Monday, November 30, 2009

Fake Diamond

A few weeks ago I wrote about the Diamond SRH805S stubby helical antenna I bought on eBay to use with my VX-8E. Its performance turned out to be much worse than expected and the antenna was not even resonant in the 2m band according to my antenna analyzer. Having looked at it a bit more closely I now believe the antenna I bought is not a real Diamond SRH805S at all.

The pictures above show, from left to right, the antenna I bought, an unbranded "short dual band SMA antenna" advertised by an eBay seller from Hong Kong, and a picture of a genuine Diamond SRH805S taken by an owner. You can see that the fake antenna and the unbranded antenna look identical apart from the "Diamond" labelling on the fake. There is a wide knurled brass band on the fake and the unbranded antennas, where the real Diamond has just a narrow smooth band. The fake and the unbranded antennas both have a double groove molded into the case, the real Diamond doesn't. The picture of the unbranded antenna gives its height as 52mm, matching exactly the one I have, while another picture I found of the Diamond SRH805S shows the height to be only 45mm.

The word "Diamond" on the fake antenna is not in the same font as on the real antenna, which uses a bolder font matching that used in Diamond company advertising and on the packaging. The labelling on the real antenna is blue while the fake is white. To be fair, I have found an image on a Canadian radio dealer's site where the labelling is white. It is also written top to bottom rather than bottom to top and has an aircraft logo on it. This may be a picture of an older version of the antenna.

The fake antenna came in a genuine-looking plastic case with a yellow back and a clear front. The forgers appear to have reproduced the lettering exactly. But on the genuine antenna cases the model number SRH805S is written in red. The genuine Diamond antenna comes with a rubber washer to seal between the antenna and the radio body if there is a gap. It also includes a printed sheet giving the specification of the product - the fake didn't.

One clue to the fact the antenna I bought was a fake is the price. I paid £6.99 including postage from Hong Kong for this antenna, which is about the same as the unbranded SMA antenna. Hams in the Far East have often told me prices there are a lot less than they are here so I was not as suspicious as perhaps I should have been.

Radioworld in the UK advertises the Diamond SRH805S for £25.96, while some Chinese and Hong Kong eBay sellers have what appear to be the genuine item (but could just be a better fake) for around £20 including postage. A Polish dealer (allegro.pl) is advertising what from the picture looks exactly like the antenna I bought for the zloty equivalent of about £14. A UK dealer (www.dvdongle.co.uk) is advertising a Diamond SRH805S for £13.99 but no picture is shown. In view of what I have discovered I would be interested to see what it looked like.

It might come as a bit of a surprise to many people that there are fake ham radio products on sale. I wonder how often these fake products are being passed off as the real thing for the full price?

What I want to do now is figure out how to get inside this antenna, preferably without resorting to use of a hacksaw, and see if I can tweak it down on to the 2m band and make something useful out of it.

10 comments:

Eldon R. Brown SR - WA0UWH said...

Just thinking -

Does the stand-alone Diamond need to resonate on 2m?

Or does the antenna system including the part that is inside of the handheld work together as the antenna?

How is the signal strength at a long distance from the TX, compared to any other similar antenna?

-

g4ilo said...

It will work with the chassis of the handheld as ground plus you/me holding it. But then the same is true when it is on the antenna analyzer which is more massive than the VX-8E. In fact I even tried a 19in pigtail "counterpoise" and it didn't shift the resonant point significantly. The signal strength is about 15dB down on the stock duck as far as I could determine. More significantly the SWR was infinite as reported by the antenna analyzer, which can't be good for the rig's PA. Whatever it is it is NOT a dummy load as some internet know-alls are fond of saying.

Adrian said...

I do have a genuine Diamond antenna, bought from a respectable dealer in Italy. It looks like the one in the right photo.
Of course, with the years passing by, the antenna suffered some damage which made me able to see inside. It is just a coil from a soft steel but with a variable pace.
Now, my antenna has no marking on it and I had to apply a black paint over.
It is right, the genuine one has a rubber on the bottom (near the SMA connector). I do have a friend who purchase a Hong Kong version which is useless (not even as a dummy load). Sorry for my english.
YO3HJV, Adrian

craig said...

Thanks for your blog, and thanks also for giving out the information about the 'Diamond' SRH805S antenna.
I bought an antenna from Ebay which can be found at-

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320660812092&ssPageName=STRK:MEWNX:IT

which was simply described as
''Antenna SMA-Female for Wouxun Radio KG-UVD1 659 669 689'' There was no mention whatsoever that it was made by Diamond so imagine my surprise when i opened the package to reveal that it was in an original 'looking' Diamond- yellow packet with the red and white writing on it etc... The antenna itself also has all the correct Diamond writing on it but not in blue or white, just embossed or laser etched. It has two ribbed bands round the main part of the antenna and a gold plated brass bottom which has been knurled similar to the original one in your picture but with no rubber piece at all... It was only £4.99 with free post and packing and i certainly wasn't expecting an original Diamond antenna for that price but it just goes to show that MANY fake Diamond antennas are knocking around- BUYER BEWARE i say. As it happens, the seller (from the UK) did not describe it as a Diamond, he only said it was an Antenna SMA-Female for Wouxun Radio KG-UVD1 659 669 689 so i've no complaints but if it had been advertised as a genuine Diamond it would have been a different matter..! I've had a short time to test it out and i must say that the performance isn't too bad for what it is but it's nothing compared to the original antenna that came with the Wouxun KG-UVD1p. In fact, i've tried quite a few different antennas on it and nothing compares to it's original. Also, i have just ordered a Nagoya NA-666 from Ebay and i'd love to be able to check whether it is genuine when it comes. I've been on their website but there isn't a good enough photo or any price to be able to compare it to.
Keep up the good work,
Regards,
Craig...

ps, i know you never do, but please dont publish my Email address or anything other than my name on your blog, just my name if you don't mind.

gibbon_ said...

Hey...

I own a SRH805S (genuine, working fine) which indeed looks like the one in the right most picture. Its performance on 2m are far from the Nagoya rubber duck, but the performance on 70cm is surprisingly good (since I only have a CEPT Novice License, I could not test 23cm). I ordered a SRH805S fake (the seller admitted, that it was not a Diamond one) just to compare for my other HT (Wouxun). Did you measure the resonance on 70cm? It would be nice to know if I fry my HTs PA with this thing on 70cm.

Another question... which antenna analyzer do you have?

73 de DO5GBN

Julian said...

Sorry I couldn't test the antenna on 70cm as my antenna analyzer only goes up to 200MHz. It's the RigExpert AA-200

Dave Gardner said...

Julian,

Check out this link:

http://www.ebay.com/itm/270857784822?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Do you think this is a real one?
I paid USD$10 and free shipping on ebay from China, awfully cheap considering it retails for USD$39 here in the states.

73, W6DRG
Dave

Julian Moss said...

I've seen so many fake Diamond antennas that my money would be on it being a fake also. It's a better looking fake than my one, but I have a similar looking antenna (which wasn't sold as a Diamond and cost less) which shows an infinite SWR across the entire spectrum. So we do know the Chinese are making fake stubby antennas that could be lettered up to look like the real Diamond SRH805S.

I also note that the seller you linked to has only 9 feedbacks, so it's unlikely he is buying in bulk to get a huge discount. Draw your own conclusion, or find someone who can test it on an analyzer.

Julian Moss said...

How to spot a fake Diamond antenna.

David said...

I just received one of these antennas as well:
http://m0mln.wordpress.com/2013/02/15/fake-diamond-antenna/

At least on mine they tried to get the font right, though unfortunately some of the ink rubbed off the antenna inside the packaging!