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I don't know why you are seeing this problem - maybe your coax is real lossy? I measure VSWR with a power meter and I get the exact same forward and reflected power whether I measure it at the transmitter output or antenna input - ignoring any losses. VSWR = (1 + (P_ref/P_fwd)^0.5) /...

freecell, VSWR doesn't change just because it is measured somewhere else. When the VSWR is 1:1, or 2:1, or whatever the VSWR condition happens to be, it will measure the same anywhere within a given length of coax. If this wasn't true, then it would be a pretty useless metric.

Actually, there is only one VSWR within a given length of feedline. The magnitude of the VSWR is a function of the transmitter ouput impedance, coax impedance, and antenna feedpoint impedance. Since VSWR is defined as Vmax/Vmin, Imax/Imin, or Zmax/Zmin. None of these values will change...

I would use a magnifying glass and good light.

That's some funny stuff... :gdlf

That is what I would do... :D

You do know that you will be wasting about half of the energy stored in the battery as heat. A 6VDC or 7 VDC battery would be a much better solution... If you really want to create a voltage divider circuit, here are some very basic calculations. Assuming the battery voltage was actually...

In almost 100% of the circumstances where the power leads are hooked up backwards, the protection diode will short too, so the fuse has not protected the radio. The fuse is designed/sized to protect the wiring going back to the battery so an electrical fire does not start, not to protect the...

Well, I am guilty of being short sometimes, ...and it is hard to capture someones intent when reading a typed statement, so I apologize Switch Kit if I misread your comments. :)

My intent is to share my knowledge, and years of experience, not to look down on anyone. I do get frustrated when I hear expert comments about concepts or practices that I know are untrue and are just part of the internet folklore. I am guilty of being terse in those instances... :oops:

Your analysis is pretty good, especially for a time lapse of 25 years... The current in the drain/source of a MOSFET is proportional to the square of the gate-to-source voltage. So if the change in gate-to-source voltage is small, the output current will be fairly linear even though a...

MOSFET's are nonlinear devices when used in a circuit designed for large gains. Since a MOSFET is a voltage controlled device, vice a current controlled device like the BJT, it will not load the bias circuit as much if it is just substituted for a BJT. This means the transconductance (gain)...

Is the beta the same between those two transistor types? If not, then the operating point (class of operation) will be different. Just a thought...

bob85, since the coil is added to the base of the antenna at the feedpoint, and since a 1/4 wave monopole is electrically short or capacitive, this will create a parallel tank circuit as a load to the transmitter. So, the inductor could be designed/sized to make the antenna appear resonant but...

bob85, the best solution is for the antenna, coax and trasnmitter to all be matched for maximum energy transfer. The next best solution is to use an impedance matching circuit right at the antennas feedpoint - aka a quality tuner. This will provide maximum power transfer from the...

I would make sure no one can come into contact with it. RF burns hurt...

What does the OP not being up to snuff have to do with theory and practices if they are correct? If the hobbiest cannot accurately calculate a 1/2 wavelength piece of coax based on frequency and velocity factor, than VSWR probably isn't much of a concern. If the coax is damaged, and I...

It really boils down to the fact that an antenna is never purely 50 ohms resistive across its entire BW unless there are wideband impedance matching devices at the antena input and then the antenna is still not 50 ohms across the BW even though it appears so... If any of the impedances...

Yes.

Should work fine. Longer is better...