[Elecraft] Elecraft technology

[N2EY@aol.com]

In a message dated 12/29/03 11:19:18 PM Eastern Standard Time, 
rondec@easystreet.com writes:

> the sudden rise of single
> conversion receivers (and transceivers) followed the availability of a
> commercially-manufactured 9 MHz crystal filter in bandwidths of from a few
> hundred Hz to 2.4 kHz in the early 1960's. 

Hycon Eastern was making such filters in 1956 (see the "What's Wrong" QST 
article). Although those filters were for 2215 kHz, they were making filters up 
to at least 10 MHz.
> 
> As far as I know, this was the FIRST commercial high-frequency filter at a
> decent price (which was still STEEP - something over $50  

I have a pair of the filters used in the "Miser's Dream" rx, with data sheets 
dated 1959. $44 per filter.  
> 
> Still, the advantage of a high I.F. using a good quality filter for
> single-conversion designs made this a very popular device in both home brew
> and commercial Ham receivers and transceivers. 

Agreed. National liked 5.2 MHz, Heath and later Kenwood went for 3.395 Mhz, 
Swan was in the 5 MHz range, and there were a few 9 MHz rigs as well. 

While we're on the subject, the old urban legend that hams use LSB on 75 and 
USB on 20 because of early rigs with 5 MHz VFO and 9 MHz filter is a myth. It 
only works with a 9 MHz VFO and 5 MHz filter

It's my understanding that mechanical filters aren't practical much above 500 
kHz because their innards become too delicate. 

73 de Jim, N2EY


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