[ARC5] BC-453 or R-23(*)/ARC-5 on 600 meters...

[Bill Cromwell]

Hi Les,

Somebody in the thread mentioned WSPR. That has to be zero +/- 2.5 Hz 
(as reported to me after queries. For transmissions on that mode you 
would want even tighter control as the stations are fractions of 1 Hz 
apart. Drifting very far would QRM you neighbors. If you go to all that 
trouble it can take all night just to claim a valid contact - call sign 
and location! I also understand that a computer data file is required so 
the "radio" can look up the info to verify it. Maybe that is a 
different, very fussy mode. I still ain't there. I do play some digital 
modes and computer based DSP (digital signal processing) and that really 
helps with noise reduction and other audio filtering tasks. With the DSP 
methods there is little to no ringing with bandwidths under 100 Hz. Even 
with a filter setting of less than 100 Hz the BC-453 stays close enough 
to keep the incoming signal in that passband. I'm suggesting that some 
of them might stay within the +/- 2.5 Hz. To be sure you measure it that 
close - how much does the timebase in your counter drift? I'm just an 
amateur with the old, bad attitude - "good enough is good enough". I can 
copy NDB transmitters and some CW here and there all night long on my 
BC-453 and R23. When I put the audio up on a 'waterfall' display I can 
see the frequency drifts up and down a few cycles but I have to look 
close. I don't know how much is the VFO, how much is the BFO, nor how 
much is the computer or soundcard timebases. So there is another reason 
I am not interested in the "too fussy" modes. Some people get their 
enjoyment from splitting frog hairs and I think it's cool. But I ain't 
there. I hope this helps.

Let us know what you find.

73,

Bill  KU8H

On 08/03/2014 04:16 PM, Leslie Smith wrote:
>    Hi Ken,
>    I'm surprised to read your words "they lack the necessary stability
>    for 'extreme accuracy' modes.
>    What degree of stability do you require?
>    I'm going to attach my old-fashioned frequency counter to the L.O. to
>    measure drift in my ATA beacon band receiver.
>    My set "settles down" very quickly after it's switched on - SSB is a
>    breeze with a simple converter in front of the "R-23".  (It's an ATA
>    not R23!)
>    I'm particularly interested because I run my set from a 60V regulated
>    B+ supply, and (at that voltage) the 'tubes' run cool.
>    (Cooler than Bob Dylan)
>
>    The limit to sensitivity for the beacon band receivers lies in (a)
>    atmospheric noise.
>    If it's "there" an ATA set will hear it on MF/HF.
>    The designers from the mid-30's knew their stuff (and all done with a
>    slide-rule too!)
>    They were really "hot".
>
>    73 de Les Smith
>    vk2bcu at operamail.com
>
>