[Elecraft] Elecraft GC receiver?

[N2EY at aol.com]

In a message dated 8/1/06 12:32:30 PM Eastern Daylight Time, 
Keith.Darwin at goodrich.com writes:


> -----Original Message-----
> Jim replies (>) to my original message (>>) ...
> 
> >> - Medium size or larger controls.
> 
> >How big is that? To me, "medium size" means 1" diameter
> > for most controls and 2-3" for tuning.
> 
> Yep, sounds sweet to me.

That means a pretty big front panel, because knobs that size fill up lots of 
space. You wind up with a front panel that looks like this:

http://www.qsl.net/k5bcq/Jim/SilverRX1.jpg

http://hometown.aol.com/n2ey/myhomepage/

> 
> > The problem is that there's a conflict between that
> > and the general coverage/low cost criteria.
> 
> Well, I don't know enough to discuss this but it sure seems to me that
> someone could come up with an R-4B style design using modern parts that
> would be easy to build and pretty cheap. 

Only if it's possible. There are a bunch of issues to be resolved in such a 
design, and they all involve compromises.

 Well, you'd think it would be
> 
> at least. 

Why would I think that? 

 After all that rig was nothing more than a receiver that
> 
> could cover a number of 500 KHz bands and it did it pretty well.

And look what an R-4 cost! Adjust the price of an R-4 (ABC, whatever) to 2006 
dollars and be ready for a shock. 

> Today's approach of using synthesizers has its drawbacks.  It may give
> us more bells & whistles (memories, direct freq entry) but it brought a
> bunch of issues that needed to be solved as well.
> 

Synthesizers became popular for whole bunch of reasons. One of them was cost. 


The R-4 family use a premixer design. There's a tunable oscillator (PTO) 
controlled by the tuning knob. There's a crystal oscillator with a crystal for 
each 500 kc. segment. The outputs of the two oscillators are mixed in a 
"premixer", then filtered, to generate the local oscillator signal that mixes with the 
incoming signals in the first mixer (a 6EJ7 IIRC).

Such a design uses a lot of custom-made parts. The PTO and dial assembly are 
mostly precision mechanical parts. There's a custom-made crystal for each 500 
kc segment. Custom-made crystals cost several dollars each in the R-4's day 
and even more now. Most of the coils in the premixer are custom made, as is the 
bandswitch. Even with Drake's buying power, all those custom parts push the 
price up.

A big part of cost reduction is using stock parts rather than custom ones. 
While homebrewers can use one-of-a-kinds, surplus, and "found parts", 
manufacturers are pretty much forced to use current-production new parts. 

One of the elegant features of Elecraft designs is its almost complete lack 
of custom parts. In a K2, the case, circuit boards, the firmware chip and xtals 
are the only custom parts. The firmware chip is a stock part that Elecraft 
programs, and the  xtals are selected microprocessor crystals.

> > Consider a K2 with the transmitter section removed.
> > You'd save the finals, a mixer, some control circuitry,
> > and a few other things. But would you save half 
> > the cost of the rig? I doubt it.
> 
> Agreed, but what if you started with a ... KX1?  That rig is already
> close to what I'm asking for (close enough that maybe it will be my next
> rig).

And look what a KX1 costs! Remove the transmitter section and you'll save 
some money, but you'll spend it all on other things like a bigger case and custom 
filters.

  I'm not looking for K2 contest level performance, just something
> 
> that can tune around and do an OK job receiving and something that has
> good sound. 

Can the KX1 drive a speaker?

 Simple is good.
> 
> 

The KX1 is hardly simple!
> 
> >> - Synchronous AGC
> 
> >  ?? What is synchronous AGC?
> 
> Oops, I meant synchronous AM detection ...
> 
> 

OK - whole bunch of issues with that.
> 
> >> I guess I'm looking for a modern Drake 2B / R-4B but with full
> coverage.
> 
> > Those receivers are really good but they lack many of the above
> features too. 
> 
> Actually, they have most of what I listed, except for memories and a low
> price.

See above for the cost problem.

  True they were not general coverage, but with a handful of
> 
> crystals (remember those :-) you could teach them to cover the bands you
> were interested in.  To me that's good enough.
> 

Then and now, the crystal cost was a big issue. Covering 1.5 to 30 takes 57 
crystals! If the stock R-4 comes with 9 crystals, you need to come up with 48 
more....
> 
> > What about things like a noise blanker, computer control port or DSP?
> 
> 
> Computer control & DSP?  Well, I for one would be very happy to do
> without those to save some money.  
> 

There's another point: A lot of the market would want those features. 
Elecraft neatly solves the problem by making many features optional, which permits 
those who are not interested to leave them out, and also permits those who have 
limited resources to add them later rather than having to buy everything at 
once.


> Thanks Jim!
> 

You're welcome!

73 de Jim, N2EY