Microwave transverters for 9cm
Microwapp HRxx series microwave transverters are a segment of BTV's production program focused on amateur radio microwave technologies.. The design solution of this series of devices is characterized by, that the possibility of working "from the hearth" is directly calculated. In particular, this whole transverter concept departs from prevailing past practice. The point of the HRxx solution lies in this, that outdoor microwave transverter, which is protected against dust and rain (protection IP54) forms a compact unit with the antenna. Toto, in radio amateur practice, an uncommon design solution, reduces significant losses of microwave energy, which are typical of a separated system.
Transverters Microwapp HRxx consist of an external unit with an integrated antenna and an internal unit, which is actually only a power supply with a power crossover, input and output MF connector and PTT TX/RX control. If necessary, the radiation polarization can be changed by turning the mechanical handle of the transverter, by which the device is attached to the mast or to the rotator.
Transverters are constructed so, to work with common UHF transceivers for the band 70 cm with range 430 to 440 MHz at a driving power of 5W. The frequency plan of the transverter was designed as follows, so that the resulting frequencies correspond to the IARU frequency table after conversion. However, in connection with the atypically long TRX/transverter "inter-frequency link" and due to the significant radiation of cheaper coaxial cables, for the HRxx transverter, an intermediate frequency was chosen for the beginning of the used microwave band 433 MHz, never 432 MHz, as usual. Intermediate frequency shift o 1 MHz helps with heavy traffic in contests (easier than switching off the supply voltage of the transverter) to exclude confusion with extremely strong signals of stations operating in the band 70 cm.
If you follow the recommended procedure for connecting the transceiver to the transverter, there is no need to fine-tune or set anything. By simply connecting the transceiver to the indoor unit, and also indoor units with a transverter only with a coaxial cable, the whole device is ready for operation. Due to the used power supply of the transverter with a DC voltage of 13.8V, considering the low excitation power required from the transceiver, even to the low performance of the transverter itself, it is possible to work without problems on a transient QTH even from chemical batteries or from a solar cell. For QRP applications, the HR 3A transverter can also be supplied for a lower excitation IF power 50 mW as HR3QRP, when a "handle" is supposed to be used. Typical high-frequency performance HR 3A in the band 3,4 GHz i 100 mW, and HR3B 1W. With the integrated FLAT antenna, the EIRP is approximately 3W, resp. 30W. If the HR3x transverter is placed at the focus of the SAT offset parabola of diameter 1,2 meter, the radiated power will increase approximately tenfold, viz fig. 2.
