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Author Topic: FT8 while portable for SOTA/POTA/WWFF??  (Read 4781 times)
WM6Q
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Posts: 37




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« Reply #15 on: October 18, 2017, 11:26:05 AM »

Thanks!

Bob WM6Q
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KC2IFH
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Posts: 24




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« Reply #16 on: October 18, 2017, 01:35:00 PM »

How do you maintain the correct time when working portable if you don't have an internet connection?

I am using the Garmin GLO bluetooth GPS/GLONAS receiver.  It provides time synchronization to my Surface 3 tablet.  Seems to work as well as the internet connected NTP utilities.
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N1EU
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Posts: 129




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« Reply #17 on: October 24, 2017, 05:50:31 AM »

I'm also very interested in operating FT8 from a SOTA summit.  I've come to the conclusion that my FT8 messages will not include SOTA references.  I will spot myself on SOTAwatch and call CQ and respond and just follow the conventional WSJT-X message format.

I like the idea of bluetooth GPS (most tablets etc only have a single USB port and may need that for other things).  What software will provide system time from the bluetooth GPS?

KC2IFH - are you using the internal soundcard on the Surface 3 or a USB soundcard?  Do you need to use the keyboard or can you operate with just the tablet touchscreen?

Thanks & 73,
Barry N1EU
« Last Edit: October 24, 2017, 06:01:42 AM by N1EU » Logged
KC2IFH
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Posts: 24




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« Reply #18 on: October 24, 2017, 09:31:33 PM »

KC2IFH - are you using the internal soundcard on the Surface 3 or a USB soundcard?  Do you need to use the keyboard or can you operate with just the tablet touchscreen?

Barry I am using a $7-8 usb soundcard off Amazon. I use a lightweight Travis USB hub, the cheap USB soundcard, 2 3ft stereo cables, and the KXUSB cable. I only use the tablet touch screen and don’t need to use the keyboard or mouse. I use JT Alert to interface with N3FJP Amateur Contact Log and everything goes great so far. I could cut out the KXUSB cable if I did the keying via VOX and didn’t want any rig control.

Let me know if you have any other questions.
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N1EU
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Posts: 129




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« Reply #19 on: October 25, 2017, 03:13:37 AM »

Let me know if you have any other questions.
Thanks Alex, very helpful!  Could you describe the software that supports your bluetooth GPS --> Windows system time ?  Is there a special driver for the GPS device plus a Windows app for the time setting or ?

73, Barry N1EU
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AA2UK
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Posts: 363




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« Reply #20 on: October 27, 2017, 11:01:59 AM »

Maybe this will help? It's rWSJT Commits revision 8188.
https://sourceforge.net/p/wsjt/wsjt/8188/tree//branches/wsjtx/lib/DXped_Operations.txt




                  White Paper: FT8 for DXpeditions
        --------------------------------

Assumptions:

1. WSJT-X will have two distinct options that enable the maximum-rate
QSO exchanges described below.  Fox must select "Fox"; all Hounds must
select "Hound".

2. There will be an announced basic dial frequency for each band, say
f0=14082 kHz for 20m.  This is the basic Channel.

3. Fox always transmits in the 1st sequence, 200-800 Hz above f0.

4. Hounds call in 2nd sequence, 1000-5000 Hz above f0. Hounds
transmitting below f0+1000 Hz will not be answered.

5. If found necessary, additional Channels may be defined in which
Hounds can transmit.  (However, I suggest that CQ-by-call-area may
be easier to implement and use; and the software could be made to
prevent Hounds in the wrong area from transmitting.)

6. Ideally, Fox and Hounds should all use CAT control configured with
*Split Operation* set to *Rig* or *Fake It*, and transceiver dial
frequencies should best be calibrated to within a few Hz.  (WSJT-X
provides tools that make this fairly easy to do.)


When Fox is running a pileup, QSOs will look something like the
following exchanges.  Here I've assumed the Fox callsign is KH1DX,
his locator AJ10:

------------------------------------------------------------------------
    Fox                              Hounds
------------------------------------------------------------------------
1.  CQ KH1DX AJ10
2.                                   KH1DX K1ABC FN42, KH1DX W9XYZ EN37, ...
3.  K1ABC KH1DX -13
4.                                   KH1DX K1ABC R-11
5.  K1ABC R 73; W9XYZ <KH1DX> -17
6.                                   ... no copy from W9XYZ ...
7.  W9XYZ KH1DX -17
8.                                   ... no copy from W9XYZ ...
9.  G4AAA KH1DX -11
10.                                  KH1DX G4AAA R-03
11. G4AAA R 73; DL3BBB <KH1DX> -12
12.                                  KH1DX DL3BBB R-09         
13. DL3BBB R 73; DE <KH1DX>
14. ...
------------------------------------------------------------------------

All messages except those containing "<...>" are standard FT8 messages
(i3bit=0, iFreeText=0).  Hounds transmit only standard messages.

Fox transmits standard messages and also special messages with
i3bit=1.  The special messages contain a callsign whose completed QSO
is being acknowledged; a callsign for the next station to be worked; a
hash code corresponding to the Fox callsign; and a signal report.
Users will see the Fox callsign enclosed in angle brackets, <KH1DX>.
The 72-bit message payload contains two 28-bit callsigns, a 10-bit
hash code, and a 6-bit signal report.  If no call has been queued up
by Fox for the next QSO, the acknowledgment message takes the
abbreviated form shown in line 13 above.

When a Hound receives a message with i3bit=1, the decoder interprets
the remaining 72 bits as described above.  If the 10-bit hash code
matches that for Fox's callsign, the message is displayed as in the
QSO exchanges shown above.  Otherwise the message is considered a
false decode and is not displayed.


Station Setup and Operation for FOX
-----------------------------------

A wide Rx bandwidth (up to 5 kHz) is selected.  The basic dial
frequency is set 1 kHz above f0 (thus 14083 kHz in my example) and the
audio TxFreq somewhere between -200 and -800 Hz.  (Yes, negative
numbers are OK.  *Split Operation* will reset the Tx dial frequency as
needed and will keep the generated Tx audio frequency between 1500 and
2000 Hz.)  Hounds with audio TxFreq set to N Hz will be received by Fox
at N-1000 Hz.

WSJT-X at Fox will maintain and display a list of all decoded Hounds
calling Fox in the past 2 to 4 Rx cycles.  The list might look
something like this (but typically will be much longer):

----------------------------
Call        Grid  Rpt  Freq
----------------------------
AA2UK       FM29  -11   240
AD9H        EN61  +02  1260
K0TPP       EM48  -15  1980
N2BJ        EN61  +11   540
N4NDR       EL98  -17  4620
NX4E        EM70  +00  3780
ON3LA       JN29  -10  3300  
PD9BG       JO21  -21  2100
PJ4/KA1XYZ  FK60  -07  1020
VE1SKY      FN74  +03  1620
WB2REM      EL97  -13  3060
...
----------------------------

Fox can choose to have the list sorted on any column.

Fox select a Hound to call next by clicking on a line.  Or he can hit
"F1" to have the program select a caller according to one of these
criteria (maybe others as well?):

 - Weakest caller
 - Strongest caller
 - Strongest one below -N dB (with N selectable)
 - Choose a call at random
 - Random choice with S/N between snrMin and snrMax dB.

After a particular Hound has been called, Fox's Auto-Sequencer looks
for a response containing "R+rpt" originating from that same callsign.
If such a message is received, Fox's next transmission will be the
special "acknowledge-and-call-next" type, with i3bit=1.  If the
expected message is not received, as in example line 6 above, the
report is sent to the same station again.  If the second attempt fails
and another Hound callsign has been queued up, the QSO is aborted and
the next Hound is called.


Station Setup and Operation for Hounds
--------------------------------------

Dial frequency is set to f0, 14082 kHz in my example. Rx bandwidth and
displayed range on the Wide Graph can be anything convenient, say 200
to 2600 Hz.  (Signal from Fox will be expected between 200 and 800
Hz.)  Enter callsign and locator of Fox on WSJT-X main window as *DX
Call* and *DX Grid*.  Choose a TxFreq offset of 1000 + 60*N for some N
in the range 1 to 80 (maybe even higher?).  Move TxFreq as desired,
hoping to find a clear slot, by using Shift+F11 and Shift+F12.

 - Hit F1 to call Fox in your next Tx sequence.  Yes, you must hit F1
   repeatedly, in order to keep calling.
  
 - The Auto-sequencer will watch for a decoded message that contains
   "MyCall DXcall rpt" or "MyCall <DXcall> rpt".  When one of these is
   received, your next transmission will be "DXcall MyCall R+rpt",
   sent automatically.

 - After you send the "R+rpt" message, AutoSeq will watch for a
   message that starts with "MyCall R 73; ...".  When that is
   received, you're in his log, and you'll be prompted to log the QSO.

Random thoughts
---------------

Fox's decoder has access to signals in a 4 kHz (maybe even 5 kHz?)
window.  At 60 Hz intervals, that's enough for around 65 (or 80?)
non-overlapping Hound signals.  If the pileup becomes too deep, more
spectrum might be used; but note that WSJT-X can't access more than 5
kHz at one time.  A better solution might be for Fox to call "CQ n
KH1DX AJ10", where n is a single digit indicating call area.  The
decoder could then limit the list of eligible calls to those in the
specified call area.  After decoding such a CQ, the software at Hound
could refuse to transmit unless MyCall falls in the specified call
area.  (Other special CQ formats can be imagined that would limit the
eligible Hound callsigns even further.)

We haven't thought much, yet, about logging issues for Fox.  I imagine
we could do what's necessary to join a N1MM+ logging network, if that's
deemed desirable.

A few questions:

Q1: Should the Auto-Sequencer allow for other cases in which a QSO has
been initiated by Fox, but one of next two messages is not copied by
either Fox or Hound?  For example, what if K1ABC does not copy message
#5?  Should he keep sending his message "KH1DX K1ABC R-11" ?  If Fox
receives this message again, should he acknowledge again?  And poor
W9XYZ, who never received an acknowledgment, will probably keep
sending "KH1DX W9XYZ R-19", or whatever.  If Fox eventually copies the
message, should the program remember that W9XYZ had been called, and
thus send him an acknowledgment?

Q2: Should we provide a stack for several to-be-called callsigns,
rather than just one?  Should re-ordering of calls in the stack be
permitted?

Q3: Can we handle WSJT-X "Type 1" and "Type 2" compound callsigns, for
Hounds?
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KC0W
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Posts: 282




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« Reply #21 on: October 28, 2017, 07:32:24 AM »

 Is anyone actually into this whole Fox & Hounds thing? I see it's listings on the Contest Calendar but have never taken part. As a matter of fact I don't think I've even heard anyone participating in it while perusing the bands................Perhaps it's the best kept secret on HF CW?

                                                                      Tom KC0W       
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AA2UK
Member

Posts: 363




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« Reply #22 on: October 28, 2017, 07:41:36 AM »

Is anyone actually into this whole Fox & Hounds thing? I see it's listings on the Contest Calendar but have never taken part. As a matter of fact I don't think I've even heard anyone participating in it while perusing the bands................Perhaps it's the best kept secret on HF CW?

                                                                      Tom KC0W       
I think it's more about a DX stations ability to manage a larger number of users. I re-posted this in this forum all by itself.
I'm not an HF guy but keep WSJTX updated here by upgrading my software daily.
Bill, AA2UK
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KC0W
Member

Posts: 282




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« Reply #23 on: October 28, 2017, 08:14:49 AM »

Is anyone actually into this whole Fox & Hounds thing? I see it's listings on the Contest Calendar but have never taken part. As a matter of fact I don't think I've even heard anyone participating in it while perusing the bands................Perhaps it's the best kept secret on HF CW?

                                                                      Tom KC0W      
I think it's more about a DX stations ability to manage a larger number of users. I re-posted this in this forum all by itself.
I'm not an HF guy but keep WSJTX updated here by upgrading my software daily.
Bill, AA2UK

 Perhaps we are talking about two different things? I'm referring to the wintertime bi-weekly Fox & Hounds CW operating event.

 http://www.qrpfoxhunt.org/

                                                                         Tom KC0W
« Last Edit: October 28, 2017, 08:18:44 AM by KC0W » Logged
AA2UK
Member

Posts: 363




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« Reply #24 on: October 28, 2017, 08:21:19 AM »

Well you might be right. I found the terminology strange especially knowing Joe K1JT well.
I hope to get additional information about this operating procedure for FT8.
Tnx, Bill
AA2UK
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N1EU
Member

Posts: 129




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« Reply #25 on: November 01, 2017, 12:37:27 PM »

So I've proceeded to put together a setup to operate FT8 portable (SOTA).  I've got everything working using a TomTom bluetooth GPS receiver providing time sync to the Windows tablet running BktTimeSync and WSJT-X.  I've heard that I can use a smartphone instead of the TomTom, by using an android app such as Bluetooth GPS Output.  Has anybody actually done this successfully (using smartphone alone to provide a bluetooth gps time sync), because it's not working for me and I'm forced to use the TomTom?

Thanks & 73,
Barry N1EU
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N1EU
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Posts: 129




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« Reply #26 on: November 01, 2017, 01:36:18 PM »

Never mind responding to my last post.  I realize it's simply bluetooth hell.  Bluetooth "kinda" works, but not really reliably over a several hour period.
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N1EU
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Posts: 129




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« Reply #27 on: December 06, 2017, 03:52:37 AM »

After many trials and tribulations I decided to discard the GPS Bluetooth time sync'ing method as overly complex and unreliable (mostly due to Windows issues).  There's a much simpler way to establish time sync that easily meets the WSJT-X needs.  Use your cell phone as the time source.  You can install "GPS Test" or "ClockSync" free android apps to get accurate time via GPS or 3G/4G Internet respectively.  On your cell phone, you will need to observe seconds ticking (either android app mentioned provides that). On the Windows device, open Control Panel - Date and Time Settings and you can set time down to the second and just click "OK" when the cell phone clock lines up.  Done.
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