Hello again Guy, Fair comment. As far as the "commercial" issues are concerned I could not agree more. I would add to the wish list the supply of real impedance information especially around the bandpass edge frequencies where the filter's port impedances will gyrate like mad, and not just the nominal impedance. But as you say, how would a few dozen characters in a calalog pass on this information. So the designers had to get samples, at least we did, but we Amateurs can't - usually.
I want to go off list to comment on your other points so as not to clutter up the reflector. But one last point before doing so. It is a great pity that the myth exists, IMHO, that double conversion receivers with a high first IF are second runners to single conversion low IF receivers. Perhaps many are because their first IF filters are so wide, and overload can and does occur further down the line. Small bandwidth VHF crystals filters do exist, I have some here, but I suspect that wideband VHF monolithic crystal filters are cheaper for the manufacturers of transceivers etc. However there is no doubt that a properly designed high first IF receiver is far less prone to spurious responses than its low IF cousin, and can have very good strong signal performance. HERESY ! I'll see you off list. 73, Geoff GM4ESD. ----- Original Message ----- From: "Guy Olinger, K2AV" <[EMAIL PROTECTED]> To: "Geoffrey Mackenzie-Kennedy" <[EMAIL PROTECTED]>; "Elecraft Discussion List" <[email protected]> Sent: Sunday, November 14, 2004 5:02 PM Subject: Re: [Elecraft] Talking filter Bandwidths > Most of the issues you address are seen in the sweep. The problem that > all the content and implications of the sweep can't be put in a 42 or > 45 character item name in a catalog. Where there is a picture in a > catalog, the sweep curve would be more meaningful than a picture of > the filter itself. But I'm not holding my breath. > > > > I personally would like to see something like BW 595/2.6 in listings, > particularly next to an alternative listed as 510/1.74. > > In any event, the few dozen characters of a > filter description could never address the engineering quality issues > you so rightly list. If they did, how would it read. > > Maybe this is one of those food labeling law issues, that all ads have > to include certain numbers and you can get slammed for telling lies. > > As to overdriving, for many rigs that is a roofing filter issue due to > their choice of IF's, AND one of the many reasons why the Elecraft K2 > design works so well. > > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
