SKIPPY - a frequency
hopping plugin for ICOM radios.
Skippy is a
unique product, designed and built at Naidia, South Australia.
unleashed Icom IC706 with Skippy frequency
Conventional radios are intended to transmit and receive on a
single channel. This fact makes them vulnerable to interception and
jamming. Whilst scramblers and speech encryption devices may provide
some degree of resistance to interception, they are
ineffective against jammers. Frequency hopping (ECCM)
is the only effective counter measure to both forms of electronic
A frequency hopping radio is capable of hopping its operating
frequency over a given bandwidth many times a second (with HF radio,
this bandwidth is limited by the antenna and the ionosphere). When
uses On-Air syncing, a sync signal is periodically transmitted to
ensure that the transmitter and receiver keep hopping in sync with each
other. In the event of Skippy using GPS, the PPS time signal from the
GPS network is used to maintain sync and there are no periodic on-air
sync signals. The hopping sequence follows a pseudo random pattern,
which has an extremely long repeat time. This renders the hopping
network virtually impossible to intercept or jam. Only the network
users who have identically configured Skippy units can communicate.
In a Skippy frequency hopping network, the station which
network is designated as Master. There can be any number of Slaves
within a network.
The HF spectrum is often crowded and
contains all sorts of signals and noise. Identifying a
hopping net is made easier if the transmissions have a
coherent or characteristic signature. For example, digitised frequency
radios use PSK or FSK, such
transmissions are well defined and readily identifiable. The
instantaneous spectrum of an analogue SSB voice transmission is
characteristically noise-like and there is no output whatsoever between
syllables. This renders SSB analogue voice hoppers like Skippy
Actual performance in the field is subject to many
variables, most of which are controlled by external factors (antennas,
ionospheric conditions, terrain and electrical
interference). An H.F. SSB analogue frequency hopping network is
extremely difficult to detect using a conventional receiver. A wideband
receiver is needed, and an active hopping network can be
detected by using a waterfall display. Nevertheless,
de-hopping the signal is
extremely challenging, and jamming it virtually impossible.
will turn your ICOM amateur transceiver into a Frequency Agile S.S.B.
- Skippy will work in SSB mode across
all bands, eg. an
Mk11G becomes an HF, VHF and UHF frequency hopper.
- Skippy’s compact size, negligable power
consumption and light
will not inhibit your portable or mobile operation.
- Skippy plugs into your existing radio, no radio
- Skippy is also powered from your radio so
are kept to a minimum.
- Skippy allows you to set infinitly variable hop
rates to suit
- Skippy allows you to set infinitly variable hop
bandwidth, and allows the user to nominate the exact start and stop
freqs of the hop band. (the hop bandwidth range is from 1Hz to
- Skippy has user selectable "ACK" tones so you can
Skippy units on your net are synched in, or you can remain deep and
quiet - you choose.
- Skippy has user selectable random sideband
- Skippy has a built in radomised hop duration and
- Skippy can select an unique optimised Hop Band
return loss of the antenna.
- Skippy autodetects the presence of an
optional P.P.S. GPS which allows the units to remain in sync
indefinitely with no on-air sync tones.
User selectable parameters include:
Codan 2110M HF Manpack Tactical Military Transceiver Barrett 2050 HF transceiver
- Hop Rate - infinitely variable
- Resync interval
- Notch frequencies - don’t hop here
- Hop band start frequency
- Hop band stop frequency
randomisation on or off.
- "ack" tone on or off.
- Three different hop band shapes are
- Selectable initial sync frequency.
- Preloader allows default hop
parameters to be quickly loaded.
- Icom radio model selection.
Skippy's unique user selectable hop band shaping allows the
match the hop band shape to the antenna return loss. These spectrum
plots here were done under shielded lab conditions using an IC706 with
175mSec hop duration. In an active band with real world signals, the
hop pattern can be quite difficult to detect.
No hopshaping appiled,
continuous audio tone. Hop-band 7000 -
Mild hopshaping appiled, continuous audio tone. Hop-band 7000
- 7300 kHz
Agressive hopshaping appiled, continuous audio tone.
Hop-band 7000 - 7300 kHz
Skippy is unlike conventional military frequency hopping
radios. For starters Skippy is not a radio, Skippy is a fraction of
the cost of a military hopping radio, and yet has more hopping
Of course Skippy is not Mil-spec, nor is it IP rated, nor does it
support digital modes, nor does it support voice encryption, nor is it
painted green. Skippy is an entry level frequency hopper,
designed with the Amateur, researcher or experimenter in mind.
Q- What is the maximum hop rate?
A- There is no real absolute maximum hop rate (given the
10mSec to change channels). Typically, somewhere
hops/second is good depending on band conditions.
Q- Will Skippy cover all frequencies?
A- Yes and no, In Australia Skippy is only for
Amateurs, and will only
work within Amateur bands,
The Export version of Skippy is "unlocked" and
only by the radio.
Q- What does Skippy do to my radio? A- Nothing, it
simply makes the radio change frequency.
Q- What does Skippy do to my signal? A- Nothing, it
simply makes the radio change frequency. The signals pass
through the radio exactly as normal. Other
than the sync signal,
Skippy is not in the signal path.
Q- Will Skippy damage my radio?
A- Not if used correctly, but you can use Skippy at your own risk.
Q- What radios will Skippy work with? A - Skippy
works with Icom IC706 & IC7000 series radios.
Q- Is Skippy’s hop
pattern compatable with other military HF/ VHF
frequency hopping radios? A- No. Skippy’s hop
pattern is unique and not compatable
Barrett, Q-mac, Tadiran, Hughes, Racal, Harris or any other frequency
Q- What does the radio interface lead consist of?
A- It is the same as
an Opentracker/Tinytrak lead with
one extra wire for the CAT line.
Q- What do I have to do to prepare for using SKIPPY?
A- Nett your radio to within +/- 3Hz. This is most
Get your radio on frequency.
are generaly 30-40Hz off from the
Q- Do I need a GPS to use SKIPPY?
A- No, it is entirely optional.
Q- Do I need a computer to use SKIPPY?
A- No. Skippy is stand alone
(requires the radio of course).
Q- Can I use one SKIPPY unit by itself ?
A- Not really – it takes two to tango.
Q– How many Skippy units can I have in my NET?
A- There is no
limit to the number of Skippy units in your NET.
Q- Will Skippy continue to be supported and upgraded?
A- Depends on initial interest.
Q- Does Skippy encrypt my signal?
A- No Skippy does not
encrypt your signal.
Q- Can SKIPPY be used to
transmit & receive data or packet? A- This
has not been tested, but Skippy may not like data or packet.
Q- I would like Skippy modifed to do XYZ.
A- Certainly, it’s a flat hourly rate.
Q- Can I have the SKIPPY source code? A- No.
Q- Can I purchase the SKIPPY source code?
Q- How do Skippy units synchronise themselves?
Either by On-Air tones, or by using the PPS signal from a GPS.
Q- How long will Skippy units remain synchronised?
Indefinitely, given adequate band conditions or GPS syncing.
Q- I would like a demo of SKIPPY.
me and make an
Q- Where can I get SKIPPY operating instructions?
A- Draft operating instructions will be supplied when you purchase a
Q- What is the emission designator for a Skippy controlled SSB
transmission? A- 2K8J3E
pre-producton SKIPPY trials prototypes are available now.
Available to Licenced Amateurs ONLY, the delivery name & address must match the licencee details on the Radcomms Database.
$220 ea including GST and postage within VK Cable $45 ea
SKIPPY has been assessed
by the Defence Export Control Office as a
purchase from overseas, permission has to be obtained from
DECO. Once export permission is granted the export process is
by a suitably licenced Adelaide based International Freight Forwarding and
Customs Brokerage company. This process takes 8-10 weeks and costs
about $AUD1000 per order (not per unit) delivered to the USA. Once
an Export Quote is prepared, full payment is required, in
advance, prior to beginning the export process.
has placed SKIPPY on
the DSGL (Defence and Strategic
Goods List). http://www.defence.gov.au/deco/
SKIPPY is prohibited without a permission from
The export of controlled goods and technology requires a
permission to be issued in accordance with Regulation 13E of the
Customs (Prohibited Exports) Regulations 1958.