# What is minimum resolution for 2 frequencies to interfere each other

I started working with HF frequency. Right now, I am working with 7 MHz frequency. I have been provided a range of 7-7.5 MHz. I have to divide that range into 132 distinct frequencies to assign each frequency to a different node. Please let me know what is the minimum frequency resolution for 2 frequencies which do not interfere with each other. For example, 7.001 and 7.002 MHz freq will interfere with each other or not??

Very basic wave propagation theory says:

No two different frequencies ever interfere in a linear system. So, any separation, no matter how small, of the occupied bands is enough in a perfect world!

However, we don't live in a perfect world. So you need to model your system more detailledly, think about bandwidths, filters, frequency uncertainty of oscillators.

I'll be a bit blunt, in hopes it helps you find a better question, sorry: you graduated in EE with specializations in RF design. I'd have expected you to ask a more detailed question here with way more background on your overall system! I think you can do better – interference happens only under circumstances where energy of one thing ends up in the other, so maybe you'd want to analyze your proposed system more for the places where that might happen!

• Wasn't sure if "any separation, no matter how small" was physically possible, but it appears to be: physics.stackexchange.com/questions/73959/… (by way of physics.stackexchange.com/questions/110463/…). Jun 11 '20 at 18:13
• @natevw-AF7TB it is, but you can only observe that arbitrarily small separation if you observe infinitely long (for all other things: there's the bandwidth–duration product limit, which means your ability to determine frequency is proportional to the duration for which you observe that frequency. Manifests itself in filter design, but also in physical things like the Heisenberg uncertainty principle, which says you can't know impulse and location of a particle exactly at the same time. Impulse space and location space are linked through the Fourier transform.) Jun 11 '20 at 19:04

That would depend on the bandwidth of the transmission.

The RSGB 'Amateur Radio Band Plans' is a very good reference.