TR 144 H +40

Transverter for 2m

144 ... 146 MHz

Over 25 years of experience in development of new transverter technologies led to this masterpiece of VHF technology. Implementing technological innovations and expertise in a timely manner and combining them into a state-of-the-art product is a thing we have succeeded in doing in a very impressive way. It's a challenge for us to extend the limits of what is technically feasible and to put this into our products. Ranking first worldwide and improving our products continously are a matter of course for us.

Introduction

Several decades of engineering and production of Transverters result in this new designed TR144 H +40 high performance Transverter. His outstanding technical data make it usable for many applications. The 2m-transverter was originally designed for VHF amateur radio applications, for example high performance contest stations. The receive path of the transverter provides very good large-signal performance.

The new design of our 2m-transverter features better performance and many new functions.

Now, an external 10 MHz reference frequency can be connected to achieve highest frequency accuracy. This is necessary for EME and WSJT. The frequency of 10 MHz can be supplied by a highly stable OCXO, a reference oscillator of a frequency counter, a rubidium frequency standard or a GPS controlled frequency source.

The new design includes the “old” options 02 (TX IF input power 60...1000 µW / 0...-12 dBm) and 06 (common IF-connector for RX/TX). So, the Transverter is compatible to most of the used HF transceivers with transverter output. The TX IF input ranges and the IF connector configuration can be done with the internal switches of the transverter. The “old” option 04 (drive gain control on the front panel) is standard now. 

Oscillator

A temperature-compensated low noise butler oscillator generates the 116 MHz LO signal. A thermostat crystal with a 40 °C precision crystal heater is used. Phase noise of the output signal is -156 dBc/Hz @ 10 kHz. This value is better than that of the HF transceivers. The oscillator output power is 100 mW.

Receiver

In the receiver frontend there is only one balanced super low noise stage with two Power GaAs-FETs. A noise figure (NF) of 0.9 dB and an output IP3 of >40 dBm are achieved. To prevent interference in case of multi-band operation, there is a notch filter for the 70cm band at the input. The prestage is followed by a high-Q helical filter and a matching network. A high-level triple-balanced GaAs-FET ring mixer with an IP3 of >35 dBm converts the signal to the intermediate frequency (IF) at 28…30 MHz. The total gain of the receiver path is limited to 25 dB to avoid overdriving of the HF transceiver. An internal preamplifier of the HF transceiver has to be switched off. The transverter provides excellent large-signal performance. Gain and sensitivity are ideal for contesting and DXing. For EME operation the use of the preamplifier LNA 144 A is recommended. This drops the total noise figure to 0.35 dB. A second N-connector permits the use of a separate cable for the preamplifier.

Transmitter

In the transmit path of the transverter a second 17 dBm ring mixer is used. The TX IF input power ranges (0.06 … 1 mW and 1 … 50 mW) can be set with an internal switch.
The TX gain of the transverter can be adjusted with the potentiometer on the front panel. For further power adjustments the HF transceiver can be used. At the mixer output there is a matching network and a helical band pass filter. It is followed by an MMIC amplifier stage, another helical band pass filter, driver amplifier and power amplifier. LD-MOSFETs are used in driver amplifier and power amplifier. The available output power is 60 W. To achieve optimum intermodulation performance, the output power is limited to 25 W. Overdriving is prevented by an ALC circuit. The transmit unit of the transverter has a protection circuit. If the antenna SWR is bad, the power amplifier switches off for 3 seconds. This is indicated by a LED. A final low pass filter guarantees spurious and harmonic rejection of more than 60 dB. The output power is indicated on a calibrated meter.

Sequence Controller

The built-in sequence controller allows time-controlled operation of an additional high quality power amplifier, a coaxial relay and a preamplifier, which can be placed directly at the antenna. The required connectors are on the back panel of the transverter.

Specifications
Type	TR 144 H +40
Frequency range	144 ... 146 MHz
IF frequency range	28 ... 30 MHz
IF input power	1...50 mW adjustable / switchable to range 60 ... 1000 µW
LO accuracy @ 18 °C	typ. +/- 2 ppm, max. +/- 3 ppm (without 10 MHz reference frequency)
LO frequency stability (0 ... +40 °C)	typ. +/- 2 ppm, max. +/- 3 ppm (without 10 MHz reference frequency)
PTT Control	Contact closure to ground
Output power	25 W
IM3 @ 20 W PEP	-32 dBc
External reference input	10 MHz / 2 ... 10 mW
Supply voltage	+13.8 V DC (+12 ... 14 V DC)
Current consumption	typ. 6 A (TX)
RX gain	typ. 25 dB
RX output IP3	typ. +40 dBm, min. +37 dBm
Noise figure	typ. 1.2 dB
Blocking	min. -106 dBc @ 3 kHz BW
IM-Dynamic	min. 102.5 dB SFDR @ 3 kHz BW
Image rejection	typ. 90 dB
Case	aluminium
Dimensions (mm)	270 x 260 x 80
IF connectors/ impedance	BNC - female / 50 ohms There are two separate IF connectors. They can be switched to one common IF connector
RF connectors / impedance	N-female / 50 ohms
DC supply and control connector	SUB-D 9-pole

Block diagram

 

Connectors