Teachers' TV is watched regularly by fewer than one in 30 school staff, its first published viewing figures show.
The "core" audience for the station, funded by the Department for Education and Skills at nearly pound;20 million a year, comprises just 25,000 of the UK's school workforce of 800,000. These teachers watch at least four programmes a month, while a further 23,000 watch two to three programmes a month.
Viewing figures submitted to Ruth Kelly, the Education Secretary, this week show that every month an average of 280,000 people, which includes non-teachers as well as teachers, tune into Teachers' TV at least once.
This falls far short of the figures for the supposedly unpopular BBC4, which is seen by seven million a month, and is fewer even than the niche-interest Poker Channel, which has more than 700,000 viewers.
However, Teachers' TV governors say they are pleased with its audience during its first six months and believe it shows the station is proving a cost-effective way to provide teacher training.
Sir Paul Judge, chair of the board of governors, said while the viewing figures might appear small in comparison with other digital channels, it was reaching a higher proportion of its target audience than channels such as BBC4, aimed at a broader segment of the population.
The channel, launched on satellite, cable and Freeview in February, shows a range of subject-specific and general programmes aimed at school staff, including Ease The Load which gives tips on teachers' work-life balance.
Teachers' TV governors said they were pleased with the channel's viewing figures so far as they indicated that more than a fifth of teachers with satellite or digital had tried it. They said that surveys of teachers who watched it showed that more than half were likely to try something they had seen on the channel in their school and that eight out of 10 said it had affected their motivation.
They argued that it was a vastly cheaper alternative to traditional professional training for teachers as the average programme cost pound;2.70 per viewer.
Sir Paul said: "It usually costs about pound;300 to take a teacher out of school for a day of CPD (continuous professional development) and you have to organise cover - then there is travel and expenses and all the other bits and pieces.
"A teacher would cover more in a whole day than they would watching a single programme, but it is still very cost-effective."
The DfES said it was pleased with the response to Teachers' TV, which, although broadcasting 24 hours a day, only shows on Freeview between midnight and 4am.
But Mark Hoban, a Conservative education spokesman, said the channel was an "embarrassing failure".