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Software Defined Radio

FMC 108-28

FM Broadcast Band to Shortwave Receiving Converter


Official DRM Supporter (Digital Radio Mondiale)


Reliable for analog FM Radio and DRM+ field tests :

Converting the FM broadcast band to the shortwave range

UKW / KW-Konverter

The FMC 108-28 converts the FM broadcast band to the shortwave range. The FM range of 87.5 - 108MHz is converted to 7.5 - 28.5MHz. Conversion is crystal stabilized, ultra-linear and non-inverted.

Screenshot of the total local FM band taken with PERSUS™ HF-Span 0-40MHz:

Perseus HF-Span FM Band

In this way the receiving range of shortwave Software Defined Radios (SDR) is extended to the FM broadcast band range. Besides the reception of conventional FM radio stations it is also possible to receive the new digital radio standard DRM+.

Sophisticated input and output filters provide high selectivity and high out-band rejection. A discrete constructed double-balanced mixer in combination with an ultra linear broadband amplifier provides good intermodulation response.

Inside view:

FMC 108-28


In the following some screenshots taken in combination with the SDR receiver PERSEUS.

Reception of a FM modulated radio station at 95.5MHz converted to 15.5MHz:

FM reception Perseus 95.5MHz

In waterfall spectrum mode:

Waterfall Spectrum Perseus FM 95.5MHz

The peak-to-peak deviation of +/-75KHz depending on modulation level is clearly recognizable.

Technical Data:

(Preliminary specification 04/2010, all data are therefore subject to change without notice)

Input Freqency Range: 87.5 - 108MHz

Output Frequency Range: 7.5 - 28MHz

RF Connectors: BNC sockets

Max. Allowed Antenna Level : +0dBm typ.

Output Third-Order Intercept Point IP3: +10dBm (@ 100.0 & 100.1MHz)

Overall Gain: 3dB typ.

Amplitude response: +/- 1.5dB

Frequency Stability (15min. warm-up period): +/- 10ppm typ.

Image Rejection: >35dB (52.5 - 72.5MHz)

Combined Output Selectivity: >55dB (0 - 60MHz)

Power Supply / Connector: 7 - 15V DC max.100mA / 2.1mm DC power socket (positive inner)

Operating Temperature: 0 - 40°C

Dimensions / Weight: 112 x 71 x 31mm / 0.15kg

High Output Selectivity for 0 - 60MHz:

Selektivitaet 0-60MHz

Customer feedback:

Converter received in perfect conditions and successfully tested. Excellent performance also in my difficult local FM band, full of strong signals with very narrow spacing between adjacent channels. I'm using a discone antenna and a Perseus receiver with WRplus software. The FMC108-28 is a good converter for FM DXing.

Thank you

F. M. / Italy