Does equipment need to be Part 15 Certified to operate legally?

In Canada YES! if it is a marketed product. Only exception is a "kit" or testing a product which is NOT marketed but you have to operate it for experimental or educational purposes only. Using a home built kit used to be in RSS-210 general as it is with the FCC but that seems to have been removed. I don't live in the USA but as I understand(and I could be corrected) a transmitter doesn't have to be certified to use it as long as it operates in accordance with Part 15 rules. Ramsey and SStran marketed transmitters that were not certified in kit form but were legal to use. Not so in Canada.

I did speak to Michelle Bradley on r e c net on Facebook because the subject was brought up about the ASMAX2 am transmitter which is a kit.

I pointed out the specifications on the harmonics and Spurs what brought down to a -60 on the ASMAX2 and the fact that the webmaster of hobby broadcaster has encouraged them to get it certified because he like the transmitter.  So here is what I was told.

It is legal to operate the ASMAX2 so long is the power levels are kept at part 15 compliance. Also observing good engineering practice meaning that if there is a problem with interference you as the operator are responsible for it.

Where it really gets sticky and Technical is the fact that it was a non-certified kit and because it was marketed it could hold them responsible or liable because technically that isn't legal to do in the United States as far as a seller. But the user so long as you observe and obey the rules can operate that transmitter.

Speaking with FCC agents they would rather that you use a certified transmitter. When you begin talking about kits again it's a very sticky situation. You can tell that some agents might not be trained to handle kits therefore if there is a problem where they deem you going over the limits you might not have a leg to stand on whereas a certified transmitter you do have so many days to repair or replace it and show proof of what you've done to rectify the situation that the complaint was about.

I sure hope this helps on the situation because it has been brought up before in different forums.

Its not a matter of agents being trained to handle kits; but rather a matter of a sensible responsible operator making sure his/her gear works properly. That means checking the device first for spurs, distortion etc before making it an active and necessary part of the operation.

There is a reason why SpaceX blows the crap out of their rockets during static tests on the ground (like they did in mid-November). They want to see if they're going to work when they have to. I don't condone blowing up our gear, but prudent testing to assure compliance within parameters is key. If that means checking the web for low-pass filter design and busting out the soldering gun, so be it.

From the user standpoint it does not have to be certified to use.  However it must meet the technical rules.

An FM Part 15 transmitter must be certified to be legally sold.  Most FM transmitters sold today are not certified.  Even if they say they are. Some claim to be compliant. That is not the same as certified.

For AM the rule is max 100 mw into the final. Range and final output are not regulated, but pretty much ARE regulated by means of the input limitation and the combination 3 meter antenna lead + antenna + ground lead (if used) rule.

FM is limited strictly by field intensity. You can be running a kajillion watts into a 10,000 foot antenna and as long as you're getting 250 uV/m at 3 meters from the antenna or less you're legal.  Keep in mind this amounts to a range of a couple hundred feet.

Of course in all cases you still must meet spectral purity standards.

Even if you're running a certified transmitter, if it's putting out too much power or splattering all over the band, it's still YOUR responsibility.  Buying a certified transmitter does not relieve you of operating legally - you can't blame it on the maker or seller of the transmitter.

Whether you're using a certified transmitter, something from a kit, or home made,  if  you get an FCC notice you are expected to reply indicating you've either shut down or taken measures to correct the problem.  And if the latter you need to detail what you've done to fix the issues.

Bottom line is a certified transmitter doesn't guarantee that you're legal. And certified or not, when push comes to shove the operator is still responsible for making sure his operation is legal.

TIB

Here's something about kits and I think Canada is similar(or maybe not)

https://emcfastpass.com/fcc-rules-kits-subassemblies/

It seems that if you get it from a  hobby book or design it yourself and not market it  that you can use it following the rules. If you make more than five of them and you market it like Sean Cuthbert for example it's now manufacturing, marketing, and selling an uncertified transmitter.
But it's illegal for the seller but not for the user! as I understand.
Now in Canada importing any transmitter not approved by Industry Canada is illegal but I don't know if a "kit" would fall in that criteria.
But the main thing seems to be marketed or not.
Can I in Canada purchase an SStran, Sean Cuthbert, transmitter which is a kit and assemble it here and use it?
Artisan seems to know this, maybe he can help me out here?
What about Heathkit back in the 1960s. They were making kits from HI-FI to transmitters and you never heard about this.

A "heads up" observation:  historically the FCC has inspected the installed transmit systems of the operators of AM and FM transmitter and antenna hardware that had been tested by an FCC-approved compliance lab and FCC-certified under Part 15, and went on to cite their operators when those installations/operations did not meet the applicable Rules in Part 15.

This is very true, Rich.  Bottom line is the user is responsible for legal operation.

In the case of FM it's quite difficult for the end user to ensure legal operation as taking accurate field intensity readings requires specialized and not inexpensive equipment.  So to some extent you have to rely on the reliability and reputation of the seller. Unfortunately most sellers of FM transmitters are not reliable or respectable and sell clearly illegal equipment. A simple rule of thumb is the phrases "long range" and "Part 15 FM" never go together.

At least with AM it's possible to test legality with simple tools -- e.g. a common meter and a tape measurer.

When it comes down to it I believe this rule does make sense, since it's real easy to buy a certified transmitter and modify it yourself for greater output, especially in the case of  FM transmitters. When you consider the legal range is so low to begin with so many want to do what they can to increase it. Simply clipping on a piece of wire with an alligator clip for a longer antenna makes a certified FM transmitter illegal.  Not to mention the many units with power adjustments on them... I tested several "Whole House" transmitters where higher power settings were available right on the panel menu and a longer antenna came in the box, both for "outside the USA use" and the only mention in the manual is basically "make sure you're operating within your local rules".  The C. Crane transmitters I tested were all legal, but it takes only 2 minutes to look up how to increase the power on the web, open the back, and turn the little adjustment to greatly increase range and make it illegal.

This is not quite as big as an issue on AM, although the simply addition of a long ground lead will make you illegal and greatly increase your range.

TIB

In the company's defense they sell their products to countries outside the US where rules may be less strict so the provision to increase power is there although not promoted in instructions. They can't get it certified for 50 different countries and have it operate at the max allowed for all places. I don't think an FM or AM transmitter is made with certification or meeting the rules applying outside the US or Canada. Everything is based on the FCC mostly. Only the Decade is certified and operates at two different powers depending where it's sold, Canada or the USA. I'm not sure but I don't think Decade will ship outside the US and Canada to a place where it is not certified. But again I'm not sure.