Monday, March 21, 2016

XW2 CAMSAT Satellite

FO-29 (JAS-2)

Some Detail:

FO-29 was in well today during a near over-head pass.

AO-73 BPSK Decoded

(click to zoom)
Using: "Funcube Dashboard"

Wednesday, March 16, 2016

Apache Labs - Hermes - Hears NP4JV AO-73

AO-73 "Funcube-1" satellite flew by tonight and I heard NP4JV for most of the pass.

Details on this bird:

Video of this pass:

Apache Labs - Hermes - Hears Birds

For almost the entire winter I've been playing around with building beacons, and using various forms of up and down-conversion of RF signals in all sorts of tests.  Mostly I'm just trying to learn more, and learn how various 'tweaks' can make a difference with my various RF projects.

The past few days I've been returning to playing around with my Apache Labs "Hermes" SDR.  This little software defined radio never ceases to amaze me.

It's funny to me how so many of my projects I putz around with can somehow intermingle with each other.  If you follow this blog then you know I've been recently playing around with Arduino's to accomplish things like acting as a CW beacon, used as an LO in a RF chain, or used as a device to read and display RF Power levels.  These things can be used with so many projects and they're seriously cheap.  The Arduino UNO I'm using cost me < $20 USD, and the Si53531A Etherkit breakout board is super handy for generating RF signals between 0 and 160 MHz (and a little higher).

So...I decided since I was waiting for money and parts to work further on my multi-band beacon project that I'd reuse some of that stuff to make a simple down-converter actually it's able to operate as a full transverter.   Meaning for example, if I want to operate on 145 Mhz I connect an antenna for that to a mixer's RF port.  Then I connect the output of an Arduino driving the Etherkit board at 100 MHz as an LO into the LO port of the Mixer.  The IF port connects to the Apache Labs Hermes SDR.  And wha-lah!  I can receive from about 128 MHz to about 160 MHz.  

This morning I was listening to aircraft between 128-135 MHz roughly.  

All afternoon I was listing to 2 meter repeaters around 146-147 MHz, and then 911 Dispatchers 154 MHz (around here).  

This evening I decided to see if I could hear any Satellites.  And sure enough I copied NOAA-18 easily during one pass around 137.620 MHz.

After that I listened for CAMSAT which is "XW2" and I heard that as well.  Here is a video of XW2 reception.

It's kinda long, and it's a little noisy and the signal was fairly weak.  But even CW-Skimmer was able to copy "CAMSAT" and "XW2" down in the noise.

So it's actually hearing pretty darn well.  My antenna is just an omni 25-1300 MHz "Discone" up about 20 feet on a chimey.  Nothing fancy there, and about 45 feet of LMR-400 Coax.  Just real basic listening stuff.

I'm using an LNA-3000 which is good from DC-3GHz.  It's good for about 18dB roughly.  But I probably really don't need that, especially where it's mounted down in next to the radio.  BUT anyway... :-) (I like to play)

Here's some helpful 'stuff' for tracking and listening for this stuff:

Thursday, March 10, 2016

Arduino Nano + LCD + Mini Circuits ZX47-60+ Power Detector (completed)

I've mostly completed this NIFTY little project today.  All that remains is to add an external power jack to it.

Migrating from the breakout board to a real device wasn't as hard as I expected.  Took one evening of close attention to detail, but when I tested it, it fired up perfectly.

Today the ZX47-60-S+ arrived via FedEx.  It was DOA (dead on arrival).  I decided I didn't want to wait for a warranty replacement so I opened the mini device up and found a cold solder joint on the +5vdc line in.  I fixed that at least temporarily.  I also bitched to MiniCircuits about the issue, but I haven't heard back from them.  I'd like a replacement, but no telling it that'll happen.  We'll see.

Anyway, once I found that and fixed it, I put the ZX47-60-S+ into my project, and fired things up again.  I used a Elecraft XG3 to put -33dbm and 0dBm into my project box's input, and wha-friggin-lah IT WORKS!!! :-)

I added a 60db step attenuator to the input and use 0dBm into the attenuator and stepped down to -60.  In all cases the device was reporting within about 1.5dBm (if the XG3 is even accurate).  But that's CLOSE ENOUGH for what I needed anyway.

Here are some pix.

EME Echo's at 50 MHz

EME F6BKI - (Worked) France

Tuesday, March 8, 2016

Apache Labs - Hermes TUN 10m vs. 6m

I haven't used my Apache Labs "Hermes" Board for Transmit much since I purchased it a few years ago.  I've most just used it for a multi-band CW Skimmer Receiver.

I've been starting to build it up for use as a Transverter "IF" and I'm noticing some odd behavior on 6m (50 Mhz) which doesn't occur on HF bands at all.

When I key up on CW or use "TUN" on 6m there's a Sweep to the RF output.  You can see an example of this below where it's sweeping on 6m, and NOT on 10m.

In the images below there are some 'other' artifacts which occur on my primary radio in the presence of strong local RF.  That is not the 'sweep'.  I'm talking about the RF shift noted in the lower box of the 6m image, and not seen in the 10m image below it.

I've also noted that when I reset the 'database' in PowerSDR that until I turn off PowerSDR the first time, 6m behaves just like all the other bands.  (At least I'm pretty sure of this).  On subsequent restarts of PowerSDR the little sweep, and reduced output on 6m is observed.  I thought at first that it was my 5vdc supply dipping in power.  But it's not.  So I'm just a bit confused by what's happening.

Anyone with ideas please comment below.

These images of screen shots of HDSDR where my FTDX-5000 is connected to an AirSpy and SpyVerter via it's 9Mhz IF out.  Note the 1KHz shift in the first image.

Note the little "1KHz Sweep" at TX start, it can be see in the LOWER box above at the bottom of the image.

Note on 10m no little "Sweep"


So turns out this is related to a software 'thing'.  I had set Hermes Sample rate at 384K, instead of the default 192K.  I discovered this after I reset the 'datebase' a few times, and fiddled with settings until I found the one that made a this happen.

Apparently this is sort of a known issue, and I'm not supposed to use 384K until they've resolved the Ethernet up to 1Gb instead of 100 Mb.  So for now I'm using all the other settings I had set, except I've reverted this setting back to 192K. 

And it seems to work fine on 6m now.

EME OH2BC (Worked) Finland

Monday, March 7, 2016

Arduino Nano + LCD + Mini Circuits ZX47-60+ Power Detector (2)

So today the Red case arrived, and I cut the front panel to fix the LCD in it.  

I also cut a copper PCB to slide into this case to mount all the hardware.  

I don't know when the Power Meter device from Minicircuits will arrive yet.  That's kind of core to this :-)  So that part is on hold, but I expect it'll be here this week sometime.

I also found a nifty Arduino Nano "Terminal Adapter" that I'll be using to connect up all the wires to it.  See this link.

Wednesday, March 2, 2016

Arduino Nano + LCD + Mini Circuits ZX47-60+ Power Detector

10 MHz to 8000 Mhz!

The beacon project I've been working on requires that I have some sort of weak signal RF Power Detector.  Something that can provide me with a dBm measurement between -60 and +10 dBm. (approximately).  This doesn't really have to be perfect.  But I need to have an idea that I'm close to spec's for things like Mixer input/output and the like.

We're talking about millwatt values here.  So these signal strength are far below (for most part) what most off the shelf "RF Watt meters" can provide.  I don't really want to spend a bunch of money on a power meter for this.

Here's what I'm thinking about doing.

I have several spare Arduino Nano 3.0's laying around.  They cost about $8 USD.  So they're fairly cheap.  I've used a bread-board (and I frigging HATE using these things) for a mocked up demo.  Just to make sure the idea works.  Once I have the Mini Circuits ZX47-60+ in hand I'll use soldered connections instead.

My gripe about a bread boards is that connections can be too loose or too tight so that the wire end plugged into it can either be contacting, or NOT.  Which can lead to thinking something in the circuit isn't wired properly, or actually damaging things while constructing it.  Every single time I use these things it takes me 3 times longer to do than if I just created a circuit board and soldered things up.  ANYWAY.  That's probably just me.  

Here's a diagram of how things are connected for this so far.

And below is what it looks like wired up and running.

Basically, this is just a DC Voltmeter capable of reading 0 to +5vdc.

Now the Mini Circuits ZX47-60+ isn't really cheap it's about $80 USD.  BUT it's able to operate from 10 MHz to 8000 MHz.  Here's a link to a PDF.  Below is a graph which shows how this operates.  When the power detector receives RF which is between -60 and +5dBm
it outputs a DC Voltage from +0.4 to about +2.2vdc.
So all that's left is to obtain a ZX47-60+ and connect it's output up to the Arduino pin "A0" which is able to read an analog voltage between 0-5vdc.

Then with a little math in some code (fairly simple) I can output the volts DC on one line of the display (to help me visually verify what the dBm power level is), and on the second line I'll output the conversion from Volts to dBm IN dBm! 

So when it's all done I'll have the actual volts DC measurement output from the ZX47, as well as dBm, and I'll display the conversion from dBm to Watts/Milliwatts as well.

This can be extended to read levels much higher than the Power Detector would normally be able to measure by adding inline to it, an RF attenuator, and in code calculate the offset from the added attenuation. 

That's the plan anyway.  I'll post updates on this as things progress.  But I need this to work to move forward on the beacon project so it's at the top of the 'project' list for now.

Here's the SIMPLE code I'm using in the photo above...


As well as the ZX47-60+ this past Friday.  Both should be here in a few days.  I'll mount them all in the Red Case (see the link above) and add an SMA bulkhead connector on the case as well as a small Buck converter to drive everything including the Arduino Nano from input voltages of between 12-24vdc.  This way I can power the devices at 5vdc, from 12vdc, 13.8vdc and 24vdc.  Good for just about every environment I might use such a device.  

I'll post photo's and test results in another post.

I'm planning to try to add some code and an optical encoder to the the mix as well as a menu select button so that I can alter the output of it when I add a large attenuator to match the input at higher levels.    

I've since posting the above code modified the code to provide VDC from the ZX47-60+ on the LCD, as well as calculated dBm, and femtowatts, nanowatts, picowatts, microwatts,  millwatts and Watts.

I'll demo that in my next post as well.