[Elecraft] Elecraft technology

Wed Dec 31 11:49:01 2003

How's this for up conversion? (I did some design work on the Tektronix =
2784 spectrum analyzer). It covers 100Hz to 40 GHz with a first IF of =
3.5GHz or 9.5 GHz, depending on the input frequency. Phase noise =
performance is quite good and the IF BW can be set from 3 Hz to 10 MHz. =
It is a quad-conversion and does have many spurs. Also goes to 1200 GHz =
with waveguide mixers. The input preselector covers 10-40 GHz (I think). =
This was my first experience with up conversion. I had thought that =
down-conversion was dead but now I see it is alive and well. =20

  Dave WX7G

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of [email protected]
Sent: Wednesday, December 31, 2003 6:56 AM
To: [email protected]
Cc: [email protected]
Subject: Re: [Elecraft] Elecraft technology

In a message dated 12/29/03 11:19:18 PM Eastern Standard Time,=20
[email protected] 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.=20

Hycon Eastern was making such filters in 1956 (see the "What's Wrong" =
QST=20
article). Although those filters were for 2215 kHz, they were making =
filters up=20
to at least 10 MHz.
>=20
> As far as I know, this was the FIRST commercial high-frequency filter =
at a
> decent price (which was still STEEP - something over $50 =20

I have a pair of the filters used in the "Miser's Dream" rx, with data =
sheets=20
dated 1959. $44 per filter. =20
>=20
> 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.=20

Agreed. National liked 5.2 MHz, Heath and later Kenwood went for 3.395 =
Mhz,=20
Swan was in the 5 MHz range, and there were a few 9 MHz rigs as well.=20

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

It's my understanding that mechanical filters aren't practical much =
above 500=20
kHz because their innards become too delicate.=20

73 de Jim, N2EY

--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
The reason this message is shown is because the post was in HTML
or had an attachment.  Attachments are not allowed.  To learn how
to post in Plain-Text go to: http://www.expita.com/nomime.html  ---
_______________________________________________
Elecraft mailing list: [email protected]
You must be subscribed to post to the list.
To subscribe or unsubscribe see: =
http://mailman.qth.net/mailman/listinfo/elecraft
Elecraft Web Page: http://www.elecraft.com
Also see: http://www.elecraft.com/elecraft_list_guidelines.htm