Nooelec TV28T V2 DVB for SDR

It isn't enough that I'm tinkering with the Stellaris Launchpad; I also got one of those $20.00 DVB dongles to play with for SDR.  It's a Nooelec TV28T V2.  Basically, it's a European/Asian digital TV on a USB stick.  The reason I have it is to tinker with SDR - software defined radio.  It turns out that this little widget works fine for that.

 This is the dongle opened up.  Not much to it, is there?  This uses the R820T tuner instead of the older E4000.  The other big chip is the RTL2832U.

To open the dongle, I used a small screwdriver at the antenna connector.  Now that I have it open, I see that the easiest way is to press in the catches at the marked arrows.  The catch is on the larger half of the clamshell, the side with the NooElec logo.

I'm thinking I'm going to re-box this and maybe put an SMA connector there.  We'll see.

CT1FFU has a neat HF converter that looks interesting.

I loaded SDR# from the 'installer'  link and the TV28T fired up like a champ after I tweaked the RF gain.  Can listen to my local FM stations even with the junky little antenna that comes with it.  Also, my local 444.000 FM repeater.

Here's a Jing capture of SDR# playing my local  FM station, WMHT 89.1 MHz with the little whip antenna.

TI Stellaris Launchpad

So I bought a Stellaris Launchpad from TI.  It's quite a lot like the MSP430 Launchpad, but it has an ARM Cortex M4F on it.  I'm going through the YouTube tutorials via the TI Workshop.  The main point of this post is to accumulate the links I'll need to get back to this.  The workshop PDF is here, and it's detailed enough to really be a grounding in MCU architecture as well as specifics on the M4F.  TI have a forum on their 'E2E Community'.  There is a great pile of application notes and other documents here.  Putty works fine as the serial console.  Just remember to check device manager to find which serial port the ICDI driver has assigned to the USB stick.

HP 11517A

Found it on eBay and it's a prize! Like anything one buys on eBay, it's a gamble. Sellers are reluctant to give a warranty on 30+ year old electronic test equipment, and there aren't many who have the facilities to test this stuff in the first place. Those who do, charge high (by ham standards) prices for their time and effort. That's more than fair, and if I were a government lab I'd be very happy to get one at say, 50% off list price.

But I'm a ham, and can't compete with those labs, so I feel very fortunate that this one had a low starting price and no guarantee other than 'came from a working lab.' It turned out very well for me.

The mixer is good from 12.4-40GHz (or as the label says, GC!) It came with a waveguide taper 11518A, P band, 12.4-18GHz, but it still picks up 24GHz signals just fine. I'll be on the lookout for a 11519A, 18.0-26.5GHz adapter.

The HP Application note for this mixer (AN 150-12) tells me that there is a low pass waveguide filter that I might want, in this case a K362A, although I bet the flanges won't match. What HP calls 'P' band is probably really Ku band, with WR-62 flanges.

There's a huge gap between here and the table below and I'll be darned if I know why that is!

HP band	Standard band	Waveguide	Frequency range (GHz)
P	Ku	WR-62	12.4-18.0
K	K	WR-42	18.0-26.5
R	Ka	WR-28	26.5-40.0
	Q	WR-22	33-50
	U	WR-19	40-60
	V	WR-15	50-75
	E	WR-12	60-90
	W	WR-10	75-110

Rectangular waveguide dimensions can be found here.
HP Spectrum analysis application notes can be found here.


Here's a photo of my new find - an HO 11519A adapter, good for 18 - 26.5 GC (GHz). Yay!


And the two adapters side by side.

EDIT: Expanded the waveguide table for higher microwave bands. Added photo of 11519A adapter.

Trying to snow...

The weather's cold enough, but there isn't quite enough moisture in the air to sustain a real lot of snow just yet. Not sure what to call this stuff; sleet, snow - the weather man knows for sure! This is the top of my car, in close-up.

Apologies for the odd layout - I'm tinkering with new Blogger features and haven't quite got the hang of it yet.

24GHz progress

Some time ago, I bought a Verticom MTS1500-151-01 oscillator from the fine Southern California hams.  I never got round to getting it going; too much to do elsewhere.  Finally, I managed to order the pieces/parts from Digikey that I needed for WW2R's Verticom driver board.  Spent a couple days putting that together and getting it on the power meter and spectrum analyser.

Couple of things to note:

• The 78L05 is a small TO-92 device, not a TO-3.
• The power supply has 2 off-board regulators; an LT1086 and a 7808.  Bollt those guys onto a very decent heat sink.  I used a small aluminum square scavenged from something or other and it wasn't big enough at 2-1/2 inches by 2-1/4 inches.  It got too hot to hold after about 15 minutes, but a small 12v fan made all the difference.
• My HP 432A measures +15dBm
• My HP 141T measures about +12dBm
• Use a 20dB pad!
• Spectrum looks very clean, but I need to cal my HP 141T...

 

11880MHz (approx)

0dBm reference

10KHz / division

23dB of attenuation in line

Softrock V8.3

From this:


To this:


I finished up the basic kit last night and wound the 40/80m band filter board toroids. Much gratitude for Robby WB5RVZ and his excellent builder's page. Wow, that was easy! Next stop, the 10m filter board, some connectors and a hook-up to Rocky software!!

Softrock on order

I ordered a Softrock Lite v8.3 yesterday. Now I'm getting all excited, waiting for it to arrive! Looking to make a 28MHz IF panadapter.