[Hammarlund] HQ-170 Questions

[DW Holtman]

Hello,

Thank everyone for the information on the clock, I will get one on order 
soon.

More questions on the HQ-170.

1. Where is the Serial Number located? Maybe the one on mine was torn 
off. How do I tell if mine is an older model 170?

2. How well does the Hammarlund Noise Immunizer work? Someone installed 
in my receiver.

3. In place of the RF amp this receiver has a couple of 6DS4 Nuvistors 
installed on top of a 7 pin tube type plug and plugged into the RF Amp 
V1. Does anyone know anything about this mod?

Thank you in advance for all of your help.

Best,
DW Holtman
WB7SSN