Re: Comparing ferrite loopsticks a box loop on longwave
Barry M Gelb
Rick,toggle quoted messageShow quoted text
Are you saying that the PL-606 has a built-in external MW antenna jack like the vertically oriented Pl-360 or that it needs modification like the PL-310's jack.
--- In firstname.lastname@example.org, "w4dst" <w4dst@...> wrote:
My understanding is that the Tecsuns use a varactor (variable >capacitance) to tune the internal ferrite to the desired frequency. >This tuning process occurs every time you adjust the tuning knob, in >which case the receiver valiantly hunts for the optimum varactor >setting. This is a neat trick, allowing for enhanced sensitivity.Not all Tecsuns, only the Tecsun receivers, and Grundig G8, using the Si4734 IC have this built-in varactor which is one of the best features of the chip. The inability to use an external MW antenna in a stock SI4734 based Tecsun or G8, PL-606 excepted, is a serious shortcoming. I've been able to tune a 24" square spiral loop, a 60 year old loop antenna from an old Zenith AM/FM radio, and several different ferrite bar antennas easily with my modified PL-380 and PL-310 using the internal varactor in the Si4734. As long as the impedance is within the chip's specs, the radio will tune it with no external capacitor needed.