Callibration frequency needed [Dublin]

CSU

Being completely green and without leaving myself open to looking like a complete goon here - may I ask if someone could give me a good strong frequency around Dublin (Tallaght?) I can calibrate to?

I'm using one of these RTL SDR devices, I've also migrated from Kali-Linux to Windows 7 for a couple of reasons (mainly performance and support of bling (graphics, display etc.), but secondly, most ham applications seem to be only available for windows.

Although I could simply use Kalibrate in Linux to calibrate the PPM value, the Windows version is waaay out...it just doesn't seem to work on Windows.

The RTL device works between 24MHz - 1.7 GHz, so if someone could point out how to calibrate to a signal I would appreciate it?

---

OT (while I have you here).

If anyone is familiar with the Digital Speech Decoder (DSD) I have a weird problem that's absolutely doing my head in (I'm hoping the problem is simply down to an incorrect initial PPM value set, hence the need behind this thread).

I am using 3 RTL_SDR USB devices, all from the same chip family (R820T) and the results are the same across the 3 devices

In Windows 7, no matter the software used to feed DSD (I have tried all the variants (DSD 1.4,1.5,1.6 & and the closed source DSD+)) be it SDR# or HDSDR (my personal favourite as it's resource friendly) I am having a problem whereby I tune a signal DSD will not decode (it used too work 90% of the time) , it simply prints a "Slot Idle" message constantly.

Here's the strange bit, if I reverse the I/Q in SDR#, DSD begins to decode (print the usual decode & debug information on screen) - but the decoded audio is obviously reversed.
Also if I leave the I/Q alone and start DSD with the "-xr" switch (expect reverse stream) the same is also true - DSD now decodes with reverse audio output.
Telling DSD to not output to any audio device (to remove the output audio device from the fault-finding-process) by use of the -n switch has no effect.

When I test DSD with WAV files from the net it decodes no problems...?

Initially I thought it might have been the Virtual Audio Cable application messing about with the input stream, but I have also tested this with another free app and the results are the same.

A further kicker to this madness is that initially this started happening in Kali-Linux, at the time it was the last straw in my decision to move to Windows as I though this was simply a performance problem...although it only happened very seldom it was annoying enough to make the move.

Given that he only variable now left common to two completely different OS's (bar me [L0L]) is hardware ie. soundcard and RTL_SDR devices I am unsure now if I even understand the problem - balls...

Alas, in Windows it started happening once or twice a day and now it's 99.9% of the time ... sorry for the long post but I'm pulling my hair out :rolleyes:

tonyham

hi,

You could use the Dublin amateur band repeaters to calibrate the sdr dongle to ,
the 2 meter repeater on Kippure is on 145.7625 Mhz Narrow FM modulation
and the 70 Cm's Repeater on Three Rock is on 433.225Mhz NFM modulation .
If nobody is talking through them, you should hear an ident signal approx every 10 - 15 mins.
you can check the irts.ie web page for other repeater frequencies.

or you could use the Dublin Airport Traffic control frequencies. 118.60 MHz
you can get other frequencies if you Google Dublin airport frequencies.

regards