PI4
Beacons On VHF At G0MJI (Mini Study Oct 2017)
Any
advice/comments to: g0mji (at) rocketmail.com - this page 'evolved' during testing...
Claims have been made about
the robustness and effectiveness of PI4. One of the most
'positive' claims is that it matches effectively those criteria
set up by various talking shops; a cynic might think the critera
appear to have be made around PI4 rather than the other way about.
Coincidence most surely. And, as anyone who enjoyed 'Chance In A
Million' back in the olden days will know, coincidence makes
fools of us all. What I would certainly offer is my gratitude to
those generous people who keep any beacon running for the benefit
of everyone.
What I can also say with certainty is that so far it has proven to
be more difficult to decode PI4 beacons at my QTH than say, for
instance, JT65B, or even JT9 beacons
on what (on the face of it) appear to be more difficult VHF
paths.You simply have to 'work' harder at IO83 to receive PI4. (Postscript:
this is improving see below). Also, it has to be admitted,
October is hardly an ideal month for VHF.
But I have managed it - at last. You can use either MSHV or PI-RX, or
as I have been doing both at once. Curiously one program might
decode the beacon when the other does not. I do not know whether
this is a comment on propagation, my PC, the software, the
operator or the mode itself. (postscript I have given up with MSHV
for PI4)
There are, apparently, several PI4 beacons on 50.005 which run in
sequence - well
definitely maybe? If they show up I shall post below...
There are also two 70 mhz beacons using PI4 that I am aware of.
Neither so far have been received here (again, see below).
Most disappointing has been the absence to date of GB3CFG
- especially given I regularly hear GB3NGI (2m JT65b) and the path
is similar. The other is OZ7IGY
(Also Here)
- admittedly a difficult path from here.
I really will keep an open mind about these different modes, but
the proof of the pudding, as they say...
To receive on USB tune 800hz down from the beacon frequency. (e.g.
Dial is 50.004200 for the 50.005000 mhz beacons). Simple equipment
used here is an aging FT847 and a commercial version of DK7ZB
a very compact but useful antenna on a rotator at 7m.
Here is the only PI4
decode on 6m so far of EI0SIX.
Note the screenshot was made after the data had moved off screen.
I had been waiting so long, I perhaps nodded off. Spots for EI0SIX
here and here...
More pudding - GB3MCB/S.
Again PI-RX decoded it. And on Cluster
(Just right click on the beacon call, choose 'Spot Beacon' and submit to cluster)
And
another one, GB3CFG at last on 4m - this is getting better -
on Cluster
and Here.
In
conclusion:
It is possible to spot PI4 beacons at G0MJI QTH.
Experience makes it easier.
Confidence grows with success.
I do not know why PI-RX apparently outperforms MSHV - at this one QTH and on this one
setup.
It was fun, even in October!
Postscript - GB3MCB, MSHV and continuous
beacon(ry)
Post-Postscript: January 2018. While it is true PI4
beacons can be received at IO83NI. It has been my
experience, after several months of testing, that the
JT65B beacons appear here more often even along similar
paths. It is difficult to conclude from this that PI4 is
less good than JT65B more generally, there are too few
samples. However, on a daily basis JT65B beacons
definitely are more reliable in terms of decodes, and
hence indicators of conditions at my QTH. Given the choice
of beacon software available, if I was running a beacon
24/7/365.25, based upon localised findings here, then I
would go with JT65B.