Dishes for Amateurs
The price was right for this dish - FREE. Wives call them BUDs (Big Ugly Dishes). It was originally used for 4 GHz TV Receive Only (TVRO). Replacing the C band feed at the focal point turned it into a great ham antenna. On a 10' dish, the tri band feed has measured 35 db of gain on 2401 MHz, 29 db of gain on 1269 MH, and 18 db on 435 MHz. 35 db of gain makes a 1 watt signal sound like 2 KW! This feed system works AO-40 with as little as 1/10 of a watt on 1269 MHz achieving maximum allowed signal level into AO-40. Take the C band feed off that old TVRO dish and attach a ham band feed system and convert the mount to elevation and azimuth automatic control for a great ham satellite antenna system.
10' Janeil TVRO Dish Converted to Amateur Use Tri Band (2401 MHz, 1269 MHz, & 435 MHz) Patch Feed
Click on a topic for a fuller explanation. Clicking on a thumbnail image will produce a larger image.
Amateur Applications for your BUD
A TVRO dish can be can be converted with minimal effort to function very well in a number of uses. I used mine to receive AO-40 on 2.4 GHz.
Though A0-40 died a few years ago, don't discard that big dish yet, as some of the near term LEO satellites may be using the S band for communications. Rumor has it that the Phase 3E, another High Earth Orbit Satellite from Europe, might be flying in the Spring of 2007 and an a good TVRO dish will be needed again.
This webpage will show you how an old unused BUD can be converted to a great ham antenna system. The existing polar drive components will be used for the elevation axis and a new azimuth system designed like the model at the left to be used on the azimuth axis.
Other uses are EME (Earth-Moon-Earth) experiments, Radio Astronomy, and SETI (Search for Extraterrestrial Intelligence). These applications may require two axis movements, though Radio Astronomy & SETI often use "Drift Scan" - letting the earth's rotation provide one axis of movement..
TVRO dishes should work great on DSP EME. JT44 mode looks like a new world is arising. Read K1JT's article in the Spring issue of CQ VHF magazine. You can read about and download K1JT's latest freeware version of JT44 here.
Dishes come in many sizes and shapes. Each has advantages and
disadvantages, so it is important to understand several items. Don't start off
on a giant sized dish; start small and build up to the giant sized dish. Doubling
the size of your dish will gain you 3 db, but may take 20 db of effort!
General - Diameter, Focal Length, Construction, Gain, Beamwidth, & Windloading
Small - 18" Hubcaps, 3' Barbecue Grills, PrimeStar Offset fed
Medium - 4' Aluminum solid, 5' Aluminum mesh, 6' Aluminum solid, 7 1/2' Aluminum mesh
Large - 10' Steel Mesh, 10' - 14' Fiberglass, 15' - 16' , Giants
You have to put out a signal to the dish or receive a signal reflected by the
dish. But all dish feed systems are not equal, and a dish feed system that works
great on one dish may be a real loser on another dish. At 2401 MHz, a Campbell's
soup can lid makes a nice antenna and a peach can makes a scalar ring reflector.
Dipoles & Reflectors
Single band Helix (2401 MHz)
Dual band helices (435 MHz & 2401 MHz)
Single band Patches (2401 MHz), (1691 MHz) and (1420 MHz)
Dual band feed systems (435 Mhz & 2401 MHz) and (1269 MHz & 2401 MHz)
Triband patch feed system (435 MHz, 1269 Mhz, & 2401 MHz)
Dual circularity patch feed systems for AO-40 & EME with your TVRO dish.
AO-40 transmits its downlink on 2401 MHz, and your rice box doesn't go that high? No problem, just get a down converter that brings the 2401 MHz downlink frequency to a receive frequency that your radio covers. New downconverters designed just for 2401 MHz satellite use are available, but most hams use converted MDS downcoverters to pick up AO-40. Sometimes the noise figure isn't so good, so just add a low noise preamp and hear the weak ones.
Rigs and Coax for Amateur Satellite Communication
There are many potential rigs, but only 4 top
runners. Some satellites are FM, but most are SSB and CW satellites. Get a good
all mode rig and antennas to match. I connected an ICOM PCR-1000 PC based receiver
to my satellite station so I can see all the satellite activities at one glance.
Amazing what you can see. The signal coming down from AO-40 is not very strong.
And the stations are 10 db (almost 2 S units) below the beacon's strength resulting
in a very poor signal to noise ratio. It's like listening to a wisper coming
from behind a waterfall. But by eliminating the waterfall with a good DSP unit
and proper use of the RF gain control, you can easily hear the weak ones. Several
have asked what AO-40 stations sound like on my 14' dish. About like a close
by 2 meter repeater. I consistently work any station in 1/2 the world at a time
running 1/2 watt into the 1269 patch section of my triband patch in front of
the 14' dish. Now that's QRP! The 7 1/2' BUDs work almost as well, just take
4 times more power.
Yaesu 736R
Yaesu 847
Icom 910H
Kenwood TS-2000
Icom PCR-1000 as an AO-40 Spectrum Analyzer
Amcom Clearspeech DSP
You will need something to hold your dish and move it around to
look at different areas of the sky. Sometimes the mount is an integral part
of the dish, but usually it is a clearly separate item. Often your application,
such as tracking AO-40, may mean discarding the existing mount and make a more
appropriate mount for your dish.
Types - Polar, GeoStationary, Altitude/Azimuth (Altaz)
Posts, Towers, Cross Arm, Tripod & Quadpod, Portable
Converting TVRO GeoStationary mounts to Altaz mounts
Small dishes with low gain and a large beamwidth can easily be moved manually so they see the satellite. But the bigger the dish, the more you will want a means to remotely move the dish.
TV antenna rotators
Ham-M seies rotators
Yaesu G-5400, G-5600, & G-5500
Linear Arms
Gearmotors, Sprockets, Chain Drives, and Pulleys
AC and DC Motors
Try
looking out the window at a dish and tell which way it's pointing. I am generally
off by at least 10 degrees in elevation and especially in azimuth. My 10' dish
only has 3 degrees beamwidth on 2401 MHz, so it's very unlikely that I'll ever
find AO-40 unless I have a good way to find out which way the dish is pointing.
A couple of wirewound potentiometers and a pair of $13 Digital Panel Meters
can provide a remote position readout to within 1 degree.
Protractors, Pulses, Potentiometers, Incremental Encoders, & Absolute Encoders
Analog Meters, TV antenna control boxes, Selsyns, & Digital Panel Meters
Tracking Programs
The AMSAT
website has several Freeware and Shareware programs that you can download
and try. Some have been kept up to date and others are rather obsolete
.
I use a piece of $60 Buyware called NOVA to handle all my satellite tracking activities. A full 7 MB version can be downloaded and tried out before registering. The maps and graphics are particularly impressive. Even talks to you, telling you when a satellite is rising, overhead, and setting. If you like computers talking to you, of course. Makes your hamshack look very high tech. If NOVA doesn't impress your visitors, nothing will.
Satellite Tracking with Yagis
The demise of AO-40 is a major loss, but it's not the end of the world. Several Low Earth Satellites (LEOs) are still operational, and can provide dependable communications even though short in time and distance. The LEOs typically use 2M and 70CM for communication, and orbit about 700 to 1100 miles up. Their orbit is essentially N-S, but with the Earth spinning underneath the satellite, the actual path is a diagonal line. With the Earth spinning beneath, a LEO will typically appear about 1 hour, 45 minutes between passes. Some passes are out of range from your QTH. Assuming you live in the USA, sometimes the pass is descending from Canada towards Mexico and due to the rotation of the Earth, another pass may be Ascending from Mexico to Canada. Typically any given QTH has coverage about 6 times each day. Each pass is short, 15 minutes or so at most. So if you don't have your act together beforehand, you will miss it.
The signals are not extremely strong, but with a good set of antennas for transmit and receive, along with an antenna mounted preamplifier and good coax, you can expect an ~S9 SSB signal on an all-mode full duplex rig. I use some older KLM long yagis shown at the top of this page. The 435 MHz (70CM) yagi has 40 elements, half horizontal and half vertical, configured to have circular polarization to match the satellite. The polarization can be either clockwise or counterclockwise, whichever produces the strongest signal (clockwise is generally the strongest). The 145 MHz (2M) yagi has 22 elements, also with switchable polarization. Each yagi has a high gain, low noise, preamplifier mounted nearby at the top of a 50' tower. Height means nothing to a satellite but it does let you see over houses and trees when the satellite is at a low angle from your QTH.
Most of the time, 435 MHz is the downlink (your receive) frequency, but a few satellites use 145 MHz as the downlink frequency, so a pair of preamplifiers is appropriate for an "any satellite station". Good coax is a must on these frequencies. Use coax with less than 3 db of loss at the frequency desired and the length needed. I use about 80' of 1/2" hardline between the station and the preamplifiers. Figure on about 1000 watts ERP max to work the various LEOs. Occasionally you will run across EME power levels being used that cause AGC clamping that screws up the other QSOs on the satellite. Never exceed the signal level of the beacon is a good rule of thumb.
For best operation an automatic tracking rotator is manditory using one of the Trackers below. I highly recommend setting up the rotator so that it can do a flip on overhead passes (start upside down and continue through overhead to right side up on the other side). This avoids a signal loss as the satellite passes overhead and the rotator is unable to do a 180 degree azimuth rotate fast enough. Since the pass lasts only a short time, have the antenna preset to the Acquisition Of Signal (AOS) bearings ahead of time, and your rig set with the correct frequencies offset for doppler.
You can use one of the tracking programs above to tell you where the desired satellite is at any given moment and then manually turn your dish to pick up the satellite. With the position sensors mentioned above you should be able to find the satellite in a short time. AO-40 moved slowly when it got out to 35,000 miles high, so it really was not too difficult move the dish to the satellite, talk for a while, then manually move the dish again. But it's a lot easier with a fully automated system. LEOs are almost impossible to track without automation. The latest KEPs and correct time in you computer's clock are manditory, especially on the nearly overhead passes.
The best known of the automatic tracking interfaces is the Kansas City Tracker.
The KCT is a small PCB that plugs 
into
a spare ISA slot in your computer. Various software programs then access the
card directly. The card connects to a Yaesu controller via an 8 pin DIN plug.
One present difficulty with the KCT is that modern computers or Laptops are
not supplied with the ISA slot to plug the KCT into. But there is a big supply
of older landfill quality PCs that can be used. And the price will be right
(free).
Satellite Tracker Mini
Automatic tracking of amateur or commercial satellites
Works with KenPro, and the Yaesu G-5400, the G-5600, and the G-5500 rotators.
A red LED and a green LED provide low cost operational feedback Green LED ON means Automatic Mode; Red LED ON means NO DATA input & placed in Manual Mode.
Can keep the antennas within 1 degree of the actual position of the desired satellite
Case colored similar to the control unit of the Yaesu satellite rotators.
Click here to read the instruction manual.
I have no Satellite Tracker Minis left, and I am not planning on making any more Satellite Tracker Minis.
Satellite Tracker Jr.
Manual or fully automatic tracking of amateur or commercial satellites
Works with KenPro, and the Yaesu G-5400, the G-5600, and the G-5500 rotators.
Can change your Yaesu G-5400's N centered meter to S centered for better tracking of AO-40.
Graphic Backlit LCD on the Satellite Tracker Jr. provides the desired and actual bearings in large 1/4" characters
Can keep the antennas within 1 degree of the actual position of the desired satellite
Colored similar to the control unit of the Yaesu satellite rotators..
Click here to read the instruction manual.
Here are some customer comments:
...."Seems to do EXACTLY what I wanted....I think you have the KCT beat hands down....Outperforms the others...." N4WYK - using the STJ on a KenPro.
..."Satellite Tracker Jr is working great and I agree with N4WYK, it sure beats KCT" K0CPX
."Unit works great & your setup instructions enabled me to get the unit up & running in less than 30 minutes." WA4SSP.
I currently (7/17/2006) have no more Satellite Tracker Juniors in stock or under construction. The cost of the Satellite Tracker Junior was $225 postpaid USA and $235 in USA funds drawn on a USA bank, postpaid, to other countries. I am redesigning the Jr, and I am going to add a number of features such as the ability to drive a medium sized dish instead of just the Yaesu rotators,. to the Tracker Junior which will raise the price slightly. I do not expect this version to become available until late Summer / early Fall.
27107 Richmond Hill Rd.
Conifer, Colorado 80433
(303) 838-6346
Satellite Tracker Sr.
Manual or fully automatic tracking of amateur or commercial satellites
Designed for running medium to large sized dishes
Dual Backlit Graphic LCDs provide the desired and actual bearings in large 1/4" characters
4 pushbuttons provide East, West, Up and Down control of the dish and menu selection
Can directly control the medium sized DC gearmotors. It can also drive external relays
Inputs can be analog precision potentiometers or incremental encoders giving this tracker the full potential for up to 1/10 of a degree accuracy.
Direct keyboard input for terrestrial dish operation. Enter a call or name, with bearings on an attached IBM keyboard. STS remembers and recalls, turning towards this station.
Front panel keys provide delta offsets to the NOVA bearings for precisely pointing a large dish
Case colored similar to the control unit of the Yaesu satellite rotators.
Click here to read the instruction manual.
7/17/2006
I have 3Satellite Tracker Seniors left in stock plus a 4th unit reserved for a 7 1/2' dish system. My PCB house went out of business and destroyed all of my negatives without warning me. I will not be working on a new design. If you are interested in obtaining one of these units, the cost is $495 postpaid USA and to other countries $510 USA funds drawn on a US Bank.
Robert W0LMD robert@ultimatecharger.com
Send check or money order to: SAI - 27107 Richmond Hill Rd. Conifer, Colorado 80433 (303) 838-6346
Digital
Wattmeter and SWR Bridge
I am currently working on a new project to supplement my ham station. Everybody has an analog SWR bridge, but I really like a digital readout. What I am doing is modifying the software inside a Satellite Tracker Jr so that it uses the 8 A/D channels of the 18F458 to read the forward and reverse voltages from up to 4 HF, VHF, UHF, and/or SHF external modules. The backlit display is 2 1/2" wide by 1 1/2" high. The digital display head will be $150 as a kit and $190 built, tested and calibrated. You can use your favorite external SWR module design with this digital unit or get an HF head for $40 kit or $75 built, tested and calibrated. The HF section has been operating for a year, currently using two HF heads to read the rig's FWD, RFL, and SWR along with my Alpha 77's FWD, RFL, and SWR. It could also read from one head at the rig or amp and the other at the antenna. Initial orders will built, tested and calibrated only, at the kit prices. The VHF, UHF, and SHF heads are still in the design stages. Availability is projected in Spring, 2005, maybe.
Dishes, Mounts & Feeds for sale
I built and tested about a dozen dish systems during the process of developing these webpages. If you do not have the time, tools or talent to complete the dish projects shown on this website, contact me about getting one of these excellent systems.
Click here to see the story of a 14' TVRO Dish converted to a great ham antenna!
Dish Systems that I have Built or Helped Build
Pictures of Other Satellite Stations
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Robert W0LMD - SAI - 27107 Richmond Hill Rd. Conifer, Colorado 80433
(303) 838-6346 robert@ultimatecharger.com)