## Cheap S-band Downconverter for P3D

A MMDS downconverter was sold for 3000yen (about US $25) in Japan. This cheap converter is used for AO-40(P3D) S-band downconverter with a few modification.
This page show you its modification.

This converter was sold out at April 2001. We cannot get it.

### Converter Specification

MODEL 2880 Microwave Downconverter by DRAKE
Input Frequency: 2.4 - 2.7GHz
Output Frequency: 140 - 400MHz
LNB Gain: 24dB
NF: 3dB
Local Oscillator Frequency: 2.2779904GHz
Power: 12 - 24V (190mA)

CAUTION: This converter is just for reciever. Don't push PTT when the converter is attached to the RIG. It makes you unhappy.

photo 1: inside of the converter

### Modification for P3D

There are 3 basic modification points to hear P3D S-band with this converter. IF AMP, Power supply and Local Oscillator are the points. The 4th modification is optional. This mod improves RF gain and NF.
If you can supply power via antenna cable, you don't need power supply modifications.
If your RIG can receive 120MHz, no need local oscillator modification. The origianl converter converts 2400MHz to 120MHz.
photo 2: modification points

#### MOD 1: IF AMP Modification
MOD 2: Power Supply Modification
MOD 3-1: Local Oscillator Modification for 144MHz IF
MOD 3-2: Local Oscillator Modification for 430MHz IF
MOD 4: RF AMP Modification

I hope to meet you on P3D S-band.

de JN1GKZ Masa / jn1gkz@jamsat.or.jp

References

- 2.4-2.7GHz converter data sheet / MilliCom
- MMDS converter modification by JA4BLC / JAMSAT Newsletter No.185 1997.7.31 JAMSAT
- ERA-3, ERA-5 data sheet / Mini-Circuits

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