วีดีโอ

Great educational Video: one suggestion when hooking up a longer Coax Cable you might want to prior to connecting the cable, short out the other end. I do not know this specific VNA, I spent Thirty-Eight years in various areas of the test and measurement field with Hewlett-Packard and the T&M offshoots and previous to that Nine years in Standards Labs. I would see various VNAs, TDRs, PNAs come in with from ”not able to pass Calibration” to “InOp” condition which were caused by a charge built on cables and subsequently connected to the ports damaging the front end. In addition, we suggested when customers sat down to the VNA, they always should have Ground Straps on their hands hooked up to System Ground also.

Are my horde of 100s of 75 year old radio crystals still good if stored properly?

What I think you're seeing: "Every quartz blank has its basic frequency. Besides this “fundamental tone”, each quartz disc has several overtones. When electric voltage is applied to the quartz, it oscillates on its fundamental tone. Its overtones are also triggered in this process, but their signal is significantly weaker than that of the fundamental tone. In fact, most of the time the overtone signal results in nothing more than normal phase noise. "By clever construction of the oscillator circuit, it is possible to actuate the overtone of the quartz instead of the fundamental tone. Therefore, an additional resonant circuit is added to the oscillator circuit in order to amplify the overtone signal of the quartz. "This technique allows engineers to “squeeze” frequencies far above its fundamental tone out of a quartz crystal. For example, if a quartz oscillates in the fundamental tone at 20MHz, the third overtone oscillates at 60MHz and the fifth overtone oscillates at 100MHz. Due to the electronic properties of the oscillator circuit, the overtones can only be stimulated in the odd integer range" .

bravo!!!!

Just got my first nanoVNA and came across your video… great information and easy to follow. Thank you.

By placing a piece of copper wire like a hairpin or some coils between the two ends, it acts as a griddip

I like these types of experiments. This is what drew me to amateur radio back in 1995. Great video.

Are you a electrical engineer? Or what is your title for your career ?

To be fair, much of this is over my head, but one thing did stick out to me as I was watching, the change in resonance was ~.02Mhz on the 80m band, correct? So is what amounts to about a 4% change, right in the middle of the band practically significant? Or was this just an academic exercise? (Which is fine BTW) I've got a fan dipole that I've put up, along with a NanoVNA-F V2 and I'm trying to learn the use of the NanoVNA and which characteristics are worth chasing and which I can control (vs which I can not)

great info how ever you need to add common mod balun the noise you getting is from non adding common mod balun I had the same issue however after adding the common mod balun all noise a re gone I hope this will help you vy 73 elan

jaja que los ingenieros no miren el video!!! Importante la calibracion. gracias por tu trabajo.

Don’t worry you’re not the only one. I Cleaned my work table in the garage only to clutter it back up again.

I'm really nervous about Ali Express and counterfeits. I've become more jaundiced against pile-em-high and sell-em cheap merchants. I've seen a lot of really good reviews of the MLA30+ which are on TH-cam I am surprised by the results that you have experienced. I've had massive interference problems at my QTH and ended up as a last-ditch a few years ago going for a Wellbrook loop. Sadly they are no longer in business and the proprietor passed...long story short the design was "copied" by a UK amateur as the "Wellgood" amplifier which may be worth having a look at. I bought one as a backup in case the amp in mine decides to go. The amp is not expensive. I did a short 1:47 video on the differences between a resonant dipole on 60m and my Wellbrook and the differences in s/n are chalk and cheese - I pretty much use my loop all of the time for <10MHz receive with my TS-990 and the FT-2000 that pre-dated it. Not sure if the link will work - th-cam.com/video/ndJbIpBTLl8/w-d-xo.html 73 de Richard M0SNR

Where did you get your "shell" or that green frame for the vna in your video thumbnail?

I have 20m of RG-213 which sat on the floor of my garage for 20 odd years. It seems to be working normally but I’ve since got some RG-58. I have ordered my nanoVNA and will look forward to check if this cable has any loss. At the moment it seems neglible.

Thanks a lot for your share !

Please abandon VSWR and use return loss (in dB). You get so much more information, particularly when you have a good match. And do remember that you are measuringa combination of radiation resistance and loss resistance. You don't want to end up matching into a loss resistance.

👍👍👍👍😊😊😊😊

You need to know the impedance at the antenna. To do this, the reference plane must be at the antenna feed and not in the shack.

Thank you very much for your detailed explanation. May I know how to get same cable that you used? From wich srore

Xtra nice video! ~ Very educational! ~ Thank You!

That was very good. You've inspired me to make some coax measurements with my NanoVNA.

I’m confused, why are you looking at matching the coax 50 ohm *impedance* with just the resistive part of the impedance of the LoG antenna? I’m wondering why you didn’t add that to your callcs for the antenna impedance. Or was it a small enough capacitance that it didn’t matter?

Peter Gore Seer, I Have AMLA-30, On A Trio,R-2000, Its North To South, With The Magnetic Poles, Its Working Good And My RF Switch Works At Its Best With Antenna.

When the loop is horizontal, it becomes an omni-antenna with little Near vertical incidence skywave.

Thanks a lot for detailed description! 73!

To 43:00 - 0.77 dB loss is fine because each connector adds 0.1 dB roughly. So, you may have 0.2 dB loss in connectors and 0.57 dB loss in a cable. Which is very close to 0.6 dB/100 ft.

Thank you for explanation. I just want to add than a point with +180 phase degree or -180 phase degree in not a resonance. It's just a point where phase goes more then 180 degree and nothing more. A device is made to show phase degrees whithin a range -179.99 to +179.99.

Twaskyou sr very interesting. Blessings

Calibration, with same connected cable, isn't how is supposed to be. All this connected adapters, cables - must be removed before calibration. After, you need to set electrical delay (port extension), to each of those connected adapters/cables

Good video. What you did is not really different from what I have seen on other videos. So, I think you are safe providing good information.

4:41 Hi, great job! I saw You turning the SMA connector into the SMA nut, You should always turn the nut and not the adapter. if You turning the Adapter, it is rotating in the connector, this will damage it over Time. 73 de DL1LEP

Thank you very much for this very informative video Gregg. Have a nice Easter weekend, PA0CMU

You can also use a spectrum analyzer and tracking generator

Great video!

Great information! You andwered my questions in the first 3 minuits. Thx. W6rch

Seems like the test fixture should be used in the calibration of the VNA.

The phase going from -180 to +180 doesn't mean anything - the phase is linear (has a linear slope to it), it's just if you keep plotting it without resetting it at some point, you end up with phase angles above 360* which ceases to mean anything, or is hard to work with. So the rule of thumb is you graph phase from -180* to +180*, and if it goes below -180 or above +180, you wrap over to the other side. Also, the phase being positive or negative has nothing to do with it being capacitive or inductive - it's not on the same scale as a smith chart. The phase plot has absolutely nothing to do with capactiance or inductance, only delay.

Good video, Gregg. My video on the LoG was among the first on You Tube and I have been using it for several years with very good success. That said, it was NOT a success at my late father's QTH, as a pesky noise source rendered the LoG ineffective. Your video echoes his experience with this design. The LoG is certainly an antenna worth trying, but as in life, there are no guarantees. Thank you for posting this (to give the other side of the coin) and 73! de WX0V

Hi Gregg, a suggestion... Instead of metal nails into frozen ground (i.e. highly conductive!), Try using plastic stakes. You may need to drill a few holes into the frozen ground, but I think you may find the nails are inducing the ground noise. I can't really duplicate your issue here in the desert - haha...😆 73

Gregg ... Nice video coverage and method reviewing your results Sir! I too tried this same type of loop at my location and came to the same conclusion as you. I do have a noise canceller that I think I might give a spin in the future. Thanks again! 73 - KF6IF

Curious to see if the loop on the ground would be more effective if you were comparing it to a vertical antenna. Thank you for the video.

Are you mastering your videos in HDR?

i put it 2 meters up and defased it with a rod antenne on a corner , -135 dBm noise floor , at night 80 m perfect , daytime 20 , 40 meter ok.

I like any program that take up the issue of Nano vna😊😊😊😊😊😊😊

At least lowering the antenna shifts the resonance down, which makes sense.

Your metallic mast may be interfering with your setup. Generally, a dipole is mounted with non-metallic (dacron etc.) lines or a fiberglass pole.

If you change the stimulus , you should recalibrate ... every time.

Just buy a circular polarisation filter for the camera, takes the glare out of anything. en.wikipedia.org/wiki/Polarizing_filter_%28photography%29

Very interesting indeed😊