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Sunday, June 9, 2019

First Use of Farhan's Antuino Scalar Network Analyzer


I was learning my way around Farhan's new Antuino this morning.  Very cool.  I decided to start with the Scalar Network Analyzer.   I've spent so much time measuring and plotting filter response curves BY HAND... the Antuino is an opportunity for me to move into the 21st Century.  

In the picture you see the results.  I was using a Heathkit SSB filter with the center frequency at 3.395 Mhz.   The Antuino was set for that freq, with the screen range set at +/- 10.  That means each division on the screen is 1 khz (right?).  The Heath filter is advertised as being 2.1 khz wide at 6 db down.  That pretty much matches what we see here.  

You can see ripple in the filter passband.  This is almost certainly the result of an impedance missmatch.   It looks to me like the Antuino is set up with 50 ohm inputs and outputs.   The Heath filter probably needs higher impedances to have a smooth passband.   I will try later to set it up for a smooth passband. 

It is easy to see how useful this device will be.  Thanks Farhan! 

More on the Antuino here: 


Tuesday, June 4, 2019

Ham Radio in Germany 1955 (video)



Don't be deterred by the lack of English subtitles -- radio amateurs around the world will be able to follow what is going on in this very interesting 1955 film.  It is only about 14 minutes long. 

This video takes us back to a time when hams were hams and rigs were RIGS!

Note the German OM who apparently slept fully dressed (with necktie) in order to be ready to spring into action on the ham bands in the middle of the night.  That's dedication my friends. 

Also note the fellow sending out QSL cards that feature the schematic diagram of his rig.  Lots of solder melted in 1955.  Great stuff. 

Thank God for the Heaviside Schicht!    

Monday, June 3, 2019

FDIM Interview with Farhan VU2ESE

I didn't realize that our correspondent in Dayton/Xenia had interviewed Farhan.  There was a typo in the audio file name and I was wondering who this UV2ESE guy was.  A Ukrainian QRPer?   I was really pleased to find out that it was Farhan.  

In Bob's interview you will hear Farhan discuss the capabilities of his new Antuino (pictured above).  Pete's Antuino is in the mail, going transcontinental.  It should arrive in the Newbury Park Laboratory later this week.  

As for the spectrum analyzer that Farhan got me last year, I am waiting for retirement (soon!) to get that one going.  But there is a danger that the Antuino will leave little room for the older tech... 

In the interview you will hear Farhan talk about the Antuino circuitry, and about the roots of the three main devices in the Antuino box.  Very cool.  

Thanks again Farhan. And thanks Bob. 

Here is the interview:

http://soldersmoke.com/VU2ESE FDIM 2019.m4a


Farhan's Antuino page: 

http://www.hfsignals.com/index.php/antuino/

Sunday, June 2, 2019

FDIM Interview -- NM0S on John Reinartz W1QP K6BJ -- Scandal on an Arctic Expedition?

John Reinartz, 1QP, at the operating position of WNP aboard the Bowdoin

Bob Crane W8SX interviewed Dave Cripe NM0S about his FDIM presenation on radio pioneer John Reinartz 1QP and later K6BJ. Listen to the interview here: 

http://soldersmoke.com/NM0S FDIM 2019.m4a

Here is Reinartz's obit in the New York Times: 

https://www.nytimes.com/1964/10/07/john-l-reinartz-pioneer-in-radio.html

Here is some background info on Reinartz: 

http://k6bj.org/Club_History/WhoWasK6BJ.htm

Dave Cripe's interview left me wondering what the north pole scandal was all about.   I found this passage from a book that seems to partially explain what happened.  Can anyone else shed more light on this unfortunate event?  


Saturday, June 1, 2019

Antuino: Farhan's Compact RF Lab In-a-Box


I now have Farhan's latest invention, the Antuino.  Pete will have his shortly.  Very cool.  SWR meter and antenna analyzer, power meter and scalar network analyzer all in one box. I put an old-school knob on the rotary encoder -- it seemed like the right thing to do.  Soon I will be able to find out if my rigs have spurs or are somehow non-compliant.   I'm sure Farhan's "RF Lab in a box" will be an important addition to my test gear arsenal. We will be talking about this in upcoming podcast episodes. 

Mike N2HTT did a nice write up of the new device: 

https://n2htt.radio/2019/05/26/hello-antuino/

And here is the info from the htsigs.com page: 

http://www.hfsignals.com/index.php/antuino/

Thanks Farhan! 

Friday, May 31, 2019

KG7SSB -- Homebrew SSB in Tuscon -- Learning from the BITX40 Module

On Sun, May 26, 2019 at 1:45 PM William R Meara wrote:

Dale: 
  I was talking to Jim W9UD on 20 SSB today.  When I told him I was running a homebrew transceiver he mentioned that he talked to another guy who is on the air with homebrew SSB gear -- you! 
There are so few of us Dale.  I felt compelled to send you an e-mail.  
What are you running?  
After several years on DSB, I started building separate SSB receivers and transmitters, mostly for 17.  Lately I am running versions of the Indian BITX transceiver. 
Please send info on your homebrew SSB projects. 
Thanks,  
Bill N2CQR

Hi Bill, 

I have two radios that are completed to date. I started out building the BITX 40 transceiver from scratch and also a companion 60 watt solid state linear rf amplifier. Then I decided to construct the second transceiver for 20 meter using some of the BITX design concepts and mixed with the UBITX design for additional rf amplification. It too is amplified to about 25 watts output. The 20 meter rig is my favorite radio at this time but I am going to go a different direction on my next build. It's presently just in the design stage but I'm thinking about using the MC1350 integrated circuits for the IF amplification and for the front end I may try using a FET rf amplifier. The beauty of the bitx design is the use of wide band amplifiers that don't have a tendency to oscillate. But, the new design I'm working on will have more shielding between critical circuits and I will use a small amount of negative feedback in the high gain circuits. The reason for changing the radio to a higher impedance design is to simplify the design build. I will basically build a receiver that I can reverse the signal direction over to transmit using the same amplifiers and filters. This will cut in half the amount of circuit building however it will increase the switching circuit complication associated with this new design. 

Today I'm beginning the build of a 100 watt rf linear amplifier design using the kit parts from China (minipa 70) amps. This provides the transformer components and circuit boards. I purchased two kits of parts and I have a large heatsink to build it on. I'm working on a current sensing circuit for protecting the final FETS.  It  will run 4 IRF530's tied together with a splitter and combiner for the input and output matching transformers. It should produce at least 100 watts at 75/80 meters and maybe a little less on 40 meters but 20 meters it will drop off to about 60 or so watts. 

I'm just having as much fun as a guy can have playing around with the homebrew radio's and like you say there's not many doing it these days. I love operating a radio that I built vs. running a factory made radio. I have two commercial rigs on my bench and a couple of Collins radios but the homebrew takes the lead. 

Jim W9UD has become one of my ham friends this year. We end up talking every week or so on the air and keeping touch with local weather conditions.
Side Note:
I wanted to build a SSB radio since I was a young lad with a technician license in the early 60's. SSB came into the picture many years after I was first licensed.  Then move forward to 2015 my ham license had long ago expired during my time in the Vietnam war. I spent several weeks studying the tech, general and finally the extra class exam information and passed on through that adventure. So I decided it's time to build my own radio from scratch. So I started to look online and in books and I still didn't have the confidence to begin building. Then I ran across Farhams BITX 40 and I thought why not buy this radio and just use it as a model of how sideband circuits work. So I did just that and I got it working fine I took the radio and placed it on the test bench and began circuit analysis and signal level evaluation until it all made perfect sense. This is accomplished while transmitting so the levels can be seen on the oscilloscope. Just kill the voltage on the final stage of the bitx. I put a 1khz signal on the mic input. That was just about the only thing I used the bitx 40 rig for and I still keep it handy when I need information. 

Good hearing from you I hope I haven't over done this reply but I really enjoy talking about this subject.
73's Bill.... keep up the building and good luck on your next radio. 

Dale KG7SSB

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And of course, Pete N6QW knows Dale and has been talking about SSB with him for some time... 
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column