Ron and I will have to just disagree with the definition of a "birdie" - and it is only a matter of definition.
My definition is the result of multiples of the various signals and oscillator frequencies present in the receiver, and since they are always multiples greater than 1 of any signal (or oscillator), will always result in a fast tuning response. OTOH, there are unavoidable mixing products in any down-conversion receiver that will tune as a normal signal. The goal of the designer is to choose the IF frequencies to keep those spurious responses out of the bands of interest to the target users - in this case, the ham bands. So, if your definition of "birdies" agrees with Ron's, so be it - I will continue to refer to extraneous direct mixing products (those responses that do not produce fast tuning signals) as spurious responses. It is just a matter of definition. BTW, this is one of the advantages of up-conversion - those direct responses are so far away from the desired signal that they do not become troublesome, but up-conversion designs have their own share of troublesome problems. 73, Don W3FPR On 8/20/2011 8:06 PM, Ron D'Eau Claire wrote: > I show one birdie here. It's a "normal tuning" (not double rate) birdie > which, with great respect for Don, I will disagree with him and say that not > all birdies tune at accelerated rates if one defines a birdie as an > internally-generated unwanted signal. That birdie is at about -100 dBm. > > If I turn on the preamp and connect a dummy load, a row of lower level > birdies does appear, but they are completely buried in normal band noise > (here at -140 dBm) with an antenna connected. > > As others pointed out, you can try moving TMP cables or, more simply, > applying the "birdie removal" software. The latter does not cause a hole at > that frequency. It just moves the oscillator frequencies around as you tune > to that frequency so that when you are tuned there the birdie is somewhere > else. > > Ron AC7AC > > -----Original Message----- > > Thanks for the suggestions guys - for those of you with P3's - tune to > 20445.11 on CW nor mode and take a look with the span on the P3 set at > 200khz. A regular picket fence of birdies! (at least on my K3) > > 73 Gill > > > -- > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
