TR 1296 H - 28

Transverter for 23 cm

1296 ... 1298 MHz / 1268 ... 1270 MHz

Over 25 years ofexperience in development of new transverter technologies led to thismasterpiece of VHF technology. Implementing technological innovationsand expertise in a timely manner and combining them into astate-of-the-art product is a thing we have succeeded in doing in avery impressive way. It's a challenge for us to extend the limits ofwhat is technically feasible and to put this into our products. Rankingfirst worldwide and improving our products continously are a matter ofcourse for us.

Introduction

Several decades of engineering and production of transverters result in this new design of our high performance 23cm transverter TR 1296H - 28. By its outstanding technical data it is suitable for many applications. The transverter was originally designed for UHF 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 transverter for 1296 MHz 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” options 04 (drive gain control on the front panel) and 01 (Band 2: 1268 ... 1270 MHz) are standard now.

Oscillator

A low noise voltage controlled oscillator generates the 1268 MHz and the 1240 MHz LO signal. The reference frequency of the used PLL is generated from a highly frequency stable VCOCXO with a temperature accuracy of +/- 0.1 ppm. A second PLL in the transverter is used to lock the VCOCXO to an external 10 MHz reference frequency. The oscillator output power is about 50 mW.

Receiver

The frontend of the transverter is build with high a performance E-PHEMT transistor. The first frequency selection is done with a helical filter. To achieve low noise figure the second amplifier stage of the RX path is also an E-PHEMT transistor. Final frequency selection is done with a HI-Q band pass filter. A high-level ring mixer converts the signal to the intermediate frequency (IF) at 28…30 MHz. The total gain of the receiver path is set to about 20 dB to avoid overdriving 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 KU LNA 132 AH-HEMT is recommended. This drops the total noise figure to 0.5 dB. A second N-connector permits the use of a separate cable for the preamplifier.

Transmitter

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 HI-Q band pass filter. It is followed by an MMIC amplifier stage, another helical band pass filter and a second MMIC amplifier stage. The power amplifier module is equipped with a high power MOSFET amplifier module. The output power is limited to 18 W and guarantees good intermodulation performance. Overdriving of the power amplifier is prevented by an ALC circuit.  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 a high-quality power amplifier and a coaxial relay with a preamplifier, which is placed directly at the antenna. The required connectors are on the rear panel of the transverter.

Specifications
Type	TR 1296 H - 28
UHF frequency range	1296 ... 1298 MHz, 1268 ... 1270 MHz
IF frequency range	28 .. 30 MHz
IF input power	1 ... 50 mW, adjustable / switchable to range 60 ... 1000 µW
LO accuarcy @ 18 °C	typ. +/- 0.1 ppm (without 10 MHz reference frequency)
LO frquency stability (0 ... +40 °C)	typ. +/- 0.1 ppm (without 10 MHz reference frequency)
PTT control	contact closure to ground
Output power @ 13.8 V	18 W
Supply voltage	13.8 V DC (+12 ... 14 V DC)
Current consumption	typ. 8 A (TX)
Noise figure @ 18 °C	typ. 1.2 dB
External reference input	10 MHz / 2 ... 10 mW
RX gain	min. 20 dB
Dimensions (mm)	270 x 260 x 80
Case	aluminium
IF connectors / impedance	BNC-female/ 50 ohms There are two seperate IF connectors. They can be switched to one common IF connector
UHF connectors / impedance	N-female/ 50 ohms
Reference input connector / impedance	BNC-female, 50 ohms
DC supply and control connector	SUB-D 9 pole

Block diagram

 

Connectors

 

 

Inside