130k resistor inside heat shrink, across R-24
SPRAT 161 (Winter 2014/15) had a very intriguing article about the Heath HW-8 by Dave M0CEM.  Dave wrote about a possible design error in the active filter of the receiver.  The center frequency and gain shift significantly when you switch from "Wide" to "Narrow."   I was very interested because for many years I have noticed this problem in my own HW-8.  I just left it in "Wide" and never used the more narrow filter.  
Dave did some excellent circuit detective work and determined that the problem was R24.  He prescribed a change:  instead of 82k it should be 49.8k.  The placement of a 130k resistor across the 81k R24 would have the same effect.

Yesterday morning I installed Dave's mod.  I did as he suggested and put a 130k resistor across R24.  Brilliant!   What a difference!  In the past, I noticed a significant degradation in signal strength when I put the filter in the "Narrow"  position.  This doesn't happen now -- the response obviously does narrow, but the center freq stays the same.

It is really amazing to me that the Heath engineers made this error, and that it went uncorrected for so many years.  There have been many, many modification articles for the HW-8 over the years, but I haven't seen any that really address this problem. 

If anyone has more info on how this design error happened and why it went uncorrected for so long, please let me know.

Thanks to Dave and SPRAT for getting us back on the straight and narrow. 

Saturday, June 24, 2017

Straight Key QRP Homebrew Adventures -- TRGHS

Last Saturday I put the Tuna Tin Two Top together with my Herring Aid Five 38 (year) Special and the Indian key that Farhan gave me.   I discovered that some of my 40 meter CW FT243 crystals had disappeared into the entropy of the shack.  But I was able to find one for 7050 kHz. That was a bit of good luck because it turns out that 7050 is the frequency of a congenial group of operators known as the Straight Key Century Club.  I felt right at home.  I have been inducted.  My SKCC number is 17272.  Very QRP, don't you think?   It is almost a Vanity SKCC.  Clearly, TRGHS.

I have been having excellent luck with this 7 transistor rig.  I have had one contact each day since I put it on the air, all of them in response to my CQ calls.  I've worked:

K1PUG Hank in Connecticut (twice)
W8HOG  Jerry in Ohio
WA4GQG Kevin in North Carolina
WA2AAW Frank in New York
KM4FO Dwight in Kentucky

This morning I added a little piezo buzzer for sidetone.  I am thinking of adding a VFO to the Tuna Tin.

Friday, June 23, 2017

The Possible Inspirations behind "Juliano Blue"

Close in color don't you think?  Dave Ishmael WA6VVL noted the NC-270 receiver's color was "Cosmic Blue."  Indeed, National noted the unusual color ("outstandingly different") in its advertising.  This now-rare receiver was produced between 1960 and 1964, so it could have influenced Pete.  Of course, the CK-722's color could also have played a role...   

BTW, shouldn't we ask Pete to get out his guitar and give us some "Juliano Blues"?  We need some music to go with the paint.

Thursday, June 22, 2017

More "Canned Seafood" Homebrew CW, from KA4IBG


My xYL hates sardines, but they look good together !

In the late 70's the community had a fetish for canned seafood and DC receivers. Do you remember the 80m Sardine Sender ? How about YL Special ? (QST Oct and Jan 1979.) I married them together in a kludged-together box made out of a bent rack-mount panel and defunct aluminum chassis cover.

The bottom board is the rock-bound transmitter. The upper deck is the receiver board. The little mini box contains VFO (so cute.) The 741 audio board is tucked under the scrounged ¼ inch jacks.

Super simple, but lots of fun. It's a handy rig for the week at the beach, although 80m propagation and beach week are 6 months out of phase.

Ed Hlywa

Wednesday, June 21, 2017

Solstice Special: Midwinter BBC Messages to Antarctica

Thanks to SWL Post for alerting us to this wonderful annual event.  BBC SW stations send a special program to the UK crews at the Antarctic bases.   SWL Posts asks for listeners to record this year's program:

Here is an excellent recording of the 2015 show.

And here is a recording of the 2017 broadcast:

Sunday, June 18, 2017

A Fishy Rig: Herring Aid Five, Tuna Tin Two, VU2XVR Key

Haunted by a fear of rapid expulsion from the QRP Hall of Fame, I decided that I should immediately do something to establish some form of QRP street cred.  Looking around the shack, I realized that all of the ingredients were there:  My Herring Aid Five Direct Conversion receiver (completed after only 38 years), my Tuna Tin Two transmitter, the VU2XVR key that Farhan gave me, one 7050 kc  FT243 crystal.   I put it all on a piece of scrap plywood. A couple of nice connectors from W8NSA supported the DPDT T/R switch and the coax connector. I keep the receiver LO running all the time.

Now, let's be clear: running 250 milliwatts, rock bound with a Direct Conversion receiver that tunes both sides of zero beat is not for the faint of heart.  The log book does not fill up rapidly. But hey, I made one contact the following morning.  K1PUG said I was 559 in Connecticut.      

Saturday, June 17, 2017

SolderSmoke Podcast #197: Farhan, Fame, 'Fest, Testgear, SSB History, Dishal Dystopia, QRP CW, MAILBAG

SolderSmoke Podcast #197 is available:

Up in NYC, met Dave W2DAB. got Steve Silverman's HP 8640B Sig Gen.

Farhan's visit to SolderSmoke HQ
Got me a TEK1401A Spectrum analyzer
Farhan at "Geekfest" @W7ZOI

BITX40 Modules.  5,000 already.   1,000 a month.
The BITX pronunciation problem. 

QRP Hall of Fame.  I suspected April 1 reprisal!    "I am unworthy" 
Dusting off my Tuna Tin 2, Herring Aid 5 and Farhan's key from India.

The Manassas Hamfest:  OLD crystal gear.   20's and 30's stuff. Leon Lambert RX and Philmore Fixed Crystal Detector. 
 Reminder of how YOUNG the radio art is.
RELATED:  Bell System 1953 Transistor Documentary.  11 year old Pete and his CK722.
Bought some good stuff from Charles AI4OT.

Armand WA1UQO gave me a big collection of Electric Radio.  So much history and HB wisdom in there. Frank Jones and Lafayette Radio.  Jim Lamb and 1930s SSB.  

Is the CK-722 the source of Pete Juliano's affinity for Juliano Blue?
Was Wes Hayward already using Juliano Blue?

"Your rig sounds real good for a homebrew rig!" 
"Well, your rig sounds pretty good for a Yaesu!"
Related topic: Going over the Waterfall:  The SDR Superiority Syndrome.  Feathering.

ARRL Arduino Book   by Popiel.    Very nice.  Right level.  Lots of good info.


Pete's Dishal Dystopia --  Is the perfect TRULY the enemy of the good enough?

Bill's  NE602 RIG: 
Replaced OLED.  Blue one seems noisier.  Shielded it with  copper flashing.
Made me yearn for bigger boxes WITH A HOOD!


Special Thanks to our correspondent in the Dayton Xenia Metropolitan area -- Bob Crane W8SX.

Jack Welch, AI4SV 5R8SV -- Our Man in Antanarivo -- Sent me a GREAT BOOK "I, Libertine" by Frederick R. Ewing.   EXCELSIOR!

Bruce KC1FSZ  Building Scratchbuilt BITX.  On the way put the VFO where the BFO should go and had a DC RX.  FB

Greg, VK1VXG   Suggestion for WA8WDQ on Arduino serial plotter

Ben KC9DLM  Mercury PTO.  In a syringe!   No thanks! Maybe add some high voltage and selenium.  And a radium dial!  Yea!

KY3R's metalized cigar boxes!  FB On Blog.

Richard WB2PEF has revived his Doug DeMaw 8P6 rig.  FB.  But bothered by PTT thump.

Update on Dave AA7EE (from Mike KC6SAX)


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