Sunday, October 29, 2017

Even More "Good News - Bad News"

Well, I just couldn't let it go.  I had to see what I could do to resolve my issue tonight without waiting to call Elecraft tomorrow.  I read the manual - no help.  I searched Google and eBay for an N-Male to N-Female 3 dB, 10-watt (or more) attenuator but nothing in my price range was available except from China and that won't get here by next weekend's contest.

However, the ever-faithful Mr. Google, did give me a hint.  I found there is a menu setting in the K3S (CONFIG: XV1 PWR) which sets the maximum K3S power output for the current transverter band.  I checked that menu item and mine was set as CONFIG: XV1 PWR = L1.50 (which is the highest level) so I turned it down to the bare minimum which was L .01 and then looked at the K3S PWR control.  Instead of the previous minimum of 0.1 mW it was now 0.01 mW.  WOW, did I just find a way to lower the power even further out of the K3S?   WHUMP - Yes he did!

I turned the amp back on, set the WSJT-X software to Echo mode, and lo and behold, I no longer had 800-watts out of the amp?  At that level "0.01 mW" and with an Audio Line Input of "1" there was no measurable power out.  I played with the Line level ending up at "10" and I brought the XV1 PWR level up to 0.02 mW and got 200-watts out.  A further increase to 0.03 mW and I now had 400-watts output.  I can work with this!!!

I'm pumped now!  Bring me the moon tomorrow and I'll try echo testing for real!  WHEEE - this will make it MUCH easier for me to get some good sleep tonight instead of worrying about this problem.

But, every time I find a solution or make a step forward, Mr. Murphy pulls me back.  In disconnecting the 1/2-inch Heliax feedline connected to the CX600-NL relay from the Bird 43 wattmeter in order to connect it to the amplifier input, I must have flexed that cable a little too much and WHAM! - the NEW $112.50 CX600-NL relay self-destructed.  This would NOT have happened if that blasted RG142 cable had had the N-connectors installed properly!


That happened before I was able to test my successful adjustments above and I had to rely on a double-female "N" barrel connector to replace the relay.  I "might" be able to put the N-connector back on the relay if I can find a small enough Allen wrench but at this point, I'm just happy to have the power output of the K3S low enough to work with while continuing to pursue this project.

Now I really am going to bed and try to get rid of this shoulder cramping obviously brought on by all this stress!

WHUUPS! Two Steps Forward and One Step Backward

OK, today was the day to get the amplifier running.  I finished wiring the 3 kW 48 VDC power supply and connected it to the 220 VAC in the shack and to the W6PQL amplifier.   After double and triple checking everything (and removing the PTT cable from the amp just to make sure I did not accidentally put it into transmit) I decided it was time to swallow a few times and hit the AC ON button.  The "pucker factor" was fairly high at this point [grin].

Well, for a couple of seconds nothing happened and I was sure I had made a big mistake.  Then I heard a relay click, fans started running in the 3 kW power supply and the amp displayed 52 VDC on the PA Voltage meter.  WHEW!!!  Time to remember to breathe now!

I relaxed for a bit and let the system just coast along.  The air coming out of the back of the 3 kW power supply began to warm a little so I might need to think about relocating that power supply.  The output of the air is blocked a little and if I am going to be running long schedules, I will need plenty of cooling.

The next step was to key the radio and see if the amp moved into Transmit.  I put the K3S on 2-M, DATA A mode, dialed the PWR control all the way to the left where it was reading -10.0dB (0.10 mW), and I stepped on the footswitch.  WHUUPS - BANG!!

There was a noise, some relay clicks and the amp displayed a red LED indicating "Load Fail."  I had been expecting nothing at all to happen except the sound of the Sequencer relays and the "Transmit" LED on the amp to come on.  BOY, was I surprised.

 After letting my heart return to a normal rhythm, I turned OFF the amp and began looking at the K3S.  Without the amp inline, when I step on the footswitch, the RF meter on the K3S jumps way up scale, not often but sometimes even to full scale.  That could explain the "Load Fail" indication on the amp by there being WAY too much drive power.  I had previously changed the input attenuator on the amp so that I could drive it with a maximum of 2-1/2 watts instead of 10-watts.  If the K3S put out a spike when it began transmitting, that may have driven the amp too far and the protection circuit shut it down.  I do also recall seeing the Forward and Reflected power indicators on the amp jump upscale briefly before the amp shut down.  I really had no plans to "test" that protection circuit but it's good to know that it is working perfectly ! ! !

I tried adjusting the drive on the K3S with a single tone on the input.  As I turned the PWR control, the RF meter would indicate full scale as I was turning it then, when I stopped turning it, the RF meter would stay at a specific level.  It almost acted like the PWR control was dirty.

I saw where there was some discussion about this online.  The comments seemed to indicate that it might be a Power Supply issue.  So, I checked the built-in meter of the K3S and it indicates a Supply Voltage of 13.6 VDC in Receive and 13.3 VDC in Transmit (PWR control at minimum.)  This is pretty much normal.

On a hunch, I increased the TX Delay in the K3S configuration from 8 ms to 14 ms and that seemed to stop the full-scale power readings when the footswitch was pressed.  At the same time I returned the input attenuator on the amp to the maximum amount of attenuation so that I could input more power without an issue.

I powered on the amp again, pressed the footswitch, and YAY!, it did NOT give me a fault!  Just the "Transmit" LED lit up.  I then put WSJT-X in Echo mode and set the PTT method to VOX so it would NOT key the transmitter by itself.  The program would be going into Echo mode transmit but until I pressed the Footswitch, the radio would not transmit.  This worked and I had about 800 watts out very briefly.  I let up on the footswitch and reduced the Audio Drive Line Input to the K3S from 17 to 2.  This time no power out was noted.  I brought it slowly up and at a level of 5 noticed that there was a spike in the Power output and a sound in the K3S speaker when it went into transmit. 

Except for the spike, there was 10 amps of PA Current being drawn by the amp but no power out shown when there was a tone being supplied except for an initial spike of 800-watts!  Without the tone, there was just 2 amps of PA Current which was probably just the bias level with no RF input.  This test was done with the footswitch putting the K3S into continuous transmit and the WSJT-X Echo mode supplying the tone for a cycle of 3 seconds ON and 3 seconds OFF.  The "spike" I observed here was not from the K3S going into transmit, it was from the tone being applied which caused the K3S to generate RF that then seemed to be "choked" down to the level of -10.0 dB (0.010 mW).

The next test I tried was just sending CW.  Without the amp on, the K3S still seemed to have a bit of a "spike" when just sending the letter "E" but sending my callsign, the RF meter only indicated 1 bar.  I set the keyer speed to 40 wpm, turned on the amp and sent a single "E" and the Forward Power indicated 800-watts out.  This was with the K3S PWR level at minimum.  I then sent my callsign and it continuously keyed at 800-watts out.  Bad news is that I was hearing RFI from one set of computer speakers - that will need to be taken care of.  But, the good news (what little there is) was that there was NO Reflected Power indicated.  Looks like Charlie, N8RR, and his famous SARK Analyzer helped me get the antennas tuned nicely!

My last step was to check the power output of the K3S on 2-M.  I pulled out a Bird Model 43 wattmeter and looked through my slugs to find what I had which would measure close to 2-M.  I had a 5W slug that covered 400-1000MHz which was close.  Using a Narda 40-watt termination that was good to 12.4 GHz, that 5W slug measured 2.8 watts output with the PWR control set to minimum.  With the K3S PWR control at -4.0 dB (0.43 mW) the slug was reading full-scale or 5-watts.  Next I used a 25W slug good for 50-125 MHz.  At the minimum PWR setting on the K3S this slug measured 4.5-watts and reached 8.5-watts with the PWR control at maximum of 1.8 dB (1.50 mW.)  That pretty much tells me that at the very lowest PWR out setting of the K3S, it is putting out enough power to drive the W6PQL amplifier to 800-watts output even with the attenuator connected.   Maybe I need a larger attenuator to be able to have more control of the drive level to the amplifier.

At this point, I'm out of ideas and ready to go "chill out" a bit.  Looks like I need to call Elecraft tomorrow afternoon and see what they can tell me.

Saturday, October 28, 2017

Continuing Progress on the 2-M EME Project

On Friday, with the good weather, I thought I should go ahead and fix the Inclinometer installation.  You may recall that I had to compensate in the Rotor Driver program for the Inclinometer reading being off by a negative 5°.  The problem with that was that the system would not rotate below an "indicated" 0° which occurred when the antennas were actually 5° above the horizon.  What was needed was for me to climb the tower and rotate the antennas until they were horizontal, then move the Inclinometer to where it read 0°.  With the help of my lovely wife, Evelyn, that is exactly what I did.  Once I had the Inclinometer showing 0° when the antennas were actually pointing at the horizon, I then had to re-calibrate the EA4TX ARS-USB controller so that the Inclinometer tracks correctly all the way from 0° to 90° (straight up.)  Once that was done, I rotated the antennas to 90° and went outside to check - Yep, they were pointed straight up!  YAY!

I then removed the "compensation" in the Rotor Driver program so whatever the Inclinometer said was what the program took as correct.  Over the next few hours, I let the system AutoTrack and I kept visually checking the antennas and the elevation now tracked perfectly!  I still have the 7° "compensation" factor on the Azimuth readout but that is not a problem.  Not much else got done Friday evening because that "tower climb" set my back off and it was difficult to just sit in a chair.  It's a good deal better today but still hurts.

Today I thought I would finish off some more of the little bits of the project that were still hanging.  The first thing I tackled was to wire up the CX-600NL relay that switches the Elecraft K3S between the RX (receive) line and the TX (transmit) line to the W6PQL solid-state amp.  I first soldered a 1N4003 diode across the coil of the relay.  This is done because an inductor (the relay coil) cannot change it's current instantly so the flyback diode provides a path for the current when the coil is switched off. Otherwise, a voltage spike will occur that may cause arcing on switch contacts or possibly destroy switching transistors.  I then wired a shielded cable with an RCA connector on the other end to the relay coil.  This cable will plug into the "TR" connector on the DEMI Sequencer so that 12 VDC is supplied to the CX-600NL relay for switching it as necessary from TX to RX.  Being honest with you all, the first time I soldered this cable I had too much tension on the center conductor and the heat of the soldering iron melted the center conductor right through the insulation.  That could have resulted in a short at a later time so I cut it off, removed the soldered ends and did it again being more careful this time.  But, I wasn't careful enough with my finger as I managed to lay it "briefly" on the soldering pen and got a slight burn for my lack of caution!

Not having an elegant method of mounting this relay, I just installed a screw-eye in the back of the equipment shelf and used a Ty-Rap to secure the relay to it.  Again, I was less than careful and my first placement of the Ty-Rap interfered with the relay's motion so I cut it off and picked a better location the next time.  The photo on the right should be horizontal but Blogger insists on putting it vertical.  What can you do?

Another "self-inflicted" problem occurred when sometime later I tried to turn on the Kenwood PS-430 power supply for the Elecraft K3S.  It would not come on.  I pulled it out and checked the fuse which was good.  Luckily at that point (before beginning more extensive tests) I noticed that the power cable for the PS-430 had come loose and fallen behind the operating table!  I guess I did that while messing with the installation of the CX-600NL relay above.  Oh, well.  At least that was not hard to fix.

I had used an ohmmeter to find which of the relay ports was NO (Normally Open) and which was NC (Normally Closed) and I marked them with my label maker.  Next I connected the cable that runs from the Common port of the relay to the Elecraft K3S and checked the continuity of the center pin of the BNC connector on the radio end of the cable to the center pin of the N-connector on the NC contact of the relay.  All was good.  At that point, after cycling the relay several times from the Sequencer and checking that the contacts switched correctly, I connected the cables to the NO and NC ports and mounted the relay.  Just before connecting the other ends of the cables, I ran a final continuity check and the cable that connects to the NC port on the relay (and goes to the Driver Input of the amplifier) showed it was open.  I removed the cable from the relay to the amplifier and checked the continuity of the center pins and it was good.  But, when I put the cable back on the relay and checked it again, it was open.  I disconnected the cable and in looking closely at the connectors, I noticed the center pins on both ends were recessed much further than they should have been.

I measured the tip of the center pin as being 6/64" recessed from the reference plane of the connector!  Most of the N-connectors I looked at have that tip of the pin either even with or just ever so slightly below the reference plane.  The depth of the shoulder of the pin was 18/64" (0.28125 inches) from the reference plane.  That depth should be between 0.210 to 0.230 inches.  That meant these pins were, between 0.05125 to 0.07125 inches SHORT.  In the picture above you can see that the tip of the center pin is well below the reference plane.  This meant that because the center pins were so far back in the connector, they simply were not making contact with the center pin of the female connector. 

I tried to avoid problems like this in my project by purchasing NEW cables.  This cable was purchased January 18, 2016 as an N Male to N Male Cable 36 Inch Length Using RG142 Coax for $13.50 plus $3.35 shipping.  I guess I'll try to contact the eBay seller who sold me this for either a replacement or a refund.  In the short-term, I found a 1m N-to-N piece of 1/2-inch Heliax that I can use in the meantime.

It turns out that my checking of each step of this project has turned out to be a good thing.  I don't know how long it would have taken me to track down this problem if I had not been checking everything one step at a time. 

I have nearly finished wiring the 3 kW power supply for the W6PQL amp needing only to put the 220 VAC connector on the end of the cable.  Once that is done, I can hook it up to the 220 line and see if it will produce 48 VDC.  At that point, I'm ready to slap some RF to the amp and see if I can blow something up!

On the photo at the right you can see I have run the Red and Black cables from the output pins of the power supply through a toroid to hopefully cut down on any RFI from the power supply.  The Green, White and Blue cables at the top are the 220 VAC input cables.  The Blue cable runs through a switch on the front of the amp that switches the power supply on and off and provides protection from high inrush current that is common to switching supplies.

I also labeled and connected the PTT cable from the DEMI Sequencer to the W6PQL amplifier.  That is one other part of this project that has taken a bit extra time.  I have tried to document everything I have done on this project so that if need be, I will not have to re-invent the wheel if I need to trouble-shoot any future problems.  Also, I have tried to be meticulous in labeling all cables so that if anything becomes disconnected or needs to be checked, it will be obvious where that cable goes.  Plus, if I should need to disassemble and move the station in the future, it will be a snap to put it all back together.

Thursday, October 26, 2017

Big Day on the 2-M EME Project

Wheeeeee!  Big-Time progress was made today.  I did some minor work on the antennas by covering the driven element screws with Coax-Seal, putting some Silica Gel packets in the T/R Relay - LNA box to keep down the condensation, taping some of the control lines together, and making a small re-alignment of the rearward boom.  

The next step was to see how far off my rotor indicators were from where they should be.  I had a good visual on the moon so I had Evelyn use the Rain Proof Hoist Crane Pendant to move the antennas as I stood out in the yard to visually align them with the moon.  Once we had the moon square in the sights of the antennas, I went inside and looked at where the MoonSked program said the moon really was in Azimuth and Elevation from my QTH, and compared that to what the rotors indicated on the EA4TX ARS-USB rotor controller.  I then repeated that same operation four more times over the next hour or two.  As it turned out, my Azimuth reading was consistently 7° greater than what it should be and my Elevation reading was 5° less than what it should be.  Here is what the antennas looked like when we had the pointing "nailed."  Note that in the photo below you can see the moon lined up with the left-hand antenna. (Click on any photo to see a larger image.)

Now here is where things got GOOD!  I have a "driver" program that interfaces between MoonSked and the EA4TX ARS-USB unit and in looking at it, there is a "Setup" button.  When I opened the setup screen, there were two adjustments to "compensate" the readings between the two.  I inserted a +7° in the Azimuth box and -5° in Elevation box and told the driver program to "AutoTrack" the moon.  It adjusted the rotors to exactly where they "should" be pointing and I ran out in the yard to see that BINGO! - the antennas were indeed pointed right at the Lunar Orb!  WHEEEEE!  This is HUGE for my project to have the antennas actually pointing at the moon consistently and the AutoTrack feature working to keep them pointed there regardless of whether or not I can see the moon!

After that, I began running WSJT 10.0 as well as the MAP65 program while the AutoTrack kept my antennas pointed at the moon.  After about an hour, I saw on the WSJT EME - 1 chat page that K9MRI was calling CQ on 144.149 MHz.  I put my K3S on that frequency and WHAM! - the WSJT 10.0 program copied his CQ!  At 2309 GMT I copied his first CQ and then at 2313 I copied him with the best signal strength of -18 dB:

231300  6  -18  2.9 -283  3 *      CQ K9MRI EN70             1  10

K9MRI is running 8-M2 XP28 Yagi's and 1 kW.  So, he has a pretty big signal.  However, it is interesting to note that at 2300 GMT, the Degradation is 5.8 dB so not the best of conditions.  That probably explains why I was not able to copy the two or three 2-yagi stations that K9MRI worked over the next hour or so.  Still, I'm totally PUMPED that my receive is doing as well as it is.

But, I noticed that while I could copy K9MRI just fine on WSJT 10.0, I had zero copy on MAP65.  I began looking to see what could be causing that program to not receive and realized that when I had selected the Audio Source (which was for the FUNcub Dongle Pro+ SDR Thumb Drive) I had chosen the DirectX audio stream.  There was also an MME audio stream so I selected that instead and a few minutes later, MAP65 copied K9MRI - SUCCESS!

Now as I sat at the computer, I could see both WSJT 10.0 and MAP65 copying the signals off the moon.  This is AWESOME!!!  One reason I was trying to get the MAP65 program running is that it basically works like CW Skimmer in that it listens to 60 kHz of the 2-M band all at once and copies EVERY station it hears.  It prints out the messages that those stations are sending along with the frequency they are transmitting on, the audio frequency offset and the signal strength!  Since I was only able to copy one station tonight, here on the right is the "Messages" window of MAP65 showing the signals I actually copied!

The color code gives the most recent messages in Red, older ones in Yellow and the oldest in Gray.  All I need now is to have a little better conditions so I can hear more stations to see just how valuable this MAP65 program will be to me.

I can't wait for conditions to get better.  And, I am really, really close to being able to transmit.  I have the TX feedline connected, the wiring of the amplifier power supply is nearly complete, and there is not too much I still need to do to finish off this project.  If nothing gets in my way, it should just be a few days until I can echo test.

NEWS FLASH!!!  -  As I was typing this, the screen I was typing on was covering the MAP65 screen.  I just took a look and WOW, I had copied another station off the moon:

149 -151 0 0110 2.6 -26 # CQ K5LA DM61 0 23 0

I actually copied two CQ's from K5LA and this was the strongest one.  K5LA runs four 9-element yagis and is located in El Paso, TX.

Finally, on the left is a shot of the antenna array.  You can see the feedlines from the back of each antenna connecting to the power divider, which then connects to the T/R Relay - LNA box on the rearward boom, and inside that PVC box is the T/R Relay and the LNA (preamp.)

Lots of work has gone into this setup and it's about time for it to pay off!  Right now the moon is down to under 14° Elevation so it's time to shut things down and hit the sack.  I took a look out the front door and the moon is beautifully hanging over Hurricane.  Maybe I'll keep the station listening for a little longer just in case a VK, ZL or JA shows up [grin].

P.S.  A ZL did indeed show up on the Chat page but my noise had jumped up to S-9 so there was no chance for me to copy him.   Another time - I will!

Monday, October 16, 2017

Connecting the TX Inhibit Circuit to the K3S

In order for the TX Inhibit circuit which I built into the Sequencer (See HERE) to work with the Elecraft K3S, I needed to wire a couple of connections from the Sequencer to the K3S ACC jack and change some Menu Settings on the K3S. Since I already have other accessories connected to that jack, I purchased a DB15HD "Y" cable as well as a DB-15 Male Breakout Board.  The "Y" cable was connected to the K3S ACC jack, my other accessories were connected to one branch of the "Y" and the other branch was connected to the breakout board.  You can see the breakout board in the photo below with a 2-conductor shielded cable which connects Pin 7 (TX Inhibit line) and Pin 13 (BANDØ line) to the Sequencer.

DB-15 Male Breakout Board
The K3S has several Band Outputs which will produce either a Ø or a 1 condition with Ø being when the line is pulled to ground (Ø V) and the 1 being when the line is floating at 5 V.  These Ø and 1 outputs can be used to control many things.  In order for these Band Outputs to be used to control the TX Inhibit circuit, some settings in the K3S need to be adjusted.  First,

CONFIG:KIO3B is set to TRN.  This sets the BANDØ-3 outputs to reflect the parameters of the CONFIG:XVn ADR menu entry.  There is a chart in the manual that shows which conditions will be produced by different Transverter Addresses.  I chose the TRN setting for the CONFIG:KIO3B menu item instead of HF-TRN because using the latter would give me a 1 output on various HF bands in addition to 2-M.  Using the TRN setting, I only get a 1 output on BANDØ when the K3S is tuned to the 2-M band.  That is where I need to enable the TX Inhibit line.

As I'm using the Internal 2-M Transverter in the K3S, it is delineated as Transverter 1 (TRN1) and therefore, I set CONFIG:XV1 ADR to Int. trn1.  This causes the radio to output a 1 on BANDØ when the K3S' VFO A is tuned to 2-M.  With the above settings, I will ONLY see a 1 on the BANDØ output line when the radio's A VFO is tuned to 2-M and not on any other bands.

To make sure I really understood all this, I connected the lines from the Breakout Board to the sequencer with clip leads and a volt-meter.   When I would change bands I could see the 5VDC output vary according to where the CONFIG:KIO3B menu item was set.  Watching the output on BANDØ allowed me to also test the TRN and the HF-TRN settings as well.  Once I had that figured out, I used a clip lead to put the sequencer into transmit and could see that my circuit (KL7UW's circuit) was functioning properly.

The Sequencer contains a 5 VDC power supply which I built from a circuit I found by KL7UW and that voltage is used to control the K3S' TX Inhibit line.  From the K3S manual: "Pin 7 of the ACC connector can be configured as a transmit inhibit input by setting CONFIG:TX INH to LO=Inh (or HI=Inh). Holding pin 7 low (or high) will then prevent transmit."  Putting the TX INH setting to HI = Inh will tell the K3S to NOT go into transmit if there is a 5 V signal on that line.  The KL7UW circuit connects to Pin 13 (BANDØ) to determine when the K3S is tuned to 2-M.  If that line is HI (5 V) then the circuit turns on a transistor which then pulls in a relay.  That relay connects the 5 VDC power supply I built in the Sequencer to Pin 7 (TX Inhibit) to prevent the K3S from transmitting.

To make this work, I had to set the CONFIG:TX INH menu setting in the K3S to HI = Inh so that a HI (5 VDC) voltage on Pin 7 will prevent the K3S from transmitting.  When there is a HI (5 VDC) voltage on Pin 7 of the K3S, the front panel of the K3S indicates this by flashing the TX indicator.

The whole purpose of this TX Inhibit circuit configuration is to make sure that the K3S will NOT transmit any signal until the T/R Relay has completely switched to the XMIT position.  Stage 4 of the Sequencer connects internally within the Sequencer box to the KL7UW circuit so that it shorts out the 5 VDC supply that is connected to Pin 7.  That places a LOW (0 V) on Pin 7 and the K3S can now transmit.  But this ONLY takes place after power is removed from the LNA and the CX-600NL relay, the T/R relay is de-energized to place it on the TX position, and the Amplifier PTT circuit is closed.  ONLY then can the K3S produce a signal.  This is a safety circuit to keep the system from accidentally transmitting when it shouldn't. 

One more piece of the puzzle is now complete.  I am down to needing to install one connector on the TX feedline (7/8-inch Heliax), finish the amplifier power supply, and a couple of other minor items and I'll be ready to transmit!!!

Sunday, October 8, 2017

Another Great Night of Listening to EME Signals

EME conditions on 2-M were not really optimum tonight.  The degradation was -2.6 dB which meant there was some room for improvement.  Still, it was the ARRL EME Contest weekend and I expected there would be a lot of activity, but the weather forecast called for rain and I felt that if I could not see the moon to align the antennas, it would not be worth the effort to get up in the middle of the night!

I woke up just after 0730 GMT and saw moonlight outside so I thought "Hey, I can visually aim the antennas!"  Therefore I got dressed, fired up the station, rotated the antennas to where they should be pointing at the moon, and went outside to see how far off the antennas were.  However, the clouds had rolled in and I could not see the moon!  Bummer!  So, I started listening to the moon anyway about 0750 GMT since everything was turned on and hoped I could get the antennas close.

At 0819 GMT I copied K9MRI at -24 dB (K9MRI runs EIGHT M2 XP28 yagis and a kW) calling RI1F on 144.108 MHz. 

FileID Sync dB   DT  DF   W
081900  4  -24  2.6 -253  3 *      RI1F K9MRI EN70           1   0

Then at 0824 GMT I copied KL7UW (-26 dB) running 1200-1400 watts to 4 M2 X-20 antennas calling CQ on 144.117 MHz. 

FileID Sync dB   DT  DF   W  
083800  1  -24  5.3-1025  2 *      CQ KL7UW BP40             1  10

Then I copied KG6NUB (at -24 dB) which is a contest call of the Stanford Club (W6YX/QRO/4X5WL Stanfordclub CA CM87wj) calling KL7UW:

FileID Sync dB   DT  DF   W  
083900  2  -24  2.3 -961  3 *      KL7UW KG6NUB CM87         1   0

Back on 144.108 MHz I copied:
first, VE2PN at -22 dB calling RI1F (VE2PN/2X10H/600 Marc QC FN46jw):

FileID Sync dB   DT  DF   W  
091500  3  -22  2.7  186  3 *      RI1F VE2PN FN46           1   0

and then W4RBO at -23 dB calling RI1F (W4RBO/4X12H/K John FL EL99kf):

FileID Sync dB   DT  DF   W  
091900  2  -23  1.9 -213  3 *      RI1F W4RBO EL99           1   0

Just after that I copied NH6Y at -21 dB (NH6Y/4X9/1K5 Tom HI BL10ts) on 144.117 MHz:

FileID Sync dB   DT  DF   W  
093800  3  -21  2.3   32  3 #      K2UYH NH6Y BL10     OOO   1   0

and shortly before that K2UYH (K2UYH 2 x XP28 + kW) reported on PingJockey that he was copying NH6Y at -22 dB:

FileID Sync dB   DT  DF   W  
0928 -22  2.4 1295 #* CQ NH6Y BL10  ====== {K2UYH Team NJ FN20ll)

It seemed that I had a 1 dB better copy on the Hawaii station than K2UYH did with his pair of M2 XP28 yagis.  Cool!

After that I copied WØXG at -27 dB (W0XG/4M2XP20/K Eric MN EN34gx) calling K8DIO on 144.106 MHz:

FileID Sync dB   DT  DF   W  
101200  0  -27  2.2 -511  4 *      K8DIO W0XG EN34           1   0

Later I copied WØXG even stronger at -25 dB:

FileID Sync dB   DT  DF   W  
102200  3  -25  2.5 -519  1 *      CQ W0XG EN34              0  10

I then copied N1DPM at -24 dB (N1DPM/4X9/KW Fred MA FN32qb) calling CQ on 144.124 MHz.:

FileID Sync dB   DT  DF   W  
103800  2  -24  2.9 -301  3 *      CQ N1DPM FN32             1   0

Then the JA window opened and I copied JJ3JHP at -23 dB (JJ3JHP/4X12 Hiro xx PM75xd) calling CQ on 144.129 MHz.

FileID Sync dB   DT  DF   W  
104700  4  -23  2.8  -24  1 *      CQ JJ3JHP PM75            1  10

Later I saw a report on PingJockey from N1DPM (N1DPM/4X9/KW Fred MA FN32qb) that he had copied JJ3JHP at -21 dB with his four 9-element yagis.

At 1115 GMT I again copied JJ3JHP (JJ3JHP/4X12 Hiro xx PM75xd) calling CQ at -28 dB:

FileID Sync dB   DT  DF   W  
111500  2  -28  2.9  110  3 *      CQ JJ3JHP PM75            0  10

And right after that I saw on PingJockey this report:

111500  3  -25  1.5   -8  3 *      CQ JJ3JHP PM75            1  10 ====== (AC7FL/4X12H300W Stuart AZ)
which said with his four 12-element antennas, Stuart had a 3 dB better copy of JJ3JPH at the exact same time as I did with my two 13-element yagis.  Plus, I was experiencing a light but steady rain at that time.  That tells me that my system is performing on a par with other stations and that's good news to me.

Then at 1208 GMT I copied the Stanford station, KG6NUB, (W6YX/QRO/4X5WL Stanfordclub CA CM87wj) calling JHØBBE on 144.131 MHz:

FileID Sync dB   DT  DF   W  
120800  5  -22  2.7 -210  3 *      JH0BBE KG6NUB CM87        1   0

During the night I saw a couple of false decodes like this:

FileID Sync dB   DT  DF   W  
122600  0   -6  3.4  -89  3 *      W8TN FS5UQ FK88           0  10

It is curious because the DT parameter (4th from the left) of 3.4 seconds could be an EME sigal.  But, the -6 dB signal strength is just WAY too strong. 

At 1229 GMT I knew from PingJockey that NH6Y was calling CQ on 144.117 MHz.  I got a decent trace on several periods but only printed this:

FileID Sync dB   DT  DF   W  
123200  1  -26  2.3 -170  3 *  
123400  2  -26  2.3 -172  3 * 
123600  3  -25  2.3 -172  3 * 

Finally I copied this:
FileID Sync dB   DT  DF   W  
123800  7  -22  2.3 -175  3 *      CQ NH6Y BL10              1   0

Although I had earlier copied JJ3JHP as strong as -23 dB, and he announced on PingJockey at 1244 GMT that he was calling CQ on 144.105 MHz., I was not able to see even the slightest trace over 3 periods.  It sure looks like Faraday rotation changed the game!  However, on the 4th period, I did copy the following which has a DT that agrees with my earlier copy on JJ3JHP:

FileID Sync dB   DT  DF   W
125300  0  -32  2.9 -552 41 *      

I did see on PingJockey that Art, N9BCA, worked NH6Y for his State No. 50.  Art said:
08 Oct 12:49 nh6y  THIS IS ONE OF MY HAPPIEST DAYS EVER TKS #50  73 ====== (N9BCA Art WI EN54ll)
Later I saw on the chat page that K2TW said he would call NH6Y on the next sequence on 144.117 MHz.  Shortly after that I saw TWO traces in the same period, one at -30 Hz and one at -192 Hz.  I decoded both and got this result:

FileID Sync dB   DT  DF   W  
130000  6  -27      -192  2   RRR                                 
130000  2  -30       -30  4   RO          

Followed by:
FileID Sync dB   DT  DF   W  
130200  4  -29      -192  3   73  

I wonder if there was another station that thought NH6Y was calling them too at the same time?

I then saw this on PingJockey:
08 Oct 13:02 NH6Y Tom tnx first HI, bet you hear that a lot! 73 ====== {K2TW/4XP9/KW Tom NJ FN20ll)
So it looks like I "sort of" copied K2TW - at least on his "RRR" and "73" transmissions.  I'm gonna count it!

At 1308 GMT N9LHS was going to call NH6Y on 144.117 MHz so I kept listening on that frequency.  But, I did not hear anyone.  My EL was down to 13° so I don't know if it was too low at that point.  I continued to listen to stations who announced they were calling CQ like BX4AP (BX4AP/4X9H Jesse xx PL04if) and N4HB (N4HB/4X7H/750 Henry VA FM17uu) but I was never able to copy anyone.  Maybe the moon was too low at this point for me.

My best copy of the night was NH6Y from Hawaii at -21 dB.  Tom (NH6Y) was running four 9-element yagis and 1,500 watts.  The two smallest stations I copied tonight were running less than or essentially the same as what I am running:
VE2PN - two 10-element yagis and 600-watts
K2UYH - two XP28 yagis and a kW

All in all, this turned out to be a WONDERFUL night of playing EME even though all I could do was receive.  I was able to copy 10 different stations off the moon from the USA, Alaska, Canada, Hawaii and Japan.  Now that's pretty sweet!  I also learned that I can copy stations even during a rain storm and that my received signal seems to be pretty close to what others are reporting for the same station at the same time.  I am really glad that I did not go back to bed when I saw the clouds had obscured the moon.  It really paid off for me!  And, it REALLY makes me want to get the transmit part of the station operational!

Saturday, October 7, 2017

First Signals Off the Moon Decoded!

This is what I've been working toward.  Being able to make QSO's via MoonBounce (EME) starts with first being able to hear stations over that path.  The old ham radio adage of "If you can't hear 'em, you can't work 'em" certainly applies to EME.

Last night was the beginning of the first of two ARRL EME Contest weekends.  I had been pushing hard for the last 17 days or so to get the station operational by the contest.  The way I have the antenna array mounted on the Hazer, I am limited by how much I can rotate the antennas around the tower until the Hazer is at the top of the tower.  Until then, I am able to only reach 180° from the West so until the moon reached that position, I had no chance to see if things were working.  Last night that meant that I would not have moon until 0620 GMT (or 2:20 a.m. EDT.)  I set my clock for 2 a.m. and got about 4 hours sleep before getting up to see if things would work.

All the equipment was ready to attempt receiving but the transmit side has more work to be done.  Once I got everything powered on and properly connected, I started running WSJT-X and immediately saw there was a problem.  The screenshot below shows the birdies that were populating the spectrum. 

The first minute or so shown at the bottom of the above image (07:56-07:57 GMT) was with no antenna connected.  Then I connected the antenna array and the birdies got much worse.  I was pretty bummed out after all the work I had done on this project.  But, after some time I finally tracked it down to the video card in the XP computer.  When the monitor went to sleep, the noise disappeared.  Just turning the monitor off did not help so I believe it is the video card.  At that point, I shut down the XP machine and went back to using the WIN 7 computer.

It took a bit to get everything re-configured to the Win7 computer but finally that was done.  I went outside several times to visually check the alignment of the antennas as I knew the inclinometer and the azimuth rotor were not calibrated.  Having the Rain Proof Hoist Crane Pendant at the base of the tower to control the rotors made it really easy to point the antennas at the moon.

Then, at 1014 GMT (6:15 a.m. EDT) I saw my very first JT65B 2-M EME signal decoded!  YIPPEE!!! 

Below is a screen shot of what I copied.
  You can see the DT parameter says the signal arrived at my QTH approximately 3.4 seconds after it was sent.  That time (about 3 seconds +/- the difference between the computer clocks of both stations) is the round-trip for the signal at "speed-of-light" to get to the moon and back.

My received signal strength on him was -26 dB and the * after the "1" in the W column indicates that an adequate level of synchronization has been achieved.  Again at 1046 GMT (6:46 a.m. EDT), I copied another CQ from N1DPM.  This time his signal was -23 dB or 3 dB better than the last time.  N1DPM is running four, 9-element yagis and a kW. 

Then, at 1110 GMT (7:10 a.m. EDT) I copied my second EME signal.  In the screenshot below you can see that K9MRI was -27 dB, and the DT was 2.7 seconds so another real round-trip to the moon and back.  K9MRI runs EIGHT M2 XP28 yagis and a kW.  BIG antenna system!

This was really gratifying to be able to copy signals off the moon even though the system is still hay-wired a bit.  I then spent some time trying to get the MAP65 software operational.  I did manage to get it working on the Win7 computer and copied a local EME'er, Roger, KD8BZY, direct but not off the moon as I could no longer see the moon to aim the antennas. That did show that MAP65 was working.

Now I need to work on calibrating the rotors and getting the transmit side working.  I won't be able to have it done this weekend but will have it operational on transmit before the next ARRL EME Contest weekend in November.  BIG-TIME Progress to this point!  I CAN now receive EME signals!!!  It won't be long until I can start making QSO's.

Tuning the Antennas

On Friday morning, Charlie, N8RR, came and brought his SARK-110 Antenna Analyzer to my QTH to check out my 2-M antennas and tune them for best SWR. With the SARK hooked to his laptop we were able to make the adjustments to the driven element pretty easily.  We would pull the antenna array up with the Hazer until it was several feet in the air and rotate it until it was elevated at about 45°.  Checking it with the SARK told us where the SWR was for the lower part of the 2-M band.  Then we cranked down the Hazer and made an adjustment to the driven element before cranking it back up to check it with the SARK again.  It took about 3 tries to reach the lowest SWR.  Interestingly enough, there was no traditional "dip" just a very FLAT response curve.  We expanded the range of the SARK Analyzer to see what happened to the curve down in the 130 MHz range and that told us we needed to shorten the driven element to move the lowest SWR up into the ham band.  Once we got an acceptable match on the first antenna, we then adjusted the second antenna to the same dimensions as the first in just one operation.

The installation instructions for the antennas said to adjust the driven elements until the opposite sides of the driven element were 908mm apart.  After our tweaking, we ended up with the opposite sides being 878mm apart.  That was a total change of less than 1.2 inches (or just over 1/2 inch per side.)

Once we had both antennas tuned, we combined them with the 2-way power splitter and measured the SWR of the combined array to be 1.27:1 at 144.473 MHz.  At 144.200 it was just 1.28:1 and essentially FLAT across almost the lower 2.5 MHz of the 2-M band.  You can see the SARK's plot of the combined antennas below:

On the above plot the blue line represents the VSWR and the red line represents the Zs or absolute magnitude of the antenna's impedance.  As you can see, between 144 and 145 MHz, the VSWR is very close to 1.3:1 and the Zs (impedance) is right near 50 ohms for the ENTIRE range!  (The VSWR scale is on the left and the Zs scale is on the right. Click on the image to see it larger.)  For example, we set the cursor at 144.2 MHz and at that point the VSWR was 1.28:1 and the Zs was 49.6 ohms.  The Blue Triangle on the plot represents where the SARK found the minimum VSWR of 1.27:1 at 144.472.804 MHz.

At that point, we felt confident that the antenna array would play and called it a day.  Charlie had to get back home so we did not have time to calibrate the inclinometer nor do a couple of other small jobs that will need to be done later.  Still, this was a great step forward in the EME project. 

Thursday, October 5, 2017

Finishing the LNA and T/R Relay Box

On Wednesday I tackled some odds and ends of this project.  More epoxy was mixed and applied to the holes in the PVC box to house the LNA and T/R Relay.  The box was free to me but had some 10 1/2-inch holes with cable feedthroughs attached.  I did not need all those holes so I plugged them with epoxy.  That was a learning experience as with the first 4 holes I tried to just put the epoxy in the hole and expected it to stay.  But gravity would pull the epoxy down and open up the hole.  For an hour and a half I kept rotating the box around and around hoping the stuff would set up but it didn't!  At that point I had Evelyn cover a 3x5 card with plastic wrap and I placed that over the 4 holes on the inside of the PVC box.  I then found a cardboard box that would fit inside and apply pressure to the plastic wrapped card.  That worked like a charm.  The next morning the plastic wrap pulled right off and the holes were filled.  Learning how to do that made filling the rest of the holes a snap.

My Step Drill Bit arrived on Wednesday but I had just epoxied the barrier strip to the side of the PVC box so I needed to let that set up before drilling the three 7/8-inch holes for the N-connectors.  A couple of trips to Home Depot were required to obtain some small hardware for mounting the T/R Relay and for the driven element connections on the antennas.  I decided to go ahead and weatherproof the cables going from the antennas to the 2-way power splitter by wrapping them with Scotch 88 electrical tape.  InnovAntennas had already prepared those cables for me with the appropriate connection tab at the antenna end along with Ferrite cores in water-sealed heatsink and N-type male connectors on the other end.  Still, I used the Scotch 88 tape to seal everything as water is a major problem with coax.  At this time I determined which terminal was connected to the center-pin of the N-connector and marked it with red tape.  Both antennas had that terminal connected to the same side of the driven element to assure the antennas would be in-phase with each other.

I then manufactured a mount for the inclinometer from a piece of aluminum angle and a DX Engineering 2-inch clamp.  I knew I could rotate the clamp around the cross-boom to adjust the inclinometer to the correct reading but when I drilled the aluminum angle part for mounting the inclinometer, I elongated one hole.  This would allow me a way to "fine tune" the adjustment.  It was well after dark when I had this ready to mount to the antenna so I asked my wife, Evelyn, to help by reading out to me the elevation angle from the EA4TX ARS USB controller while I made the appropriate adjustment to the inclinometer mount while up on a ladder.  That worked great!  However, when I rotated the antenna and checked the elevation with a digital level, the reading on the ARS USB box did not agree.  Looks like I need to calibrate the inclinometer.

Using the Step Drill Bit it was a SNAP to enlarge the one hole and drill two others large enough to pass a cable with an N-connector attached through the PVC box.  Having the right tool makes a huge difference in any job.  This is probably not the best tool for this job but it worked great for me!  Once I was able to pass a cable through the side of the box (simulating the cable that would come from the power divider) it was easy to position the T/R relay and drill a couple of mounting holes for in in the metal plate that was already attached to the bottom of the PVC box.  The LNA would just be supported by the connectors so no mounting was needed there.  With the T/R Relay mounted, I now moved on to wiring the relay and LNA to the barrier strip.

I made sure to put a diode across the coil of the T/R Relay.  This is done because an inductor (the relay coil) cannot change it's current instantly so the flyback diode provides a path for the current when the coil is switched off. Otherwise, a voltage spike will occur that may cause arcing on switch contacts or possibly destroy switching transistors.

The T/R relay I am using (Relcom RDL-SR012) has a set of contacts that will indicate when the relay has switched.  There are three contacts: C-Common, NO-Normally Open, and NC-Normally Closed.  I wired those to the Barrier Strip and a shielded cable brings them down to the shack.

 12 VDC connections for the LNA and 24 VDC connections for the T/R Relay were also wired to the barrier strip.  They will be connected over separate shielded cables to the appropriate voltage sources in the shack.  In the photo on the right you can see everything hooked up.  Three shielded cables exit the box through one of the feedthroughs that came with the box and they are color coded (to try and prevent me from making more mistakes!)  The LNA is at the bottom (mounted on a slight angle to allow for easier cable entry into the box.  The T/R Relay is on the bottom and the Barrier Strip on the right.  You can see markings on the inside of the box above the Barrier Strip to note what gets hook to what screw.  The LNA is connected to the Normally Open contact on the T/R Relay with a right-angle N-connector.  This just keeps the loss to a minimum and makes the box less crowded than if I had used a cable.  All the spade lugs are crimped AND soldered.  Why?  Because I'm excessively fussy (some would say "anal!") You can click on any photo to see a larger image.

The last few things I did before calling it a day was to install a clamp to hold the 7/8-inch Heliax (TX feedline) to the Hazer cage.  Then I put the cover on the LNA and T/R Relay box and weather-proofed the holes around the cables.  Finally, I rotated the antennas to exactly vertical (90.0° on the SmartLevel) in order to calibrate the inclinometer.  Much to my surprise, the EA4TX ARS USB controller says the array is pointed at 94° so that was nice.  I may not have to do much to finish the calibration of the inclinometer.

I woke up this morning at 4:00 a.m., checked the beautiful moon, but then could not get back to sleep - I was too excited and my mind would not stop thinking about this project.  Right now my battery has pretty much run down and I'll be crashing soon.  Should have no trouble sleeping tonight!

Tuesday, October 3, 2017

WHEEE! The Antennas are Mounted and Aligned

WHAT A DAY!  My good friend Tim, K8RRT, came by today to give me a hand with mounting and aligning the antennas.  It's pretty certain that without his help, I would not have been able to do this on my own, even with Evelyn helping.  There is only so much I can do by myself at my age and having Tim give me a hand when I need it is priceless!  THANKS, TIM!!!

Yesterday was a day that did not go very well.  I spent a lot of time trying to find a drill bit or some way to drill a 7/8" hole in my PVC box for the LNA and T/R Relay.  The local electrical supplier had a Unibit that would have worked but they wanted $51.60 plus tax for it.  Too rich for me.  Finally I ordered one from Amazon that will be here tomorrow for $9.98 total.  But all the running around yesterday including getting blood drawn led to me forgetting to take my daily medications.  Coupled with a couple of short nights, I was pretty bummed out and "couch bound" for the afternoon/evening.  But, after a good night's sleep and taking my meds, I got up this morning in a much better mood and feeling like I could whip anything.

On Sunday I had gone to Lowe's and purchased a 1-3/8-inch diameter Poplar dowel rod.  I bought this because when I first attached the antennas to the Fiberglas boom, I was uneasy with tightening the bolts too far for fear of cracking the Fiberglas boom.  I bought the dowel to make a plug to fit inside the boom and provide strength for it.  Unfortunately, the dowel was just a tad too big to fit.  Therefore, my first job this morning was to clamp it in the WorkMate and run sandpaper over about a foot of the rod until I sanded off enough wood that it would fit.  It only took about an hour or so and four trips up the stepladder to check the fit.  Once I had the dowel sanded down to size, I cut two 6-inch pieces off the end and sanded them again.  At that point I gave them a light coat of Polyurethane as you can see in the photo on the left.  Throughout the morning, I gave another coat every 1-1/2 hours for a total of 3 coats.

When Tim and I had reached the point where we were about to align and tighten the antennas, Tim inserted the dowel plugs with a light coating of glue to make sure they stayed in place.  When he tightened the antenna-to-boom mounts, he said he felt very comfortable with the plugs in place and was really able to tighten the antennas to the boom.  NOTE:  After looking at the photo on the right, I decided to drill a drain hole in the lowest point of the Fiberglas cross-boom to allow any accumulated water to exit the tube.  This should prevent water build-up and subsequent freezing that could fracture the tube.

Tim and I also installed the rearward facing boom to support the LNA and T/R Relay Box as well as the 2-way power splitter.  We aligned it in the same plane as the antennas and put most of the hardware (LNA, T/R Relay, barrier strip, coaxes, etc.) onto the rearward facing boom to see how well the system was balanced.  Once we had all the materials in place, we engaged the Elevation rotor to pull the front of the antennas off the roof.  Everything held in place and the Elevation rotor was easily able to move the antennas up and down so we decided that the balance was close enough.

There was a good bit of "trial and error" in getting the antennas aligned and Tim was really patient with me (who wants everything PERFECT) and we did it again until the two antennas were "nearly" perfect.  "Good Enough for Government Work" was the standard we settled on - Hi!

Once the antennas and the rearward boom were aligned, we raised the Hazer cage high enough to be able to play with the rotors.  My external Rain Proof Hoist Crane Pendant shown at the right was just exactly what was needed.  Not running into the shack to turn a rotor!  SWEET!  At this point we calibrated the elevation rotor to the array by loosening the clamps on the Elevation rotor and running the rotor until it matched the measured angle of the array.  In practice I will be using an Inclinometer but I wanted to make sure the rotor was not near a "stop" that could cause operation of the rotor to cease at an unexpected point.  Click on any image for a larger view.

When we finished all the above work, Evelyn had prepared a scrumptious lunch of "Meat Lover's" Lasagna, tossed salad, broccoli with cheese, Brussels Sprouts, and Garlic Bread.  Then chocolate iced chocolate cupcakes for dessert.  YUMMMMM!  Just what a couple of tired Antenna Jockeys needed!  THANKS, DEAR!

We then took a 15 second video of the antennas in motion which you can see on YouTube at the link below:

The video shows the antennas moving DOWN and then CCW.  Note that at that point they are moving in both directions (Down & CCW) simultaneously.  If you pause the video just before it ends, you can see a square metal tube (the rearward boom) extending to the rear of the array between the antennas.  Near the end of this is the grey PVC box for the LNA and T/R Relay.  Beyond that is the Power Splitter to which each antenna connects.  The antennas will normally be much higher on the tower.  I just kept them low so that we can adjust the tuning of each of the antennas and so that I can wire the cables into the LNA/Relay box.

This was a BIG-TIME day on the 2-M EME project.  I'm getting so close I can almost taste the moon-rays!