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Hissy FM from Rowbridge
For quite a while now I have noticed that FM from Rowbridge
on the Isle of Wight seems to be more hissy than the previous 38 years. It seems to be worst on 88.50 Mhz, which is R2. I used to have an Aiwa AX7400 receiver which was utterly brilliant at receiving FM and the signal strength meter showed a good signal where I live, about 50 miles north east of the transmitter, but slightly hidden by the South Downs. My Onkyo replacement has no signal strength meter so all I have to go on is what my ears are telling me. It was fine from 2006 to about 2014 (subjective assessment). How do we know if the transmitter has been downgraded to save on power ?, (and to 'persuade' people to switch to the awful DAB) ?. Apart from hiring some expensive measurement kit, how could I measure what I am receiving these days ?. |
Hissy FM from Rowbridge
In article , Andrew
wrote: For quite a while now I have noticed that FM from Rowbridge on the Isle of Wight seems to be more hissy than the previous 38 years. It seems to be worst on 88.50 Mhz, which is R2. I used to have an Aiwa AX7400 receiver which was utterly brilliant at receiving FM and the signal strength meter showed a good signal where I live, about 50 miles north east of the transmitter, but slightly hidden by the South Downs. My Onkyo replacement has no signal strength meter so all I have to go on is what my ears are telling me. It was fine from 2006 to about 2014 (subjective assessment). What arrangements do you have as the antenna, etc? My first reaction to your question is to wonder if something about your antenna or the downlead has altered. e.g. bent or rotated antenna, or water getting in the cable. That sort of thing happens over time. How do we know if the transmitter has been downgraded to save on power ?, (and to 'persuade' people to switch to the awful DAB) ?. Pass. For all I know some other distant TX has started up at a frequency near to the one(s) you want, and the RF section of your tuner has wound down its gain in response. But I suspect the likely cause is near to you rather than far away. Could simply be your tuner's IF alignment drifting. No idea about any relevant change to Rowridge, though. Apart from hiring some expensive measurement kit, how could I measure what I am receiving these days ?. What you'd really need is to measure now wrt an earlier time if you want to see if the level has altered. There are cheaper way to measure the levels than buying/renting a calibrated spectrum analyser or filtered meter. But they tend to involve you finding your own was to calibrate if you want reliable power values rather than "the more the better" comparisons of what you are currently getting. Can you try a different FM tuner that is known to work OK in general, and which has a useful level meter? Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html Audio Misc http://www.audiomisc.co.uk/index.html |
Hissy FM from Rowbridge
I'd not say the drift is the cause. Most receivers of the vintage noted are
pretty good. As its changed over time far more likely to be aerial related. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please! "Jim Lesurf" wrote in message ... In article , Andrew wrote: For quite a while now I have noticed that FM from Rowbridge on the Isle of Wight seems to be more hissy than the previous 38 years. It seems to be worst on 88.50 Mhz, which is R2. I used to have an Aiwa AX7400 receiver which was utterly brilliant at receiving FM and the signal strength meter showed a good signal where I live, about 50 miles north east of the transmitter, but slightly hidden by the South Downs. My Onkyo replacement has no signal strength meter so all I have to go on is what my ears are telling me. It was fine from 2006 to about 2014 (subjective assessment). What arrangements do you have as the antenna, etc? My first reaction to your question is to wonder if something about your antenna or the downlead has altered. e.g. bent or rotated antenna, or water getting in the cable. That sort of thing happens over time. How do we know if the transmitter has been downgraded to save on power ?, (and to 'persuade' people to switch to the awful DAB) ?. Pass. For all I know some other distant TX has started up at a frequency near to the one(s) you want, and the RF section of your tuner has wound down its gain in response. But I suspect the likely cause is near to you rather than far away. Could simply be your tuner's IF alignment drifting. No idea about any relevant change to Rowridge, though. Apart from hiring some expensive measurement kit, how could I measure what I am receiving these days ?. What you'd really need is to measure now wrt an earlier time if you want to see if the level has altered. There are cheaper way to measure the levels than buying/renting a calibrated spectrum analyser or filtered meter. But they tend to involve you finding your own was to calibrate if you want reliable power values rather than "the more the better" comparisons of what you are currently getting. Can you try a different FM tuner that is known to work OK in general, and which has a useful level meter? Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html Audio Misc http://www.audiomisc.co.uk/index.html |
Hissy FM from Rowbridge
Andrew wrote:
------------- For quite a while now I have noticed that FM from Rowbridge on the Isle of Wight seems to be more hissy than the previous 38 years. It seems to be worst on 88.50 Mhz, which is R2. I used to have an Aiwa AX7400 receiver which was utterly brilliant at receiving FM and the signal strength meter showed a good signal where I live, about 50 miles north east of the transmitter, but slightly hidden by the South Downs. My Onkyo replacement has no signal strength meter so all I have to go on is what my ears are telling me. It was fine from 2006 to about 2014 (subjective assessment). How do we know if the transmitter has been downgraded to save on power ?, (and to 'persuade' people to switch to the awful DAB) ?. ** That is pure paranoia. Apart from hiring some expensive measurement kit, how could I measure what I am receiving these days ?. ** All you need is another, known hiss free receiver ( or just a tuner) to try. After nearly 40 years, the odds are very high your low signal level is due to one or more a common antenna problems - a result of the damaging actions of rain, wind or birds. Also check your internal antenna wiring, splitters and down leads for corrosion and loose contacts. If in doubt, renew the lot. ..... Phil |
Hissy FM from Rowbridge
The use of the term "most" noted. :-)
The point here is that "most" simply accepts that "some" may do so, and they will be the instances someone will them find gives them a problem. Thus - perhaps - asking for advice. Even "a few" when many thousands were made can mean some will. But - as per my first posting - the stats indicate that an antenna or downlead degraded by water, birds, etc is more likely. Followed by some other change in reception conditions - change in multipath, or a new TX in the same tuned RF band, etc. Jim In article , Brian Gaff wrote: I'd not say the drift is the cause. Most receivers of the vintage noted are pretty good. As its changed over time far more likely to be aerial related. Brian -- Please use the address on the audiomisc page if you wish to email me. Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html Audio Misc http://www.audiomisc.co.uk/index.html |
Hissy FM from Rowbridge
In article ,
Jim Lesurf wrote: e.g. bent or rotated antenna, or water getting in the cable. That sort of thing happens over time. Cable problems of one sort or another are very common - especially since so many aerial fitters used the cheapest stuff they could find. Also the connection box at the aerial very rarely stays 100% weatherproof for ever. -- *It was all so different before everything changed. Dave Plowman London SW To e-mail, change noise into sound. |
Hissy FM from Rowbridge
On 02/02/2018 09:34, Jim Lesurf wrote:
The use of the term "most" noted. :-) The point here is that "most" simply accepts that "some" may do so, and they will be the instances someone will them find gives them a problem. Thus - perhaps - asking for advice. Even "a few" when many thousands were made can mean some will. But - as per my first posting - the stats indicate that an antenna or downlead degraded by water, birds, etc is more likely. Followed by some other change in reception conditions - change in multipath, or a new TX in the same tuned RF band, etc. Jim In article , Brian Gaff wrote: I'd not say the drift is the cause. Most receivers of the vintage noted are pretty good. As its changed over time far more likely to be aerial related. Brian The irritating chattering and buzzing that affected 88.50 Mhz disappeared after a few hours. Mystery. The worst of the hissing must have been my loft-mounted FM 3 element horizontal aeriel because the cap that seals the connectors is missing. The humidity levels in the loft vary with the seasons and weather, being ventilated and the connectors needed a good clean with some wire wool. All ok now, though still some hiss which I never used to get with my old AIWA 7400. I should have kept it, it had a signal strength meter which showed an obvious reduction when there were aeriel issues. I've been looking at this site :- http://aerialsandtv.com/fmanddabradio.html And I didn't realize that I could have an external vertical half-wave dipole that would work quite well for FM and DAB, since Rowbridge has mixed polarity. The reason I avoided having an external FM aeriel before was because we have a large flock of rooks locally who patrol all the bird tables. They are big birds and seem to like bouncing up and down on aeriels. |
Hissy FM from Rowbridge
Andrew wrote:
---------------- The irritating chattering and buzzing that affected 88.50 Mhz disappeared after a few hours. Mystery. The worst of the hissing must have been my loft-mounted FM 3 element horizontal aeriel because the cap that seals the connectors is missing. The humidity levels in the loft vary with the seasons and weather, being ventilated and the connectors needed a good clean with some wire wool. ** Loft mounting is still essentially an indoor antenna with all the associated drawbacks. The antenna is close to multiple sources of interference in the house, has no line of sight over other roofs and whenever the roof material becomes wet, it acts like an RF shield. As you live "50 miles" from the FMTX and are "slightly hidden" by terrain PLUS you chose a low gain 3 element antenna the signal level has always been marginal - at best. ..... Phil |
Hissy FM from Rowbridge
On 03/02/2018 06:25, Phil Allison wrote:
Andrew wrote: ---------------- The irritating chattering and buzzing that affected 88.50 Mhz disappeared after a few hours. Mystery. The worst of the hissing must have been my loft-mounted FM 3 element horizontal aeriel because the cap that seals the connectors is missing. The humidity levels in the loft vary with the seasons and weather, being ventilated and the connectors needed a good clean with some wire wool. ** Loft mounting is still essentially an indoor antenna with all the associated drawbacks. The antenna is close to multiple sources of interference in the house, has no line of sight over other roofs and whenever the roof material becomes wet, it acts like an RF shield. Being in the loft, it's likely to be a lot larger than an indoor aerial, purpose built for the job (although maybe not the best choice here), and have a better aspect. So, while far from perfect, likely to work better than an indoor aerial. I lashed one up in my old house - went from practically nothing to 100% on all channels (according to the Freeview box's meter) Didn't know about the RF shield bit. -- Cheers, Rob |
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