#1476

Episode 1476
get rid of that stupid connector!
original video: • #1473 800MHz to 6000MH...
PC Software: nanorfe.com/na...
Be a Patron: / imsaiguy

[@Critical-Thinker895]

Don't open up a can of worms by trying to please the critics on here. After today they'll try to get you to use something that they do because they've decided your effort wasn't enough. Just do you, never mind them. Nice video, thanks.

[@cyberyogicowindler2448]

AFAIK log-periodic antennas are supposed to be fed from their front tip because else the directionality will be messed up. It is something with wave propagation and the way waves from adjacent tines are supposed to sum up at a certain phase (see Wikipedia about their physics). It may be that this mainly matters as an EMC testing or direction finding antenna and less for things like wifi, but there is a reason for the connector position.

[@chrisscott1547]

I don't mean to be a heckler, and thanks for the extra effort - impedance bandwidth looks reasonable for a log-periodic. But because I've been burned by almost all chinese antennas I've bought off of ebay, before I would agree that it's the real deal, I would check the front-to-back ratio at about mid-band. For a real log antenna, it should be at least 10 dB. You can easily check this outside. Open garage door, and run about +10 dbm from your sig gen to any small antenna just outside the door. Then with the antenna in hand, with your trusty portable spectrum analyzer, walk at least 20 feet into your front yard (away from the mini-cooper to avoid reflections), and slowly spin around, noting the signal level. You will still see a lot of variation from reflections, but you should see the general pattern - and note the level facing your garage, and away from it. The difference will be the F/B.

[@mnoxman]

As an old two-way tech from the 80s a PC on the bench is better than a "suitcase" programmer. Either the Panasonic HHC for GE or the Epson for the Moto radios. A modern laptop seems easy. As someone who also wrote GPIB stuff in basic on the pc for a stack of HP, Tektronics and Megadac equipment as part of a industrial automation setup some things you can't do with out a computer.

[@tfrerich]

Maybe you could move the laptop running nanoVNA Saver out of the shot--i.e. off the bench--and just feed it's HDMI output into the recording the way you have (I think) in the past used the output of your Rigol oscilloscope? At least I'm trying to minimize your editing time. BTW, nice episode. Now all I need to do is figure out what I'd use an antenna like that for, but that's not a bad thing. These days I'm finding it a lot of fun to search for a problem to solve after I've found a product. You know, it's the "that's a really neat board--now what am I going to do with it" kind of activity.

[@Gengh13]

I also prefer self contained test equipment, unless complex scripting is required.

[@originsdecoded3508]

Perfect example of using the principles of Step Up Energy. Theres a reason pyramid shapes are considered to be energetic in nature. The energy/electricity/signals flowing through this particular shape is condensed, compressed, and amplified with every stepping level as it goes up and becomes more and more narrow. The frequency signal generated should increase to with this effect. basically your getting a stronger signal wright?

[@IMSAIGuy]

you are 100% wrong

[@originsdecoded3508]

@@IMSAIGuy how it works then? it seems hard to imagine any other processes going on.

[@IMSAIGuy]

@@originsdecoded3508 the coax is fed on the small side. the traveling wave follows the antenna until it finds a dipole size that it can fit. the impedance will then be low and it can radiate.

[@IMSAIGuy]

@@originsdecoded3508 maybe this would help: kzbin.info/www/bejne/a6aoq2SBoK1-l9U

[@originsdecoded3508]

@@IMSAIGuy Thak you, makes a lot more sense now. I was thinking in terms of the behavior of sound/vibration modulation and how to manipulate its path and frequency. and how it relates so much to electricity because electricity is essentially really high vibrations going through specific conductive materials that stimulates an electromagnetic field which then enduces an electrical charge. But I'm seing that when it comes to electricity, and magnetism the behavior and mechanisms of how modulate them become a little more complex. Have you ever seen the similarities between vibration flowing through sound conductive materials, and electricity flowing through conductive materials?

[@spacewolfjr]

You seem like a man I could be a best friend with.

[@johnwest7993]

Thanks for the fix for the antenna. But we can get 50 Ohms out of a carbon comp. resistor. What we want to know is an antenna's actual gain. I realize you aren't set up with an RF anechoic chamber and calibrated antennas, but some idea of whether or not the antenna actually has some RF directional gain would be nice. I have very little faith in the Chinese vendors' ability to do anything right, even if the first problem is fixed.

[@ivolol]

I can empathise not liking having to shove the laptop on the bench! But it does let you produce that one or two nice screenshots of the critical measurements ^_^ So I'd suggest, maybe you don't even need to be "using the laptop" during a video take, but could later connect it quickly just to get the relevant screenshot later to overlay on the video? Thanks!

[@richardmassoth8237]

I'm curious about the semi-rigid coax that you are using, as it would be very useful for various PCB-based antennas. Do you have a specific go-to type, like an RG specification or a Belden or other manufacturer's model number?

[@IMSAIGuy]

I just had some removed from equipment

[@silverXnoise]

To my knowledge Joe Smith (@joesmith-je3tq) has the most advanced software development for the NanoVNA going. He's also known for producing one of (if not the) fastest oscillators on a breadboard in the world, according to EEVBlog forum rules anyway. Absolutely priceless work on the NanoVNA.

[@muzzdeni28]

any length for the coax? I have the same antenna and looking to improve it.

[@IMSAIGuy]

any length

[@darkobul1]

There is a phonr app for OBS that you can add second camera from your phone. Maybe thst vould help to make disolay recordings

[@jspencerg]

Re:PC clutter I have a wireless connection to a wall-mounted monitor over one work area. There is no space for PC at main equipment bench. There is an app for the nano vna that runs on Android. Have not tried that. Perhaps a tablet PC for you?

[@Janom66]

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