By ‘Aren’t Always Absolute’, I’m referring to how manufacturers wear their product certifications for a product like absolute proof of legit compliancy but it’s nowhere near that absolute.
Example - When a radio first gets it’s TA Cert, it’s pass/fail tends to be based on both the consistency of a submitted sample batch (as far as I know of, single sample based TA certs are very rare these days, hence one reason why lots of low volume stuff never gets a cert.) in terms of an overall tolerance (nominal stability) within the submit batch and that nominal average vs the actual requirements.
So the cert is actually only truely and absolute valid for the exact version/revision as certified. Any post cert issue changes which can affect (and with notably VHF/UHF/SHF, even changing track lengths by mm or less can alter it’s EM/RF capacitive/resistive/inductive/reactive characteristics). So where it’s a matter of a tidy up/simplification/physical rearrangement of non-RF/EM dependent components it’s hardly a TA buster for preproduction materials/process optimisation. That said, it’s still a minefield with VHF/UHF/SHF stuff.
So effectively any change whatsoever that can and under some circumstances definately shift it’s EMC/RF characteristics in a revision should, by strict compliancy rules, require a new certification process to confirm if there’s no change and if changed but still compliant despite altered characterising - need a revised issue revision specific certification.
Now take a look at a lot of stuff out there, especially in the budget sector where there’s a glut of cheap, varied revisions, NOS and current versions/revisions, you could easily find the TA is somewhere between inapplicable because it refers to the original spec or a major revision or two previous or be utter fakery and BS where it’s merely a cloned cert with new submitter/manufacturers details.
Now I’m not accusing all PAC region manufacturers of certification fakery, I strongly believe that the ones who’s products are the original items others clone (often badly) are promoting some valid TAs on some level, it’s every ‘chinese copy’ bandwagon jumping cash-in and re-use/repackaged cheapo cloning manufacturer I seriously hold zero confidence their certs are effectively valid and in a lot of cases were true fakery of the lowest order of forgery skill.
Example - Whilst the TA, where valid, is reliable, it’s often only valid for the feature set as stated by manufacturer for the market in question. Subsequently, this means that a radio with cross band repeater function that may be TA compliant including its CBR function in the market certification was obtained for is good, however, if to bypass issues in other markets, it’s certified on a basis of being simplex operation with low power extender repeater capability as far as intended use goes - then a pass for that purpose/scope of use is valid. However, if the cert was based on say a 25W o/p max when in extender type repeater mode (and that maybe cross band or same band specific or both, any combo could be the case), then you’ll find a valid cert radio for your region will enforce the certified limits for that extender/repeater use - such certified compliancy use doesn’t recognise (commercial and leisure market use) a need for user invoked settings adjustment for correct TA compliant use. So your lovely cheap 50W dual bander with cross band RPTR isn’t necessary legal to use in a RPTR role in your specific market depending on TA or if it is, it may not be compliant if it doesn’t auto restrict Tx level and subsequently the ERP/EIRP when set into it’s Repeater station mode. Now that’s even assuming, where the Radio Service permits repeater usage and/or permits such usage with your sub-tier of license.
So, it’s not hard to see how easily your legit purchased bargain (relatively, as it could be a discounted high end unit or simply a super cheap set) may have certification that’s more suited to clearing up animal fetal waste than be of any legit value towards your maintaining a station within license requirements where those requirements constrains you to specific categories of TA certified gear (most leisure and most commercial/professional use gear requires such).
So be advised, when weighing up options and deciding if you have faith in source and brand and manufacturers in question, that maybe you should dig deeper and ask a lot more questions and demand evidence from those who want to grab your money.
Whilst I respect people avoid it since the reading and interpretation of can be a migraine inducer on a good day (I’m a severe migrane sufferer, so that effect can be double purgatory for me), it’ll so you no harm to understand what the TA for your equipment class requires as once you get a grip on it, it can rapidly help you fish out the legit gear from the certification forgery stuff and actually what elements of features are permitted for market usage - your license tier defines your actual legit usage rights/permissions.
Maybe it’s of zero interest to many, but if you supply or are responsible for sourcing bulk purchases for group and business/commercial use - given fines you actually get charged for breaches include the offenses and per instance of breach scope, a $10000 fine could easily be a life wrecker (financially and psychologically) as much as it bankrupts the operation in question and still doesn’t even address the long term validation and potential non-eligability consequences even if you could just pay up like it’s just a bill.
It’s one of many minefields in serious and commercial usage of radios.
So be warned and consider yourself advised that it’s not all as simple as merely having a proof of cert with equipment meaning all is rainbows and unicorns from here outward.