The "public channels (R1)" have disappeared!

I may turn my antenna slowly in those two mentioned directions, sometimes I get channel 2/3.5, etc., but not M6, W9, etc.
Could the antenna (which is 6 years old) have suddenly become defective? Could the small box to which the down cable is connected short-circuit? (What is its role in relation to the antenna and the amplifier?)

Thank you in advance.

Hello
a few comments: a six-year-old antenna doesn't become bad all of a sudden unless it loses too many elements due to a storm (breakage). However, it may be unsuitable in terms of reception; let me explain. First, the number of channels received: a few years ago, the same TDF transmitter grouped channels in UHF (TF1, France 2, France 3, La 5, M6) within a channel range, for example, between 21 and 30. The antenna model used by most installers only covered those channels and poorly or not at all other frequencies. The advent of DTT imposed different choices; at my place, for instance, DTT channels range from 21 to 52, and for that, a wideband antenna is required (like the three-element antennas we see everywhere nowadays). Moreover, and this is important, the power in DTT is different, especially on HD multiplex channels that are quite weak. Therefore, an antenna with more gain, meaning with a larger number of elements, is needed. Lastly, "one train can hide another" (figurative transposition); using an indoor amplifier can deteriorate the signal due to the coexistence of weak and strong signals from the antenna. The "strong" signals saturate the amp, which can no longer "see" the weak ones. It would be necessary to have the ability to adjust the channel levels (balancing) before amplifying, as is done with collective amplifiers (which are understandably quite expensive). The ball is therefore in the court of an installer who can find a solution for you. Alone and not a specialist in the subject, you won't be able to do anything good!
One last word regarding your remark about the variable directionality of antennas: it may be possible to pick up another transmitter? **Would it be received better at your place? That is a question to ask an installer too, as he knows the characteristics of these transmitters near you. You'll have to go through that to achieve satisfaction because it's not simple at all!
good luck
** check this out and provide the postal code of your location:
www.tousaunumerique.fr

Hello Bernorenard,

The explanations you've given me, I've "internalized" in my research, and it's clear that the antenna is the issue:
a) when I got back on Monday, all my channels were there (at least the ones I flipped through... for 45 minutes). And the next day, I found myself in the situation described in my post: 15ch/21.
I did an auto search on my main TV, and it's still the same. I then checked my two other TVs, and the same channels were missing.
I connected one TV directly to the antenna cable (without an amplifier, so only the antenna and its cable remain), and I still only have... the same channels.
I rotated the mast, and that's when I saw the obvious: within 2cm, I could clearly receive either one set of channels or the other, but never all of them, with some being clearer than others. It was either "all or nothing."
I decided last night to get an antenna, and on the first try, oriented it as originally, ALL the channels were present.
This morning, I opened the small box - the connection on the antenna, and I noticed there was a tiny circuit board inside: it seems to have a broken filament...

Finally, it works, and that's the main thing. The antenna technician would have also replaced the antenna at no charge... but at what price? Including the trip and troubleshooting?

P.S.: I received the link you proposed, and they only "offered to send me the state's request for the €250 for the difficult TNT coverage (off-topic here) for a "detailed antenna technician report...," being a taxpayer myself, I prefer to refrain from this process, which I would pay for myself.

Hello
excellent approach, you found the solution to your problem. What worried me was the amplifier. I had some issues with two or three indoor amplifier models, all of which saturated on the strong channels and of course, I couldn't see anything anymore. A friend who installs antennas showed me a professional amplifier with adjustable channel filters at the input. I won't tell you the price; it's for a collective installation. The solution for me was to set up a more powerful antenna (N X higher elements) and it works well without an amplifier with a six-way splitter in case of an occasional TV relocation in the house.
Have you figured out the mystery of antennas in two directions on your side?
The website "Tous au Numérique" doesn't bother much and offers you the satellite solution (for difficult reception), what they don't understand is that despite possible aid depending on resources, the satellite installation is worth at least one more zero, but only for one TV. What I thought and is possible is to gather information about the location of your transmitter(s) that you are capable of receiving.
Best of luck
Cheers

Good evening,

For these 2 antenna directions, even the nearby residents/neighbors concerned do not know the explanation from the technician who set it up for them (or they don't remember!). It's only 60m from our door, in the same housing development, 13km from Rennes. The only transmitter I know of is in "BECHEREL".

Have a good evening and thank you again.

already discussed in the TNT forum:

https://forums.commentcamarche.net/forum/affich-30701099-tnt-gratuit