The name Michael Kuhne, DB6NT has been associated with high performance VHF-SHF equipment for decades. Michael and Monika’s company, Kuhne Electronics, have been producing high grade equipment for well over 25 years and is well known for the extensive range of ‘best in class’  VHF-SHF equipment. Michael’s gear is highly regarded and most serious VHF-SHF ops will have a Kuhne box tucked away somewhere. They certainly are top notch and hard to beat.

But the question is… when your gear is THAT good – what do you do for an encore?

Of course Kuhne have the answers and the recently announced TR144-PRO is the latest development and improved version of their TR series of high performance trTR displayansverters.

The TR series transverters were built to meet the toughest performance demands in the harshest of RF environments – central Europe. The TR series offers just that, providing the best possible specifications and yet still capable of operating in the tough EU RF environments during contests or during large scale band openings without collapsing. For the ultimate in DX’ing tools , the TR series offers the operator the best possible noise figures, exceptional oscillator phase noise, and it’s built by someone who understands the need for flexibility in station integration.

So how do you improve on that?

Pretty hard to do I am sure but there have been some nice changes revealed. The TR 144 – PRO is now offers software customization of its connections and functions. Previous versions of the TR series required the changing of small switches internally which required a dive into the transverter. Now the selection of features like single / dual IF lines, or high/low drive levels etc can all be done from the menu controls on the front panel. The front panel analogue meter of the TR144 has been replaced in the Pro series by a bright LCD display showing the status of the transverter and menu displays. It is also possible to change the assignments of the two sets of N types associated with RX – TX lines – this means the transverter can be quickly set up for split RX lines found in high power EME stations. The use of a uProcessor driven menu also means the transverter can be controlled over serial data lines. Control of the internal sequencer and switching is also possible from within the extensive menus.

One majorTR PA 144 RF improvement is in the local oscillator. Amazingly Michael’s team have managed to improve the phase noise of the LO even further that the original TR series was capable of and this reaches figures of about -145 dbc/Hz @ 1 KHz and a whopping -160 dBc/Hz at 10 KHz away when measured at 116 MHz (28 MHz IF)

Improvements have been made in the input stages with new mixer/IF amplifiers and this has improved the IM3 figures. and receiver OIP now measures 40 dBm. Additionally a new PA block is fitted improving the transmit side with intermod now at >35 dBc @ 20W PEP. The new PA also now utilises LDMOS devices in the TX chain.  On the receiver side a second IF output is now provide to allow user of an off port SDR, or sun/moon noise meter.
Externally the transverter looks to be the same size, and apart from the lack of analogue meter, looks very similar. Internally the major visible difference is the new PA block and the new solid aluminum transverter housing.

Pricing seems to be about the same as the current TR transverters at 1385 EUR. Only the 144 MHz band has the PRO version available just now and no information as to planned changes to other bands.

More details can be found on the Kuhne Electronics website.

New features

  • Status readout with an easy-to-read LCD-Display
  • New Local-Oscillator with VCTCXO and +/- 0.5 ppm stability and  phasenoise better than -155 dBc/Hz @ 10 kHz
  • Output from Local oscillator for a second converter or synchro receiver or predistortion downconverter on software defined radios
  • Second independent IF Receiver port to connect a second receiver such as Spectrum readout, SDR receiver or a „sun and moon noise meter“
  • Two equivalent HF-Antenna ports free configurable as receiver port  or transmit port or two independent antenna systems
  • Monitored power amplifier with several protection circuits
  • A lot of possibilities to configure the transverter for the most popular HF-transceivers
  • Free configurable delay time of the internal sequence generator and open drain outputs for maximum flexibility
  • Possibility to control the transverter with serial interface direct with PC (not RS232)
  • Internal Blower now temperatur-controlled

Well-tried functions and features

  • Input for external reference frequency for synchronizing to 10 MHz source and automatic changeover if an adequate power level is detected
  • The internal antenna relay provide an Isolation of typical 70 dB
  • Intermodulation >35 dBc @ 20 W PEP by new designed RF power amplifier with newest LDMOS technology
  • Infinitely variable transmit gain adjustment on front panel
  • Spurious rejection is better than 60 dBc, achieved by using an 5th order low pass
  • Usable for all modes like SSB, PSK, FM and many more
  • Low noise preamplifier with typical 0.9 dB NF and an OIP3 of about 40 dBm

RF range 144 … 146 MHz
IF range 28 … 30 MHz
IF input power 1 … 50 mW / 60 … 1000 µW switchable
LO accuracy @ 18 °C typ. +/- 1 ppm (without ext. ref.)
LO frequency stability (-5 … +55 °C) typ. +/- 0.5 ppm (without ext. ref.)
Output power 25 W
IM3 of output signal 36 dBc @ 20 W PEP
RX gain typ. 25 dB
Noise figure @ 18 °C typ. 1.3 dB, max. 1.5 dB
RX output IP3 typ. +38 dBm
IM-dynamic min. 102,5 dB SFDR @ 3 kHz BW
Blocking min. -106 dBc @ 3 kHz BW
Image rejection typ. 90 dB
External reference input 10 MHz / 2 … 10 mW (sine or square wave)
Reference input connector BNC-female, 50 ohms
PTT control Contact closure to ground
Supply voltage +13.8 V DC (+12 … 14 V DC)
Current consumption typ. 6 A (TX)
Case aluminium
Dimensions (mm) 270 x 260 x 80
IF connectors / impedance BNC-female, 50 ohms (sep. / com. switchable)
RF connectors / impedance N-female, 50 Ohm (separate RX/TX connectors)
DC-supply and control connector SUB-D 9-pole

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