[ARC5] BC453 FET BFO Success!!!

[millerke6f at aol.com]

Me thinks the 1 Hz  2 foot drop stablilty test is a bit wishful thinking as even well made receivers with conventional local oscillator systems would probably move a bit more given the kinetic energy of an 80 lb radio dropping 2 feet onto a solid bench... but a bit of hyperbole is good for an entertaining chat.  As to the old NC157 and narrow band modes, I'm amazed that the fellow was able to get any kind of performance out of the beast.  But back in my RTTY days on 20 meters my NC303 would provide me hours of copy on 170 Hz shift along with my CE100V responding in kind.  Not that the old 170 Hz mode was all that demanding, a shift of around 20-30 Hz would indeed bias the signal enough as to be problematic for error free reception.  


Bob, Ke6f



-----Original Message-----
From: Kenneth G. Gordon <kgordon2006 at frontier.com>
To: J Mcvey <ac2eu at yahoo.com>
Cc: Arc5 <Arc5 at mailman.qth.net>
Sent: Mon, Dec 18, 2017 3:31 pm
Subject: Re: [ARC5] BC453 FET BFO Success!!!

On 18 Dec 2017 at 22:17, J Mcvey wrote:

> 
> I'm not the only one with this situation on a boat anchor.
> take a look at 4:34 on this video  
> https://www.youtube.com/watch?v=vZ37HmgJQkw

That is an interesting video for several reasons. 

The first, as far as I'm concerned, is the really terrible instability of his NC-173 !!! 

Although I have not used an NC-173, I have used other National receivers, and even a 
simple one like the NC-57 is FAR more stable than his NC-173!.

I am wondering if he restored that radio or if he simply fired it up after finding it somewhere?

Unfortunately, he has not implemented any way to leave him a comment on those youtube 
videos, nor to contact him via e-mail.

The only receivers I have ever used with such terrible instability were Hallicrafters, including 
the SX-101. Even the SX-28 was MUCH more stable than either his NC-173 or the other 
Halli receivers I've used.

Tapping on the table resulting in such instability indicates to me, at least, that there is some 
sort of mechanical or electrical problem in that radio which has not been addressed. Such 
terrible instability should NOT, EVER happen in any decent receiver.

NONE of my working "ARC-5" receivers exhibits such instability. I would never attempt to 
use any receiver that did.

Here is a test for you: tune in a weak signal, then pick the receiver up, raise it about 2 feet 
above your operating bench, and drop it.

If the tone of the signal being tuned-in moves even 1 Hz, then the receiver is 
MECHANICALLY unstable.

Gee...

Ken W7EKB

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