Podcasting since 2005! Listen to Latest SolderSmoke

Showing posts with label UAE. Show all posts
Showing posts with label UAE. Show all posts

Tuesday, March 21, 2017

FB IBEW HB DC CW de UAE: A65DC's International Homebrew Rig


Good evening!

After my JOO moment, Bill put me in contact with Pete Eaton, who suggested that I would have a look at the schematics for K4GC 40m CW Transceiver.
And I did, It was just perfect for me, low part count, lots of things done in software!!! Perfect Bryan!


I started off the build and both Bryan and Pete supported me along the way, thank you! 

So here we have it:

The design slowly deviated further and further from the original, but I think I learned quite a lot by starting to make it “my own”.

The Arduino was changed to an UNO, yeah they are clunky and big, but I was not shooting for a pocket-size anyway… and they do have a proper USB port.
The RF-path is now switched by a relay straight after the filter, when the relay is relaxed the antenna is connected to the mixer, when I touch a paddle it connects to the TX circuit.
I have a short hang time from the last key input and it goes back to RX, VOX Delay I guess.

I completed the 700Hz bandpass filter, boy! this makes it a much nicer rig to work CW, I originally I skipped this filter for no good reason? That is the board standing up in the picture.


The TX circuit is a two stage, the first stage is a replica of VK3YE beach40 amplifier circuit, that also uses DB139. The second stage is a spin of the EMRFD Page 2.38 IRF511 Amp.
I have cranked it up to 17w, but it gets too hot too fast, as you can see I don’t have any proper cooling yet, I need to redo this board and plan for the heatsink a bit better.. it is now set around 10w, still getting hot, "599 TU 73”.
To be honest my CW does not go much further anyway, but I guess with this radio now completed I have one more reason to get my speed up.
 I use for convenience both CLK0 and CLK1, when I go into TX I switch off CLK0 and do the keying on CLK1, both transmitter stages are powered up the whole time (until I stop keying as described above)

As the 700Hz filter worked so superb, I decided that I wanted to introduce “modes” to the rig, I can now switch the audio either thru the filters (CW) or straight to the AF amp (AM).
I do enjoy listening around, and we have a lot of AM stations on offer in my region.

I kept the smart RX mute transistor circuit and when I ask the Arduino to change mode, it will mute the receiver quickly, pull the relay and then un-mute again, no ear pain from the loud relay click. (I am happy with that detail).

The 2 line display became a four line, and I can change Tuning Rate, RIT, Key Speed and Mode by using only the encoder and the one button built into the encoder.
The front panel sports, on off, Headphones, Paddle and volume, the display and the big knob.
Power connector and USB Port on the side. I did complete the CAT control changes while working on this radio, it now uses the classic Kenwood interface e.g. TS480. (A lot fewer questions from the PC to answer.)

The CAT control works very nice while using N1MM, it works a lot less nice using CQRLog, I guess it has to do with the number of times the software in the PC is asking about things from the radio.
I will look into logic to only worry about incoming serial requests if I have not answered for some time, and never answer while in TX…

By pressing the VFO button a small arrow appears next to TR, if I push again it moves the arrow down to RIT and so on.
if I turn the knob with the arrow standing in front of e.g. KEY it will increase or decrease the KEY speed, when I press again, it will return to frequency control.

Oh, another detail (that I am happy with) while the arrow is in front of the KEY, you can fiddle with the paddle with out transmitting.. practical for testing the speed.

So this is a K4GC transceiver with bits and pieces from VK3YE and bits from the A65DC laboratory in Dubai, truly international.

To trim things in I scheduled a QSO with a local ham here, and things worked very nice, later the same night I made my first “DX” contact with RM2D!!! Moscow!!
What are the odds that a Swedish guy living in the UAE makes the first contact to another Swedish ham who lives in Russia!

73,
Martin A65DC

Friday, February 3, 2017

A Mighty Mite, a BITX40, an ILER, some Arduinos, and the Joy of Oscillation in the United Arab Emirates


Martin A65DC sent us this wonderful report on his efforts in the UAE.  His e-mail nicely conveys his enthusiasm.  I was especially pleased to see that wooden enclosures are catching on (another fellow on the BITX20 group is using a cigar humidor).  Thanks Martin!  Please keep us posted on your UAE homebrew adventures.

Hi Bill and Pete,

My name is Martin, and I am listening to every episode, sometimes more than once, thank you for an excellent show boys. I am a ham in the United Arab Emirates and operate radio as A65DC.

I just wanted to share my "JOY OF OSCILLATION” moment with you, I had the moment two days or so ago.. fantastic!

Well it is not super tidy, but as a proof of concept is totally acceptable. red and green goes to the variable cap (above).

Next to the Mighty Mite (above) is my bitX40, what a fantastic board!! I have big plans for this radio. But for now it will stay in its wooden box and keeps me company.


This (above) is another kit build, 20m SSB kit from EA3GCY Javier. ILER20, please have a look, this is where you should start if you are into kit building!! the instructions are fantastic.
I added some Arduino magic to it with a SI5351, and then I was sitting and looking at my big UNO board, hmmm USB port, why not further develop the code and use the port as CAT control.
I can now connect this rig to e.g. N1MM and control it, read and write frequency (in current version) I am simulating the protocol of a TS590, but that turned out to be a bad choice, I should have gone for a simpler radio, like a 140 or something, the 590 has loads of CAT commands that my code needs to answer… this radio is my QRO 20m as rig it sports the 20w amplifier kit from K5BCQ and will put out a whooping 22w!  Several contacts from A6 into Europe and some over to Indonesia.. fun stuff, two kits from different vendors together with some own building and coding.. I love it.


On the workbench now is an Arduino CW keyed based on K3NG, the Arduino code is very well written and it has loads of functionality, most of what I will never use.. but as a keyer it is superb.
This is my keyed circuit, super simple stuff, it is here connected to the Mighty Mite as a test, works 100%  I am now researching a good circuit for a CW transmitter/transceiver for 40m that will be in the 5 to 10w range to use my new keyer with.

Again, thanks for a fantastic show guys,

73
A65DC, Martin
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column