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Licence free two-way radio services that now includes both FM and digital channels. Discuss models, modifications and other similar worldwide standards such as FRS and GMRS.
Strange results time - I bought a stubby antenna from AliExpress so that I could carry my Quansheng UV-K5 around discreetly and listen for activity, then switch over to the longer antenna if there's any action. I didn't intend to use it to transmit on but tried it for the laugh and have had some unexpected results.
* 50 miles Wolds to Pennines
" 50 miles Vale of York to Pennines from inside my car
* Up to 18 miles from 490ft hill
*:11 miles from inside the car from low to high ground
* Improved reception of weaker signals over the much longer stock antenna
The stubby cost £1.20. It will not, of course, transmit as well as the stock or 771-style antennas (I've recorded S3 difference over 40 miles) but it is shockingly good for what it is.
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At a high spot chances are you'll have very strong commercial signals whizzing around your ears close to the band. With a less efficient antenna your receiver might have a better chance of not being swamped...
That makes sense - I was 200m from a telecoms mast at one location. I think there is something else though - with the stock and the longer Retevis RHD 771 antennas, I often have to open the squelch because some contacts - even strong ones - are staccato. If I switch to the stubby it often resolves it.
The same happens if I switch to my Retevis H777D with a short, fixed antenna. This may be particular to my radio as I don't see other Quansheng owners mention it.
There is so much physics going on here. It’s an antenna that clearly is compromised technically. Receive and transmit performance on a tuned antenna is the same, so it means it’s badly compromised impedance wise, so your radio sees a problem and throttles back on RF output, but the radio has a decent receiver, gain wise, so is happy. You have a 770 style antenna. These too are probably the most variable product ever. I used to sell these, but after I built a little test rig for a video, I realised that buying a box of twenty, produced some that were really good ranging through to some that struggled to not be a decent dummy load. Everybody on the internet was banging on about their excellent one, which was a real Nagoya, and the bad ones were of course cheap Chinese fakes. One of my really good suppliers told me they’re a product that smaller radio factories, as in a small office and work room can make for very little start up cost. The injection moulding machines are available second hand for very little. The internals take little work, just a dab with a soldering iron and a couple of bins of parts cut by hand. Many buy the internals from other suppliers over length, and cut them on the bench with two sharpie marks. As a result, what goes into the antenna is not even tested! The green and orange sleeves are made by another firm or ten. We assume Nagoya means something. It doesn’t. There is NO Nagoya factory in any way we in the West understand it. It is a generic name. The ‘factory’ might have a bank account in the name of Nagoya Quanzhou antenna company ltd, but it has no connection to Nagoya Communications company Ltd.
Small vhf and uhf antennas are exactly the same. Three parts, connector, wire and lump of plastic. Next weeks batch may be absolute rubbish for your chosen band.
I buy base and marine antennas from the same firm in China. I have used them for 15 years. Every order, they double check what I actually want, then go and make me a batch of 25 by hand. Occasionally, one is wildly out of tune, and I have to repair it. Usually it’s really silly stuff, as in the soldered on extra length required for tuning, as in the U.K. 430-440MHz band being different to some other countries. Without the extra bit, the antennas are tuned for 420! When a batch appear, I have an antenna outside wired to my office and a square taped on the window sill. I have an ancient Icom radio connected to it. Through a switchable attenuator. I stick every antenna onto the base on the window sill and press transmit. The base is connected to a receiver in the rack. I drop the antenna onto the base and the receiver gives me a weak noisy signal. Then swap and repeat. I’ve got an excel spreadsheet with the attenuator settings. I can test a batch of 25 antennas quickly and one or two will always need a bit of examination. There is NEVER a surprise brilliant performer, just degrees of less so. Consistency is pretty good, by quantity. Doing this with 770 antennas or other flavour of the month types is much, much worse. 25% fail maybe, and being moulded wastage is high. I used to separate them into bands. If they were a bit short, then maybe still useful on 450MHz rather than ham bands. VHF ham might be useful on marine band, but I got fed up and stopped messing with portable antennas, just too time consuming compared to profit.
Nagoya is a place so it's no wonder a few companies have it in their name. I've been to the Nagoya factory near Taipei and met its owner and staff.
It was quite a small place and with no space at all not used for something - at least at that time (14-16 years ago ish). As my boss had predicted there were people outside 'on the door step' in the very pleasant weather doing simpler assy stuff. They have good test gear and know how to use it - at least they do in the R&D. At that time their main business was antennas for Taiwan police vehicles. For us they were making audio accessories for our police hand-helds (which do operate on 380 to 420MHz) and some amateur stuff for our retail side. Same applies to JDI (Jing Deng Industries). The variety and quality of the seafood there is to dream of...
Voxtech had a factory there too I just saw their office. One thing I remember was my host saying that the difference between their Taiwan and Shenzhen operations was that in Taiwan you would need something like 2 or 3 supervisors for 25 operators, but in China they needed more like 10!
Part of the problem (at least at that time) was explained to me. In China the workforce tends to come from the interior of the country, which is very agricultural, and goes to work in the cities for a year or two years to make some money, then they go home and another lot arrive. They sleep in special dormitary buildings and sometimes there's even hot-bedding when shift work is happening. Those dorm buildings look quite respectable, and are often the building next to the factory. At Chinese New Year (February?) everything stops for a week or two. After that the production staff are mostly a fresh intake that have to learn all the doins' from scratch. Best not to order from China in March!
Gentlemen, thank you for those very interesting posts.
Paul, I've heard before about the batch variability of cheaply made HT antennas and bear it in mind when testing any. I have one Retevis 771 that I bought for my RT24s and it works very well with them. The Quansheng is the opposite SMA fitting so I bought another which doesn't do so well - perhaps it is one of the runts of the litter.
I spent only a quid on the stubby and only intended it for discreet monitoring. I bought it along with a CB rubber duck and a fake N773 antenna. Given the whole lot was just over £6 I didn't really care if they worked or not . As it turns out the stubby and fake 773 aren't too shabby and the rubber duck is about as good as the Thunderpole TX stock antenna (yes, both made in China ).
I'm not going to go mad on HT antennas since, as you describe, none will do better than others of the same length and a fair proportion will do worse, though I may take the odd quid punt.
I see Diamonds are reassuringly expensive - any idea if they are better made and do any better than Shenzhen Specials?
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