Front view (click to magnify)
This transceiver is out of production since 2005.
TRX2/4S is intended
for use outside the Eupean Community (EU) only.
Shipment only to addresses outside of EU. Special applications
(military, research) upon request.
User Manual: Download the complete users manual (1,6 MByte Acrobat .pdf)
Data Sheet: Details and all technical data
Questions and answers TRX4 / TRX2S data transceiver
Software and hints for TRX4S users
Front view (click to magnify)
We are proud to indroduce our new 430 MHz data transceiver TRX4S.
Here the most important qualities:
 | variable frequency, 10 programmable frequecies selectable with a switch. |
| frequencies, transmitter-power and receiver bandwidth (narrow/wide) can be programmed and stored for every channel in eeprom via rs232 interface. |
| s-meter (signal strength indicator) can be read out via rs232 in dBm
directly, the reading is individually calibrated and stored in eeprom for every transceiver. |
| very fast receive-transmit and transmit-receive switching for any
frequency and shift: tx->rx: 10 µs; rx->tx(wide): 50 µs; rx->tx(narrow): 200 µs. |
| smoothed transmitter keying in narrow mode (200 instead of 50 µs) to reduce clicks |
| frequency range: 10 MHz (standard: 430 - 440 MHz) |
| transmitter output power: 20 Watt (regulated and constant over frequency), programmable in 4 steps (3, 6, 12, 20 W) |
| audio-frequency ressponse (transmitter) 10 Hz to 10 kHz linear without
distortion of amplitude or phase (for 9600 and 19200 baud G3RUH-FSK) |
| audio-frequency response of receiver: 10 Hz bis 10 kHz völlig linear, no distortions (use of group-delay optimised if filters) |
| good rf sensitivity (0.15 to 0.2 µV for 12 dB SINAD), excellent large
signal qualities (symmetric diode mixers), dynamic range -120 dBm to -40 dBm. |
| minimal spurious emissions (harmonic and nonharmonic products) under -60 dBc. |
| minimal interference to adjacent channels, even while tx/rx switching. |
| wide-modus (audio: 100Hz to 100 kHz bandwidth) for 76800 and 153600 Baud FSK . |
| 100% continuous transmitting (e.g. for digipeaters) with additional fan |
| very stable frequency (within 2 kHz over temperature). |
| cooler temperature can be read-out vie rs232 in Celsius or Fahrenheit (calibrated). |
| overtemperature protecttion of power amplifier (switches off at 65 C). |
| supply: 12 (13.5) Volt 0,3A (RX) 5A (TX) |
| small size (ca. 100x160x29 mm) plus cooler |
| optional: reduced size and weight (500gr) for special applications |
Standard FM radios are
not suited for high speed data communication with amateur radio.
Because of the typical architecture, the following problems are found:
| much too slow TX/RX delay time (typ. 50 bis 250 ms). |
| lower corner frequency of modulator is too high (typ 200 Hz) caused by negative feedback in PLL |
| upper corner frequency of modulator is too low and limits the data speed |
| IF filter group delay is not flat over frequency (poor phase response). RX signals get distorted. |
| IF bandwidth is too narrow. This limits the data rate to 9600 baud FSK maximum. |
| interference on adjacent channels with frequent T/R switching. |
A real data transceiver has to meet the following requirements:
|
| TX/RS switching delay less than 1 ms for duplex AND simplex mode. |
|
| Modulator response 5 Hz to 10 kHz (9600 baud) or 75 kHz for 153600 baud without phase distortions. |
|
| IF-filter bandwidth 30 kHz with flat group delay (for 19200 baud). |
|
| IF-filter bandwidth 250 kHz with flat group delay (for 153600 baud). |
|
| T/R switching without interference on adjacent channels (click / chirp). |
|
| Sufficient output power (>20 Watt) possible to reduce, continuous transmit allowed. |
|
| Receiver with excellent large-signal capabilities and good sensitivity |
| Frequency programmable in 12.5 kHz steps. |
With the TRX4S, we have developed a data transceiver without compromises, which allows transmission and reception of signals with up to 153 kBit/s data rate without limitations.
The time needed to transmit a single byte with 9600 baud needs approx. 0,8 ms. A normal transceiver has a delay (from PTT to transmit) of typically 100 ms. With the TRX4S, this time is enough to transmit a complete data packet (100 byte). Using higher data rates (153 Kbaud), the packet-length is 5 ms only, hence the TX-delay should be less than 0,5 ms.
TRX4S / TRX2S are suited for amateur radio, but the rugged design and the excellent large-signal quality makes the transceivers suited for continuous operation (digipeater use), commercial or space applications as well.
Thouhh designed primarly for data communication, the TRX4S max be used for FM (audio) applications as well. The bandwidth makes the TRX4S also suited for high quality audio-applications hi-fidelity or special audio measurement).
The printed circuit board and the power module is mounted on a thick 5mm aluminium base (100 x 160 mm). Around the base there is a 30 mm precision frame and a second aluminium cover with the speaker and display makes the TRX a brick-like very compact and small size transceiver. The base with the power module is cooled by a big cooler good for 50% transmit to receive ratio.
circuit board of TRX4S, click to magnify.
Requirements for high speed data transceivers:
| any frequencies programmable, 16 frequencies stored, automatic resume at power-on |
| programmable frequencies, bandwidth (narrow, wide) power for each channel |
| s-meter calibrated in dBm and read-out via RS232. |
| receive to transmit delay less than 500 microseconds delay, even in simplex mode |
| transmit to receive delay less than 100 microseconds for any frequency and shift |
| slow keying of rf power in narrow mode to avoid adjacent channel interference (clicks). |
| frequency range 430 - 440 MHz or 144-148 MHz |
| transmit power 20 Watt (regulated, constant over frequency), programmable in steps (3, 6, 12, 20 W) |
| AF-frequency response (TX) 10 to 10 kHz linear (no phase or amplitude distortion) for 9600 and 19200 baud FSK |
| AF-frequency response (RX) 10 Hz to 10 kHz linear, group-delay optimised IF-filter |
| good sensitivity, high 3rs interception point (large signal quality) |
| harmonics and spurious signals (RX and TX) attenuated below 60 dB |
| minimised adjacent channel interference when keying the transmitter |
| wide band mode (100Hz to 100 kHz AF-bandwidth) for 76800 and 153600 baud FSK |
| continuous transmission (100%) e.g. for use as digipeater |
| good frequency stability over temperature |
| display of power-amplifier temperature via RS232 |
| overtemperature-protect for foolproof operation in any environment |
| supply 12 Volt 0,3A (RX) 6A (TX) |
| small size (ca. 100x160x29 mm) plus cooler |
rear view (click to magnify)
TRX4S with antenna, power, data and RS232 cables (click to magnify)
This is how the eye diagram at the data output of TRX4S looks like.
Setup: FSK modem at 153kBaud, TRX4S as transmitter, TRX4S as receiver. (2us/div)
TRX4S is available for 2m
band 144-146 MHz (TRX2S).
Other custom frequencies (100 to 560 MHz) upon request.
circuit diagram (receiver, IF-amplifier, PLL) (click to magnify)
circuit diagram (transmitter, amplifier, antenna switch) (click to magnify)
1 year full warranty, free update service
Any more questions? Call us or write an e-mail!