23cm EME Roving Station Checkout Complete March 5, 2022

I drove an hour away from my base location in EL87 to the Eastern edge of EL87 in a nature preserve.  As expected this was a very quiet RF location.  I was able to complete final testing of my 23cm EME roving station and it is ready for the road.

Today I made 20 Q65 contacts on 23cm.  Thank-you everyone who took the time to call.  I was able to complete QSOs with several stations I could not hear at my base location.  Today's location did not have any man-made noise visible when I scanned the path of the Moon.  In my home location I see up to 17db of man-made noise above the noise floor.  I will not set up my station at home in the future :-)

From parking the truck to the station on the air took 15 minutes this morning.  Packing the station back into the truck also took only 15 minutes.  So I guess I don't have any excuse to not use the station.

The key components include:

• ICOM 9700 (running on 144mhz using transverter)
• Q5 144 to 23cm transverter
• 500W 23cm PA built using W6PQL pallette
• Honda 2200 generator
• 3000W 110v to 220v autotransformer
• W2HRO 2.4M folding dish
• Yaesu G5500 AZ/EL rotator
• Homebuilt tripod with tiedowns to large stakes
• LNA .21dbn/f WD5AGO preamp, 23cm cavity filter, silver plated
• Patch feed for dish (W2HRO)
• 25' LMR600 connecting dish to PA in back of truck (<1db loss)
• Digital protractor for leveling tripod and verfiying elevation

Following are photos and descriptions of components

Front view of the dish.  The feed is held by a stiffened fiberglass pole that has no sag.  Notice the minimal blockage of the dish area.  The feed remains on the dish when it is folded and stored in a patio umbrella storage bag that hangs in the back seat area of the truck

Closeup of the feed assembly.  WD5AGO preamp connects to isolation relay that terminates preamp in 50 ohm dummy load during TX.  Black box underneath is the hybrid combiner between the RX/TX connections and the patch feed to produce circular polarization.  The 23cm cavity filter is after the preamp.  The loss in the cavity filter is only .7db so it could be put in front of the preamp is extreme conditions.  The RX small coax (37db gain in the preamp) and 5 foot section of LMR400UF are connected at the right.  27VDC for the relay and 12VDC for the preamp are delivered through shielded coax.

Rear view of the dish.  G5500 rotator is mounted on a 1 inch thick wooden base with three 48 inch pipes for the tripod legs.  A steel mast section runs through the elevation rotator and the dish quick-release clamp is mounted to the mast section.  The wooden box contains a 20 lb counterweight.  The counterweight is removed when the elevation exceeds 50 degrees.  The orange straps are under tension and hold the tripod base completely still.  The digital protractor is on the right side of the rotator with magenetic attachment to the pole.  The tripod is adjusted to level after the dish and counterweight are installed.

Closesup of the 3 foot 1 inch diameter stakes with tie-downs attached under the dish.  Tension is applied to level the tripod base under load

The 110v to 220v autotransformer is visible in front of the PA box.  The autotrnasformer and PA are mounted in the truck bed.  Four cables, rotator, 12v/27vdc, RX coax, TX coax coil for storage to the leve of the PA and are rolled out and connected to the dish.  Only takes a few seconds to connect dish to truck systems

The 500W PA and 3500W 48VDC Meanwell power supply are mounted in a plastic box.  Input from the transverter is at the top.  At the bottom is a 250W circulator which connects to the 25' of LMR600 to run to the dish.

One of two Honda 2200EUi generators is shown connected to an external gas tank.  I use one generator when operating a single band and two generators when operating on two bands at the same time.  Both generators are fed gas from the external fuel tank which can run both generators for two days of operations before refilling the external tank.  No pouring of gas into generators.  On top of the truck are the 2M, 222Mhz and 70cm EME yagis in assembled form.  In the box on the right are the EME antenna tripod, 30 foot mast for back of truck used for MS and FT8 operations.  Not visible are a 2M7 7element 2M yagi for terrestrial use and two 6M3 3-element 6M yagis that can be stacked and phased on the 30 foot mast

This is a Windows 10PC with two additional monitors that mount on the side.  I use the center screen to run two instances of WSJT-X.  The left screen is used for chat pages.  The right screen is used for rotator control, tuning the SDR and monitoring RX noise level in realtime.  The right WSJT-X instance was used today to run 23cm QSOs.  The left instance was using an SRDPlayDuo SDR radio to provide an RX monitor for the 23cm band.  WSJT-X can display 5khz bandwidth when using the SDR.  I would tune the SDR to look for other stations to see if I could copy them while I ran QSOs with the right screen.  I can also run MAP65.  When running on two bands simultaneously, the WSJT-X instance on the left uses a second ICOM radio.  A single USB cable from the PC goes to a USB hub attached to the side of the ICOM radios.  I tried multiple USB hubs and found one that is RF quiet.  The USB cables from the hub to the ICOM radios, SDR, GPSDO are only 6 inches long with multiple ferrites. When I point the dish at the truck I don't see any USB noise.

This is a closeup of the right monitor.  The Spectravue program runs on the lower left and monitors the RX base noise level in realtime in db.  When I set up I set the RF level of the RX path so that in the quietest direction the noise line (FFT) is at the bottom of the screen.  I then point to the sun and set the Sun noise level to the maximum on the display.  As the dish tracks the moon I can clearly see when the dish is encountering increased background noise.  Today the background noise did not vary by more than 1 db as I tracked the Moon.  At my home location I see 17db variation!  The pstrotator application is at the top right.  The upper left is the tuner for the SDR radio.  The Doppler control for the WSJT-X radio instance is on the lower left

The screen on the left is used for chat pages.  When running two bands at once I have two windows open

I am using the ICOM 9700 GPS stabilized and the ICOM 7300 at the primary rafios.  The ICOM 9700 is used as the exciter for 2M, 70cm and 23cm.  The 7300 is the exciter for 6M, and 222 Mhz.  The ICOM 705 is the backup radio and can be used for any of the roles.  The two ICOM radios are mounted together.  The sequencer on the top used for 70cm is mounted to the 7300.  The SDR is mounted to the left of the 9700 and the USB hub on the right of the 9700.  The GPSDO and PTT protection devices for the ICOM radios are mounted on the bottom of the 9700.  The complete stack is stored sitting on the wooden table to the left below the console.  All power/antenna/switching, etc cables remain connected.  As a result preparing the inside of the truck for operations only requires moving the ICOM radio stack from the storage table up to the location on the console.  The PC closes up and sits on the passenger seat.

This is the view out the front of the truck from the operating position before setting up the sunshades

Custom fit metalized and insulated sunshades cover the front window and the two front seat windows.  The shades make it dark inside and block almost all of the heat from outside

The umbrella bag containing the folding dish is hung using bungy cords in the "passenger" section of the truck.  The KW PAs for 6M, 2M, 222Mhz and 70cm are mounted as before in the back of the truck.  When 23cm is not being run, the dish hangs where it is while other bands run.

On my trip this Summer I will be taking spare PA's for 6M, 2M, 222, and 23cm.  I have spare LNAs for all bands and spare relays.  I have spare rotators and computers. I also have spare antenna elements in case I manage to drop/damage antennas.

I plan to do several local "grid activations" on 23cm before going on longer trips.

Currently it looks like I may start activations in the New Mexico/West Texas/Oklahoma area starting in April and May.  In June I will go back to Florida and grab my RV trailer to start the June-October trip.

Only one bad photo from today.  Filled the truck with diesel on the way home :-0