> Log Periodic Antennas can overload the front ends of so called modern
> receivers and their untuned mixers.
> There is a passive circuit that uses 2 tank circuits back to back
> connected with a small capacitor between them. It inverted the 50 ohms up
> a Hi-Z and then back to 50 ohms which creates great selectivity. It has 2
> simple tank circuits per band and fully peakable on any frequency. I
> to build it myself and will have to find the circuit. In was in CQ. Look
> under all band preselectors. Just going through a regular antenna tuner
> give some selectivity.
Don't have access to CQ Mag. If someone finds this sure would love a copy.
> When the bands open I'd suggest testing a several new rigs first on a
> coax switch on trial to see how selective it is to adjacent
> buying. There are a few rigs now that are OK. k7gco
Other than the high-end 1000MP and JRC JST-245 what others, please?
I expect many of us are priced out of those options so the passive circuit
will have to get it done ... in my case for my TS-690S/AT.
BTW: One need not be a DX contester to need this feature. Many Nets
suffer intentional and careless-operator QRM ... grossly over-driven amps
poorly designed (CB-type) amps exacerbate the problem. When trying to
assist weak-signal missionary stations with phone patches I have encountered
a real need for high selectivity.
Thanks! & 73, DavidC K1YP
NetZero - Defenders of the Free World
Get your FREE Internet Access and Email at
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com