Hello Kent,
Mark introduced himself as an 'RF newbie' and I was, somewhat clumsily, trying to point out that transmitting RF is not an unregulated activity. I understand that very low power CW transmissions might not be noticed. But adding an RF Amplifier could change the game.
Cheers,
_Norman._
Sent from my GNU-Linux ThinkPad.
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On 06/10/2021 16:37, KENT BRITAIN wrote:
Hi Norman
On this side of the pond the FCC does recognize the need to radiate signals during testing.
I have an antenna range and commonly transmit on many commercial frequencies.
I am expected to minimize radiated signals per "Good Engineering Practice" and are responsible for any interference I cause.? ? ? The NanoVNA certainly falls into this category.? ? Just leave it on long enough to get a good reading and you meet FCC guidelines.? ?In the real world you would probably leave it on for a week and no one would notice.? ? ?Kent
On Wednesday, October 6, 2021, 09:45:24 AM CDT, Norman_G8EYM <brycek.fs@...> wrote:
Good afternoon Mark,
In most parts of the world, transmitting a radio frequency signal is a
carefully regulated and licensed activity, whether for experimentation
or any other purpose. Holders of transmitting licences are required to
adhere to the local regulations concerning frequency, power, mode of
transmission and harmonic content, to name but a few.
Assuming that you can conform to the required standards and conditions,
the appropriate filtering methods are well documented.
My initial assessment of your planned experiment is that it wouldn't be
legal as, for starters, the 'bare foot' Nano-VNA doesn't have the
capability to be modulated and provide your station ID.
I could be wrong, of course.
Regards,
_Norman, G8EYM_
Sent from my GNU-Linux ThinkPad.
On 06/10/2021 11:36, msat via groups.io wrote:
Hello everyone!
RF newbie and first time poster here. Recently purchased a NanoVNA-H for a specific experiment I'd like to perform. Without going into the unnecessary details of the experiment itself, what I'd like to do is use the nano as a fixed RF frequency gen, probably in the ~900MHz ISM band, to be fed to an amp and transmitted via an antenna. A probe on S21 will then be used for obtaining relative phase angle measurements.
I know the nano generates a square wave output, thus the dominating frequencies are the fundamental and odd order harmonics, along with some even order and spurious frequencies. I also know that the nano will rely on the 5th harmonic of some fundamental in order to reach my desired fixed frequency. Since not only would it be irresponsible to transmit those various other frequencies, but I also think my experiment would be better served by having as spectrally pure signal as is reasonably possible. To avoid any confusion, my intended TX signal chain is as follows:
nanoVNA S11 -> bandpass filter (probably LC?) -> RF amp -> antenna
So my question is this: how sophisticated does the filter realistically need to be? Would a 1st order LC bandpass do, or do I need something else? Are there any common "gotchas" that trip up newbs that I should be aware of?
Thanks!
Mark
