B
BOOTY MONSTER
Guest
just because your meters show 300-400 wats pep per 2879 doesnt mean they are really doing that much . yess there is some headroom and using a 14.4 volt power supply helps get a little more out of them , but no where near as much as some suggest/claim .
http://www.firecommunications.com/notreal.txt
heres a small quote that gets to the meat of the matter showing what those meters are actually showing .
"the largest factor contributing to the highly erroneous readings produced by the majority of hf
wattmeters is created when energy begins to appear at frequencies 3, 5, 7 (and higher) times
the fundamental operating frequency. the more the drive and operating voltage is increased the
more pronounced the effect becomes. in addition to the sum addition of the energy present at
these multiples of the operating frequency the problem is compounded by the wattmeter design
itself. the line section is designed to sample a specific amount of energy at the fundamental
operating frequency in a direct relationship to the physical length of the line section as that
length correlates to a given fraction of a wavelength at the intended operating frequency. when
energy begins appearing at the odd harmonics not only is the power added by the line section but
it is also amplified because as frequency is increased the line section becomes longer with
regard to the fractional wavelength represented by the line section initially at 27 mhz.. there
fore the line section is "oversampling" the energy levels occurring at the frequencies previously
mentioned. once these harmonics begin to occur the environment is ripe for a sort of controlled
"oscillation", the harmonic energy present acting as the trigger.
now in addition to the energy present at 27 mhz. you now have substantial levels of vhf and in
some cases even uhf energy directly affecting the accuracy of the measuring device."
id suggest reading the entire article
http://www.firecommunications.com/notreal.txt
heres a small quote that gets to the meat of the matter showing what those meters are actually showing .
"the largest factor contributing to the highly erroneous readings produced by the majority of hf
wattmeters is created when energy begins to appear at frequencies 3, 5, 7 (and higher) times
the fundamental operating frequency. the more the drive and operating voltage is increased the
more pronounced the effect becomes. in addition to the sum addition of the energy present at
these multiples of the operating frequency the problem is compounded by the wattmeter design
itself. the line section is designed to sample a specific amount of energy at the fundamental
operating frequency in a direct relationship to the physical length of the line section as that
length correlates to a given fraction of a wavelength at the intended operating frequency. when
energy begins appearing at the odd harmonics not only is the power added by the line section but
it is also amplified because as frequency is increased the line section becomes longer with
regard to the fractional wavelength represented by the line section initially at 27 mhz.. there
fore the line section is "oversampling" the energy levels occurring at the frequencies previously
mentioned. once these harmonics begin to occur the environment is ripe for a sort of controlled
"oscillation", the harmonic energy present acting as the trigger.
now in addition to the energy present at 27 mhz. you now have substantial levels of vhf and in
some cases even uhf energy directly affecting the accuracy of the measuring device."
id suggest reading the entire article