in-line VIRTUAL GROUND NODE GENERATOR
also known as the
the network that works miracles!
Errante's in-line virtual ground node
Freq. range: 1 to 30 MHz
Input imp.: 50 Ohm
Output imp.: 50 Ohm
Input/output SWR: 1:1 within range
Insertion loss: -0.01 dB
RF power: 3 KW cw
Sockets type: SO-239
Weight : 1 Kg ca.
VIRTUAL GROUND NODE GENERATOR : what it is, how it works and what it
Universal R.F. VIRTUAL GROUND NODE
by Francesco Errante
The Errante's in-line virtual ground node generator is a
radioelectric circuitry based on the same principals and schematics of his
own original patented virtual ground monopole HF antenna design. The reader who's not already familiar with the virtual ground node
mechanism is strongly adviced to read about the "virtual ground monopole HF antenna and its
background prior to proceeding to the reading of
The in-line VIRTUAL GROUND NODE GENERATOR (in-line V.G.N.G. for short) is a
symmetric radioelectric network which converts an unbalanced RF signal into
two precisely identical signals and re-converts them back into a non-inverted
single unbalanced RF signal. While doing this, a virtual ground node is
generated at its center. It can be effectively described as being an
In practice the device, as presented in here, has both the input and output
gates terminated onto a 50 Ohm impedance value and SO-239 type of connectors
to match the most common co-axial line impedance standard and it is optimized
for HF operations between 1 and 30 MHz. Within its specified range, this
device appears to be "transparent" between the RF source and the load [SWR =
1:1] and exhibits an extremely low insertion loss [-0.01 dB] However, it can
be made to suit any other input/output impedance values and frequencies
The in-line V.G.N.G. can generate a virtual ground node at any point
of a co-axial line in un-balanced transmission line system. This is, infact,
its function. This device is also available in a
version for balanced lines.
1) It can be employed to stabilize a
whole RTX un-balanced system, however complex it could be, by providing a
reliable and centralized RF earth grounding system. As most people may have
already experienced, RF earth grounding is a very difficult task and has
nothing to do with the conventional safety earth grounding solutions; N.B. For safety reasons, where required, all the equipment
must also be earthed the conventional way and the chassis of the in-line
VGNG can also be wired to the building safety earth grounding circuit. All
the system equipment chassis should be wired to the provided earth bolts on
the in-line VGNG chassis by the shortest route.
2) It can be employed to provide a reliable way to
short-circuiting antennas who have not antistatic protection, without the
need for modifications or even reaching them up on the roof. Since the
in-line VGNG exhibits a solid short circuit to the DC current on both its
gates, all the electrostatic charges collected by the aerial and/or the
co-axial outer conductor will be discharged via common ground and into the
building safety earth grounding circuit;
3) It can be used to stabilize RF
co-axial lines exposed to third party hertzian radiation;
4) It can be employed to stabilize
reactive loads at their feeding points.
The in-line VGNG enables physics and RF laboratories
to have a reliable RF earth grounding systems as a precise reference
for test and measurement.
a. the in-line VGNG is easy and fast to deploy;
b. in-line VGNG helps to improve E.M.I. compatibility within high
equipment density environment.
Question: I run a virtual ground HF
antenna, do I still need an in-line VGNG ? ANSWER: NO ! Your virtual ground antenna system already
provides all the R.F. earth grounding you need. However, while using a
different aerial an in-line VGNG might be needed.
Question: Where should I place it
along my transmission line? ANSWER: Where the un-balanced RTX system comprises only
of a TX/RTX-SWRmeter-coaxial-antenna, the in-line VGNG must be placed
right onto the TX/RTX antenna socket. N.B. If an antenna tuner is used, the in-line VGNG must
always be placed before it, right on its input socket.
If a linear power amplifier is used the in-line VGNG must be placed on
its output gate.
Where the system comprises of TX/RTX, a linear power amplifier and an
antenna tuner, the in-line VGNG must be placed between the amplifier and
the antenna tuner.
If a filter, such as an anti TVI, is used place the filter between the
amplifier and the in-line VGNG. Moreover, the filtering should improve
and the system will also benefit by the added VGNG's out-of-band own
signal rejection. N.B. The in-line VGNG should be inserted in the
transmission line by using a short but comfortable RG-213, or better,
patch lead. Wherever possible use double male connectors to plug the
in-line VGNG in.
Euro 160,00 +V.A.T. and shipping costs.
For an useful currency converter click here
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