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[linrad] MAP65 version 0.8

To:      Users of MAP65
From:    Joe Taylor, K1JT
Subject: MAP65 v0.8

Version 0.8 of MAP65 will be available soon. This note is to let you know of its principal new features -- and to ask for any other good ideas that I might still be able to incorporate before I release it.

New features in Version 0.8:

1. The Setup -> Options window now permits user entry of the following parameters:

- Timeout (min): elapsed time before entries disappear from the Messages and Band Map windows

- Dphi (deg): Phase shift to be applied to vertical signal to compensate for a hardware phase shift relative to horizontal

- Fmin (kHz): lower end of frequency range to be
displayed in upper waterfall and searched for JT65 signals

- Fmax (kHz): upper end of frequency range

- Fcal (Hz): Calibration adjustment for all received frequencies

- CSmin: Minimum length of callsigns included in Band Map

- SaveDir: directory for saving *.tf2 files

The "Timeout" parameter defaults to 20 minutes. You might want to set it to larger or smaller values, depending on EME activity.

"Dphi" defaults to 0. If your system has equal phase shifts in the X and Y (normally horizontal and vertical) channels, you can leave it alone. However, if your X and Y feedline lengths are different or something else introduces a significant differential phase shift, you can correct it here.

MAP65 now provides a means to determine the phase difference
between channels. Find an EME signal that produces roughly equal signals in the X and Y channels. Set the QSO Frequency and DF to this signal, and reduce "Tol" so that no other signals will be decoded; then click "Find Delta Phi" on the Setup menu. MAP65 will decode the signal 13 times in quick succession, using assumed values of Dphi = 0, 30, 60, ... 360 degrees. The resulting output in the main text window should look something like this:

Freq  DF Pol  UTC   DT  dB  Decoded message      KV  DS Dphi
110   -9  60 0746  2.1 -19  LX/PA3FPQ W0HP         1 204   0
110   -9  74 0746  2.1 -20  LX/PA3FPQ W0HP         1 173  30
110   -9 108 0746  2.1 -20  LX/PA3FPQ W0HP         1  53  60
110   -9 121 0746  2.1 -19  LX/PA3FPQ W0HP         0  17  90
110   -9 124 0746  2.1 -18  LX/PA3FPQ W0HP         0  11 120
110   -9 124 0746  2.1 -18  LX/PA3FPQ W0HP         0  11 150
110   -9 120 0746  2.1 -19  LX/PA3FPQ W0HP         0  17 180
110   -9 106 0746  2.1 -20  LX/PA3FPQ W0HP         1  58 210
110   -9  72 0746  2.1 -20  LX/PA3FPQ W0HP         1 177 240
110   -9  59 0746  2.1 -19  LX/PA3FPQ W0HP         1 204 270
110   -9  56 0746  2.1 -18  LX/PA3FPQ W0HP         1 203 300
110   -9  56 0746  2.1 -18  LX/PA3FPQ W0HP         1 203 330
110   -9  60 0746  2.1 -19  LX/PA3FPQ W0HP         1 204 360

Use the DS "quality factors" (next-to-last column) to find your best value of Dphi. You can see that for my system it is about 310 degrees.

Default values of Fmin and Fmax are 100 and 160, so as to display and decode JT65 signals over the range 144.100 to 144.160. I find this to be a good match for the everyday EME activity patterns on 2m.

My system has a frequency calibration error of about 330 Hz. I enter this value in the entry field "Fcal".

CSmin (with default value 4) was introduced to prevent short "words" like "OOO" from showing up in the Band Map. If you want to be sure not to miss any 3-character callsigns, you could change this to 3.

MAP65 now has a "Save All" feature like the one in WSJT. Checking it will cause MAP65 to write each minute of received data to a file named YYMMDD_HHMM.tf2. The location for saved files defaults to subdirectory ./save under your MAP65 installation directory. You can specify a different save directory on the Setup -> Options screen. Beware: the data rate is about 46 MB/minute, so your hard disk will fill up in a hurry when saving files!

2. The "Rx noise" indicator turns red and says "No data" if multicast packets are not being received from Linrad.

3. When the mouse points to a frequency in the upper waterfall, the callsigns of any stations recently decoded at that frequency are displayed just above the frequency scale. This is a good way to remind yourself which callsign goes with each visible blip on the waterfall.

4. The signal level in dB has been added to each line in the Messages window.

5. The problem of some dropped multicast packets has apparently been fixed. I believe you should now see the number of dropped packets very close to zero.

6. A "Measure" mode has been implemented. If you activate it, values of "Rx noise" will be written to the screen (and also to file "meas24.txt") at a 1 Hz rate. The numbers are in dB, with an arbitrary reference level. I find this feature useful for making pointing tests, etc.

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