work on docs

This commit is contained in:
Andreas Eversberg
2016-07-10 16:00:34 +02:00
parent b3b42e8bc4
commit ce86f62b11
20 changed files with 1229 additions and 227 deletions

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@@ -24,11 +24,11 @@ This software uses <a href="http://www.alsa-project.org">Alsa</a> kernel driver
<p>
Use a radio transmitter for 2-meter band to transmit to A-Netz or B-Netz phones.
Use a radio transmitter for 70-cm band to transmit to C-Netz or NMT phones.
An amateur radio can be used, but be sure it is not limited to amateur radio frequencies and channel rasters.
For A-Netz the transmitter must be able to transmit arround 162 MHz.
For B-Netz the transmitter must be able to transmit arround 153 MHz.
For C-Netz the transmitter must be able to transmit arround 465 MHz.
For NMT the transmitter must be able to transmit arround 463 MHz.
An amateur radio can be used, but be sure it is not limited to amateur radio frequencies and channel spacing.
For A-Netz the transmitter must be able to transmit around 162 MHz.
For B-Netz the transmitter must be able to transmit around 153 MHz.
For C-Netz the transmitter must be able to transmit around 465 MHz.
For NMT the transmitter must be able to transmit around 463 MHz.
</p>
<p>
@@ -39,8 +39,8 @@ This image shows a two-band amateur radio receiver without limitations for the f
<p>
I built several transmitters out of modified taxi radios.
It features a simple digital PLL (configurable by junpers) and allows to directly connect the audio signal to the oscillator.
This is highly recommended for the C-Netz, because signalling is done by sifting the carrier directly.
It features a simple digital PLL (configurable by jumpers) and allows to directly connect the audio signal to the oscillator.
This is highly recommended for the C-Netz, because signaling is done by sifting the carrier directly.
One unit has a switch to change between A-Netz and B-Netz (2-meter version) and the other units to change between C-Netz and NMT (70-cm version).
I added an input to switch between two channels for the B-Netz.
(Whenever a B-Netz phone is paged, the channel must be temporarily switched to the paging channel.)
@@ -51,13 +51,13 @@ I added an input to switch between two channels for the B-Netz.
<p>
Use radio receiver for 2-meter band to receive from A-Netz or B-Netz phones.
Use radio receiver for 70-cm band to receive from C-Netz or NMT phones.
The transmitter cannot be re-usedr, because all networks are full duplex.
A seperate radio is required to simultaniously transmit and receive.
For A-Netz the receiver must be able to receive arround 162 MHz and 157 MHz.
For B-Netz the receiver must be able to receive arround 153 MHz and 148 MHz.
For C-Netz the receiver must be able to receive arround 465 MHz and 455 MHz.
For NMT the receiver must be able to receive arround 463 MHz and 453 MHz.
The receiver must support both uplink and downlink frequencies, to make a test loop for the calibration process.
The transmitter cannot be re-used, because all networks are full duplex.
A separate radio is required to simultaneously transmit and receive.
For A-Netz the receiver must be able to receive around 162 MHz and 157 MHz.
For B-Netz the receiver must be able to receive around 153 MHz and 148 MHz.
For C-Netz the receiver must be able to receive around 465 MHz and 455 MHz.
For NMT the receiver must be able to receive around 463 MHz and 453 MHz.
The receiver must support both up-link and down-link frequencies, to make a test loop for the calibration process.
</p>
<p>
@@ -71,7 +71,7 @@ This image shows a two-band amateur radio receiver that supports all the frequen
The best solution I could find for low price is the Uniden UBC360CLT.
It is actually some kind of clock radio with scanner.
It supports all relevant bands up to about 950 MHz.
In all bands the channel raster is freely selectable.
In all bands the channel spacing is freely selectable.
Up to 300 channels can be stored and simply selected by using up/down keys.
</p>
@@ -79,14 +79,14 @@ Up to 300 channels can be stored and simply selected by using up/down keys.
<p>
I added a discriminator output to the radio, to get undistorted receive signal.
This is highly recommended for the C-Netz, because signalling is done by sifting the carrier directly.
This is highly recommended for the C-Netz, because signaling is done by sifting the carrier directly.
</p>
<center><img src="discriminator.jpg"/></center>
<p>
In order to keep RF emission low, use a dummy load for lab test.
Use two seperated antennas for outside use of the mobile phone.
Use two separated antennas for outside use of the mobile phone.
Connect one dummy load to the transmitter and another one to the mobile phone's antenna connector.
</p>
@@ -99,11 +99,11 @@ My phone did not work correctly with a 5 Ampere 12 Volts regulated power supply.
I suggest to use an amateur radio power supply with low ripple.
In my case I use modified ATX-2 power supply for 12 or 13.8 Volts.
The voltage can be adjusted in most power supplies, but 12 Volts is good enough.
These power supplies have built-in overcurrent/overvoltage protection.
These power supplies have built-in over-current/over-voltage protection.
The ATX-2 power supplies are regulated on the 12 Volts rail.
I added two plugs and a switch.
The switch connects to the PS-On line.
In case of an overcurrent, the switch can be used to reset the protection circuit.
In case of an over-current, the switch can be used to reset the protection circuit.
Note that opening a switching power supply can be dangerous and may cause death.
If you don't have the knowledge about power supplies, ask an expert to help you.
</p>
@@ -111,18 +111,18 @@ If you don't have the knowledge about power supplies, ask an expert to help you.
<center><img src="power.jpg"/></center>
<p>
Early tests were done without any wireing between radios and sound adapter.
Early tests were done without any wiring between radios and sound adapter.
This may worked for early tests with the B-Netz, but turned out to be a pain in the as.
It is not possible to keep the levels and avoid feedbacks.
It is not possible to keep the levels and avoid feed-backs.
</p>
<center><img src="headphone.jpg"/><img src="microphone.jpg"/></center>
<p>
The sound adapter must be connected to a transmitter and a receiver.
Coils are suggested for galvanic seperation.
Coils are suggested for galvanic separation.
I don't use coils, instead I add extra grounding wire between earth (power supply) and sound interface.
For adjustemnt I highly recommend to use variable resistors.
For adjustmnt I highly recommend to use variable resistors.
This makes the adjustment process faster.
I use 4.7 K resistor for connecting headphone output to radio input.
I use 10 K resistor for connecting radio output (discriminator) to microphone input.