Chinese 2 way radio HW with WBFM potential interference issue - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: November 01, 2018, 04:39:45 am
content: When i first saw the publication from the (US) FCC about the non-type acceptance of some Chinese radios I thought they were specifically referring to Baofeng and indeed they are probably the most widely used non-type accepted radio. But i was surfing the net and I just saw some radio modules that advertised a bandwidth of 25 khz and I suspect that kind of thing was really what spiked their anger. Because thats really wasteful of spectrum and its likely to cause interference to people on adjacent channels.So what is the situation with the more likely compliant (Baofeng?) radios and is there any way they can be used legally? It seems to me that its the users responsibility to make sure they are behaving in a legal manner. Of course it does come down also to whether the radio is capable of putting out a clean, in band signal but I suspect many are. Before I heard this I was planning on getting a Baofeng because frankly, I cant afford to spend >$100 on a walkie talkie, or any VHF/UHF rig, when I dont know if I will use it that much, but I dont want to break the law if indeed they cant or arent compliant. That would not be a good way to start out in ham radio!I want to know specifics, I dont want to break the law, and if its ambiguous, I will err on the side of caution. Does anybody know?

author: JoeyG
author_rank: Regular Contributor
timestamp: November 01, 2018, 06:43:20 am
content: The importer/seller/distributor/manufacturer is generally responsible for FCC compliance of a complete operational product.RF Modules can have FCC modular compliance, but generally speaking a module is not a complete end operational product, it requires power supplies and other electronics to make it work. This is also termed a sub assembly.It is the responsibility of the #integrator of modules and electronics to know what levels of compliance is needed for the end product.ANDIf the sell them... they are classed as a manufacturer .Sub assemblies can be sold without compliance as it is assumed the integrator knows what he/she is doing.#integrator = a person that assembles a product. ie manufacturer.Joe

author: cdev
author_rank: Super Contributor
timestamp: November 01, 2018, 03:50:55 pm
content: Thank you.Thinking about it, it really would be best if the manufacturers would seek type acceptance in the US so they could continue to offer products which fill an important niche as far as cost.

author: tkamiya
author_rank: Super Contributor
timestamp: November 01, 2018, 06:56:09 pm
content: Only things legally binding is spectrum purity, bandwidth, and not transmitting out of band. You probably have enough test equipment to prove it to yourself, if the radio is legal to use or not.On receiving side, I'd be cautious of nearly strong signals but that's not a legal matter.As far as Chinese radio stuff go, I'm more angry about modules and parts that make it so easy for anyone to be an illegal station. High power WIFI adapter, cell phone relay, and all sorts of DIY module are sold with impunity. I've even seen 50 watt FM band transmitter sold on eBay.

author: cdev
author_rank: Super Contributor
timestamp: November 01, 2018, 07:22:14 pm
content: When something like potential interference to other hams and emergency communications is at issue, I would be fine with ebay or other auction sites not showing people in a country where its noncompliant a product.But in the case of Pofung or whatever the company's name is, because they are almost there, efforts should be made to help them become compliant so that the hobby can expand since the high cost of ham rigs is a significant obstacle to many people and the benefits of having this means of introducing (responsible!) people to technology and having (responsible) ham operators help in emergencies are both quite substantial.Quote from: tkamiya on November 01, 2018, 06:56:09 pmI don't own a spectrum analyzer, the substitutes that I have are totally uncalibrated and home-made hacks that could not be trusted to tell the difference between a signal that was almost there but not compliant (as in spurs x db down) and one that was compliant (spurs a bit more down) by itself. However they can show the frequency and be trusted. (But the response is non-linear as far as dynamic range).OTOH, I do know my way around RFSIM99 and Elsie and know that I could build a filter that could be reasonably assumed to clean a signal that was already pretty clean up to the point where it was almost certain to be so.Quote from: tkamiya on November 01, 2018, 06:56:09 pmThe people who sell things like that are probably targeting outside of US, probably Third World buyers.

author: dmills
author_rank: Super Contributor
timestamp: November 05, 2018, 06:58:18 pm
content: The people who are selling the things (from outside the country) are NOT the importer, the person who causes the thing to be imported is the importer (So that often means YOU if you import toys from the far east are the party legally responsible for the compliance or otherwise of the product).For example, I can under UK law quite legally sell an RF power amplifier that has say 30dB of gain and 1kW output right the way from 1.8-54MHz (or wider if I could pull it off), (note that this includes the 11m US CB band), I have to do some regulatory stuff if bringing it to market but there is nothing (except cost, paperwork and lack of profit in that market) stopping me putting that box on the market.If a customer from the US buys the thing, and decides to import it into the USA, that is their issue, and if it gets curb stomped by the customs at the behest of the FCC for being an illegal CB amplifier, or while in use for failing to meet one of their limits, that is a legal risk for the importer, not me. Of course if the importer is a thinly disguised agent of the manufacturer then things get messy (See US Vs HobbyKing).If someone is importing far eastern HTs and selling them locally then the FCC should absolutely bring the hammer down, especially if they are being sold as anything other then ham radio kit (Hams are generally allowed to buy non compliant kit on the assumption that we know enough to put it right before putting it on the air). It is possible for a radio to be compliant for ham use but not for example for FRS or maritime or whatever, and sometimes this is more then just a paperwork matter.If a ham wishes to import experimental kit that is not certified, there is a way to do that, Apache labs had to use it with their HPSDR boards for a while.Regards, Dan.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: November 05, 2018, 07:28:23 pm
content: After several authorities took chinese radios out of service, I don't buy that stuff anymore, but it also doesn't really interest me.clearly 25khz bandwidth is too much, at least on HF and VHF; as far as I just remember, first starting on 70cm is more than 12,5kHz, somebody correct please if I'm wrong.There was once an SSB-module available on ali but I read it had, like many other electronic modules severe design flaws; so in the end, there is a lot of work to invest to get such a module to specs - I guess it's easier to design from the scratch

author: cdev
author_rank: Super Contributor
timestamp: November 05, 2018, 07:32:06 pm
content: I'm not concerned about reselling, I just want to know if its legal for me when I am licensed, to buy a low power, inexpensive Far Eastern HT - like a Baofeng, possibly directly, and use it totally in a FCC-compliant way, within the 2 ham bands it covers, and with as much due dilligence on my part as to frequency, signal quality, etc as is possible. (I have a frequency counter, and a frequency standard, I have a well stocked parts box and could make any kind of band pass filter. Just a couple of watts, enough to get into my local repeaters would be fine. I don't own a spectrum analyzer and I don't plan on buying one near term unless a used one literally falls into my lap, cheap.)I ask because at least as far as UHF/VHF equipment, the price differential is so large and the expected use I see for myself, just ragchewing with local hams, is not at all demanding of an expensive rig, it just isn't.Also, there dont seem to be a lot of hams in my area who are active. At least I rarely hear them on my RTLSDR.If there are I have not run into them often. Maybe I just don't know where they hang out (DMR?) but either way, the price differential being huge, I don't see myself spending more than >$100 max on a VHF/UHF FM rig at the start.I don't care about status symbols or its appearance at all. I can even live with a coax and filter box hanging off of it when I use it. I just want it to be a clean signal and legal.HF is a similar story and there its even more important to me to save money because they are even more expensive. But there I may be able to build at least part of my own rig, or build a PA for a QRP rig. I know a lot for a beginner, I think that's almost within my capability, especially if I can build a kit or get some advice from my local hams, who I don't even know yet. I know how to build filters and I think I can make even a home rig a clean rig.To be honest, that looks like the most cost effective route as the sunspot cycle is at its minimum and the higher hand bands not active, I likely could get away with a cheap Soft Rock rig. Maybe I could buy some RF power transistors surplus or from a Chinese provider and save money there too.(even the Far Eastern HF (SSB) rigs I have seen are too expensive for me right now).Quote from: dmills on November 05, 2018, 06:58:18 pm

author: cdev
author_rank: Super Contributor
timestamp: November 05, 2018, 07:52:35 pm
content: Have any of the ARRL or similar trusted publications analyzed the cheap Chinese HTs as to whether their transmit signals are compliant with FCC regulations on transmitting, assuming the frequency is a legal one, and somebody is licensed? I find it hard to believe that they could possibly have become so popular without at least being compliant as far as that goes.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: November 05, 2018, 08:04:06 pm
content: There were reviews and measurements in some QST, the Baofengs are known to be prone of poor harmonic suppression, like the UV-3R and UV-5R - others are not much better.To be sure, I'd buy on the local market and avoid importing. My guess is, that a seller has to follow FCC regulation when importing; so I'd say that can be sure a radio complies to legal specs when bought on the local market; here in Europe it's no problem to buy all those Retevis, Pofung, Baofeng & co. HT locally; they will likely cost some bucks more, but still cheaper than one from the Big 3 from Japan, and saver than direct import.My other guess'd be, that such a radio ends up in the drawer quite quickly; several hams operate a hobby in buying dozens of HT but rarely to never use one; most hams own a HT, but it's just lying around - I'm one of those; ok even my TS2000X is much more idling than my scope and multimeter.Just don't expect too much fun from any HT, it gets quite fast quite boring.Sure the SSN is not great, but some DX always works on 40m and 20m; the last maximum was not very great either; it's also fun to work the lower bands.

author: vk6zgo
author_rank: Super Contributor
timestamp: November 05, 2018, 11:58:45 pm
content: Quote from: cdev on November 05, 2018, 07:52:35 pmWell. I'm not a "trusted publication", but in my last job before retirement, I had access to some decent RF test gear.I'd heard how "bad" the Chinese handheld radios were, so tested my little 2m Quansheng for harmonics, etc.I was pleasantly surprised, the Quansheng at 4watts was better than an iCom IC208H at 5watts.(closest power level I could get)Any "sprogs" on the former were down in the noise floor, whilst the latter had one definitely visible spurious signal ( I hasten to state, still "within spec").In fairness, the iCom is a dual band device, so it would be a bit harder to ensure good spurious suppressionI also have a Baofeng, but it is faulty, so it has never been used.

author: cdev
author_rank: Super Contributor
timestamp: November 06, 2018, 12:14:34 am
content: If we used spread spectrum for everything, with a little bit of thought, all the devices we use for everything today likely could all interoperate and not collide with one another, and spectrum crowding would likely never happen.

author: djacobow
author_rank: Super Contributor
timestamp: November 06, 2018, 02:13:15 am
content: I don't have the equipment to measure, either, but various folks on the internet have measured different Chinese hts and it seems that the cheapest are sort of marginal: marginal pass, marginal fail - but none really egregiously bad.I also noticed that most measurements were done using attenuators connected to their SA's, rather than measuring with the antenna connected. That might make the difference between a close fail and close pass.As for channel bandwidth, in the us on 2m, many repeaters still use 25kHz channels. There's nothing wrong with a radio supporting that.Personally, I think the Chinese gear gets a bad rap, mostly because of an emphasis on flexibility over usability. The quality of the radios I've used have mostly been fine. The bf's are not great, but acceptable. The tyt and anytone have been fine, imho.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: November 06, 2018, 08:49:49 am
content: It's common practice to measure on the antenna outlet and not with an antenna connected to the gear - that's how it is done and all what counts in such a test setup.After all, nobody can assure that people use the right antenna with the needed harmonic suppression.I don't know about the situation in the Americas; but here in Europe, crowded spectrum above 30MHz rarely happens; whenever I scroll over the VHF and UHF bands, there's just silence; outside of contests there is barely anybody out there running a QSO

author: cdev
author_rank: Super Contributor
timestamp: November 06, 2018, 01:45:13 pm
content: As a ham, I would like to have a radio available for those bands for group excursions, hamfests, Field Day, etc. butifthere is not much in the way of usage around here at other times, spending a lot of money on an HT or mobile rig, would be a waste of $$$ until I found myself using it a lot.There may be people on DMR.One thing though, I am into VHF/UHF antennas for fun, to receive, and because of my proximity to NYC and the huge number of people here, I hear lots of interesting non-ham stuff here.And being into antennas I could definitely see myself possibly getting into VHF/UHF DX and homebrew. My current setup just isnt good enough to receive it with any consistency but if I got an antenna up high enough I think that would change substantially, then I could likely get out okay.

author: djacobow
author_rank: Super Contributor
timestamp: November 06, 2018, 04:36:01 pm
content: Quote from: HB9EVI on November 06, 2018, 08:49:49 amDefine crowded. I'm in the San Francisco Bay Area. There are a LOT of repeaters and there is contention for free frequency pairs. A fair bit of effort goes into planning and allocation.Now, does anybody actually TALK on those repeaters, well, that's a different question. In short, no. Except for a few standouts, the vast majority of repeaters are idle the vast majority of the time. A lot of repeaters are vanity projects only.So, is the spectrum crowded? It's a bit of a koan.