[600MRG] WSPR Flavors

[John Molnar]

Regarding the U3S, this is a rig that probably will find a use in every
600m
shack.  Mine is used extensively here at WG2XKA.  Item 3) is really cool
(2x frequency output),  as anyone fooling with Class D amps can attest. The
performance/price ratio for this rig is huge...

John ETD / XKA

On Thu, Jan 26, 2017 at 2:59 PM, Hans Summers <hans.summers at gmail.com>
wrote:

> Hi Frank
>
> My question - On the receiving end, in order to maximize the ability to
> decode a WSPR signal, does the receiving station have to use the same
> "flavor" WSPR as the sending station?  By flavor I mean:  (1) The same
> transmit / receive duration in  the 10 minute cycle?  (2) The same
> revision, e.g., WSPR-X vs another version such as an early issue of WSPR
> that is a number of years old? (3) And on occasion, I have seen / heard
> stations referring to things such as WSPR-1, WSPR-1.2, WSPR-15, or
> whatever.  What are these and their impact on successfully decoding a
> signal if the receiving station is not using that same version (flavor) as
> the transmitting station?
>
>
> There is only one WSPR encoding scheme. The only two variants are the 2
> minute cycle WSPR (actually just under 1 minute 52 seconds transmission
> time), and the 15 minute cycle. The use of the 2 minute WSPR version is
> almost universal and is supported by all versions of WSPR encoding/decoding
> software.
>
> The 15 minute WSPR (called WSPR-15) is only possible with some of the WSPR
> software packages. Not all. WSPR-15 was intended for LF operation but does
> not seem to have become popular. Standard WSPR has a tone spacing of 1.46Hz
> (which is 375/256) and the symbol duration is 256/375 seconds. There are
> 162 symbols in the transmission. In WSPR-15 the sequence of tones is
> exactly the same, but the tone spacing is 1/8th and the tone duration is 8
> times longer. Hence it takes almost 15 minutes to send.
>
> The WSPR encoding protocol has been unchanged since the beginning. So it
> makes no difference what software version is used by transmitting/receiving
> station - except of course that they both need to be on either 2 minute or
> 15 minute (LF) transmissions. When people referred of WSPR-1 or 1.2 or
> whatever they were probably talking about some specific features of a
> particular version of the PC software.
>
> The only exception to that is the "extended" mode WSPR which sends TWO
> 2-minute transmissions, and allows sending callsign prefix/suffix (with
> certain constraints) or 6-character Maidenhead Locator precision instead of
> the usual 4. This variation in the encoding wasn't available in the early
> software versions, it was added later. If an early software version heard
> one of these "extended" transmissions it would only be able to decode the
> first of the two parts. You do see the "extended" system used sometimes. In
> my opinion it's a bit of an abomination except in certain limited
> situations (I won't bore you with my reasons, this email is long enough
> already) so I consider it fortunate that "extended" mode is not used much.
>
> There were also improvements to the decoder in the last couple of years.
> Much of that was innovations by K9AN. The latest software versions use the
> K9AN decoder. It has deeper search capability, and successfully decodes a
> larger number of weak signals than the earlier decoder. This is not a
> change in the WSPR protocol, as I said that is unchanged... it is just an
> improvement in the digital signal processing to enable weaker signals to be
> recovered better. Even K9AN's decoder has room for improvement... but
> everything is a trade-off and the law of diminishing returns applies...
> beating K9AN will take a lot of work and probably only marginally improve
> the decode capability.
>
> FYI my Ultimate3S transmitter kit http://qrp-labs.com/ultimate/u3s can
> send
> both the most common 2 minute WSPR, and the (fortunately) rarely used
> Extended type  (prefix/suffix/6-char locator) and WSPR-15 below 1MHz. It
> generates RF output directly on any band from 2200m to 2m. Power output
> depends on frequency. 250mW mid HF. More power lower frequencies, less
> power higher frequencies. An optional 5W HF PA kit is available. GPS can be
> connected for frequency and time discipline (important for WSPR). It's a
> standalone system requiring 5V power and an antenna only (no PC to control
> it or configure it). A lot of fun starting from $33.
>
> Since this is a 600m group I should mention a number of features that were
> added specifically for 600m users:
> 1) WSPR-15 mode
> 2) configurable second frequency output from the Synthesizer with inverted
> phase, for driving push-pull amplifiers
> 3) x2 configuration for generating double-frequency output, for 600m amps
> that require this double frequency input
> 4) PTT delay feature, to key a Power Amplifier a configurable number of
> milliseconds before the RF transmission starts (and after it ends) to avoid
> hot-keying big amplifiers.
>
> 73 Hans G0UPL
> http://qrp-labs.com
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