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Ericsson 8801E-1 receiver for the 70 cm band
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The 8801E-1 module is a very nice receiver, initially designed as a test receiver
for the mobile telephone system as used by the Dutch PTT in the late 80s. This was the
2nd generation mobile telephone in The Netherlands, also known as ATF-2 or the NMT
network. The receiver parts of the unit are equal to the receiver modules from the
Ericsson F955 base station transceiver. The various modules are
integrated in a solid aluminium case (42 x 20 x 5 cm) and were build by Magnetic AB
of Sweden around 1985.
Sold out
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The modules
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Inside the case you'll find the following circuits:
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- A synthesizer with VCO, prescaler and phase comparator
It uses a reference oscillator at 4.225 MHz.
The signals are fed through the prescaler and a HEF4751 (divider)
onto the HEF4046 phase comparator.
Two HEF4009s are used to program the required division onto the HEF4751,
just like in the Ericsson F955. The result is a frequency in the 70cm range,
which is mixed with the incoming HF into an IF signal.
- A sophisticated filter section with an MCL RAY-1 mixer
This is where the signal from the antenne is first fed through a 3-stage
helical filter onto the first pre-amplifier. After another 3-stage
helical filter, the signal is fed into the RAY-1 mixer that converts
it into a 21.4 MHz IF signal. Although this PCB look very impressive,
it is pretty well layed out, which greatly helps when experimenting.
- A very nice IF/demodulator at 21.4 MHz
From the mixer, the signal is fed through an impressive 21.4 MHz IF filter.
A good old SL6601 mixes the 21.4 MHz with the 21.320 MHz from an XTal.
The resulting 80 kHz IF is subsequently amplified and demodulated.
A loudspeaker can be connected directly to this unit as it is equipped
with a TDA2002 LF amplifier circuit.
- Some additional logic, consisting of 2 smaller PCBs
These were used to control the receiver from the backplane connector.
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The 8801E-1 module can be converted easily to the 70 cm band by the more
experienced radio amateur. It can be used for numerous applications, such as:
- Receiver for the 70 cm amateur band (also for listeners);
- Packet-RX;
- Part of a DIY spectrum analyzer / panorama receiver for the 70 cm band;
- Receiver for a direction finder on 70 cm. The nice helical filters come in handy here.
Two radio amateurs that are known to have converted this 8801E-1 module are:
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Steef, PA0-IB
He is the author of the F955 conversion handbook. The handbook contains
many examples and hints that can be applied to the modules used in this
receiver as well. Especially the pages on the synthesizer are very useful.
Unfortunately the handbook is only available in Dutch.
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Han, PA0JHC
Han was probably the first user to convert this receiver for amateur use.
With help have Steef, PA0IB, he found out how to program the synthesizer.
More information in the next paragraph.
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Converting the receiver for the 70 cm amateur band
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Han van Heuven, PA0JHC, was one of the very first amateurs to convert this
70 cm receiver. With help of Steef, PA0IB, he managed to find the required
division parameters for the sythesizer. Below is a full description of his
findings when carrying out the conversion. He also made this picture of the
receiver's interior. Click the picture to view a larger version of it.
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Availability
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Due to the enourmous demand for these wonderful 70 cm receivers, they have
now been sold out completely. Unfortunately we don't expect any new stock,
but you may be able to find similar units on radio shows and flee markets.
Alternatively, you may be interested in an Ericsson F955 transceiver
which features the same receiver components. We have plenty units of the latter available.
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Download
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Channel table (9 KB) 9K ZIP file
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This ZIP file contains a complete channel table in both XLS and CSV format.
XLS files can be read by Excel. CSV files can be loaded into any spreatsheet
program.
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