The pocket-sized VA1 is designed to check and adjust antennas, feedlines,
and RF networks. It includes a microprocessor, A/D converters, and a
low-power "transmitter" with 4 digit frequency readout, continuously
variable from 0.5 to 32 MHz in 6 bands.Like its little brother, the RF1,
it measures RF values of true impedance (0-1000 ohms), SWR (1 to 15:1),
C (0-9999pF) and L (less than 0.04 to 300 uH).
The VA1 adds a true SIGNED RF PHASE DETECTOR to give you the antenna or load
R and signed X components, plus all the functions
Is your load inductive or capacitive? The VA1 tells you instantly. It even
tells you the value of series coil(uH) or capacitor(pF) to add to eliminate
series reactance and yield lowest SWR. Readout of equivalent parallel R and
X yields the parallel X value needed to yield lowest SWR. (All of this is
described in the instructions.)
The VA1 is not limited to 50 ohm lines. You can select SWR readout on over
10 common feedline impedances from 25 to 450 ohms.
The VA1 can even calculate the (series) R and X components of your antenna
when measured at the far end of the feedline. So you know the impedance of
your antenna even if it's 100 feet in the air. No 1/2 wave line required.
Just measure of calculate the feedline length using the VA1.
As you can see, the VA1 makes noise bridges obsolete, and does much more
than expensive network analyzers.
Don't be fooled. Other meters claim to be advanced and
measure X, but
they don't tell you the sign of X !
They can't even tell a capacitor from a coil. In contrast, the VA1
instantly displays the sign of X.
All parameters are read out digitally for highest accuracy.
The VA1 is extremely easy to use. Its large 1/2" LCD display is not washed
out in sunlight..it loves sunlight. And it can cycle between several
measured values so you can watch them together.
L and C are measured
at the RF frequency of interest, not at 1 KHz or 100 KHz as on other meters.
So the effects of stray capacitance, toroid parameters, and other
frequency-dependent factors are taken into account. The VA1 can even
measure the inductance of less than 1/2" (1 cm) of straight wire!
The VA1 is truly pocket size. 4.5 x 2.5 x 1.5 in. The battery pack
on other units is
actually larger than the entire VA1! The VA1 runs off a
single 9 volt battery in a real battery compartment on the
back with a pushoff cover...similar to a TV remote control.A
standard 9 V alkaline battery has a life of about 5 hours,
and can be replaced in seconds. In addition, the unit turns
itself off after about 20 minutes if no buttons are pushed.
(The auto-off feature can be disabled if desired.)
The illustrated instruction manual discusses many applications in
detail, not just instrument operation. Whether you're an expert or
novice, the manual will show you many of the things you can do
with the unit.
Besides its use by Amateur Radio operators, this unit is in use all over
the world at antenna manufacturers, production lines, and laboratories.