> The second one was a mediocre performance of the 1.8 filter > (see table below). It had worse close IMD than the 2.7 > filter, in some cases by 20db!
Careful reading of the review will reveal that the particular 1.8 KHz filter was probably defective. Elecraft run much higher signal levels in the first IF filter than other radios. That higher signal level can cause filter generated IMD if the crystals are not absolutely clean. Elecraft (and INRAD) are working on improved testing procedures to weed out those filters that are insufficient to handle the signals levels in the K3 (and divert them to use with Yaesu transceivers <G>). 73, ... Joe, W4TV > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ignacy > Sent: Tuesday, November 25, 2008 4:20 PM > To: [email protected] > Subject: Re: [Elecraft] K3: New (Jan 2009) ARRL review > > > > According to the review, the radio is nearly perfect. Very > strong performance nearly everywhere. > > There were only two sets of numbers that could raise questions. > > The TX 3rd order IMD performance was not that good (29db) but > it was on the worst band. Not sure the testing was before or > after the firmware changes to decrease TX IMD. W8JI praised > K3's low SSB IMD. > > The second one was a mediocre performance of the 1.8 filter > (see table below). It had worse close IMD than the 2.7 > filter, in some cases by 20db! On the other hand, everyone in > this group praises the 1.8 filter so perhaps the filter is > still doing something useful. Also perhaps the latest 1.8 > filters were improved. > > > Third Order Intermodulation Dynamic Range (dB) at MDS > (preamp off, 14 MHz) > Spacing (kHz) Roofing Filter (Hz) > above/below > 2800 2700 1800 500 > 400 > 20 104/104 105/106 101/98 104/104 > 105/106 > 5 105/103 96/106 90/84 102/101 106/105 > 2 99/100 90/89 74/82 90/90 106/103 > 1 94/81 89/79 72/81 87/82 99/99 > 昀� > > -- > View this message in context: > http://n2.nabble.com/K3%3A-New-%28Jan-2009%29-ARRL-review-tp15 77963p1578264.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ 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 _______________________________________________ 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
