Notwithstanding your previous commentors, I believe you should attach the antenna directly to the meter and then hold it like you would hold the radio. Then your body will form the other half of the antenna, which is how they are intended to be used. If that's still bad, fair enough! 😊
I believe also part of the official testing procedure adds a head to the mix as you'd hold this near your mouth. This won't cure the fake here I promise!
As a lot of people already Said. Connect antennas directly to VNA, if it Is not possible use as short coax as you can And use that calibration set to calibrate VNA with this short coax, thats why you Have that set in box in the first place, otherwise it could be just calibrated in factory.
I cut one of these open and it was literally just a 36cm whip, no loading whatsoever so it is essentially a 1/2wl end fed on 70cm except it has no loading and is too short to be a 1/4wl on 2m. So no use on either band.
The extended lead will also effect the SWR and input impedance probably. I wouldn't use a too long table. Just make sure you do the test under repeatable defined situation ;-)
Want a good budget antenna? Get an Abbree tactical or other foldable antenna. They're ugly and unwieldy, but they are superb antennas. Don't know about the tri-band models, but they should work fine. I have a Nagoya NA-24J and the Abbree works just as well if not a little better. Thee 24J is far more difficult to copy, so you're more likely to get an original. Order from BTech or Amazon. Once you get a genuine Nagoya, you can easily check other antennas claiming to be Nagoyas by putting them side by side. The thing is, Nagoya antennas are well made, but they don't really extend one's range as much as you'd think. Looking at a graph is one thing; field testing's quite another. If it were me, I'd buy a Diamond Signal Stick or the 24J Nagoya.
Hi Fred, be VERY careful about the use of wrench on the SMA connectors! The key point is to tighten the SMAs properly. Not too loose and not too tight! Overtightening the connectors can cause the internals of the female connector to spread out, which can cause intermittent connections later on. Also be careful with how you're applying the torque at the connector. On there NanoVNAs, the connectors aren't installed in a very secure manner. They're usually just soldered on the pin side, and the other side of the connector has often no solder. This, together with use of a wrench, can cause the solder joints to crack, which can again lead to intermittent connections. There are proper SMA Torque Wrenches, which will automatically disengage when you reach the appropriate torque, but such a wrench alone could cost around 2-4 NanoVNAs, so obtaining a proper one might not be economically justified in this case.
i dont think having the antenna away from you would make much difference for swr. the antennas are made for hand held radio its designed to be used right next to you. your not holding the radio at arms length away when using it. i used my uv5r for the Australian 80 channel cb 476-477 mhz and the fake antenna did perform a little better than the standard one but not by great amounts. is testing the swr going to be accurate on such a little antenna they are not the same as a mobile car antenna or base station. more to the point before you tested the antennas with swr meter did they beform better? if they did i would'nt worry about the swr i dont think the standard antennas would perform any better on swr meter.
Yes, we did the same on PMR446 and the talk range increases greater than the standard UV5R/888s stock antenna etc. The VSWR results is still dubious and better to double check with analogue SWR meter such as SX600 etc.
@@CB-RADIO-UK nice one for the heads up I will put the rubber ducky back on the other one... do you recommend me getting one of these fake nano.. it's in my watch list👍🏽
That does seem like a surprising result. Could you perhaps consider sacrificing an 888 by doing a practical test with one of these antennas? A simple "does it actually get fried" / range check should surely be able to confirm whether or not the SWR really is that bad 🤔
@@CB-RADIO-UK Thanks! I just watched that video, actually the fake 771 sounded a lot better than the standard antenna. So, something doesn't add up... This is intriguing, needs more investigation surely? Thanks for the interesting videos.
I bought a Btech Nagoya 771 for an Australasian plan CB (476-7mhz) .... "120-900mhz" - Sweet!! ...but missed the bit where it says receiving only - I think it's optimized to 430 & suspect this is true of most general antennas out there - I also suspect some are being marketed for use outside of their working spec's too.... Anyway, so out of CB & GMRS range :) notarubicon did a vid on tuning antennas (trimming with wire cutters)... I don't know what frequency's you use most, but might this be an option to tweak the swr back into the park? I guess it might be academic if faith has been lost but might be an interesting exercise if the only other option is to bin the antennas..... ....Ah, & ground plane - wondering if you can use a metal plate as one, as is recommended for mk2 surecom SW102's???
Another good video Fred. Would it be worth doing a comparison test on an in line swr meter of a reputable make. I suggest something with a reasonable price like the Avair AV601. Something is telling me not to put too much faith in that VNA.. How about also checking a reliable antenna with the VNA like your amtron99.?
Prob a good idea Barry. Iam not going to get too much into these 2m/70cm antennas as really iam just using them to learn about the meter. What i really want to use the Nano for is building dipoles.
@@CB-RADIO-UK That's fare enough Fred but you need to know that the VNA is a reliable one otherwise you will be making dipoles that are way off resonance. That puts your other gear at risk. Maybe use it now to build a dipole then connect it to an in line swr meter that you know is reliable. I'm just not sure if I would be trusting that VNA tbh.👍
It is amazing how far off an antenna can be made on purpose. They must think that most radio operators would rather cheap god looking antennas rather than a performer.
Good morning Fred. Could you please try to use analogue SWR meter as a cross reference when testing the fake RH771 at f=446Mhz? TX at max 5W and see the reflected power. Very good video review of yours. Cheers!.
These seem to be really bad fakes! I saw some other videos testing the (fake) NA 771 with much better results! There is also a video were they open up both a genuine and a fake antenna. The genuine had some matching circuitry in the bottom part with small coils and little caps! So i guess they do a quick manual matching for each antenna - resulting in the higher price tag. With my (probably fake NA 771 but for around 6 Eur) i managed to hear the ISS space station 3 times when it passed. I wasn't able with the orig. baofeng antenna (signal stick copy). Also try to use a counterpoise (wire attached for virtual ground) - this can really change a lot! Consider in real life your hand and body would act as a counterpoise for the antenna!
Can you try the other OEM antenna(s)? The Baofeng one which tapers in and then continues fairly thinly to the top is supposed to be better than the "chunky" one, particularly on the amateur bands. I have both, myself, one of which came on each UV-5R I have, and I ordered another one of the "slim" ones as the chunky one, as tested in the first video, wasn't great.
Hi again Fred. Have you considered using a counterpoise or as it's sometime called "a Rat Tail". There are a few youtube Vids about these . With the supplied antennas you only really have one part of a half wave. If you add a counterpoise you are effectively completing the antenna. My friend has tried this on a handheld and got really excellent results. SWR came right down to a useable level and the signal went up by 3 S points. He told me the the counterpoise was 19.3 inches. Just an idea you might consider trying. Cheers & 73s Keith
What you are finding out is something I've seen for a long time , basically I ripped apart a cheap 'clone' and it had no loading , the closest it came to resonance was about 160Mhz. The best thing for these is trim them down to a UHF quarter wave!!! I jest you not. The main problem is that people buy these and convince themselves they're an improvement. they aren't. best antenna i've seen is the stock uv5R antenna for tune. great on 2m and 70cm! I guess 90% of the chinese antennas are crap , I have a big pile of them and theyre all shite! please people wake up and listen to this guy!!! I do have 1*771 which actually tunes on UHF and VHF. I also find 701's useless too!!!
John your prob right. When ive finished playing with it i will take these fakes apart on another video and give you a shout out. It will be interesting to see if there is any base loading.
It's never gonna measure right without a ground plane on the aerial to balance it out. Unless you are measuring a Slim Jim you must have a ground plane 😉 Any aerial without a decent ground will peg the meter as you found out with your loft aerial experiments 😊
Well, rip. Wonder how practical would it be to homebrew handheld antennas because it doesn't make much sense to pay 20 bucks for an antenna for 10bucks bf-888s
Have you a way to see if the antenna uses the radio as a counterpoise?I would try a field strength meter and compare the fake to an genuine.2CM3284/KE5SRB.CHEERS from the States mate!
Not convinced this test is accurate as the antenna has no ground plane, mounted on a car or handheld held in hand the result would be different. The mag mount alone is not enough. It has to be connected directly to ground through body or car, if not the ground plane/radials need tuning. I would check on car for best result, if only using on PMR you can cut the antenna to a quarter wave whip, the antenna is a 1/4 wave whip for 70cm with a trap/loading coil added. On 70cm the antenna only transmits from about 17.5cm of the antenna. On 2m it works as a top loaded antenna. 2e0deq.
Seen a mod ... rat tail ground plane... Quick question Fred.... First ssb.... I've seen your videos championing Ss 6900 n What about the Alinco Dr 135 dx ( 10dx )
Yeah, I know this might seem a daft reason, but I think im gonna go for it, purely for its looks. Not sure if clarifier is "clicky" but the one plus I suppose is the programming cable has an external port.
Coincidentally, I was testing my NA-771's this afternoon before I saw your video, having also acquired a NanoVNA. I tested how others have suggested - attaching the antenna directly to the VNA (with a gender converter where necessary) and holding it like I would a radio. I'd (wrongly) assumed that Nagoya was a cheap (mainland) Chinese brand, and hadn't realised it was actually in Taiwan and rather better, hence worth faking. All three of my NA-771's were fake, but at least usable, and with roughly the same curve. Optimum SWR around 200MHz but usable (just - SWR
@@CB-RADIO-UK On second thoughts, only just about usable. ;-) One of them I only ever used on 70cms (a slightly unusual yellow one that I bought to match my slightly unusual yellow BF-888S) so I decided to cut it down. As predicted, it's a simple steel (?) cable, quarter wave resonant at around 200MHz. Why does it seem thicker towards the base? Simply 'cos there's a double thickness of shrinkfit. Anyway, I chopped it down with a bolt cutter, carefully removed and transferred the rubber titty off the end, and it works a treat. SWR better than 1.5:1 over both 70cms and PMR446. ☺ I'll carry on using the bogus Diamond - it's obviously fake, but it works fine - and keep the "Nagoyas" for emergencies only. Though I might treat myself to a genuine one from a UK source - my TYT handheld is opposite gender to my Baofengs and using a coupler is a bit fiddly.
I'll add that I checked the various stubby antennas that were supplied with the radios, and they were all fine. The optimum SWR tended to be a little lower - about 410 - 420MHz - but still well below 2:1 on 70cms / 446.
Go for it, I'd like to see! I've got one of these fake 771s and it does work better on the ham bands than the stock antenna, more on 2m than on 70cm (maybe not surprising because of the physical length). I tried ordering a Nano VNA but the seller asked me to cancel for some reason. Not got round to ordering another one.