[ARC5] Quick sensistivity comparison

[Glen Zook]

Actually, tube-type ("valve") receivers routinely give better LDS / MDS (least descernable signal / minimum descernable signal) signals than solid-state equipment.  Things like phase noise are definitely higher in "modern" solid-state equipment.  Now, generally for operation on MF and HF, the ambient noise levels on the bands negate a lot of the LDS / MDS.  That is, the noise level is often substantially above the weakest signal that the receiver is capable of receiving.  As such, the improved sensitivity is not needed when an antenna is connected to the receiver.

I routinely get LDS / MDS level of well under 0.1 microvolt (and the leakage from the generator is extremely low) on receivers like the Collins S-Line, Heath SB-Line, Drake 4-Line, etc.  Even on general coverage receivers like the HQ-140X, SX-100, etc., the LDS / MDS is often below 0.1 microvolt.
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: Richard Hankins <g7rvi at richard-hankins.org.uk>
To: ARC-5 Mail List <arc5 at mailman.qth.net> 
Sent: Thursday, June 13, 2013 2:37 AM
Subject: Re: [ARC5] Quick sensistivity comparison
 

Ken,

you don't say what you were surprised by?   I am surprised that /any 
/valve HF receiver gives apparent sensitivities this low (either set), 
and would suspect leakage from your signal generator.

Either way, both sets of figures (if accurate) are academic. Aerial 
noise on the HF bands will swamp these figures by some 10 - 20 dB.