Yes he did not say what amp he was using already, if its an unknown one,
might be a good thing to try a well tested one in case he is getting
interference from out of band signals which might explain the most of the
time it works issue.
Brian

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"williamwright" wrote in message
...
On 24/01/2021 18:13, wrote:
We're in a "variable reception" area for Ridge Hill mast, about 20 miles
away. The Humax STB reports a very weak signal on most channels but the
picture is OK for much of the time - the boss would like it to be OK all
the time so I need some advice.
The current aerial is a 16 element Yagi, with a masthead amp and newly
replaced Webro WF100 cable; all connections are good. The house is tall
and the aerial is on a 1m'ish mast attached to a tall'ish chimney
(worryingly, a bit above the lightning conductor!).

From experience of lightning damaged aerials and houses it appears not to
make any difference how high the aerial is relative to the lightning
conductor or anything else. Lighting rarely strikes the aerial direct; if
it does it's fairly obvious because you can't find the aerial or the cable
the next day. Most lighting damage to aerials is caused by a strike to the
building.


It looks like I need to replace the aerial with a higher-gain type so I'm
wondering whether to go for a group A multi-boom type, a Yagi18A, an
XB16A or ... ?

Heavy/big aerials need a strong fixing, and they need to be well away from
masonry or anything else.

Also, the attic has lots of headroom (about 9 feet in the
centre) so, with a higher gain aerial, I'm tempted to try it in the Attic
to make life easier, but have no idea what attenuation the block walls
might cause(?).

No no no no no no no no no no no no no no no no no no no no no no no no no
no no no no no no no no no no no no no no no no no no no no no no no no no
no no no no no no no no no no no no no no no no no no no no no no no
please don't put it in the loft.

I suggest you check the aerial alignment and make sure it isn't near
anything, then fit a masthead amp of moderate gain (at the aerial) and see
what happens. Even if you change the aerial you'll need a masthead amp.

Blakes:

Proception proMHD11M 1-Way UHF Medium Gain Masthead Amplifier; 1 Input; 1
Output-16dB

PROPSU11F 1-Way F-Type Inline Power Supply; 1 Input; 1 Output-12v 100mA

Bill