Mark, Have a read in an ARRL Antenna Handbook about antenna measurements, test site set up, absolute gain and pattern measurements. Might shed some light on your project. Also near field versus far field distances and characteristics.
That forum’s presentations are on demand online until April 15th. Working my way thru. I’ve only seen a few so far. RH > On Mar 22, 2021, at 5:32 PM, Mark Brantana via BVARC <[email protected]> wrote: > > FSD = Field Strength Drone > > We have had some fun discussions about this idea. I wish I could have visited > the forum held recently, but I had to miss it. I understand someone had > someone talked about a related topic, and I have looked at the article Jeff > kindly sent me. I hope I did not miss anything else, but I have tried to read > and follow up on all the comments. This educational jaunt has given me some > help in better understanding field strength meters. > > Antenna Orientation: I was especially struck by one very old and classic demo > showing the response of a receiver in a non-aligned configuration with the > antenna orientation. For example, a horizontal receiving antenna and a > vertical transmitting antenna, or vice versa. This demo showed clearly that > the antenna needs to be properly oriented, and that a 90 degree > disorientation gave no response at all. So, an FSD would have to have 360 > response in order that the orientation does not introduce falsely attenuated > response simply due to the antenna orientation. It might look something like > a Van der Graff ball somehow; and possibly this is why it the dangling > antenna looks like a ball in Jeff’s reference. > > Antenna Length: Then, there is the question; how big does it need to be. > Since a field strength indication is really a relative reading, this may not > be an issue. It does introduce a complication in that the field strength > meter would need to be tightly tuned to a testing frequency, even if the > antenna is really inefficient. Without tuning, the field strength antenna > will very strongly tend toward resonation on shorter wavelengths, and thus > provide false readings. > > In other words, the little wire coming off of the field strength meter we may > have, but have never used, may qualitative only and not quantitative, since > the reading will depend on the orientation and length of its antenna. An > antenna for the Field Strength Drone would have additional requirements to > satisfy the measurement requirements. It is not going to be a matter of just > flying a field strength meter through the field. > > Food for thought. Opinions? > > Mark > N5PRD > > >> On Mar 10, 2021, at 5:36 PM, Mark Brantana <[email protected]> wrote: >> >> Thanks for all the great comments. The real question at this time is, does >> anyone have an interest in working with me on this project? It is a purely >> ham project and we get paid in bragging rights. >> Mark >> N5PRD >> >>> On Mar 10, 2021, at 5:17 PM, Mark Brantana <[email protected]> wrote: >>> >>> Rick, >>> >>> Agreed. And it is beginning to look like there is a need to build and test >>> such a thing to really learn it’s value. For instance, I never knew how >>> useful an my nanoVNA would be until I bought one. Sure, I could do an SWR >>> study the old way, but the new widget enables me to do a lot more, faster >>> and easier. >>> >>> I just threw this question out this morning for discussion, and got my >>> money’s worth from everyone. It was academic at that time, but now I am >>> wondering all the more why there isn’t some video on YouTube showing some >>> ham who has built such a device. It seems like this is something wanting to >>> be made, at least for ham use. >>> >>> Mark >>> >>>> On Mar 10, 2021, at 2:59 PM, Gary Sitton via BVARC <[email protected]> wrote: >>>> >>>> Rick: >>>> >>>> I really agree especially since I've looked into the drone motor >>>> controllers. >>>> They typically emit so much onboard and radiated hash that special by-pass >>>> precautions are taken with some of the onboard sensors, e.g. accelerometers >>>> for orientation sensing. I disagree that modelling software is adequate >>>> for >>>> the typical antenna environment, e.g. antennas below a wavelength. Also >>>> conformation of directional antenna's front-to-back and forward gain for >>>> optimization purposes would be nice if even perhaps extravagant. >>>> >>>> 73, Gary K5AMH >>>> >>>> PS: Most drone controllers use the STM ARM processors for which there >>>> is free open source drone software: https://betaflight.com/ >>>> >>>> >>>>> On 3/10/2021 2:34 PM, Rick Hiller via BVARC wrote: >>>>> Comment: Is an FSD applicable? >>>>> >>>>> Although an FSD would provide a close-in Far Field pattern of an antenna >>>>> antenna installation, which is very cool indeed. Is it really necessary >>>>> in the world of Ham Radio? >>>>> >>>>> We already have antenna modeling software based on the NEC which is quite >>>>> accurate, depending on the set up parameters provided, of course. That >>>>> model analysis provides us with a pattern and a fair amount of >>>>> operational information. >>>>> >>>>> But what do we (I) really want? I want to know what and how my antenna >>>>> is performing in the real world outside of my QTH. Is it getting to >>>>> Europe or VK? When is the best time and frequency to get to Japan or >>>>> South Africa? Questions like this are not to be answered by a FSD. >>>>> >>>>> What we really need is a world wide system to detect our signals wherever >>>>> they may occur. So let's start thinking of that. We just need a few >>>>> hams on every continent to participate........Wait! Not so >>>>> fast.......there is already a system that does this. WSPR and it is >>>>> available from a local amateur radio dealer -- SOTA Beams >>>>> https://www.sotabeams.co.uk/wsprlite-classic. QST Dec 2018 even has a >>>>> review of this system. >>>>> https://www.sotabeams.co.uk/content/QSTREVIEW.pdf >>>>> >>>>> Now look, I am not poo pooing the FSD concept , ideas, discussion, etc. >>>>> Very cool indeed to get a group of folks excited and discussing antenna >>>>> stuff. Woo Hoo! I'm all for it, being the antenna phreak that I am. >>>>> I'm just taking a step back and seeing if it is necessary, practical or >>>>> even applicable for Hams. Plus, maybe some don't know about WSPR. >>>>> >>>>> 73...Rick -- W5RH >>>>> >>>>> >>>>> >>>>> Virus-free. www.avast.com >>>>> >>>>>> On Wed, Mar 10, 2021 at 1:57 PM Jeffery MacMillian via BVARC >>>>>> <[email protected]> wrote: >>>>>> Here is a good paper on this very topic..... >>>>>> >>>>>> https://www.narda-sts.com/en/selective-emf/srm-3006-field-strength-analyzer/eID/pd/pdce/9063/pdfr/9500/ >>>>>> >>>>>> have Fun, >>>>>> Jeff >>>>>> KC5TT >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> On Wed, Mar 10, 2021 at 1:31 PM Tom Watson via BVARC <[email protected]> >>>>>>> wrote: >>>>>>> Brilliant! >>>>>>> >>>>>>>> On Wed, Mar 10, 2021, 12:22 AM Mark Brantana via BVARC >>>>>>>> <[email protected]> wrote: >>>>>>>> OK, what is an FSD? It is a Field Strength Drone. It’s an idea I am >>>>>>>> sure others have had, and I don’t expect to get around to designing or >>>>>>>> patenting such a thing. But inventions are often just the merging of >>>>>>>> new technologies, and this is not much different. I don’t see any >>>>>>>> YouTubes about this or any other reference, so here’s the idea: >>>>>>>> >>>>>>>> With all the capabilities of little drones I wonder if anyone has >>>>>>>> designed one which can carry a field strength meter and fly a grid >>>>>>>> around an antenna to evaluate antenna performance. The guts of my >>>>>>>> little Radio Shack FSM would have weighed way less than an ounce. >>>>>>>> >>>>>>>> Ideally, the field strength meter could communicate to the base >>>>>>>> through the drone transmitter, reducing weight. Software at the base >>>>>>>> could link the drone 3D location data with the FS reading. The drone >>>>>>>> would have to wait at test locations for the operator to >>>>>>>> transmit, and ideally would move to the next location. Finally, >>>>>>>> the software might be able to link with existing simulation software >>>>>>>> for comparison with theory and allow for simulation model improvement. >>>>>>>> This looks like it would take a small team to develop. >>>>>>>> >>>>>>>> This sounds like it would have many uses besides antenna evaluation, >>>>>>>> like RFI evaluation. >>>>>>>> >>>>>>>> What about it? Has anyone done this? >>>>>>>> >>>>>>>> Mark >>>>>>>> N5PRD >>>>>>>> ________________________________________________ >>>>>>>> Brazos Valley Amateur Radio Club >>>>>>>> >>>>>>>> BVARC mailing list >>>>>>>> [email protected] >>>>>>>> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >>>>>>>> Publicly available archives are available here: >>>>>>>> https://www.mail-archive.com/[email protected]/ >>>>>>> ________________________________________________ >>>>>>> Brazos Valley Amateur Radio Club >>>>>>> >>>>>>> BVARC mailing list >>>>>>> [email protected] >>>>>>> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >>>>>>> Publicly available archives are available here: >>>>>>> https://www.mail-archive.com/[email protected]/ >>>>>> ________________________________________________ >>>>>> Brazos Valley Amateur Radio Club >>>>>> >>>>>> BVARC mailing list >>>>>> [email protected] >>>>>> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >>>>>> Publicly available archives are available here: >>>>>> https://www.mail-archive.com/[email protected]/ >>>>> >>>>> >>>>> -- >>>>> Rick Hiller >>>>> e-mail: [email protected] >>>>> Cell: 832-474-3713 >>>>> Physical: 9031 Troulon Drive >>>>> Houston, TX 77036 >>>>> >>>>> >>>>> ________________________________________________ >>>>> Brazos Valley Amateur Radio Club >>>>> >>>>> BVARC mailing list >>>>> [email protected] >>>>> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >>>>> Publicly available archives are available here: >>>>> https://www.mail-archive.com/[email protected]/ >>>> >>>> -- >>>> Gary Sitton, K5AMH >>>> [email protected] >>>> SDR/DSP Consultant, >>>> "Have FFTs, Will Travel." >>>> ________________________________________________ >>>> Brazos Valley Amateur Radio Club >>>> >>>> BVARC mailing list >>>> [email protected] >>>> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >>>> Publicly available archives are available here: >>>> https://www.mail-archive.com/[email protected]/ >>> >> > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/
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