[Elecraft] OT: QST's review of the Yaesu FTDX5000MP

[Ron D'Eau Claire]

Sometime in the 1960's or early 70's one company started offering a 9 MHz
filter at a decent price that was widely used by homebrewers back then and
the subject of many QST and ARRL handbook designs as well as a number of
"commercial" rigs. 

Obviously, those rigs up-converted the lower MF frequency bands and
down-converted the higher MF frequency bands.

Early M.F./H.F. superhetrodyne receivers all "down converted" to an I.F. in
the low MF range (usually 455 kHz) but designing input filters for the M.F.
range that would adequately reject the image response at 2X the I.F. became
very difficult. Filter technology limited the selectivity available at
higher frequencies, forcing designers to use a low frequency I.F., but the
press was on from the beginning for better I.F. filters at higher
frequencies.

Like all designs, it's always a compromise. The best designers are those who
make the best compromises using the components available at an acceptable
price.    

Ron AC7AC


-----Original Message-----
There is a serious misconception by some true believers that Elecraft
"invented" down-conversion (or at least conversion) to an i-f in the 8 to 9
MHz range.

Nothing could be further from the truth, and I know that the folks at
Elecraft would never claim as much.  I had a Henry Radio Tempo-1 (Yaesu
FT-200) back when radios warmed up the shack.  It was a 9 MHz i-f
transceiver.

Wes Stewart,  N7WS

--- On Tue, 11/16/10, Benny Aumala <benny.aumala at gmail.com> wrote:

> 
> When K3 came I told this RX architecture will soon be a
> standard
> (as Rob Sherwood told long time ago).