Thanks Dave. I'll read your review. Having been out of HAM radio for over a decade, I'm just trying to understand where each company involved in selling radios is heading and what their priorities are.
Dave G4AON wrote: > > Shane > > In the case of 14 MHz and the K3, the first IF is 8.215 MHz. An > oscillator at 22.215 MHz mixes with 14 MHz to give the difference > frequency of 8.215 MHz, however there is another difference of 14 MHz > minus 8.215 MHz which is 5.785 MHz which is the image frequency. The > ratio in dB between the wanted frequency and the image gives the image > rejection. There are other images involving the 2nd IF of 15 KHz too. > > With the K3, the main images are greater than 70 dB below the wanted > signal. My own measurements give figures of 70 dB on 28.1 MHz (worst > case) to better than 110 dB on 1.8 MHz and 50 MHz. > > The big advantage of a low 1st IF is the ability to use narrow "roofing" > filters to reject nearby interference. The disadvantage is potential for > poorer image rejection. > > Image rejection is only one aspect of a transceiver design, of model A > was better in all respects than model B (and was cheaper) everyone would > buy model A, but life isn't so simple! > > 73 Dave, G4AON > http://www.astromag.co.uk/k3/ > ---------------------------------------- > Does the K3 manage to obtain image rejection comparable to Icom's and > Yaesu's flagships? If so then it seems to me that Icom and Yaesu seem to > be > relying on a proven RF design and instead are concentrating their current > efforts on ergonomics and presentation. There's nothing wrong with that > though. > > Thanks, > Shane > VK5ABQ > > _______________________________________________ > 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 > > -- View this message in context: http://www.nabble.com/K3-IF-Design-tp17418898p17418993.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
