Mike, My explanation stands, but "not really usable" isn't a fair assessment. I frequently use the KX3 in the BC band. I can clearly copy all the same stations with the KX3 that I can hear using other AM- capable radios at my QTH.
The KX3's receive sensitivity does fall off by design below about 1.5 MHz (as described below), but in many cases you don't need a lot of sensitivity here due to high atmospheric noise. The exception, of course, is if you're a serious BC-band SWL. In that case you might want to consider a simple broadcast-band receiving converter using an IF of say 7 MHz. The KX3 provides up to 9 built-in transverter bands, one of which could be programmed for this purpose so the VFO would still display the actual target frequencies. 73, Wayne N6KR On Jul 7, 2012, at 6:15 AM, Mike Morrow wrote: > A discussion of KX3 MF lack of sensitivity recently took place > on the KX3 list. The KX3 should not be considered really > usable below about 1500 kHz, as Wayne explsined: > > ---- Original Message (from KX3 list) > >> I thought there was some advantage to AM BCB reception >> to be had with the KXAT3. > > If a KXAT3 is installed, harmonic images are attenuated, > but this has little effect on signal strength. > >> Why wouldn't the T/R PIN diodes be as well protected by >> high pass filtering that rolled off below 400 kHz rather >> than 1500 kHz > > The carrier lifetime of the diodes is roughly 1.5 microseconds. > This means that strong signals at the low end of the broadcast band > could cause IMD (IP2) if not attenuated. The HPF provides > about 20-30 dB of rolloff by this frequency, ensuring that > this isn't a problem. The KX3 is optimized for ham-band use > so this is entirely appropriate. > > Wayne > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
