Author Topic: MMDVM CALIBRATION ON PI-STAR  (Read 1103 times)

0 Members and 0 Guests are viewing this topic.

Offline Robert K4WZV

  • Administrator
  • Sr. Member
  • *****
  • Posts: 456
  • Location: BrooksvilleFlorida
  • Referrals: 2
MMDVM CALIBRATION ON PI-STAR
« on: December 28, 2018, 07:52:26 pm »
To use pistar-mmdvmcal to calculate TXoffset
A. Preliminaries:- Set DMR rig to desired hotspot frequency, CC1 Slot1 TG9. Call it Fd (in Hz) In Pistar set TXoffset and RXoffset to zero, otherwise they'll screw up the calculation.
B. connect to your pi-star setup with ssh.
C. Type:- sudo pistar-mmdvmcal" <enter>
D. Tap E key & enter TX frequency of your hotspot in Hz
F. Tap <M> key. Hotspot generates a dmr tone.
G. Tap <Space> Hotspot transmits tone. You should hear tone on rig.
H. Repeat presses on f key until tone disappears. Note this frequency as F
I. Repeat presses on F key until tone reappears, keep going until it disappears again. Note this frequency as F.
J. Q to quit.
The calculation:
You have 3 frequencies, Fd, f and F to play with. f is the lower edge of the hotspot transmission and F is the upper edge of the hotspot transmission. Assuming the transmission is symmetrical around its peak value, the average of f & F gives the peak frequency of the hotspot transmission ie where it is transmitting.
So the hotspot is TXing at freq. {(F+f)/2} Hz
TXoffset is the difference between rig and hotspot TX frequencies.
TXoffset = Fd - {(F+f)/2}
TXOffset & RXoffset don't have to be the same, but for starters set both to the calculated value. If ber isn't good, vary RXoffset only until it is.

Share on Facebook Share on Twitter


 

Related Topics

  Subject / Started by Replies Last post
3 Replies
393 Views
Last post February 02, 2020, 11:53:51 am
by N1KK
0 Replies
603 Views
Last post February 07, 2020, 07:39:54 pm
by VE3RD
0 Replies
295 Views
Last post August 31, 2020, 11:52:14 am
by KC1MAC
2 Replies
499 Views
Last post October 04, 2020, 01:20:40 pm
by w4rss
3 Replies
233 Views
Last post February 18, 2021, 03:18:09 pm
by WB3IHY