There are different issues with phone and television.

With regard to telephones, harmonic output of the transmitter makes little
difference. The phone is acting as an untuned crystal set. It is simply
defective design based upon mass production. It does not make any
difference what type of transmitter is being used, nor what frequency it is
on (generally). Interference is caused because the telephone has no
rejection. Interference can be reduced by moving the transmitting antenna
away from the telephone and telephone lines and/or by preventing the rf from
getting into the telephone. Interference filters are sold for telephones
that work in most (but not all) cases. Also, ferrite clamp ons may help.

The television is a bit different. Most likely, the same problem as
outlined above applies to televisions, also. But, if the affected
television uses an antenna (rather than cable or satellite), then harmonics
could be involved. Since older tube rigs were not required to meet as tight
of harmonic specs as the newer solid state rigs, it is possible that older
tube rigs might be more likely to cause interference to television sets.

In most cases, it is the television that is the problem, rather than the
transmitter. A more modern tube transmitter would be about the same as a
solid state transmitter in terms of liklihood to interfere.

Colin K7FM