Great video. Did you perform the VNA calibration at the end of the long patch cable? If you do the short/open/50 ohm calibration at the SMA jacks on the VNA, then plug in a long cable via some adapters and finally onto the antenna, what you're measuring is the combined cable-adapters-antenna system as a whole, whereas if you do the calibration at the far end of the cable where the antenna plus in (which might need different calibration standards to suite the connector at that end) you get accurate results.
@zeljkoadzic1692Ай бұрын
Can you make a new video with new frimware from DiSlord 1.3.25 with new features
@wb7ondАй бұрын
Great video, one of the best explanations on what that "phase saw-tooth" is really describing. Sent here from NanoVNA io group posting. Thanks for making that video. I am anxious to try this out... Regards wb7ond...
@best31402 ай бұрын
Can we measured single core cable velocity?
@jean-francoisavon622 ай бұрын
the focus makes this video unbearable. better too listen to the audio only.
@Miller77473 ай бұрын
If you use manual focus, and set the distance equal to distance from camera to NanoVNA you will get perfect focus every time, regardless of what you do with your hands.
@greenstripeypaint4 ай бұрын
outdoors test needed
@buddhistsympathizer11364 ай бұрын
It looks like a standard 1/4 wave vertical antenna with a coil 'trap' for 70cms. Simple, effective but no gain.
@eagleviewhd5 ай бұрын
why didn"t you shut off the other traces, so the SWR Trace would be easier to see?
@9A4GEMilan6 ай бұрын
Excellent! First video of many explaining it correct way. I am about to program frequencies for ISS and other AMSAT satellites. You made it easy. Just got today radio, and no programming interface, so I should to do it manually.
@kg4dmb20117 ай бұрын
This is a split not crossband
@dpiljevic8 ай бұрын
What if I cant activate Dive Mode? No Depth info! Need new firmware or restart
@a.v.stechs93988 ай бұрын
Sir if I have copper pipe solid antenna then I have to cut Please advice
@ltlt61179 ай бұрын
Hello! It's my question that how we can test an antenna for a bipolar monopulse uwb signal for example if that signal has a 5ns width and 100khz repetition..What is the frequency that I have to use as start and stop on nanovna to measure my antenna parameters?????
@wombatbeire639 ай бұрын
Regarding the USB to DB9 serial cable: are true RS232 levels used or are they TTL ? Are popular USB to TTL (3,3- 5V) FTDI based boards giving correct voltage levels to use this circuit ?
@Rlaay10 ай бұрын
How do I apply this procedure to measure the VF in a vertical antenna? Do I have to take the length L of the antenna or 2L?
@Lareo196411 ай бұрын
to autofocus or not to is the question
@dbwstein Жыл бұрын
Excellent video. Super clear.
@k8osradioscience545 Жыл бұрын
Well Done! Many Thanks!!
@DePalma. Жыл бұрын
Are there radios that will function as a crossband repeater? Meaning that whatever they receive on their RX frequency, they will immediately TX on a different frequency
@la7yka Жыл бұрын
That's cool. I did not knew that was possible. Thanks.
@sanmeethundal3397 Жыл бұрын
what is the significance of "300"?
@izzzzzz6 Жыл бұрын
When doing stuff like this try to mount your antenna on a pole or in free space dangling on a fishing line etc. but note it will act differently in each situation. If mono-band you can add a coax transforming loop (balun /tuner / filter) at the feedpoint to minimize any effect of the coax shield acting as part of the antenna which can also help to minimise some unwanted swr results / changes due to coax lengths and some objects in proximity to coax runs. Adding such tuned transformers such as these coax loops or baluns as well as ferrite sleeves at the feedpoint can also change your radiation pattern as well as help to maximise efficiency and reduce unwanted noise both in and out of the system.
@izzzzzz6 Жыл бұрын
Could anyone help me with how i can do this for an open wire or balanced feedline. I would like to measure the velocity factor and impedance of the home made feedline or ladder line. I would also like to be able to then compensate / calibrate for the balanced feedline length on the vna so i can hoist it up 100ft to the antenna feedpoint and then read the parameters of the antenna back at the tuner end with the VNA. From what i understand i will have to make a 1:1 unbal and a 1:1 balun to be able to calibrate the vna with the open wire feedline attached and then be able to look at the antenna with the vna attached at the transceiver end of the balanced or open wire feedline. Problems could include a difference in velocity factor of any pigtails used to get to and from the 1:1 unbal and 1:1 balun. For example the pigtails could have a velocity factor of 66% and the open wire might have a velocity factor of 88%. The mission is to build a balanced HF antenna, probably inverted v or doublet, then measure it's parameters at height (100ft high feedpoint). After this, design and build a ladder line as best matched in impedance to the antenna as possible and then finally to be able to measure the impedance back at the tuner in order to choose the best ratio balun for the tuner in order to go back to 50 ohms. Just trying to get a vna to do all these things and in the correct manner and order does not seem easy to me. lol One solution i thought of was to hoist the vna up to the feedpoint to either connect back to me, either via powerful bluetooth, with a complicated array of usb extensions or by observing it with a camera such as a gopro. or to first use coax and calibrate the vna at the end of the coax, then use coax to observe the antennas parameters in order to find out what parameters my ladder line or balanced feedline should be to best match that antenna. finally to build the ladder line and then to measure it back at the tuner to help choose the correct balun. I have some 300 ohm ribbon feedline which i could initially run up to the feedpoint but it's all starting to sound complicated just so i can observe the antennas parameters at height and then build the ideal balanced feedline as every open wire feedline has it's own impedance depending on spacing and wire diameter. Ideally i want my feedline to have the same impedance as the antenna. So step one will be finding out the antennas parameters at height, step two decide on feedline impedance and try to build it in order to obtain an impedance matched to the antennas impedance once built. Step 3 will be to measure total impedance of the system at the tuner end and step 4 will be selecting the best ratio balun for the tuner to convert back to 50 ohm unbalanced. If anyone has any ideas on this i would much appreciate any input. Thanks.
@IK8XOO--Paolo Жыл бұрын
In the beginning of the video you said that you want... "to see the performance of the antenna". Thank to a so low SWR, now we know that the losses in that antenna are almost 28%. After the coax losses, only a 72% of the remaining power will be radiated
@Gruuvin1 Жыл бұрын
Some clarification: The wording here implies that this Baofeng will operate as a cross-band repeater. It will not. What's done here is program a memory location to be able to transmit to and receive from a DIFFERENT radio that is configured as a cross-band repeater. Confusion aside, it's a good instructional video on how to configure a channel for a cross-band offset, as I think a lot of people may not realize that you can set a very large offset like this. I am configuring my Wouxun KG-UV980P (cross-band repeater capable) to receive on a VHF frequency and transmit that received signal (repeat) on a UHF frequency (cross-band). This is so that low-power handhelds can transmit on a frequency that propagates better and receive from a high-power high-altitude antenna. Cross-band repeater = good performance using the same antenna without buying two radios and a duplexer. Win-win.
@debohannan4315 Жыл бұрын
Sir , great presentation on cross band operation but that's not crossband repeater if it was anyone transmitting on one band frequency will make the radio transmit on the other band .
@DrunkPacifist Жыл бұрын
Second time I use this video to compare cables length, very useful
@keithbowman8492 Жыл бұрын
This video is very good I had to watch it over and over to see what you were doing finally I got it but now you need to show a video on it actually working as a repeater
@Gruuvin1 Жыл бұрын
It won't work as a repeater. This is for use to/from another radio that can be configured as a repeater. He mispoke.
@MrTalaue Жыл бұрын
You are not measuring any performance! You are just measuring SWR in a 50 ohm system
@mohawk14616 Жыл бұрын
Very very nicely done video. Concise, flows and is understandable and learnable. Well done sir and thank you.
@pitila8315 Жыл бұрын
Why don't test to our see.
@turiluis Жыл бұрын
exelent explanation! thank you to take you time for this!
@atlantis922mhz92 жыл бұрын
All good with swr but what about conductance or capacitance behaviour of this system, (coax cable & antenna)? I mean when i have an antenna with transmission line which give to me a good swr factor and z, (aprox 50Ωμ), but i have a small value of capacitance, (200pF for example), to smith graph. Is this value of capacitance affect the tramsmission signal or not?
@timnewton83082 жыл бұрын
Dewalt has a version which doesn't need modification.
@Derpherppington9 ай бұрын
Yeah it would cost 5 times.
@metalfabman54772 жыл бұрын
Pretty cool, I think I might need to get one of these to play with my home brew antennas, thanks for the demonstration..
@stanelef44492 жыл бұрын
Good review! Thanks for the info.
@kavindugilshan2 жыл бұрын
So it means antenna element should be 78% shorter ??
@TalpaDK2 жыл бұрын
As this is an education video wouldn't it have been nice to have described that the calculation was and included the units? Something like "wavelength = speed_of_light / the frequency" or 299792458 m/s / 61MHz here. And for common usage you can just divide 300 by the frequency in MHz.
@usernamemykel2 жыл бұрын
So, the longer the antenna, the higher the SWR?
@zembalu2 жыл бұрын
I think, you must adjust the VNA to the length of the coaxial cable.
@brompton652 жыл бұрын
tot nu toe begrijp ik er geen moer van.....................
@mrtonicsvls36242 жыл бұрын
Crossband repeat means the radio will automatically retransmit what it receives onto the transmit frequency (i.e. the radio functions as a repeater). This radio transmit when the PTT button is pushed... it has no crossband repeat function.
@surfreadjumpsleep2 жыл бұрын
how about hart tools? do they require thermistors to work? know anything about bauer tools? i picked up a cheap driver i hoped to use for automotive but i can't get it to run. don't want to buy that overpriced battery.
@mbstxb75792 жыл бұрын
Why does hart tools have 3 wires a red black and green, what's the green for?
@thunfischunternixda66152 жыл бұрын
Hi, thank you for the video, but I have one question left: You can enter in Offset 3 number fields. In my device I can only enter 2 number fields. So why is this? Do you programm the device? Thank you for answering.
@k7ilo_Las_Vegas Жыл бұрын
I had the same issue with the particular UV5R version I had which you probably have the same version. I bought the TP version like his for this purpose because this setup works with satellite's with UHF/VHF repeaters onboard.
@FuzzyWCTX2 жыл бұрын
You need to recalibrate when you change the frequencies.
@kpowers742 жыл бұрын
Love
@RC-Heli8352 жыл бұрын
It would have been neat to see what would have happened if you could change the radials some leaving the vertical at its last best SWR setting.