Saturday, October 25, 2014

Ultimate QRP DX: 4M Moon Mission!

China's recent effort to send a spacecraft to the moon has had a nice benefit for VHF ham radio.  Attached to the last stage rocket is a radio transponder developed by LX0OHB, that outputs a 1-watt signal in JT65B mode on 145.980 MHz USB.  The transponder sends repeated callsigns, messages, voltages, temperatures, and has an on-board experiment monitoring space radiation levels.  More information is at the 4M website.  The spacecraft was launched 10/23/2014, will briefly orbit the moon on 10/27, and then will return back to earth on 10/28.

I was very surprised to find out that my small EME station (two 7-element VHF yagis and a preamp at the mast) was more than capable of reliably decoding the telemetry from this spacecraft!  Capturing a QRP (one watt) signal from over 300,000 km away is pretty remarkable.  I use exactly the same setup as I do for EME, and also run the 4M Data Delivery Client to automatically send the received packets from the 4M back to their central data warehouse.  Seems at this point in time there are around 30 stations providing the warehouse with live feeds of packets coming down from 4M as it heads towards the moon!
















The keplerian elements for tracking 4M seem are near the bottom of this post:  http://moon.luxspace.lu/receiving-4m/ and the current position of the spacecraft is shown on their webpage at http://moon.luxspace.lu/tracking/ (for doublechecking your own tracking software).

Monday, June 30, 2014

ISS Contact - Field Day 2014

In the days prior to the ARRL 2014 Field Day, there were postings on the internet indicating that crew on board the International Space Station (ISS) might be making voice contacts for the event.  How exciting!














To get ready, I set my home satellite station to run on emergency (battery and inverter) power, and waited for the first pass of the ISS at 11:11am local time here.  Sure enough, just after AOS, at around 11:12am I could hear FM signals coming through the noise on the 145.800 FM downlink.  A minute or two later and the ISS (using call NA1SS) was full quieting!  I tried to make a QSO, and they came right back, woohoo!  I had a voice recorder running at the time, here's the audio from the quick contact:

video

In the first pass at 1811z, I heard NA1SS copy NU6S, K6LCS, KB5WIA, W6TO, WD9EWK, KO6TS, and a few more.  An hour and a half later (1949z), the ISS came by on a second pass (this time to the north), and I heard them copy quite a few more stations:  K6GHA, KJ6ZL, KE1B, K6XX, W6CKL, V7?LGY, WB6NOA, W6HQ, W6HTY, N7OY, VA7VW, N7OY a second time, WA2TND, VE7N, W6NN, KE6IWM, KJ6PFW, VE6EGN, VA7GAB, and AC0RA.  At that point (1957z) the ISS went LOS, but were still making contacts.  Links to the the full audio recordings from both passes are here:

ISS Field Day 2014 - Saturday 1811z
ISS Field Day 2014 - Saturday 1949z

All in all, a pretty exciting experience!  It's not often I get a chance to make contact with someone in orbit!

Friday, November 22, 2013

Having Fun with FUNcube!



Yesterday marked a successful launch of the UK's FUNcube amateur radio satellite.  The satellite contains both educational experiments and a linear transponder, and for these initial orbits the satellite is relaying telemetry containing data about the satellite's status (voltages, temperatures, etc).  The FUNcube designers have built software that will automatically read and decode the telemetry from an attached software-defined radio (the FUNcube Dongle Pro+), and relay this telemetry to a central data warehouse.  This way, students in the UK (and around the world) can see the status of the satellite in almost real-time!


Right before launch, I set up my home station with the software to record and upload the telemetry, and configured my satellite tracking program (SatPC32) to steer the antennas (a pair of VHF yagis) and track the satellite in the expected orbit.


The first visible pass of the satellite over California was around 9:30am yesterday morning, and all systems worked great!  Not only was the satellite operating perfectly, but the home station was able to decode and transmit its telemetry to the warehouse.  After the pass, I could see on the website that KB5WIA had uploaded 121 frames of data to the warehouse.



I'll leave the system tracking FUNcube for the next while, to add to the pool of satellite data that's being collected right now.  It's nice to be part of a truly global effort to help out with this satellite.  Fun stuff!

More details on the data being received at:
https://warehouse.funcube.org.uk/

And lots more details on the FUNcube project itself at:
http://funcube.org.uk/



Monday, November 18, 2013

Installing MAP65 and the FUNcube Pro+ for JT65 EME, Part II

Here is an updated article for installing the FUNcube Pro+ receiver and MAP65, this time without using Linrad.  In this article, we'll see how to install the system with the receiver providing direct input to the software.  The advantage?  Faster and much easier installation!


SUMMARY

A software-defined receiver coupled with MAP65 software will allow the amateur radio EME (Earth-Moon-Earth) operator to visualize the entire EME sub-band at once. This can be a great benefit to both small and large stations, since monitoring the entire spectrum simultaneously will tell you exactly where other EME stations (strong enough for your system to decode) are located.

This article describes how to install a FUNcube Pro+ (FCDPP) software defined radio (SDR) into an exisiting EME station.  It assumes that the operator is already familiar with EME exchanges using the JT65B protocol, has experience with WSJT software, and has basic EME station hardware.


HARDWARE

A typical EME-capable station will have a mast-mounted preamplifier, sequencer, and separate transmit and receive lines.  For my 144 MHz EME, I use two M-Squared (M2) 2M7 antennas coupled with a M2 power divider, feeding an Advanced Receiver Research (ARR SP144VDG) GAsFet premplifier with +24dB gain.  Received signal is sent through a separate receive coax (75' of RG-8/U) to a hybrid splitter combiner (ie. Mini-Circuits ZFSC 2-2 Power Splitter, 10-1000 MHz).  The FunCube Dongle Pro+ is connected directly to the output of the splitter, the other port goes directly to the analog radio.


Appropriate coax relays are controlled by a dedicated sequencer and protect the mast-mounted preamplifier and switch between the separate TX/RX lines.  I also found it helpful to add a dedicated coax relay to switch the input of the splitter to a 50-ohm dummy load during transmit; this also helps to prevent spurious JT65B decodes.  The main hardware list is as follows:

- Antenna(s)
- Sequencer
- Mast-Mounted LNA
- A/B coaxial RF relay at mast (high-power)
- Separate RX / TX lines.  RG-213 or RG-8/U is OK for RX side.
 - High power amplifier
- A/B coaxial RF relay in shack (low-power)
- 2 port hybrid splitter
- SDR (in this case, the FUNcube Dongle Pro+)
- Traditional transceiver and WSJT9 software
- Multi-Core CPU (MAP65 is more CPU intensive than WSJT)
- Second 1080p monitor (optional, but recommended)

If separate transmit and receive lines are not used, careful attention needs to be placed on protecting the FCDPP receiver from damage during transmit.  The configuration settings described below will likely need to be optimized if station hardware differs significantly from the above.  It should, however, provide a good starting point.


COMPUTER SETTINGS

A reasonably fast computer is required, and modern multi-core processors should be fine.  These instructions are written with the Windows 7 operating system in mind.  It helps to disable power saving options on the computer used to run the SDR.


INSTALLING THE FUNCUBE DONGLE PRO PLUS

Read the user manual for the FUNcube Dongle Pro+ (FCDPP) and install the software according to directions.  The main steps will be:
  • Obtain documentation at http://www.funcubedongle.com/?page_id=1225
  • Download FCHid (called FCD+ Frequency Control Program v2.002)
  • Download SDRSharp
  • Install both programs
  • Verify the FCDPP demodulates signals
  • Update the FCDPP firmware to latest
  • Verify (again) the FCDPP demodulates signals
The FUNcube Dongle can be attached directly to the computer's USB port, but some operators have reported that it's better to use a short USB extension cable.  This allows the FUNcube to be physically separated from the computer (reducing RF ingress) and also takes some of the strain off of the USB connector.  I have not seen any RFI issues myself, but use a 3-foot USB extension cable with a ferrite core.


Re-read your FCDPP user manual, and re-verify that it can hear signals with the SDRSharp software.  There's no point in continuing any further if you haven't got your receiver working!


CONFIGURING THE FUNCUBE DONGLE PRO+

You'll run the FUNcube Pro+ receiver using the FCHID program.  This program is the one you downloaded  earlier, called "FCD+ Frequency Control Program v2.002".  Start the program and enter your center frequency in the big black box in the upper left:




Next, boost up the IF gain a little (like 10dB), by clicking on the up-arrow next to the IF gain window.  Your FUNcube Dongle Pro+ is now sending an RF stream out via the soundcard port.


INSTALLING MAP65

Download and install MAP65 from Joe Taylor's website at http://www.physics.princeton.edu/pulsar/K1JT/map65.html.  Comprehensive installation directions (and a great manual!) are included on Joe's webpage, just follow them step by step.  Be sure to install to the path [C:\MAP65\].




CONFIGURING MAP65

Well next set up MAP65 to listen to the output from the FUNcube Dongle Pro+.  Start MAP65 and go to Setup > Options > I/O devices.




















Make sure the radio button next to SoundCard is selected.  Next, select the output from your FUNcube Dongle in the drop-down list.   Make sure the sample rate is set to 96000 Hz.

Now make sure that your MAP65 wide graph display shows the right frequency.  Check the Force Center Freq checkbox and enter the same value you had in your FUNcube control application (144.137).


Next, check to be sure MAP65 is receiving data.  You should see the bar graph on the left have some sort of display:


Verify your noise floor.  On my system, at this point, the noise floor on MAP65 will fluctuate around +21dB with antennas pointed away from noise sources into a cold sky.  It's also normal to see the noise levels go up by +8dB when the antennas are pointed towards the horizon in a suburban environment.

If your noise floor with the antennas pointed at cold sky is high (higher than +25dB), you should next to to the Windows audio control to turn down the audio gain of the FUNcube.  Choose Windows Start > Control Panel > Sound > Recording, and look for your FUNcube:




















Select this by double-clicking, then choose the Levels tab and decrease the audio level so that your MAP65 signal reads in the +20 to +30dB range.  I have my "gain" set to "6":




















Next, verify your preamp is functioning.  Turn off the mast-mounted preamplifier and verify that the noise floor drops significantly (at least 10dB, preferrably 20dB).  On my system, the noise floor drops to around +7dB when power to the external +24dB preamplifer is removed.

Adjust the NAvg on MAP65 to a value of 10, so that 1 minute of time corresponds to approximately 1cm of vertical space on the waterfall.  Averaging the lines (a slower waterfall) will help you see weak traces.

Zero the MAP65 waterfall brightness.  After zeroing, the waterfall should be a blue color.  I'll typically zero the waterfall with antennas pointed at the cold sky, so the color of the MAP65 waterfall can tell me how much local noise I'm seeing at any point in time:  Blue = nice and quiet; Green = Marginal; Orange and Red = only the big guns will get through!

Increase the gain on the MAP65 waterfall to 5 or so to get more "snow".  This will help you visualize weak traces better.

You can turn on MAP65's noise blanker if you'd like.  Personally, with my local noise environment, I don't see much impact one way or the other.  Keep the blanker from "eating" too much signal, so adjust it so it's less than 5 to 10%.

Verify the frequency display is correct.  Look for a birdie (or set of birdies) on the MAP65 wide screen waterfall.  Take a note of the frequencies, then tune your analog radio to the same frequency.  Verify that you can see the same birdies on both radios.  On my system, they are pretty close, about 40Hz apart.

Configure the MAP65 output to your analog radio (transmitter).  You'll need to specify the sound card output, and the COM port used to key the PTT line.  These should be the same settings that you are using in WSJT9 software.  Try calling CQ on an open frequency and verify that the MAP65 transmissions and levels seem correct.


IMPORTANT: Update MAP65's call3.txt.  Download the latest from http://www.mmmonvhf.de.  The program WSJTMerge from http://www.k2txb.com/WsjtMerge.htm can be used to merge an existing call3.txt file with the new one.  Also, if you're not in the Make More Miles on VHF Database http://www.mmmonvhf.de/dbase.php already, then you're potentially missing out on +4dB of coding gain because other EME stations may not have you in their own call3.txt files.  Be sure your call is in the call3.txt from this site.  It's difficult to stress how important this is -- if you're a small station, and you're not in the other station's call3.txt file, it's going to be much, much more difficult to have a QSO.

Make sure to turn on aggressive deep search in MAP65.

MAP65 has a Setup option to reduce the font size in the Astronomical Data window. Set it to something like 12 or 14 pt so you can see everything in the window.


USING THE SYSTEM

By now you have a system that is decoding JT65B signals on two separate radios:  the FCDPP and your traditional analog radio.  With the settings described above, the FUNcube Dongle Pro Plus should be about the same sensitivity (able to decode JT65B signals about as well) as your analog radio.


By running both MAP65 and WSJT9 simultaneously, you now have an even better ability to decode signals on the frequency you're looking at.  For example, if one of the two radios misses a decode (random noise, etc), the other one may pick it up.  You can also use one radio to check on the decodes of the other -- for example, seeing both radios decode the same message virtually rules out the chance of a false decode.

Moreover, you can now visualize the entire EME sub-band on the MAP65 waterfall, so you can quickly check other frequencies for active EME activity.  Even better, MAP65 has the band map / message list, and will decode stations that you're not even looking for (albeit, with slightly reduced sensitivity).



Importantly, using MAP65 you're no longer limited to finding stations calling CQ on the internet chat rooms.  You'll find stations that *your* station can hear, since by definition MAP65 is only going to report to you the stations that you're capable of receiving.  As a bonus, you can also quickly use MAP65, which displays the last 5-10 minutes of spectrum activity, to zero in on a station that you saw calling CQ in an internet chat room to see if you can find any traces of signal.

You can also use the two radio systems (analog and digital) for optimizing one or the other.  For example, you can experiment with different Linrad settings, or different filters, on the SDR side and make A/B comparisons with the decoding on the analog side.  Given the high degree of variability of EME decodes, having a direct A/B comparison greatly improves your ability to optimize one or the other.

Overall, the incorporation of an SDR and MAP65 into your station should greatly enhance your ability to make EME contacts, even with a smaller station.



ACKNOWLEDGEMENTS

Much assistance from the W6YX team is appreciated with regards to getting this system working!


REFERENCES AND NOTES

[1]  Ordering a FUNcube Dongle Pro Plus:  Howard Long G6LVB has ordering instructions on his website at http://www.funcubedongle.com/, look for the tab called "The New FUNcube Dongle Pro+", you can find out about how to order it right there.  When I ordered mine, there was a waiting list of a few weeks -- put in your name and Howard will send you an email telling you when yours is ready to order.  Pricing is on the website also, and proceeds from these units go to AMSAT-UK's FUNcube satellite project, so it's also for a very good cause.

[2]  The original version of this article, designed for those wishing to install Linrad as an intermediary between the FUNcube Dongle Pro+ and MAP65, is located here:  http://kb5wia.blogspot.com/2013/01/installing-map65-and-funcube-dongle-pro.html

[3]  I've written about optimization tips that have really helped me, as a small EME station, make contacts.  That article is located here: http://kb5wia.blogspot.com/2013/06/a-checklist-for-optimizing-small-144mhz.html







Thursday, October 31, 2013

EME: 28 Grids in 36 Hours!



This last weekend was the first (144 MHz leg) of the 2013 ARRL EME Contest.  The contest scores 100 points for each two-way QSO via the earth-moon-earth pass, multiplied by states / provinces / countries.  For this contest, I used the regular EME station (FT-817ND running WSJT9 software and the FunCube Dongle Pro Plus running MAP65 software), relying on MAP65 to find other stations across the EME sub-band (144.100 to 144.160 MHz).  It worked out pretty well!

The moon didn't rise above the local noise (= RFI from neigbor's houses) until 1:30am both days, so I worked at trying to make contacts from 1:30am to 6:30am, then again from 9:00am to moonset.  Staying up all night doing radio was rough, but still pretty exciting to be making so many EME contacts!  

Here's the list:

Num Call Grid Location
1 I2FAK JN45 Italy
2 PI9CM JO22 Netherlands
3 RU1AA KO48 Russia
4 OK1UGA JO80 Czech Republic
5 K9MRI EN70 USA - Indiana
6 UX0FF KN45 Ukraine
7 OK1DIX JN79 Czech Republic
8 UR7D KN18 Ukraine
9 3Z4EME KO03 Poland
10 DK9ZY JO40 Germany
11 DK3WG JO72 Germany
12 KB8RQ EM79 USA - Ohio
13 WS3Z FN20 USA - Pennsylvania
14 K1JT FN20 USA - New Jersey
15 AA4SC EM94 USA - South Carolina
16 AD4TJ FM08 USA - Virginia
17 KE7NR DM33 USA - Arizona
18 7K3LGC QM06 Japan
19 K6MYC DM07 USA - California
20 SK6EI JO68 Sweden
21 YT1AR KN03 Serbia
22 RK3FG KO86 Russia
23 SP2OFW JO82 Poland
24 VE1KG FN84 Canada - Nova Scotia
25 AA7A DM43 USA - Arizona
26 PA5MS JO21 Netherlands
27 K3RWR FM18 USA - Maryland
28 W2DBL FN20 USA - New Jersey
29 W7MEM DN17 USA - Idaho
30 NT0V EN08 USA - North Dakota

30 contacts beats my previous weekend record by 1 contact (previous was the DUBUS EME contest in the summer, there I managed to log 29 QSO's over the weekend).  What's interesting is the DUBUS contest allows station operators to find stations by any means (email, internet spotters, chat rooms, etc) ... yet I was actually able to make one more contact by completely relying on my own station.  Comparing the two contests, it seems that with a well-functioning station, the use of chat rooms / internet spots can become a distraction, rather than an aid.

A number of highights from the weekend:  Seeing K1JT Joe making contacts -- he's the Nobel Prize winner who developed the software that allows small stations like mine to "see" the signals reflected off the moon. Working K6MYC Mike, and seeing both his direct signals from a few hundred miles away, as well as his moon reflection at the same time.  Also making a few new contacts with stations that I hadn't worked before (SK6EI, 7K3LGC, W2DBL, OK1DIZ, 3Z4EME, PI9CM) was quite enjoyable.

I was discussing weekend's contacts with a neighbor, and they asked what the furthest station I had contacted was -- I answered either Russia or Japan, I'm not sure which is actually further from California.  To me, however, what's far more amazing than contacting another station several thousand miles away, is that these contacts were all made completely via moon reflections.  So -- the signal received in Japan actually went from my backyard, 250,000 miles through space, then reflected off the rocks and dust of the moon, then travelled 250,000 miles back through space, to be reached on the other side of Earth.  That's a half-million miles that the signals travelled!

Overall, it was a fun weekend.  It's pretty amazing to see how well earth-moon-earth communication works!

Dave

Sunday, September 15, 2013

September ARRL VHF Contest - Mt Vaca


For this year's ARRL September VHF Contest, I set up the portable system near the summit of Mt Vaca.  Mt Vaca is close to 3,000' in elevation and is located west of Sacramento in grid square CM88.  The mountain has good radio views of the surrounding San Francisco Bay Area and the Central Valley.  The ridgeline is accessed by the 5-mile long narrow, winding, Mix Canyon Road; near the top, a private road turns to the south to access the commercial radio towers, and I turned north for another mile along the dirt road to a relatively open spot along the ridgeline.

The equipment I used was the same as in the June 2013 VHF contest:  the Yaesu FT-817ND QRP all-mode transceiver, connected to a 2-element Diamond 6 meter beam for 50 MHz, a 4-element Arrow VHF yagi for 144 MHz, and a 15-element Diamond  UHF yagi for 432 MHz.  All three antennas were mounted on a 20-foot Buddipole mast that I set in the bed of the pickup truck.  I also brought along the Yaesu VX-6R and a 5-element 223 MHz yagi for 1.25m FM contacts.  Power came from the 6.4 Ah LiFePO4 battery that I've used for contesting in the past; four hours of operation didn't deplete the battery enough to need the solar panels that I normally use.

This contest was just casual operating -- in that I set up around 1pm on Saturday, and took the station down just after 5pm.  There were quite a few other stations out there.  Some of the best contacts were KK6BQU in the South Bay (he was with me in the June Diablo contest), and AL1VE and others on Mt Shasta in the relatively rare grid CN81.  It was also great to hear quite a few of the contest regulars out there!

BandQSOs Grids
50 21 7
144 31 8
223 11 4
432 21 7

The weather was just about perfect -- temperature in the low 80's and virtually no wind.  All in all, it was a fun day to be doing radio on top of a mountain!






Tuesday, August 6, 2013

RF Maps of the Sky, Continued...

Here are a few more of the RF Noise Maps that I have been creating.  Each one is made by sweeping the 2m antenna array in a grid pattern across the sky, and recording the absolute level of RF noise seen by the antennas and SDR receiver.  The noise is measured in decibels (dB), with an arbitrary setpoint of roughly 21dB for the lowest noise seen (the "cold sky").

The first map shows a typical morning.  In the lower left is a bright red blob, corresponding to high noise coming out of a neighboring house (across the street, a few houses down).  In the upper right, there's a mild source of noise centered exactly around where the sun is located in the sky.  The cold sky in the upper left, away from most noise sources, is in the low 20's.


The next one was recorded during an evening when many TV's, fluorescent lamps, microwaves, and toaster ovens must have been running - there's very high noise near the horizon in all directions.


Next we have a nice morning with very low noise levels.  The sky is a very dark blue, indicating low RF signals at higher elevations.  Even the lower elevations have a nice (relatively!) low noise level.  My radios (and associated computer equipment) are located at 270 degrees azimuth on this map, and it's possible to see the orange "blob" from the RF that the computers, internet router, etc give off.


Next is a map created just as the sun appeared over the hills to the east in a July morning.  Accompanying the sunrise was a huge amount of radio noise that obliterated all EME reception right away.  Notice the huge red blob surrounding the sun in the sky, as viewed by the antennas:


One could argue that it's not sun noise at all in the lower right of the above plot.  Maybe it's my neighbor's TV?  Well, if we hypothesize that the noise is coming from the sun, then if we look at the same sky a few hours later, the noise should have moved and followed the sun.  This is exactly what we see, in the following plot from later on that morning:


Was the sun that noisy all day?  I took a reading a few hours later, and while there is still noise centered around the sun, the level has gone down quite a bit.  You can also see that my RF-generating neighbors at 248 degrees still have their noise going, and my neighbors to the south have turned something on as well:


The last plot is from a later July morning, with sun just coming over the hill but with little associated noise on that day.


The neighbor to the south at 180 degrees has whatever RF-noise box running, but on the whole noise levels are fairly low across the sky at 40 degrees elevation and above.

By way of reference, to hear a 4-yagi EME station, I pretty much need to have the Rf noise levels at that azimuth and elevation to be at 24dB or below (green or blue in the above plots).  When the noise is above 24dB (yellow, orange, and red in the plots above), I can only hear the strongest of the EME stations.

One nice thing about these plots is it lets me compare the local RF-noise environment from day to day, on a more or less absolute basis.  It helps to identify sources of noise, and to determine which noise sources are constant and which change over time.  It also helps to predict the best times and directions with which to listen for EME signals. Finally, it serves as a "reality check" that helps to verify system performance -- even if there's high noise that suddenly appears in one direction, by mapping the sky and seeing the rest of the noise levels are as expected, I can attribute the noise to a particular source rather than a system malfunction.

An example Excel 2003 spreadsheet that has these maps, and the macro that generates the color coding, is available here.  My previous post on this subject is located here.