Hi John what’s the switch on the front of your 817 mic please?
Hi Andy,
It’s the CW key. A miniature toggle switch, RS Components stock No 317-033. Left for dashes, right for dots and biased off in the centre. It’s wired in parallel with the up/ down mic buttons which are very difficult to use in their CW mode.
73, John
Hi Pete,
Despite there being no sightings of anything nearby, I am keeping an open mind. Many activators have been plagued by nearby stuff that even the strongest RX struggles to keep out. Sometimes it’s a very nasty noise and others you hear nothing. I get it with all my handhelds while walking locally in Scarborough but it’s only a problem within a few hundred metres of the source. In this case Row Brow and Oliver’s Mount.
‘As a result I only use the Baofeng on long hikes where weight is an issue and RF isn’t.’ This is mainly my intention and weight/ 5 Watts is the reason I bought it.
73, John.
Thanks Evan. I think that could work well. Mostly 160 & 80m are the focuses with FM an afterthought. VHF beam not often carried, I’m afraid.
John
Thanks for the adjacent channel figures John. The big difference between these radios and many others is that the guts is a single chip SDR setup. The antenna connects straight to the RF input of the chip and there is no bandpass or front end filtering. The chip covers 134-174MHz and 200-260MHz and 400-520MHz. This means that you effectively have a wideband amp connected to an antenna and as a result it is wide open to any RF received, often tens of MHz away from your own working frequency. The performance gets worse the better the antenna as more out of band RF is fed to the input swamping it.
It’s not the only set overloaded when used with a bigger antenna. I could list handfuls of radios that suffer, some costing hundreds of pounds. Some are very good on the other hand. However, the point is that whilst all suffer to some degree, some are really bad. People saying the performance is acceptable when you only paid a pittance for it are the people ignoring the elephant in the room. If I buy a cheap car, I don’t expect it to be as fast, luxurious, well handling and all round delight compared to a £150000 supercar. But I do expect it to be able to stay on the road, keep up with traffic, not be a danger and to get me around the country when I want. If these uber-cheap radios were cars then you’d find quite a lot of the time when another car was a few hundred yards in front or behind you, that yours would not respond to the steering wheel and veer off the road or the engine would stop till the other car was miles away. “Hey maybe it’s only usable when the roads are deserted but it was cheap” is exactly the mindset people have about a radio that does suffer quite badly from other signals. The problem is the roads are not deserted. And neither are the bands free of out of band signals.
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See my post 12 days ago re fixing that. Cost depends on your junk box.
4 t of 18 g cu wire on a 5 mm former, 1 - 22 pf trimmer capacitor. 2 coax connectors, one to match rig, one to match antenna. 1 small box - or make one from scrap PCB. One morning building and tuning. It worked for Marconi, it will work for you.
73
Ron
VK3AFW
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Yes Ron the way to go!
I produce two an number of years ago when I found my Vx 8 just couldn’t hack it on sites that where inhabited with commercial installations. One has less than <1dB insertion loss (two chambers LC thru LC).
The other is almost square in it’s passband shape 
but suffers a higher insertion loss due to the tightness of the passband. Physically smaller than the other filter. It’s usually the one I use even with the higher insertion loss. (it was out the Rx front end out of a Storno CQM700 - beautiful little filter - 6 silvered cavities with a helix and screwed stub in each cavity - nothing gets through this baby but 145MHz sigs)
73
Jack(;>J
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That’s why I’d be reluctant to condemn the Baofeng - pleasure to be had from understanding the weakness and improving it.
If newcomers can only either build their own, or purchase top performing equipment, there isn’t much scope in between for experimentation. (In my formative years there was lots of cheap surplus military stuff around, as well as old commercial mobile radios to fiddle with)
YMMV, and I can clearly see the elephant - 'course in my day, they were woolly mammoths - 
73
Adrian
G4AZS
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Reply to MM0FMF, GM4COX, VK3AFW & G4AZS:
Thanks Andy, Ron, Jack & Adrian,
There’s little more I can add to this except maybe a summary.
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The UV-5R-2 was bought with prior knowledge of possible poor performance aspects in mind but was obtained for its light weight versus 5W o/p. Intended use was mainly as a backup in case of HF equipment or propagation failure.
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Something caused S2S failure from a GM/SS to GW/NW-001?
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My UV-5R-2 and a UV-5R were tested for receive sensitivity and adjacent channel interference (above) and found to be generally satisfactory. This proves they are not deaf but not that they can’t be deafened in certain circumstances.
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I accept that failure to S2S may have been due to de-sensing in (possibly out of band) strong RF field but geographically where the source is located in relation to Snowdon, is unclear.
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Most of my handhelds suffer from overloading within a few hundred metres of Oliver’s Mount and Row Brow, Scarborough. This happens with supplied duck or a half-wave. More than half a mile away and they all (pricey and otherwise) seem to work OK.
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RF filtering? Yes, a good idea if going to summits which are close to commercial sites giving out high levels of RF. A SARS meeting about 15 years ago showed us how to make a tunable cavity for 145MHz from two paint tins etc. The amateur who gave the lecture was the builder of four of our North Yorkshire repeaters so I took full notes. That unit would have been perfect for home use but impractical for SOTA. Jack and Ron’s offerings, are worthy of consideration for SOTA work with handheld rigs intended for front-line use in places known to have strong RF fields.
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It was informed to me while using the UV-5R-2 on Snowdon that an M6 was calling me. I have no idea what his working conditions were but for some reason or another, I didn’t hear him, despite calling him in (de-squelched) several times.
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There could still be another cause of the S2S failure in this particular case? There were 37 chasers trying to get through albeit not all at once and many were close-in. Alternatively, if my XYL is to be believed, I am deaf (or is it just my ‘filters’).
I am left not knowing and possibly even worse, never likely to know for sure just what was happening on this one specific occasion. The tests have given me some confidence at least. It would be good to know whether any other Snowdon activators have had any problems of this kind. I have activated it on VHF before (once with a Jingtong JT208) but can’t remember anything that might support (or otherwise) the theory’s.
I didn’t understand the elephant picture so I didn’t reply to it. Now I know I liked the wooly Mammoth comment from Adrian. I too can identify with that.
Thanks to all contributors on here and to Andy for starting the thread. A big thank you to Dave for bench checking the various radios.
I hope that covers most of it with nothing further to add at present, so I’ll get back to seed planting, mending a dripping tap, attending a funeral and getting ready. I am off to GM/NS next week. 1-week; Monday 8th to Monday 15th inclusive (Dave: Won’t be at the club either Monday to pick up the handhelds) so hoping to do at least one mountain if the WX and ionosphere and ticks are kind. It’ll be HF with (sorry) UV-3R as backup.
73, John.
PS: Liked the Arrow beam antenna. Worth another look since Richard stopped making Sotabeams some years ago.
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The blocking test is certainly a useful test.
I think there are many times when something works fine on the test bench but fails in the field. I suspect the problem is worsened when there are not just one but many out of band signals and if you are really unlucky, there are two giant digital tv or fm signals with a frequency difference roughly equal to the first IF. No mixer can defeat that problem, the mixing product goes straight to the IF and that problem can only be fixed with a good band pass filter in the antenna circuit. If the frequency difference between the out of band signals is almost equal to the first IF, it doesn’t prevent the radio from hearing loud signals, but the giant signal just down or up by 50 khz is still dominating the relatively wide IF. Stop band suppression of 50 db or less in a simple ceramic filter is nowhere near good enough.
I dimly recall the early Icom mobiles, sold in Australia as IC22A and the synthesised version IC22S. They had helical bandpass filters in the front end and you never knew there were other signals in the spectrum.
Andrew VK1DA VK2UH
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And OR Bandstop / Notch (trap)
Its a direct sampling radio, the mixer (if fitted) will be part of a SoC.
It is what it is I am afraid. I don’t think a good BPF will resolve all the mixing products which will den sense the HT. It’s somewhat embarrassing when people below cannot understand why you carn’t (and should) hear them.
That’s why I’ve just bought an FT-60E…
My UV5 BaoFeng has just been assigned to the loft.