Buying radio gear on eBay is like gambling. It's addictive, but often you lose. You win often enough to keep you coming back in the hope of finding that absolute bargain.
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| Is the antenna on the right a fake? |
I thought that I would buy a dual-band handheld antenna that was long enough to have a bit of gain but not too long to use in the shack. (I have several gain antennas but at over a metre in length they are not suitable for indoor use.) I have a Nagoya NA-701 which works very well for its length (22cm) so I thought I would get a NA-771 which is 40cm in length and ought to perform a couple of dBs better. I know only too well that there are a lot of fake antennas on eBay so I bought this one from 409shop, or rather from radiobanker which is one of the eBay IDs used by 409shop. The general consensus is that 409shop is a trustworthy trader and doesn't sell fake stuff.
When the antenna arrived I was concerned to see that instead of the silver-on-black label showing the make and model number the details were printed on in blue. I have had
other fake antennas with printed-on labels, even ones with the same shade of blue so it was not a good omen. When I tried the antenna on one of my handies I found that it performed no better than the much shorter NA-701.
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| SWR of the alleged NA-771 |
I put it on my AA-200 antenna analyzer and found that the SWR at 145.000MHz was about 4:1. There were two dips to the HF of the 2m band, the best of which was at 195.000MHz with 2.7:1. This is not the worst I have found but it explains why the antenna did not perform optimally.
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| SWR of Nagoya NA-701 |
For comparison I looked at the SWR of the NA-701 with the silver-on-black label. This was a really good match - better than 1.5:1 at 150.000MHz though closer to 2:1 at 145.000MHz. Given that the resonance at any given time will be affected by conditions surrounding the hand-held antenna that's close enough.
So is the NA-771 from radiobanker a fake or not? The plastic sleeve the antenna came in bears a silver hologram label that says "Nagoya", and the name "Reuex Industrial Co. Ltd." That is the name of the company that manufactures Nagoya antennas and apparently they do use blue lettering.
So I conclude that this antenna is probably genuine and performs as well as it was meant to, which unfortunately happens to be not as well as I hoped. The Nagoya NA-771 is not worth its extra length.
FYI using an SWR/power meter I measured the SWR of the two antennas at 433.000MHz to be: NA-701 3.4:1, NA-771 4:1.
7 comments:
Wow, that is a surprising outcome Julian. I remember I considered 1 of these for my UV-3R. But bought another one that was recommended to me. I think overall you better get a genuine Diamond antenna. Although....you never know. 73, Bas
Julian, you say that the NA771 doesn't perform poorly enough for you to ask for a refund yet doesn't operating with a 4:1 SWR degrade the finals over time?
Hi John. I think a handheld has to cope with a wide range of SWR due to the fact that the antenna may be deployed in a variety of situations from out in the clear to worn on the belt. I have actually measured a worse SWR on a dual band antenna from Kenwood (that was a poor performer as well.)
I know you tested the antenna down to 95MHz but see what the AA-200 says about 6 or 4 meters.
I'd say, your blue marked NA-771 is a fake.
I have bought a NA-771 from a reputable source
(Maas Elektronik here in Germany, a major well known wholesale importer)
and it has a silver lettered label on it like your NA-701.
Plus, bad performing blue marked fakes of other Nagoya antennas
had been reported elsewhere (e.g. on funkbasis.de).
And of course, my NA-771 performs like it can be expected
from an antenna of this length.
Nohab, that's a very interesting comment. I suspected a fake too, but someone from the US claimed to have contacted Nagoya and been told that new antennas are now marked in blue.
I don't think any reputable dealer in the UK sells Nagoya products. Perhaps I'll order one from Germany...
From the pics on the manufacturers site -where visible-
they are still using the silver lettered labels.
http://www.nagoya.com.tw/
I guess, the only way to protect yourself from fakes is
to ask the manufacturer for the official importer/wholesale agent
for your country and in turn ask that one for a reputable dealer,
if they don't sell directly to end users.
If you do want to order from Maas, they do send to the UK,
however, shipping will be 15 Euros for a parcel up to 30kg.
Minimum order is 15 Euros as well.
http://www.maas-elektronik.com/
(Disclaimer: I am in no means connected to Maas,
I just know them for a very long time.)
Best regards
Nohab.
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