Pass Band Frequency vs. Real Frequency
In ham radio transceiver's we have what is called a filter and it does as the name applies "filters" It will filter a certain amount of a frequency range depending on the hard ware filter or software filter will allow, some can be adjusted and some can not be adjust very easliy.
Let us look at the figure below this is a typical SSB pass band..Notice that the audio spectrum starts at 0 hz and goes up to 2000 hz range, This is not showing the whole SSB filter range but it is showing you 2000hz worth of audio spectrum that can be displayed as you will notice there are smaller tick marks each tick mark in this situation is representing 100hz increments , starting at the 0 hz mark we can see itthere are 4 tick marks inbetween 0 and 500hz (not counting the 0hz or 500hz marks)
When we speak of a VFO frequency we are talking about the surpressed carrier frequency of a SSB signal and in a USB situation a low tone will be the closest to the carrier frequency as the tones get higher and higher the further that tone will actually be away from the surpressed carrier frequency the actual RF frequency. i.e. surpressed carrier for 14.070 is 14.070 mhz.
Here comes the more trickier part as we move away from the surpressed carrier frequency we are no longer actually using the surpressed carrier frequency(as a reference) if the mode is very narrow for example lets use the scenerio that you are using BPSK31 in USB mode and the tone is say 100hz to make things easy on the VFO Frequency (surpressed carrier frequency of 14.070mhz) . We would actually be modulating the carrier frequency of 14.070,1 Mhz. In USB the higher the tone the higher the actually frequency and it is the exact opposite on LSB the higher the tone the lower you are in frequency an mirror image of USB. Now lets look at another example using USB mode in BPSK31 and say we are using 1100hz tone or one mark to the right of 1000 tick mark the actually RF we are modulating for a reference would be 14.071,1 Mhz All I did is add 1100hz to the 14070 frequency to come up with the correct carrier frequency.
Some tips and tricks to DX spotting
What you neeed to give on a proper spot is giving the correct call sign of the DX station, no cute things like spotting one self or using DX for a callsign and of course use your own callsign as the sender of the spot.
The frequency for CW,Digital modes is NOT the VFO frequency it is the actual frequency that the signal lives at usually expressed in Khz for example 14.070 mhz would become 14070.0 khz also rounded to the nearest 100hz ie. 14071.590 would become 14071.6.
Then of course having the correct time but this is usually done automactically when spot is sent.
then for the Infos, In the Infos you should put what type of mode it is i.e. BPSK31 , QPSK31 then other infos, i.e. BPSK31 CQ DX, sometimes you will see things like EL96<ES>EM86 This means Grid Square to Square using some type of propgation mode in this example it would be sporadiac Es other example would be MS (meteor scatter). This is used mostly on VHF,UHF and beyond.
Remeber you are trying to point people to the correct frequency in use and also what mode etc. This is helpful with people that have software that are looking for unworked stations etc... They do not want to get excited over a CW station when they were looking for a digital contact for example. It is the way most software are setup to look for tags to identify which mode it is , because CW and Digital can be in the same place.
In this waterfall example is displaying zerobeat freq, in USB you would add to the VFO frequencies to come up with the correct frequency in the picture we see two stronger signals at 500hz and one at 1750hz. the one is close to 500hz so it is safe to add 500hz to the VFO freq in USB on the other one it is a little more guess work, just round it to the nearest 100hz mark, in this case I would say he is a little closer to the 1800hz mark, so I would add 1800hz to the VFO while in USB
In this waterfall example it is displaying the actual zero beat carrier ,instead of zero beat feq or audio spectrum frequency using it with CAT Control , we see the same two stronger signals in the waterfall when I spot via this software it will always spot to the nearest 100hz mark because I am using the actual carrier frequency instead of zero beat frequency display, which makes life easier.
