This weekend I replaced my existing Fringe MHA / PSU with a Triax combination.
Whilst 'up there' I increased the aerial incline from about 3 degreees to between 10 and 15 (thanks for that tip, Roxof). This was done not only to try and reduce traffic induced interference but also to aim over the top of a large tree in the path of the transmitter. This angle change doen't seem to have had any impact on signal strength or quality.
My time viewing has been minimal, but initial observations show that moped interference has not been eliminated, but still is a great improvement on my untouched original set up. The improvement between the changeover fron Fringe to Triax gear is not vast, but on paper there is an improved (lower) noise rating and screened MHA which can't be a bad thing... I still get the occasional see-sawing on signal strength (and quality) - a total mystery that one
Channel 5 on terrestial is still very poor, but the ghosting on other channels appears less pronounced. ITV still looks 'soft' focus wise (if that makes sense).
I've reached the stage now where I feel no more can be done at the aerial end. I guess any interference pick up now will be through the existing low loss cable that runs downside of the screened Maxview distribution amp. To replace all seven runs will be a daunting task, but probably worth it when time (and inclination) allows.
I think I was a bit premature with my findings on the latest Triax install. An evenings viewing last night showed that I've made the setup more prone to impulse interference than before
I have to say that the Triax MHA, which has saddle clamp terminations, didn't seem that 'installer friendly'.
Unless I was missing something, I couldn't see an obvious way to lift the internal screened assemby clear of the plastic housing to aid wiring. I had no choice but to push the 'bared' coax through the grommet which sits immediately in front of the termination.
This meant that a only tiny amount of braid (due to lack of working space) was available to clamp onto. I know that the terminations sit in a pressed tin box but I'd have preffered a greater quantity of braid to contact the clamp.
At least the Fringe MHA allowed for the circuit board to be lifted away from the housing for connecting.
As a follow on from your advice about incline ange to reduce impulse intereference, would I be right in assuming that this applies to positions where traffic passes in front of the aerial?
In my case, vehicles travel across the rear of the aerial - does the same advice/rule apply? I now have a jaunty 10-15degree tilt.
Bearing in mind the road position, could this large rise (plus the average MHA connection) make the setup more prone to impulse interference?
Hmn, not sure why the interference has become worse - it might just be that the signal is currently on the low side, the weather being what it is. As long as there's a reasonable amount of braid contact it probably isn't the connexions.
Upward angling is rather a suck-it-and-see thing - yes, it's potentially effective where the road is in front of the aerial, but the deep null behind is the best place for a road - i.e. the body of the reflector shielding the active element from as much road as possible, other things being equal.
.....the deep null behind is the best place for a road - i.e. the body of the reflector shielding the active element from as much road as possible.....
:cool:
Roxof,
Does that mean that the incline angle in my case would have little/no effect?
The deepest null is directly behind the element train, so "pointing" that at the road to some extent, i.e. angling up, can still help.
Perhaps you suspect that the signal is being diminished by doing so - that's possible although, as we discussed, the field distribution and hence the apparent direction of strongest signal is likely to be complex at your location.
It's a matter of trying all of the possibilities - even, perhaps, a rotation of polarisation (i.e. no harm in turning the elements to 45 degrees or even vertical as an experiment - although that probably won't work on all multiplexes).
.....Perhaps you suspect that the signal is being diminished by doing so.....
:cool:
Hi Roxof,
I understand from what I've seen through experimentation that the signal strength does not seem to suffer with increase in inclination (to a point). I merely wondered if this extra tilt exposed the aerial to rear impulse interference pickup.
As you say, some further experimentation in incline etc. may be in order - other than time and effort, all it's costing me is electrician tape for binding downlead to pole! :rolleyes: (I'm also getting grief about all the other DIY jobs that are being neglected..... )
Comments
As posted earlier, my time is free, so I'm only forking out for the hardware fortunately (around £69 to date including my ordered Triax MHA & PSU) .
IMHO all this experimentation is worth while as the time spent tweaking is significantly small compared to the years spent viewing.
At least if things aren't ultimately perfect, I can take comfort in the knowledge that I've investigated every avenue...
Very true, I await you results with baited breath
henry
Hi Roxof, efo,
This weekend I replaced my existing Fringe MHA / PSU with a Triax combination.
Whilst 'up there' I increased the aerial incline from about 3 degreees to between 10 and 15 (thanks for that tip, Roxof). This was done not only to try and reduce traffic induced interference but also to aim over the top of a large tree in the path of the transmitter. This angle change doen't seem to have had any impact on signal strength or quality.
My time viewing has been minimal, but initial observations show that moped interference has not been eliminated, but still is a great improvement on my untouched original set up. The improvement between the changeover fron Fringe to Triax gear is not vast, but on paper there is an improved (lower) noise rating and screened MHA which can't be a bad thing... I still get the occasional see-sawing on signal strength (and quality) - a total mystery that one
Channel 5 on terrestial is still very poor, but the ghosting on other channels appears less pronounced. ITV still looks 'soft' focus wise (if that makes sense).
I've reached the stage now where I feel no more can be done at the aerial end. I guess any interference pick up now will be through the existing low loss cable that runs downside of the screened Maxview distribution amp. To replace all seven runs will be a daunting task, but probably worth it when time (and inclination) allows.
Many thanks for all the guidance,
¬Emm
:cool:
Hoping that the results are at least tolerable and perhaps mopeds will go out of fashion or switch to diesel or something :rolleyes:
:cool:
Hi Roxof,
I think I was a bit premature with my findings on the latest Triax install. An evenings viewing last night showed that I've made the setup more prone to impulse interference than before
I have to say that the Triax MHA, which has saddle clamp terminations, didn't seem that 'installer friendly'.
Unless I was missing something, I couldn't see an obvious way to lift the internal screened assemby clear of the plastic housing to aid wiring. I had no choice but to push the 'bared' coax through the grommet which sits immediately in front of the termination.
This meant that a only tiny amount of braid (due to lack of working space) was available to clamp onto. I know that the terminations sit in a pressed tin box but I'd have preffered a greater quantity of braid to contact the clamp.
At least the Fringe MHA allowed for the circuit board to be lifted away from the housing for connecting.
As a follow on from your advice about incline ange to reduce impulse intereference, would I be right in assuming that this applies to positions where traffic passes in front of the aerial?
In my case, vehicles travel across the rear of the aerial - does the same advice/rule apply? I now have a jaunty 10-15degree tilt.
Bearing in mind the road position, could this large rise (plus the average MHA connection) make the setup more prone to impulse interference?
Many thanks,
¬Emm.
Hmn, not sure why the interference has become worse - it might just be that the signal is currently on the low side, the weather being what it is. As long as there's a reasonable amount of braid contact it probably isn't the connexions.
Upward angling is rather a suck-it-and-see thing - yes, it's potentially effective where the road is in front of the aerial, but the deep null behind is the best place for a road - i.e. the body of the reflector shielding the active element from as much road as possible, other things being equal.
:cool:
Roxof,
Does that mean that the incline angle in my case would have little/no effect?
The deepest null is directly behind the element train, so "pointing" that at the road to some extent, i.e. angling up, can still help.
Perhaps you suspect that the signal is being diminished by doing so - that's possible although, as we discussed, the field distribution and hence the apparent direction of strongest signal is likely to be complex at your location.
It's a matter of trying all of the possibilities - even, perhaps, a rotation of polarisation (i.e. no harm in turning the elements to 45 degrees or even vertical as an experiment - although that probably won't work on all multiplexes).
:cool:
Hi Roxof,
I understand from what I've seen through experimentation that the signal strength does not seem to suffer with increase in inclination (to a point). I merely wondered if this extra tilt exposed the aerial to rear impulse interference pickup.
As you say, some further experimentation in incline etc. may be in order - other than time and effort, all it's costing me is electrician tape for binding downlead to pole! :rolleyes: (I'm also getting grief about all the other DIY jobs that are being neglected.....