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Presumably the LO-Z input, not the HI-Z. Switching between inputs can
have some interesting and maybe useful effects, the differences varying with frequency. I use the Lo-Z which is for coax, what are some of the 'interesting and maybe useful effects' Tom? I think I know what you mean, I've never used the HI-Z, between the two, which one do you prefer? ~*~*Monitoring The AirWaves~*~ *****GO BEARCATS***** Hammarlund HQ129X /Heathkit Q Multiplier Hammarlund HQ140X Multiple GE P-780's(GREAT BCB Radios) RCA Victor *Strato- World* RCA Victor RJC77W-K(Walnut Grain) 1942 Zenith Wave Magnet 6G 601M Cathedral/ Ross#2311/Rhapsody-MultiBand DX100/394/398/399/402 OMGS Transistor Eight/Realistic 12-1451 Henry Kloss Model One/Bell+Howell ~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* Alpha Delta DX Sloper 57ft. 600ft. 12AWG. (non-terminated) 120ft. 12 AWG Sloper 2 Radio Shack Loop Antennas Radio Shack Amplified Antenna 30X30 DiamondLoop(six section 830pf Cap) * Diamond Loop mounted to Lazy Susan TurnTable* |
#12
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GO BEARCATS wrote:
Presumably the LO-Z input, not the HI-Z. Switching between inputs can have some interesting and maybe useful effects, the differences varying with frequency. I use the Lo-Z which is for coax, what are some of the 'interesting and maybe useful effects' Tom? I think I know what you mean, I've never used the HI-Z, between the two, which one do you prefer? The system comprising an antenna and receiver is so complex that there aren't any hard and fast rules. The impedance characteristics of both vary with frequency and that of the receiver at any fixed frequency can change as the receiver is tuned. Thus the impedance match and voltage or power transfer is all over the map. The RF energy in the vicinity of the antenna changes with time and all receivers are susceptible to overload from too much reaching the front end. Connecting an antenna alternately to the LO-Z and HI-Z input almost always results in a difference in the desired signal's strength but more importantly can affect the signal-noise ratio. For example, I found that with short antennas (say under 1/10 wavelength i.e. under 15-20 ft for the 49 metre band) and the DX-394 that the HI-Z input would give higher signal readings. But with the strong local MW stations overloading the receiver the background hash would be much higher. Connecting it to the LO-Z input results in the antenna-receiver input combination acting as a basic high pass filter that markedly improves the signal-noise ratio. The DX-394 has some unique properties that differ between the two antenna inputs that may not come into play with other radios. Only the LO-Z input has a 20dB pad and the VHF image filter is probably more effective on this input, if at all on the HI-Z. I wrote a couple of articles about these issues that can be found at http://www.mods.dk/view.php?ModelId=573 and at http://groups.yahoo.com/group/RADIOS...iles/Mods/ANT/ . In "Options for the DX-394 Telescoping Whip Antenna", I describe how I adapted the whip antenna to the LO-Z input with an optional clip to the HI-Z input that proves necessary for reception of low frequencies and can be a plus or a minus at mid-frequencies. Since everyone's situation is different and changing with time, there is ample opportunity to experiment to find what works best at the time. 73, Tom |
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