[HBR] THE BEST receiver

[N2EY at aol.com]

In a message dated 7/29/05 3:06:08 AM Eastern Daylight Time, roomberg at ptd.net 
writes:

> I was not looking for a specific rig as much as I was looking for a 
> specific technology.

There isn't one. There's no magic bullet that's lots better than all the 
rest.

> 
> 
> I am not comparing rigs as BEST because it has ALL bands or all modes.
> Money is not an issue.
> 
> I specificly am interested in learning what is the best  40 meter CW  
> circuit to pull weak
> signals out of the noise using a modest 40 meter dipole antenna.

Again - there isn't one. "Best" covers a lot of ground, such as "what sort of 
noise?"

> 
> I live in the mountains .... at the bottom of a canyon... so I want to 
> know how to do better than what I
> have now.... which is storebought... KENWOOD TS570... which does not 
> impress me at all.
> 

Here's a very simple test:

Tune the receiver to a quiet spot on the band - one with no signals. 

Turn the AGC off.

Adjust the selectivity to what you normally use for CW reception.

Turn the gain up so the background noise is a loud roar in the speaker.

Now disconnect the antenna from the receiver.

Did the roar go down, or disappear? If so, then your receiver has all the
gain and sensitivity that can be used in your location with that antenna.

No receiver can pick out what the antenna doesn't pick up. 

> 
> One response I got said :
> 
> Tubes generate NO internal noise, as ALL "PN" junctions do, thus tubes ARE
> quieter in the noise-floor department.
> 

That is simply not true. Tubes make internal noise, same as semiconductors.
How much noise a particular design makes is determined by many factors, and
one cannot usually make blanket statements about one technology being quieter 
than another.
> 
> 
> Then this advice confused me a bit:
> He said that the Drake will bring signals out of the mud that the best DSP 
> would not.

Sometimes. Not all the time, 

> Is the Drake 2b a superhet or what?

It's a triple conversion superhet from 40+ years ago. That's not important, 
however. The Drake 2-B is a very good receiver, but not the absolute best, IMO. 


It's important to differentiate between "best for the money" or "best I have 
used" and "absolute best there is".


> I want to know what kind of circuit is the best.. not a rig model to buy.

There isn't one. 

> 
> =================================================================================================================
> Every design and technology is a compromise - a trade-off. Maximizing
> some things results in reductions in others. What's "best" depends on
> what tradeoffs *you* prefer.
> 
> For example, it is possible to build very sensitive receivers - 0.1 
> microvolt 
> or better for 10 dB signal-to-noise ratio. But such sensitivity is usually 
> attained at the cost of dynamic range. And on 7 MHz, with most antennas, 
> that 
> much sensitivity is wasted
> because the background noise picked up by the antenna is much greater than 
> 0.1
> microvolt.  
> 

I wrote the above. 

Perform the simple test I mentioned above. If the noise goes down 
significantly or disappears, your receiver has all the sensitivity that can be used at 
that location with the specific antenna.

73 de Jim, N2EY