Last updated 2002 January 30
A useful accessory to extend the range of an inexpensive 2.8GHz Frequency Counter to 12GHz.
The new design is based on the HMC363S8G Hittite prescaler IC.
Latest info - the new version using the lower cost "Hittite" device has a pre-amp/power limiter in front of the prescaler. This improves sensitivity and also reduces the possibility of damage through overload.
DOWNLOAD PCB Layout, Photos and other info as a Zip File -rev01d
ADDITIONAL INFO: The layout was designed for Rogers RT/duroid 5870 material with a Dielectric thickness of 0.254mm and Foil cladding thickness of 0.0173mm.
Tests were carried out at Martlesham - to check out the range of frequency and power over which the unit would work correctly. The results are plotted below:
Correct operation of the assembly was obtained whilst working between the two curves
The upper limit displayed is the recommended limit for no damage (13dBm). It should be noted that correct operation was also obtained when the input was raised to 20dBm at frequencies from 1 to 10Ghz. Beyond 10Ghz, 20dBm could be applied but the correct operation stopped at a lower value.
2000 Oct 24 - A second unit has been constructed using the same layout on 1.6mm thick FR4, and it worked. The sensitivity was lower than the original but still usable at 10368MHz. Unfortunately Measurements could not be made at Martlesham, but it is clear that it has less sensitivity than the Duriod dielectric version.
Here's a pic of the FR4 experiment: