The SDR revolution has brought a new element into MW DXing: the use of offsets in signal analysis and pre-identification. In order to use any offset based tool in Jaguar, the software must be calibrated reliably.
KALIBRATE is Jaguar's calibration function. Compared to other SDR software, Jaguar's calibration method is exceptionally easy and it doesn't have to made before recording. In addition we support the "4th decimal" even though the last 4th decimal is not necessarily always correct: the error margin is 0.0005 kHz. So if you want to be on the safe side, use offsets rounded to nearest 3rd decimal in your public offset loggings. However also that 4th decimal can be used but it requires experience and that you have monitored the particular station for a longer period of time.
KEY = K
With keyboard key K you'll calibrate JAGUAR’s frequency accuracy, based on the accuracy of the current frequency. You must tune in to a frequency where the station has a known and stable frequency accuracy, with a sharp peak visible. For example, in Europe, 810 kHz can be used: both BBC Radio Scotland and Radio Skopje are known to be pretty exactly on 810.0000. After the K key is pressed, the SPECTOR peak should show the exact .0000 frequency. You can repeat the process if the conditions make the peak to wobble, and it is difficult to get an exact calibration match. The calibration has an error range of 0.0005 kHz so the last 4th decimal is not necessary always correct – but it can be, you cannot be always sure. This is why it is recommended to use only 3 decimals in official loggings.
You can repeat this process any time you see that calibration is not spot on. This may be due to many things, e.g. a change in the hardware temperature. Calibration can be done either in the LIVE mode, or while listening to any ARCHIVE file (in JAGUAR, calibration can be done also afterwards for old files).
KEY = ALT-K
Calibration can be done also based on some exactly known offset frequency using ALT-K. Normally, calibration is done with a station known to be on the exact .0000 frequency. If you know that a certain station always sits on the exact offset frequency, you use it as your point of reference, and press ALT-K. Move the visible SPECTOR peak with the left/right arrow keys to the position where the SPECTOR peak matches the known offset and press ENTER. Then, make some additional offset checks on other frequencies to make sure that this alternative way of calibrating has succeeded.
FAST CALIBRATION (JAGUAR PRO ONLY)
The previous two methods require that you tune to the nominal frequency of the station used in calibration. In addition to these two methods, there's also a third option called "FAST CALIBRATION": you can KALIBRATE your setup being tuned to any frequency and press the keyboard key K. All what we need is a good solid calibration frequency for your setup (naturally it must be available at any time you calibrate).
At first you must define your calibration frequency to [CUSTOM] using FAST_CALIBRATE parameter. For example
[CUSTOM] FAST_CALIBRATE=810
Now if you press K (when listening to any frequency !), Jaguar makes the calibration in the background (the playback control does not jump to 810). Of course user can go to 810 and check if that was done correctly but if it seems to be "always OK", quite likely user starts to trust it and there's no need to check it after pressing K. When user presses K in "normal" calibration Jaguar triggers a "Do you really want to ..." confirmation but there's no need for that when FAST_CALIBRATE is used: it doesn't harm if user presses K accidentally because the calibration is just done once again - using the correct frequency.
In many European setups 810 is often visible (but not always audible in full daylight) so we in EU can successfully do this "blind calibration" quite freely.
In the future we can further develop calibration to be more accurate: everything goes always OK if the carrier wave is a sharp needle but sometimes we have a strong fat carrier on our calibration frequency and the top peak needle can vary a bit on the "fat top". However also in that case the main signal power is spread equally on both sides of the exact .0000 => in addition to the top peak we could analyze also the shape of the fat carrier and calculate "the center of the power" from several points instead of the one top peak and thus get more accurate calibration.
FAST_CALIBRATE uses MONITOR structures in the code so you can't use the MONITOR feature if FAST_CALIBRATE has been defined.