Date: Mon, 09 Apr 2012 16:52:59 +0200
From: Steinar Aanesland <saanes@broadpark.no>
In-reply-to: <87B6713738004650B13893BB874CBF8B@GaryPC>
To: rsgb_lf_group@blacksheep.org
Message-id: <4F82F7CB.6010907@broadpark.no>
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Subject: Re: LF: Re: New release (4.21) of MULTIPSK
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Gary , it is possible for you to run a 0,5,10,15 beacon interval? 15
minutes is a long time to wait ;)

la5vna S






Den 09.04.2012 14:16, skrev Gary G4WGT:
> Hi Steinar, LF,
>=20
> Lentus QRP beacon now running on 136.300kHz USB dial (1000Hz audio =
=3D
> 137.300kHz).
>=20
> 15 minute beacon period started at 1205utc.
>=20
> 73, Gary - G4WGT.
>=20
> ----- Original Message ----- From: "Steinar Aanesland"
> <saanes@broadpark.no>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Monday, April 09, 2012 12:18 PM
> Subject: LF: New release (4.21) of MULTIPSK
>=20
>=20
> Hi all of you that like to try LENTUS on LF.
>=20
> The beta testing is over . Here is the latest multipsk release with=
 the
> new mode Lentus is included.
>=20
> http://f6cte.free.fr
>=20
> This mode is used for QRP transmissions  (down to a minimum S/N rat=
io of
> -34 dB) either in LF, MF and HF (14 MHz maximum) but not beyond.
>=20
> The recommended frequencies (on the XCVR) are the following (with a=
n AF
> frequency of 1000 Hz, in USB): 136.3, 1837.0, 3589.0, 7037.5, 10138=
.7,
> 14074.0, 14095.6 KHz.
>=20
>=20
> *LENTUS*
>=20
> LENTUS means " Slow " (but also indolent, nonchalant, quiet=85) in =
latin.
> _Created by_: Patrick Lindecker (F6CTE) in 2012
>=20
> *Description :*
>=20
> _Baud rate_: 0.1465 (4800/32768) or 6.827 seconds by 5 bits symbol
>=20
> _Messages_: a message of 293.5 seconds duration (43 symbols) begins=
 at
> t=3D4 sec of the UTC minute 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 5=
0, or
> 55 (it is necessary that the PC may be synchronized on a =93Standar=
d=94 clock).
>=20
> _Note_ : in manual transmission, it can also start at 4+6.827=3D10.=
827 sec
> (42 symbols sent) or 10.827+6.827=3D17.654 sec (41 symbols sent) or
> 17.654+6.827=3D24.481 sec (40 symbols sent), to =AB pardon =BB the =
Ham
> operator for a delay to answer, but with reception probability a bi=
t
> weaker.
>=20
> The message is normally composed of 43 symbols (but can be reduced =
to 40
> symbols, see above), each one with a length of 32768 audio samples =
(or
> or 6.827 seconds). The 9 first symbols carry a tone allowing the
> determination of the transmission central frequency. The 31 followi=
ng "5
> bits symbols" carry the message (allowing the Reed-Solomon coding o=
f 75
> bits). The last three symbols are transmission central frequency ca=
rriers.
>=20
> Messages can be either plain text (13 characters, preceded by a bit=
 =93CQ
> de=94 and a bit =93Beacon=94) or formatted text according to differ=
ent
> possibilities, listed below:
>=20
> =B7    _A standard CQ call_composed of a bit =93CQ=94 + a bit =93Be=
acon=94 +
> complete call (with 3 characters max in the mantissa, as for exampl=
e
> =93AZ2/FL5XYZ/MM=94) + optionally, a 6 characters Locator (accuracy=
 +/-2.31
> km in latitude and +/- 4.63 km in longitude).
> Note: without the =93CQ=94, it is an information transmitted by the=
 Ham
> answering to the CQ call,
>=20
> =B7    _A =93Station description=94  type CQ call _composed of a bi=
t =93CQ=94 + a
> bit =93Beacon=94, a 6 characters call + suffix (as for example =
=93FL5XYZ/MM=94),
> a =936 characters Locator=94 + Power level + =93mW/W=94 bit + relat=
ive gain of
> HF antenna + directivity of the antenna.
> Note: without the =93CQ=94, it is an information transmitted by the=
 Ham
> answering to the CQ call,
>=20
> =B7    _A =93Meteorological=94  type CQ call _composed of a bit =
=93CQ=94 + a bit
> =93Beacon=94, a 6 characters call (as for example =93FL5XYZ=94), a =
=936 characters
> Locator=94 + Temperature + Wind force + Type of weather + Humidity.
> Note: without the =93CQ=94, it is information transmitted by the Ha=
m
> answering to the CQ call,
>=20
> =B7    _A CQ call with precise geographical position_composed of a =
bit
> =93CQ=94 + a bit =93Beacon=94, a 6 characters call + a geographical=
 position
> (latitude + longitude) in =B0 =91 and 2 figures decimal (as for exa=
mple
> =9348-49.83N 002-22.02E=94). The accuracy is equal to 9 m in latitu=
de and in
> longitude (about 60000 times more precise than a Locator position).
> Note: without the =93CQ=94, it is an information transmitted by the=
 Ham
> answering to the CQ call,
>=20
> =B7    _An answer to a CQ with Locator 4 characters _composed of a =
6
> characters Call 1 ( as for example =93FL5XYZ=94) + 6 characters Cal=
l 2 (as
> for example =93FL5XYZ=94) + Locator 4 characters  (accuracy +/-55 k=
m in
> latitude and +/- 111 km in longitude), in answer of Call 1 to a CQ =
done
> by Call 2,
>=20
> =B7    _An answer to a CQ with S/N ratio and drift _composed of a 6
> characters Call1 (as for example =93FL5XYZ=94) + 6 characters Call =
2 +
> Suffix (as for example =93FL5XYZ/MM=94) + S/N ratio (12 to -37 dB) =
+ drift
> (-4 to 4 by step of  0.1 Hz/mn), in answer of Call 1 to a CQ done b=
y
> Call 2,
>=20
> =B7    _An answer to finish a QSO_composed of a 6 characters Call 1=
 (as
> for example =93FL5XYZ=94) + 6 characters Call 2 + Suffix (as for ex=
ample
> =93FL5XYZ/MM=94) + =9373 GB SK=94.
>=20
> _Moments of decoding :_
>=20
> _Reception start_: the reception normally begins at t=3D4 sec and l=
asts 40
> or 43 symbols (see below). In case of failure of the operator, the
> reception can also begin at t=3D24.481 sec and lasts 37 or 40 symbo=
ls
> (it=92s a degraded working).
>=20
> _Decoding start_: the main decoding takes place after reception of =
40
> symbols (i.e. 273 seconds), which normally leaves about 25 seconds =
to
> answer. However, there is still a margin of 20 seconds (to reach
> 25+20=3D45 sec), the message being, in that case, truncated but bei=
ng able
> to be decoded.
>=20
> In case of failure of the main decoding, other decoding attempts ar=
e
> done after 41 symbols (280 seconds), 42 symbols (287 seconds) and 4=
3
> symbols (294 seconds). In this last case, it remains 6 seconds to
> answer. However, there is still a margin of 20 seconds (to reach 6+=
20=3D26
> sec), the message being, in that case, truncated but being able to =
be
> decoded.
>=20
> _Mode of transmission_: Lentus can be used to do QSO (two_way
> communication) or as a beacon. In that last case, no answer is requ=
ired:
>=20
> =B7    a beacon transmission  could be done at minutes 0, 5, 10, 15=
, 20,
> 25, 30, 35, 40, 45, 50, or 55.
>=20
> =B7    for a QSO, by mutual agreement , the Ham calling CQ will tra=
nsmit
> at minutes 0, 10, 20, 30, 40, 50 and the Ham answering to the CQ ca=
ll
> will transmit at minutes 5, 15, 25, 35, 45, 55.
>=20
> _Repeater_: Lentus can also be used, for very specific use, as a
> repeater. As a repeater, it simply transmits  what it is received s=
o as
> to forward the message to other stations or to broadcast a message =
(with
> several repeaters).
>=20
> _Speed_ : 75 bits (or 13 characters maximum in plain text) by 5  mi=
nutes
> period (with only one message by period) or 0,43 wpm
>=20
> _Modulation_ : MFSK 32 tones (for 5 bits) with a shift between tone=
s of
> 0.7325 Hz (5 x baud rate).
>=20
> The synchronization tone transmitted during the 9 first symbols
> corresponds to the central frequency of the transmission bandwidth.=
 It
> permits to determine this frequency (with a precision of about +/- =
0.1
> Hz) and the drift speed (up to 3 Hz/mn). The 32 possible 10^th symb=
ol
> (first data) frequencies will be estimated from these two pieces of
> information. The synchronization frequency search bandwidth toleran=
ce is
> variable from +/- 20 Hz to +/-80 Hz, counted from the frequency cli=
cked,
> by the user, on the waterfall.
>=20
> _Receive mode_: USB. Each transmitting or receive period of 300 sec=
 must
> start at t=3D4 sec of the UTC minute 0, 5, 10, 15, 20, 25, 30, 35, =
40, 45,
> 50, or 55 with a maximum tolerance of +/-0.1 sec of the PC clock. A
> margin of 20 seconds is given as indicated in =93Messages=94 above.
>=20
> It is possible to introduce an advance (from 0 to 0.1 second by 10 =
msec
> steps) to compensate from a possible transmission delay (due to a b=
ig
> distance to the zone to target or a delay due to a Wifi link, for
> example). Symmetrically, in reception, this advance will be taken i=
nto
> account as a delay to start decoding.
>=20
> The time to switch the transceiver is supposed to be very short
> (definitely less than to 100 ms).
>=20
> _Characters set_(46) : ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 <SPACE>=
 / +
> - . ? ! @ % $
>=20
> _Shape of pulse_ : rectangular
>=20
> _Bandwidth_: 23 Hz
>=20
> _Synchronization:_using the very accurate time from an Internet Tim=
e
> Service as the NSIT, through a SNTP or NTP protocol (but not throug=
h the
> RFC-868 Time Protocol) so to have an accuracy widely better than 50=
 ms.
> The use of the =93AboutTime=94 freeware is widely encouraged as the=
 PC time
> error is determined by the soft, simply by setting time twice, the
> second time (and the followings) will give the PC time error.
>=20
> _Coding code_: Reed Solomon (31, 15) or 31 symbols of 5 bits for 15
> symbols of 5 information bits (so a yield of 0.48). The irreducible
> polynomial P(x) is equal to X^5+X^2+1.
> The generator polynomial G(x) is equal to a product of (X+alpha^i) =
with
> i minimum=3D1.
>=20
> _Convolution code_: no
>=20
> _Interleaving_ : no interleaving nor Gray coding is used.
>=20
> _Scrambling_ : each of the 31 Reed-Solomon symbols (which value is
> between V=3D0 and V=3D31), which order is defined by O=3D0 for the =
first
> transmitted symbol until O=3D30 for the last transmitted symbol, is
> associated with a XOR f(O). In other words, for each symbol, it is =
done
> the operation V =3D V XOR f(O). This is done to avoid that a carrie=
r
> produces a suite of same symbols (suite which could be interpretabl=
e by
> the Reed Solomon coding as a correct code). At reception, the V ini=
tial
> is found again by doing Vinitial =3D Vreceived XOR f(O). The f(O) f=
unction
> is random.
>=20
> _Pmean/Ppeak_: 1
>=20
> _Drift tolerance_ : 2 Hz/mn (note that the performance in S/N ratio=
 term
> is degrading with drift)
>=20
> _Lowest S/N_: -34 dB (without any drift, for more than 90 % of the
> frames), however  some frames are decoded at -36.5 dB. At -37 dB an=
d
> below, no frames are decoded.
>=20
> Specifications of this mode will be found in the document
> "Specifications 1.0 of the Lentus mode"  written the 10th of March =
2012
> ("Specifications" on my WEB site: http://f6cte.free.fr/).
>=20
>=20
>=20
> ----------------
>=20
>=20
> 73 and good LENTUSING from LA5VNA Steinar
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20