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Cubic CDR-3250


The Cubic CDR-3250 is an American-made professional receiver about which there is hardly any information on the internet. These radios are mainly used by the military and by embassies. The radio I have here comes from Israel.
The Cubic CDR-3250 is a DSP-receiver. Demodulation, bandwidth filters and the AGC are software defined.

Most important  features:
-- Frequency range: 10kHz - 30 MHz
-- 51bandwidth filters: 100 Hz - 16 kHz
-- Step size: user-selectable in 1 Hz steps 1 Hz-10Mhz
-- Modes: LSB, USB, ISB, CW, AM, FM, FSK
-- 250 memories, scan with 100 steps/sec
-- Multiple scanning functions
-- Built-in TCXO (temperature compensated oscillator) with an accuracy of 1ppm
-- Built-in continuous preselector
-- Two low-pass filters below 1.6 MHz
-- Selectable AGC in SSB, CW and FSK. In AM only fixed value
-- Strong signal handling capability: IP3 30+dBm
-- Built-in BITE self-test
-- Weight: 9.9 Kg



Because of its rather user-unfriendly concept, the CDR-3250 is probably remote-controlled. The receiver has two knobs and 19 rubber push-buttons. Behind these buttons is a menu structure on two levels and several sub-levels. Navigation through the menu is done by the VFO-knob and the menu buttons.

If you buy such a receiver, there should be enough room on your table. The CDR-3250 is a 19" radio with half the height. Interestingly, only the left part of the front has controls. The right side is empty because basically, the CDR-3250 is half a 19" radio. The CDR-3250 is the install version of the CDR-3280. With its 9.9 Kg the radio is a light-weight in its class. Other receivers weigh double as much. The CDR-3250 is sturdily built. Like many other professional receivers, the CDR-3250 has no tools to eliminate disturbances, except a PBT for CW; only its sharp DSP filters can attenuate adjacent channel interference. Despite its small display, all important pieces of information are shown. The vacuum fluorescent display is protected against radiation by a fine metal lattice, which makes reading a little hard.

A good colleague of mine put the CDR-3250 at my disposal for some weeks. During this time, I could familiarize myself with the radio and test its qualities. Of course, I compared it to other pieces of equipment which I own. Mostly, I used the JRC NRD-545 DSP as reference because it is similar to the CDR-3250. The NRD-545 is also a table top receiver. All other radios are SDRs and were used from time to time. The first big difference between the CDR-3250 and the NRD-545 is its sound and its noise characteristics. The audio amplifier of the CDR-3250 is designed perfectly and has no internal noise. The NRD 545, on the other hand, always produces some internal noise in the background. The sound of the CDR-3250 is in a league of its own. It simply sounds outstanding! You can listen with your headphones on for hours without any trouble. Just like the NRD-545, the CDR-3250 a fixed AGC value for AM and so I used the manual control "MGC". In SSB you can adjust the AGC within wide limits. In this respect, the NRD-545 is similar. With the CDR-3250, listening to broadcast stations in AM was pure joy! This was due its noise-free and very clear audio. In this respect, the NRD-545 lags behind. As regards the reception of SSB stations, both radios were on the same level. The CDR-3250 scored with its excellent and noise-free audio. In terms of sensitivity, there was no noticeable difference between the two radios. The weak point of most professional receivers is the lack of a noise blanker, passband tuning, and notchfilter. The NRD-545 sports all these features. The CDR-3250 is actively cooled. The fan on the back is noticeably audible. If you use your headphones, however, you won't notice anything.
The Cubic CDR-3250 is a top receiver which has the at least the same audio qualities as a AEG/Telefunken 1800/3. Unfortunately, operating the radio is rather user-unfriendly! If you live outside densely-populated area with its many sources of interferences, the CDR-3250 will serve you well. The audio is one of the best I have heard so far!

posted 05.02.2017


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