Total posts : 45366
Seals wouldn’t work on the Rangemaster or ProCaster, as you have to tune them (by opening up the box). For devices such as the Talking House, Talking Sign, etc. it would be OK.
There have been some certified transmitters that the FCC has had problems with due to long ground leads – the 100 mw input to the final stage is only one factor in the equation – the other is that the antenna plus feedline plus ground wire cannot exceed 3 meters. And having an elevated transmitter, grounded even with a short ground wire to a metal structure such as a mast has been deemed illegal in at least one high profile case.
I do agree that using a certified transmitter increases your chances of staying under the radar of the FCC (or whatever the regulatory body is in your country) but some specialized knowledge is still required to run within the rules.