All posts by Desperate
Below are all of Desperate's postings, with the most recent are at the bottom of the page.
Attenuator.
Currently have masthead amp.
Assuming after 18th, too much signal, which make attenuator would be best suited for use at at the digibox input end. Don't want to mess around with aerial end if possible. Or if I cut off the power to the mast head amp, will the signal "pass though" un-amplified so that an attenuator would not be necessary?
Tks
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Crystal Palace (Greater London, England) Full Freeview transmitWednesday 18 April 2012 8:03AM
Stansted
CM24 8DL - Stansted. Rooftop wideband aerial horizontal + masthead amp- std coax in house. Analogue TV. DVD HDD recorder Panasonic DMR EX75 with digital tuner inbuilt & Sony digibox VTXD800 which feeds TV. Scart connections. Aerial path first to Panasonic and then looped through to Sony and then to TV. All retuned successfully. PROBLEM - Tuner sensitivity of Panasonic is less than Sony so it appears that on the Sony we are possibly overloading on the D3+4 mux so that ITV and ITV+1 (and possibly the others) are dropping out periodically. Otherwise all OK on other channels so far. Switching off masthead amp gives no signal at all - no pass through. Should I try and attenuator on the aerial loop from the Panasonic to the Sony to dampen its enthusiasm? Thoughts appreciated.
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Crystal Palace (Greater London, England) Full Freeview transmitThursday 19 April 2012 7:56PM
Stansted
Technical questions please.
1) When looping the aerial feed through a HDD/DVD recorder to a good quality digibox, does the signal to the digibox get amplified or reduced and by how many dB. I seem to have read somewhere that a + 3 db could occur?.
2) By what % does a 12 dB attenuator reduce the signal . By 90%?
3) With a 2 way passive splitter, is the signal split 50/50 assuming minimal down line coax cable
Tks.
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Freeview intermittent interference | Freeview InterferenceWednesday 1 November 2017 12:02AM
Stansted
CM24 8DL postcode. Gable end aerial. Wide band, mast head amp. Crystal Palace Transmitter, Mobile masts due south 1 Km Tall trees due south 0.1km
Current aerial need replacement. Normal non HD channels normally good strength (60%).. HD channels poor
However this evening normal channels no signal to very poor. No CP engineering reported .
A) atmospherics??
B) In choosing new aerial , with coming changes 2018, what should I go for ?? Log periodic A ??
Thanks
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MikeP:
Thanks for the feedback.
Still had problems later that morning, vast majority of channels 0%. Signal matters resolved by a) blank (aerial unplugged) re-tune followed by aerial in retuning both HDTV and DVR. Not sure whether "atmospherics" miraculously righted themselves in the 20 or so minutes taken to carry out the procedures, OR whether something caused the tuning to go out ( aerial/mastehead amp wise) Had checked power supply to masthead amp and was OK.
Anyway sorted for the moment, if anything signal stronger ;).
Re new aerial, will take your suggestion re long log periodic, as it will have far less wind drag factor than the "Chip Pan" Televes wide-band I have at the moment, that has started to fall apart after many years use. The local pigeons appear to use it as a copulation point!!
Will also look out for an LTE version of of the LogP as mobile masts have started to accumulate in some ground nearby ( <1 km)
Thanks again for your help.
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Attenuators, Crystal Palace transmitter- Gable end Televes aerial..
Signal from masthead amp loops through DVR to HD TV. . It seems signal is boosted by the DVR as a result of the loop though.
DVR signal strength all channels circa 45%, Quality 100% - Very rarely use HD.
HDTV Signal strength all channels circa 90%+ ,Quality 100% - Sometimes lose channels - Overload??
Can not loop through HD TV to DVR. So attenuator needed between the DVR and HDTV.
What -db size of attenuator should I aim for. Thank you
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StevensOnln1:
Thanks for the input.
Your suggestion re:-
A) connecting after mast amp direct to HDTV ( i.e. not looping through DVR) results - very little, if any change, to Signal Strength (High 90s%) & Signal Quality. 100% .
B) On reconnecting to the DVR ( loop through), there was only a DVR setting to switch on or off the loop connection to the TV.. No means of adjusting any strength on loop output.
From the above, quite surprised that the signal strength for the various channels reported by the DVR is so much lower , compared to those obtained by the direct connection to the HDTV.
So off to ebay to get an attenuator. Do you think a variable one would be OK, save having to buy two of different -db values. Also as I am going to have to renew the aerial - (latter beginning to fall apart - result copulating pigeons, corrosion etc. ) , a variable attenuator might give greater flexibility??
Thanks again for your help/feedback.
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MikeB:
Thanks for the suggestion. My concern is that splitting at the wall will lower the signal to the DVR which is already at circa 55% . However this could be due to the tuners of the DVR being less sensitive than the tuner of the HDTV..
However, I will give it a try and see what happens, I think I have enough bits a pieces to rig your suggestion up.
I will let you know. Thanks.
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Wednesday 22 February 2012 9:32PM
Stansted
4G interference - need for filters or worse.
Anyone know what this is likely to mean for Crystal Palace transmission. - Stansted CM24 8DD