Interesting, I had an analog computer course exercise at the U of I Urbana when we had two verticals separated and phased to define the coverage pattern. I don’t remember the length of them. It’d be interesting to recall what it was.
Chuck KE9UW Sent from my iPhone, cjack > On Dec 18, 2018, at 1:55 PM, Fred Jensen <[email protected]> wrote: > > Indeed. AM broadcast vertical antennas are rarely 90 or 180 degrees, > especially if they are a Class A station. I think both KFI and KNX in Los > Angeles have 195 deg verticals. The design goal is to maximize field > strength in the service area, accomplished by adjusting the height of the > current maxima in the antenna element. All resonance means is that the > reactive component of the impedance at the feed point is zero. A bigger > problem for stations at the low end of the band ... KFI is at 640 KHz ... is > that the usable bandwidth of the antenna can be less than the bandwidth of > the DSB signal. [:-) Last time I saw KFI's tower from Interstate 5, it > appeared to have a fairly large capacity hat. > > Elecraft ATU's [even the KX1 which is necessarily small with a limited number > of L-C selections] seem to handle reactive loads just fine suggesting [to me > at least] that designing an antenna for azimuth and/or elevation pattern may > be more beneficial than achieving resonance in the desired part of the band. > > 73, > Fred ["Skip"] K6DGW > Sparks NV DM09dn > Washoe County > >> On 12/17/2018 7:45 PM, W2xj wrote: >> Coming from the broadcast side, especially AM broadcasting, I never >> considered resonance particularly important. Really it’s just the >> transmitter that cares. We always put matching at the antenna but in ham >> radio we usually have tuners at or in the TX. >> > > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
