NX7U

Scott Townley
Gilbert, AZ

Initial Equipment
Motivation
Why not HRD?
Piece Parts (software)

- com0com
- USB over Ethernet
- LabJack helper
- IP-Sound
- CW-Type
- SatPC32
Interfaces (hardware)

- NOMIC  AF transformers
- labjack
- optoisolated cw keying
- Wattmeter
- ALC
- edgeport/4
- relay board
- G-5500 rotor controller + Fox Delta ST-2
Internal Functions (IC-910H via CAT)

- preamp on/off
- PTT
Block Diagram
Operational Considerations

satpc32 cat delay
af level setting
Initial Equipment
Motivation
Why not HRD?
Piece Parts
Interfaces
Operational Considerations
Some notes:
IC-821H uses electret microphone, measured AF input at MIC jack ~6mV rms @ nominal MIC GAIN setting.
Rear panel ACC jack rated 300mV or 2mV at ?, measured ?
HP NC6230 laptop (for remote), measured 0.3V rms max AF output
Delay parameter in SatPC32 CAT
Calibration equation for Bird 43 wattmeter:  %FSPower=0.0762V**2+0.2167*V-0.0051
Private ports 49152-65535
Block Diagram
I started with a functional satellite station–an Icom IC-821H VHF/UHF all-mode radio, 2m and 70cm mast-mount preamps from Advanced Receiver Research, and a 2m and 70cm set of HO-loops from M2 Antennas.  I also have a laptop in the shack running SatPC32 for satellite pass prediction and radio control (SatPC32 is very good at Doppler adjustments).  Eventually I acquired a Yaesu G-5500 Azimuth-Elevation rotator and controller box for a pittance, and after much searching a pair of old KLM dual-CP yagis (2M-14C and 435-18CM).  Now I could have a "real" satellite station with auto-tuning, auto-tracking, and directivity!
The problem is that I don't really have a good place to put the satellite yagis.  I live in the suburbs on a larger-than-average (for this area at least) city lot, but with the notorious HOA restrictions on towers.  The best place for the antennas is in the back corner of my lot, as far away from all the neighboring houses as possible, but of course this is about as far away from the shack as possible too.  I was looking at two 250' runs of coax, two sets of heavy-duty 6-conductor rotor wire, preamp power, polarization control...a small fortune in copper.  Not to mention how good it would look to run all this across the backyard. 

It occurred to me that a solution would be to put all the radio hardware right underneath the antennas and remote-control the lot of it from the shack.  Minimal coax loss and even better, minimal copper expense!  Just AC power (an outdoor extension cord) and a single CAT 5 run.  I then started reading up on everything related to Internet Remote Base installations.
All the stations that I found with any detail around their configuration were HF stations.  This information was certainly useful, but didn't address some of the specific requirements of a satellite station, primarily:  (1) automatic and autonomous dual-VFO control for Doppler tracking, and (2) support of az-el rotators.