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Saturday, July 8, 2017

Steve N8NM Gets Modular -- With Both Hardware and Software


Steve N8NM has an excellent article on his blog about the benefits of modularity.  He breaks new ground by extending the concept into the software realm.  Check it out:

https://n8nmsteve.blogspot.com/2017/07/sr-16-lets-get-modular.html 

Subscribe to Steve's blog, or link to it.  Hopefully this will encourage him to post more great things like this.

Thursday, July 6, 2017

Another LM373 Rig - Pete Is Not Alone!


Tuesday, July 4, 2017

The Radio Laboratory at Bandung, Java -- SSB in 1927


Anton PA0AST alerted me to this important piece of radio history:

The first phone radio between Indonesia , the city of Bandung ( Dayeuh Kolot, Jalan Radio 1 ),  and Holland , Radio Kootwijk  were made  in SSB already in 1927... Before that time they had only a CW  1 Mega Watt spark transmitter in Malabar.
One of the receivers still exists in a museum in Amsterdam (cdvandt ). It is 3 meters in length and 2 meter in  height....  All made with plug-able units with 1 tube inside .


The transmitter was 10 kW. Ua was 6kV was made by dynamotors. Transmitting Tubes locally made by craftsman in a workshop.  Both  buildings as well  in Bandung and in Kootwijk still exists .


Anton

The old images come from:
http://www.cdvandt.org/bandung-lab-kwk.htm


At the other end was Radio Kootwijk in Holland. 

Before you jump to the English version of the page, be sure to check out the Drone video of the site, and the audio file of the Morse transmissions: 

http://radiokootwijk.nu/     Thanks to PA0JWU for the wonderful site.

Quite an impressive shack!  My favorite part is the note indicating that local residents cleaned out the cooling pool and used it for swimming each summer.

Sunday, July 2, 2017

AC9JQ's Mini Digi VFO/BFO Al Fresco with OLED (and noise test)



From Dean AC9JQ:

Just completed the VFO/BFO/Arduino/OLED module for my radio.  I also have the LPF, BPF and crystal filters completed and tested.  Next will be the audio amplifier and NE602 modules.  I will probably build one of the NE602 modules and test things out as a DC receiver.  My ultimate plan is to have the rig no more that 1"x3.5"x3".  I still have a lot of "stuff" to stuff into that size of box.  I'll keep you posted.


I have been able to contain the entire Arduino/Si5351/OLED into a small cube in the front.  The rest of the radio has to fit on two levels in the rest of the area behind the Arduino/Si5351/OLED.  I think I will build the audio section and on NE602 mixer and run it as a direct conversion first to vet out any noise or other problems.  Bill, that small coax that you pointed out will really help on this build.  I used a small piece as a power feed-thru and will use it to feed out the VFO/BFO signals, thanks again for that pointer.

I decided to test for noise on the TIA transceiver test bed.  See the video of the results.  Not too much noise.  I'm only using my indoor magnetic loop for an antenna.  Video is kind of sloppy, but taking off the antenna and turning up the volume shows how little noise is left in the system.  Now time to stuff the rest of the radio into the tight quarters.

I purchased OLED from ebay.......

They are nice and compact, although as time goes on, I'm sure they will be harder to read.  I'm hoping to have an alfresco version in a week or two.  I used much of Pete's code from the shirt pocket transceiver upgrade, modified the code to address the smaller display and add USB/LSB capabilities. 

73's  Dean AC9JQ

Saturday, July 1, 2017

G7WKE's Crystal Tester

Wow, this is an example of dedication to the cause.  I think many of us wimped out when confronted with the complex circuitry of the test device prescribed by DeMaw, but Rob G7WKE actually built the thing, and did a great job on it.  I'm tempted to suggest that Rob might want to set up a small business leasing this rig out to less dedicated filter builders.  Or perhaps he could have batches of crystals sent to him for DeMaw-ian analysis.

Hi Bill,
 
After listening to you and Pete discussing crystal filter design during SolderSmoke 197, I thought you might be interested in my latest project.

This is the Crystal Tester from January 1990 QST that is reprinted in W1FB's Design Notebook, which I believe is the circuit you and Pete were referring to.

It all appears to function as it should, so the next step is to sit down quietly with a pile of crystals and hopefully start along the road to a working filter!

73s
Rob G7WKE.



 

Thursday, June 29, 2017

Smoke Test Failure!


This is why you need fuses!  And reverse polarity protection!  Yikes! 

The Workshop at AA8V

Field Day was a big success for me this year.  I was in category "1E" which meant that I was home in the air conditioning, but doing my bit for emergency service by using a gel cell as my power source.  A SOLAR CHARGED gel cell.  So don't anyone call me a slacker, OK?

I was on my HW-8 and made a total of two contacts.  The second was with AH6AX.  I wasn't fooled -- I knew they weren't in Hawaii.  But the op gave me his home call:  WB8YYY.  Curt is a SolderSmoke listener.  In a follow-up e-mail he alerted me to the web site of AA8V.   Great stuff.  Thanks Curt.

Here is the AA8V workshop:

http://faculty.frostburg.edu/phys/latta/ee/workshop/workshop.html#electronics1

AA8V was on the QSO Today podcast not long ago. 

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