logo


Cluster Activity

Spots per uW band today:
UK spotter or spotted only.

Solar data:
SFI
177
A-Index
5
K-Index
3
Exp.K
0
Sunspots
127
Activity
act
GMF
qui
Aurora?
no

My Weather

ArrayDate:19/03/24 Time:11:53
Temp:15C
Wind Speed:7.5mph
Wind Dir:270deg
Pressure:1010.41mB
Humidity:87%
Dew Point:12.4C
UKHASnet
77GHz Doppler Module - Part2

Here's a short update on the progress with this module.

I re-visited the 76GHz project the last 2 weeks and decided that having a larger antenna would be useful, the pcb antenna at somewhere around 20dB gain was not quite enough.
I ended up removing the pcb antenna to gain access to the wave-guide ports:

INSERT PHOTO

The wave-guide ports had cutouts for the pcb launch so i had to mill of the face to get a flat surface to mate with, i then built an adapter plate to present something resembling a regular flange connection for connecting to another antenna. This gives access to two of the many ports available, i picked these based on the length of the RF path to the LNA/PA.

INSERT PHOTO
INSERT PHOTO

Measured power is around 7dBm, 5mW.
RX Noise figure maybe around 15dB but i did not have the baseband output wired up correctly to check accurately.
The baseband output is very low so i will need to build some extra gain stage for Rx.

In the process of doing these tests/modifications i managed to damage the 19GHz VCO IC on the unit!!, the new arrangement is not ideal but has better phase noise performance and smaller frequency step than the original.

INSERT PHOTO

The VCO RF path is like this:
ADF5355 at ~9.5GHz - LNB PCB Amplifier from -9dBm to +8dBm - LNB PCB doubler to 19Ghz at 5dBm















Last page added:25/03/00 18:32
M0DTS.co.uk