I bought my PCR1000 in 1998, so I have had time to test it with several different signals. I do not think that the reception on the shortwave-bands is as good as my "good old" IC-751A, but the PCR1000 is a broadband receiver capable of receiving most common transmission-modes from 10kHz to 1300MHz.
One problem is that when used, the PCR1000 must be connected to a computer. My computer has only two serial ports, where one port is already used for the mouse. Using a modem as my AEA-PK232 or TAPR-modem is therefore not possible, but I guess that I just have to buy a new computer or some type of RS232-splitter...
Satellites and reception of satellites
There are many types of satellites. Some satellites are used for public radio and TV, some are used for taking different types of pictures of earth etc.
Satellites can be divided into two main “groups”, geostationary and “orbiting” satellites.
A geostationary satellite is an orbiting satellite but the big difference is that the geostationary satellite is rotating around the earth with the same speed as earth. An observer on earth would therefore say that the satellite is fixed on the sky, ie geostationary.
In this explanation an orbiting satellite has a lower, or more seldom a higher, orbit. A low orbit indicates that the satellite would move faster observed by somebody on the earth surface. These satellites often are called LEOs, Low Earth Orbiting.
A HEO, High Earth Orbiting, can move slowly at some times seen by the earth observer, since the orbit is elliptic. The elliptic orbit indicates that the HEO is as fast as a LEO when the HEO-satellite is close to earth.
If a satellite is geostationary the distance from earth to the satellite is about 38000km! (This is about 40 times the shuttle-orbit.)
If the satellite were closer to earth, and still “fixed”, the satellite would burn quite a lot of fuel! Satellites would be much larger to carry the fuel, or small with very short life-time.
If you are interested in geostationary public satellites I recommend a visit at Lyngsat. On the Lyngsat-pages there are information about nearly all geostationary public-service satellites in the world.
Most geostationary satellites transmit public radio and TV channels since it’s very practical for the receiver to have a fixed antenna.
This make it much easier to receive and the price of the receiving antenna will be lower than if it had to have motors to control the antenna-direction. It’s also much easier for the satellite-operator to calculate a recommended dish-size. (The dish-size is the same as received signal-quality.)
If you have decided to receive a geostationary-satellite the first thing to do is to take a look on the coverage-diagram. If the satellite does not cover your part of the earth the signals will not be easy to receive. First check “were you live”, ie on what latitude you live. Satellites are positioned on special “satellite positions” and these are above a certain earth-latitude. If the satellite-position is on the other side of earth– do not bother to try!
In the same way it is no point in trying to receive a satellite above USA if you are living in Europe. If you will be able to receive something you will be forced to use VERY large dishes! (Once I were involved in a project were we received a TV-channel in C-band from Chile in the southern parts of Sweden. This resulted in three dishes, two 4.5m and one 7m in diameters, all connected in a redundant system!)
If you are interested to look at coverage-diagrams you could take a look at Swedish Microwave. SMW have a downloadable software were it is possible to calculate what direction the dish should be pointed at and one can also calculate how large dish that is needed. The software also includes coverage-diagrams for some European satellites but information can be obtainable from other satellite-operators and then put into the software.
Reception with LNBs
One can use a normal parabolic dish with a LNB and connect this to a receiver as the PCR1000, if you supply the LNB with a proper power-supply. (LNB stands for Low Noise Block down-converter.) The received frequency-band is normally in Europe 10.7-12.75GHz. This is down-converted to L-band, ie 950-2150MHz.
An often used type of LNB, is the universal-LNB. The universal-LNB has two different frequency-bands, this is the reason why it’s possible to receive a bandwidth of about 2GHz with a receiver-bandwidth of 1GHz. The localoscillators are 9.75 and 10.6 GHz.
There are many solutions to supply the LNB. One easy way is to use an ordinary satellite-receiver and a splitter with DC-pass with diodes or a capacitor. If you are unsure check with a ohm-meter because one can not be to sure what would happened if you feed DC into the PCR1000. There should be a capacitor at the input of the PCR1000, but this capacitor might be damaged!
The satellite-receiver then controls the LNB and you choose polarisation and frequency-band with the satellite-receiver. The other output from the splitter feed the PCR1000.
In this way it is possible to receive, with a universal-LNB and the PCR1000, 10.7-11.05GHz and 11.55-11.9GHz. You will have some more bandwidth, ie when the PCR1000 is put below 950MHz, but this depend totally on the used LNB and its output filters.
Modifying the LNB is possible, changing the local-oscillator and output-filter, but this will not be discussed here.
There isn’t much to receive with a PCR1000 since most capacity is used for TV-channels, but since most uplink stations have very large antennas, 4-15m, their beams are very narrow. (It’s nearly like balancing a ball on a needle.) These antennas must be corrected continuously since the satellite is not perfectly still. (It could be, but this would cost more fuel!) A large station therefore has a tracking receiver receiving a beacon transmitted by the satellite. By adjusting the antenna every 20 minutes it will always point at the satellite! These beacons can be received by the PCR1000 since it’s just a carrier, (sometimes this carrier is also used for transmitting data from the onboard computer – often PSK or QPSK). If you are searching for a beacon first take a look at the edges of the first and last transponder, or if there are transponders used for several carriers as SNG, (Satellite News Gathering).
Weather-satellite reception on 137MHz
Some of my first tests with the PCR1000 was receiving weather-satellites, LEOs, on 137MHz. I began using my 144MHz yagi. The 144MHz yagi has a narrow bandwidth, but it works. With this yagi it is possible from my QTH in the southern Sweden to receive NOAA-satellites from the north of Africa to the Artic regions. This is a range of about 5000km! This gives rather large BMP-files of about 3,5MBytes per picture and I have to move the antenna continuously. The result is not good for reception directly over my QTH, since I do not have any elevation on my antenna, but the reception has been sufficient for my first experiments.
Pointing the antenna towards a roof seems to “scatter” the signals and this gives me some better results when the satellite is over my QTH.
For the reception of NOAA-satellites I use Wxsat for decoding of the satellite signals and the PCR1000 is put into FM with a bandwidth of 50kHz.
There are some different satellites to choose from, one large operator is NOAA – but there are also Russian satellites etc. The most often used frequencies are 137,500 MHz and 137,620 MHz.
If you are interested to receive weather-satellites but unsure about software-setup then record the satellite-signals and you will later have time for experiments with the software.
Leif, a friend of mine, has made a nice Quadrifilar Helix Antenna, QHA, in copper-tubing. I am now building a pre-amplifier to be fitted inside the antenna to get a low total noise-factor in my receiver system. The pre-amplifier will be fitted inside the plastic-tube supporting the copper-tube. This will give protection against the "cruel" outside world. This will also give a good total noise-factor for the antenna system. The pre-amplifier must always be mounted as close to the antenna as possible since attenuation in the feeder from the antenna to the pre-amplifier will be added to the total noise-factor, ie Friis-formula.
(The pre-amplifier is not ready for presentation and one important reason for this is that I have special demands since I often transmit on 144MHz and this is very near the received 137MHz-signal from the satellite. The pre-amplifier will then need good filtering and I’m just not ready building this.)
The voltage supply to the pre-amplifier will be through the coaxial cable. The voltage will be supplied via a bias-tee. This kind of DC-insertion will not influence the performance of the system and for receiving purpose it’s not necessary to use N-connectors as described in the biastee-link above.
A cheap and effective way is to use F-connectors. F-connectors are easy to fit on cables and they work up to at least 2,2GHz with good results. (Beware of cheap types since these are often made for indoor-use only.)
0-1300MHz can’t be received in a effective way with only one antenna. That’s were an automatic antenna-switch would be nice!
The PCR-1000 is very good for DRM reception. The best way to do this is by modifying the PCR-1000 by putting an extra PCB into the receiver. This extra PCB is an extra mixer, mixing the IF from 450kHz to a base-band of 12kHz. This base-band is then fed into a computer soundboard. Easiest way is to buy the PCB from Sat Service Schneider and in the beginning of 2005 the PCB cost 55 Euro. You find Sat Service Schneider at www.sat-schneider.de . There is also a cheaper PCB, but I decided to buy the crystal-version.
I decided not to put any pictures on the web on my own installation since this is very nicely made at www.drmrx.org/receiver_mods.html.
I have also tested a receiver from Coding Technologies, the “Digital World Traveller”. This receiver is ready made for DRM and is of course very simple to install and use. From my tests I found out that there is a very big difference between these two receivers and the PCR-1000 is outstanding, but at higher cost etc.