300 ohm to 75 ohm impedance matching "transformer"

Started by Joe in sci.electronics.basics15 years ago 3 replies

I bought a 300 to 75 ohm "matching transformer" to hook up to a home built TV antenna. The matching transformer looks exactly like the one on...

I bought a 300 to 75 ohm "matching transformer" to hook up to a home built TV antenna. The matching transformer looks exactly like the one on this URL: http://www.solidsignal.com/prod_display.asp?PROD=WMXFMRPT I have a couple of questions: Can these matching transformers be used in either direction? That is, my antenna will get the 300 ohm end, and the TV antenna input will get the ...


Litz wire for AM ferrite Rod Antenna?

Started by Bill Bowden in sci.electronics.basics16 years ago 28 replies

How much improvement can I expect using Litz wire to wind a AM ferrite Rod antenna as opposed to using solid copper wire? Is it worth the...

How much improvement can I expect using Litz wire to wind a AM ferrite Rod antenna as opposed to using solid copper wire? Is it worth the trouble to obtain Litz wire, or can I expect almost the same response at say 1 MHz using regular solid enamaled copper wire? -Bill


equation: dBm to mW/cm^2

Started by Winston in sci.electronics.basics11 years ago 26 replies

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the...

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the reading presented in mW / cm^2 I understand that my antenna has a gain of 1 dBi. In this chart http://www.geopathfinder.com/Conversion Chart.pdf ..I see that 0 dBm (for example) is equal to 0.0121 mW / cm^2 The chart refers to an equation sou...


S/N Ratio dependent on impedance match?

Started by Bill Bowden in sci.electronics.basics10 years ago 11 replies

Why is S/N ratio dependent on impedance match? It would seem a ferrite loopstick antenna would deliver twice the voltage if connected to a...

Why is S/N ratio dependent on impedance match? It would seem a ferrite loopstick antenna would deliver twice the voltage if connected to a high impedance rather than matching it to it's characteristic impedance. But I have heard this is not a good idea since the S/N ratio would degrade. Any truth to this idea? -Bill