NASA DWPR 2015-07-30 Interference @ 50 MHz

NASA Form to report reception of this sort of interference

These two video's show the NASA KSC DWPR very strong into the 50 MHz Amateur Radio Spectrum allocation.  These video's show 2.5 MHz of spectrum starting about 49.000 MHz. 

To view more like this back as far as 2011 visit this YOUTUBE Playlist

The following is what the DWPR might look like if you only have a limited spectrum display.
Note the ON/OFF nature of it.  Also the Spacing between carriers changes as the pattern changes.  Sometimes they'll be closer (more of them) sometimes less.

Click to Zoom

This Radar's location is at about EL99pp Maidenhead Grid Square.

• Work Begins to upgrade drwp @ NASA
• KSC writeup on DRWP
• Some detail about the system
• More in-depth Detail
• ITU M.2013 mentioning WPR @ 50 MHz
• 50 Mhz Doppler Radar Wind Profiler Filters

CW Skimmer > Aggregator 4.0 & 4.1 (double posts?)

UPDATE:

I found the cause of this after I posted this.  At least I'm pretty sure.

Aggregator allows you to setup a Primary Skimmer, and several "Secondary" skimmers.  I had mistakenly added the same detail for my Primary Skimmer as a "Secondary" skimmer in addition to my REAL secondary skimmer.

To the author of "Aggregator" I'd recommend checking any secondary skimmer's against what's setup in the primary and disallow the same detail to be added as a secondary and connected at the same time.

This shouldn't have taken me so long to figure out.  And certainly wastes a lot of resources.  I feel kinda stupid about it.  But anyway if anyone else runs into something like this just be sure your 'Secondary' Skimmer isn't also setup as the Primary, at the time of this writing Aggregator allows it, and WILL DOUBLE SPOT to the RBN because of it.

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Black box at the top of this image below is a telnet into my CW Skimmer, the same way

"Aggregator 4.0 & 4.1" would.  This 'should be' what Aggregator reports...but instead it's sending a spot two times to the RBN.

Click on the image to see zoomed.

I can't seem to resolve why I'm getting double posts for things like this.

This results in DOUBLE posts on the RBN seen below

Another Example

N7JW/B (spurs & key clicks)

Normally N7JW/B center freq @ 50.060.93 (on my vfo) is very clean and well behaved.  2015-07-14 @ 16:40 UTC it showed up with some spurs and some pretty major Key Clicking out as far as 5 kHz from zero beat.  Below is a screen shot, and below that is a video with audio.

Airspy ADC1 HF - without HF upconverter

About a month ago I bought a used Airspy and have been using it with good results since then.  Anyone who's been following this blog knows I've been in search of the most frequency stable SDR setup I could build or cobble together for several years.  I think I've finally come up with a combination that meets my requirements.

I am an avid CW operator on the Ham bands.  So any drift from an RTL, Funcube, HackRF, Airspy setup makes it a hassle to continually re-calibrate HDSDR for the drift-of-the-moment.  Some setups (even the Nooelec TCXO RTL) drift way to much to be useful and practical for CW operation.

My setup is like this.  My Primary Transceiver is a Yaesu FTDX-5000.  It comes with a 9 MHz IF output on the back of the radio.  This is then connected to whatever I'm using as the SDR to feed HDSDR software with IQ data in order to visualize the band I'm on.

Since 9 MHz is lower than most of the Cheap SDR's can tune to (most seem to stop around 24 MHz for the low end) I've needed to use an HF Upconverter.  The commonly available upconverters have drift of their own which further exacerbates the overall displayed drift.  Total drift on some setups has been as much as 1khz!  So when I'm using narrow filters, and trying to click-tune to a signal I see I end up way off the actual signal, and have to fiddle around to try to get zero-beat on it.  

I spend most of my time on 50 MHz, so this 'fiddle-time' can mean the difference between coping a callsign, and never hearing it again.

After reading reviews and doing a little research on the Airspy SDR I decided to buy one.  Two major factors for me that seemed encouraging are that the Airpsy is a 12 bit SDR instead of only 8 bit.  This a huge difference.  The other was that the Airspy has the ability to be 'clocked' by an external 10 MHz source.  It so happens that I have a Jackson Labs "Fury" GPSDO which uses GPS to generate an accurate 10 Mhz Sinewave as a clock output.  This is then connected via an SMA<>MCX connector and plugged into the Airspy.  The Airspy detects that the signal exists and syncs it's internal clocking to it which causes it to never really deviate (drift) in frequency.  I have yet to see it drift using this setup.  

The trouble that still existed was that I still needed to use an upconverter to get my 9MHz IF into a range that the Airspy would receive.

I recently read that it was possible to connect an HF antenna to the "ADC1" port internally on the Airspy.  I read that there was also some special Firmware developed to enable use of the ADC1 as the Airspy's input.  So I bought a cable with the proper connector to fit the port on the Airspy, I connect that to an band pass filter, and the filter connects to an LNA which then connects to the 9 MHz IF out from the FTDX-5000.  I flashed the firmware on the Airspy with the special firmware to enable use of the ADC1, and talked IW0HDV into creating a special EXTIO DLL that would UNLOCK the low end (HF<24 MHz).  He sent me an experimental version this past weekend and today I set this all up as I just mentioned.

And wah-lah!  It all works.

Note the small coax and connector at the bottom of this picture.  This is the connector and coax that runs from the ADC1.  The MCX/SMA on the right side is the GPSDO input connector.  The white cable is the USB for the Airspy.  NOTE: that the normal SMA connector is not used.

Bottom of the image shows the Mini-circuits BPF (band pass filter) above that is the LNA HF http://lna4hf.blogspot.com/ top of the image runs directly to the 9 MHz IF from the FTDX-5000.

Stay tuned for some more images, and possibly some video of HDSDR running with this configuration.

Update

After a few weeks of testing a few very strong openings on 50 Mhz (40/s9 type openings) I realized that I needed to be able to control the signal strength input to the Airspy.  I tried to simply add a 30 db step attenuator inline, but as soon as I added as little as 1db all signals would drop out on HDSDR.  

I contacted W9RAN who was the first I'd seen attempting to use the DDC method to operate the Airspy on HF.  After some discussion I decided what I need to try to do was to increase the gain, and see if I could use the step attenutor without signals completely dropping out.

I added a 34dB+ gain Miteq LNA which covers 1-100 MHz.  And a static 10dB minicircuits attenuator.  This sould give me about 24db gain to play with.  And I can then attenutate signals to -6dB below what is coming out of the FTDX-5000.  The point being I need to be able to see weak EME type signals but be able to attenuate way down when need be.

This seems to work.  I can operate the 30 dB step attenuator all the way through Max from 0 without having HDSDR completely drop out.

I have a second 30 step attenuator I may attempt to add to the chain for those extremely strong 50 MHz openings.

On HF I have a lot of local line noise garbage, but this'll give you an idea how it works at least.  I mostly work 50 MHz here.  Also I don't use the Audio output form HDSDR except to feed IQ to CW Skimmer.  So I don't normally use the audio out to 'listen' to.  It just gets piped to VAC and on to CW Skimmer.

I'm also seeing some images in this that are probably coming from up-band, so I'll be working on a better pass band filter for this.

Also this demo doesn't really show you what I was most concerned with unfortunately; that being freq drift of the TCXO RTL vs. Airspy.  But I'll just note here that the drift is ZERO.  Nothing I can detect anyway.  It works perfectly for my needs.

W9DR/b 50.072.1

JA7QVI reception recording of NW0W on 50.053 MHz

HackRF One - EXTIO DLL - HDSDR (WORKS!)

I've been searching for an EXTIO DLL for the HackRF One that will work with HDSDR for years now.

https://github.com/jocover/ExtIO_HackRF

Finally came across this today!  AND BONUS!  IT WORKS!

I contacted the author and asked him to add some smaller sample rates of 4 and 2 MSPS.  He did that and posted the new release in just about 1-2 hours.  This is useful for weak-signal stuff I most do.  It allows the ability to get HDSDR's "Resolution Bandwidth" down to 7.6 hz when MSPS is @ 2.  Which in my experience shows weak CW signals up very well!

A little about how I use HDSDR. 

I use the 9 MHz IF OUTPUT from my Yaesu FTDX-5000 as the input source to whatever SDR I'm using to feed HDSDR.   I've been using a TCXO based Nooelec RTL and an OCXO upconverter I built myself.  Even with all that 'stability' the TCXO RTL drifts all the time.  Which is a total pain in the butt for CW over the coarse of a day.

After swapping out the EXTIO for RTL in my HDSDR install I fired it up with HackRF.   Although the HackRF has advertised a low range of 30 MHz or my experience has been that it works just fine down as far as 3.5 MHz in it's stock config.  Mine is about 1.5 years old now with recent firmware installed.

Anyway I setup HDSDR initially to use 9,000,000 hz.  HDSDR has a nifty option to display the VFO frequency of the Yaesu FTDX-5000 as it's frequency regardless of what input you're really using (9 MHz in my case).

There is also a way to automatically remove the DC Spike that would show up in the middle of the display if left as noted above.  To accomplish this I set the OPTIONS > RF Front-end Frequency "IF frequency" to 9098000 and the Global Offset to 98067.  This pushes the DC Spike well below my normal viewing area, and then the 'Auto RX DC Removal' notches it down to nothing.

In this way the DC spike goes away but everything stays lined up PERFECTLY for CW.

I also connected a GPSDO I've had around for a long time that I use with my Apache Labs "Hermes" SDR.  Tee GPSDO emits a super stable 10 MHz signal that Hermes and now the HackRF lock onto.  

In a 24 hour test just completed there was 0 hz drift noted on the HackRF.  Which is what I had expected (and hoped for).  This has been my experience with the GPSDO and Hermes so I didn't expect any difference.

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So all of this Eliminates use of an RTL (which are drifty little bastards, but VERY VERY useful I've used them for over 5 years now with very good success), and because the RTL's are limited to 24 MHz I have always used an Upconverter which has the potential to add noise from it's OSC, and add drift to the resulting signal input to the RTL.

I'm using the HackRF because it's what I have currently and because this EXTIO is now FINALLY available.

I plan to also buy and test the AirSpy and SDRPlay at some point since I've read they hear better than the HackRF.  BUT at this point I think I can actually relax after years of muxing around with RTL's that drift like crazy and spending way to much to make a $8 device do something it doesn't really wanna do LOL.

Time will tell, but for now I'm setting my upconverters and RTL's to the side to collect some MUCH NEEDED DUST.