HP 8411A HARMONIC FREQUENCY CONVERTER
For use with HP 8410C Network Analyser, reference and test channel inputs. Covers 110MHz to 12.4GHz, or with Option 018 110MHz to 18GHz, both using special APC-7 connectors. Cost new $3,850 in 1980. HP Manual downloaded from the Web, (with 8410B).
Rear view showing special connectors
Note the special 9 Pin Socket connection to the 8410C, a very rare connector. Also the 8411A uses the APC-7 hermaphrodite connector to interface to the reference and test channel inputs. Apparently these inputs are very sensitive to static, so 'ground' cables before connecting them. 50mW +17dBm is the input power damage level, or more than ±3V will take out the Step Recovery Diodes (SRD) which are irreplaceable. This is the only item of equipment that I have that uses these connectors so APC-7 to N-type adaptors are essential.
Bought the 8411A Option 018 (S/N 2004A) on eBay FR together with a 8410C & 8414A.
Bought a 2nd unit Option 018 (S/N 2004A) on eBay UK.