Hi to all,
Hi LuRaichu,
a consumer grade VHF TV modulator is a "dirty" device :
For one, it uses full dual-sideband modulation vs a Broadcast quality unit like the Blonder-Tongue generates a Vestigial sideband TV signal which is compliant with broadcast standards.
What this means in practice, is that a consumer grade unit will "pollute" the channel below & above the selected channel.
Furthermore, consumer units have no or minimal RF filtering of the output. Fine for connecting by cable or very low power local transmission but amplify THAT to 5 or 10W of RF power you may seriously pollute the RF spectrum at frequencies very far from your intended channel.
Example : Ch 2 is in the 45-50MHz band, have some spurious output at harmonic 2 in the 110-136MHz aircraft band = guaranteed pronto visit by FCC & police (interference to aircraft comms).
Anyone interested in significant RF power output (beyond 1W) should have a spectrum analyzer to ensure "cleanliness" of his signal.
Units like the TinySA Ultra are a revolution; for 120$ you achieve more/less what a HP analyzer did for 20-50k$ 30 years ago.
Note : buy it from a SERIOUS source, most Ali-Express/E-Bay units are fake copies.
https://tinysa.org/wiki/pmwiki.php?n=Main.HomePage
There is a "where to buy" page.
in the 90s, i used professional modulators & Avantek or Minicircuits RF power amps with 1W power.
Avantek is defunct but MiniCircuits is still alive & well :
https://www.minicircuits.com/product...mplifiers.html
I don't know what's your project (pirate TV for an entire town?) but a 100mW BT modulator of the AM-60 Series comfortably covers a house/property. They are still cheap & cheerful secondhand on E-Bay.
Many of us here use them as low power personal TV transmitters.
Blonder-Tongue AM-60 Series search on E-Bay/PicClick:
https://picclick.com/?q=Blonder+Tongue+AM60%2A
Best Regards
jhalphen
Paris/France
Avantek UTC SEries wideband RF amplifier Series spec sheet.