The River Getting Boosters?

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  • Posted In: Boston

  • #140011

    Below are links to maps from FCC Data.org of the four proposed on-channel boosters that would rebroadcast WXRV-92.5, giving it a better signal in Metrowest and (for one of the boosters) Downtown Boston.

    It should be noted that these are applications, and not approvals.

    WXRV-1 (city of license Framingham; transmitter ion Natick):

    http://www.fccdata.org/?facid=198698

    WXRV-2 (city of license Dover; transmitter in Waltham):

    http://www.fccdata.org/?facid=198697

    WXRV-3 (city of license Newton; transmitter in Lexington):

    http://www.fccdata.org/?facid=198696

    WXRV-4 (city of license Boston; transmitter in Charlestown):

    http://www.fccdata.org/?facid=198695


    Member
    #140108

    Now THIS is fascinating stuff. There’s been a lot of talk and small-scale experimentation with SFN’s (Single Frequency Networks) but I’m not sure anyone has tried it at quite this big a scale AND in this major a market.

    Conventional wisdom is that you don’t use boosters unless there’s significant terrain shadowing that protects your main signal from self-interference by the booster. Recent advances in SFN’s have allegedly *mostly* eliminated that problem. But the devil’s in the details: it’s impossible for a moving receiver to maintain the desired/undesired ratios between the main and the booster’s transmissions in order to keep the receiver from going nuts trying to “lock on” to the “correct” desired signal. The idea of an SFN is that every signal is so identical that it doesn’t matter. But that’s the theory. In reality, well, there’s multipath. For digital signals like HD Radio, you can largely get around that thanks to the delay…even a few milliseconds…that gives a receiver time to compare the two signals and pick the “right” one, but for analog I’m not entirely sure that it really works as well as advertised.

    I recall about 2, maybe 2.5 years ago Harris (now GatesAir) released a really cool FM booster system that could use over-the-air reception of the primary to create the booster signal. You needed to mount the RX and TX antennas with a proper amount of separation, but just that it was possible AT ALL was nifty as hell.


    Participant
    #140123

    Though this will give WXRV improved coverage near each repeater, I think it will cause severe multipath distortion in many areas around greater Boston and metro-west when between repeaters, or where the strength of a repeater is not stronger than the much more powerful (but distant) parent signal from Haverhill.

    WXRV doesn’t have HD radio even on their parent signal, but should they decide to adopt it I don’t think it would necessarily help in many situations here because I find that HD radio doesn’t always react to multipath by picking the best signal, it more often becomes completely unable to process the multipath signal and the radio defaults to the main analog signal(s) on an HD1 channel, and often simply goes silent on HD2 and HD3 channels because there is no analog of those channels behind them.

    But, I guess when there’s no way of moving their primary signal closer to their target market, a network of low-power repeaters will have to do.


    Member
    #140124

    Anyone looking to do this might want to consider WUMB’s experience doing it with sites in Qunicy, Paxton, and Falmouth, all on 91.9.

    In particular, take a drive out the Pike from the Weston tolls to 495, listening to 91.9.


    Participant
    #140125

    Anyone looking to do this might want to consider WUMB’s experience doing it with sites in Qunicy, Paxton, and Falmouth, all on 91.9.

    In particular, take a drive out the Pike from the Weston tolls to 495, listening to 91.9.

    I was also going to mention that WUMB example, but it’s a bit different because WUMB’s are all full-power Class A signals spread farther apart, not closer low power (100 watt max.) repeaters like WXRV is proposing, but it’s a similar phenomenon.

    #140174

    Wouldn’t WXRV-92.5 get better luck in Boston and points south by buying WPLM-99.1 in Plymouth??

    Buying WPLM would give “The River” a strong signal, on various frequencies, from Cape Cod all the way up to the White Mountains.

    Besides the proposed boosters, WXRV-92.5 has one translator (W243DC-96.5) now on the air, which is licensed to Needham, and has a good signal in Needham, Newton, Wellesley, Brookline, West Roxbury (a neighborhood of Boston for the benefit of those who are out of the area), and Dedham.

    It transmits from 499 feet above the ground/650 feet above sea level (I think that’s from the top of the short self-supporting tower next to the “Candelabra” at the Needham antenna farm).

    With a better FM radio, this translator can be heard in Norwood, Dover, Milton, Watertown, and Waltham. Downtown Boston probably gets poor reception, if at all.

    W243DC coverage map:

    http://www.radio-locator.com/cgi-bin/pat?call=W243DC&service=FXstatus=L&hours=U


    Participant
    #140178

    Wouldn’t WXRV-92.5 get better luck in Boston and points south by buying WPLM-99.1 in Plymouth??

    Why would you assume that the owner wants to sell WPLM, or that the owner of WXRV would have the amount of money he would want?


    Participant
    #140180

    Why would you assume that the owner wants to sell WPLM, or that the owner of WXRV would have the amount of money he would want?

    Because it’s an internet discussion board…and it’s fun to speculate! 😉


    Participant
    #140192

    Why would you assume that the owner wants to sell WPLM, or that the owner of WXRV would have the amount of money he would want?

    Because it’s an internet discussion board…and it’s fun to speculate! ?

    Dear OldNewsGuy,

    I really love this answer! This is what I thought these forums were intended for, but occasionally I see ideas get stomped on simply because they originate with certain individuals, and for no good reason, IMHO.

    Heck, there’s not much enjoyment (from the listener standpoint) left in radio anyway, so why not speculate on what might have been, or what could be, or what should be?

    Thanks for the encouraging words!


    Member
    #140477

    Though this will give WXRV improved coverage near each repeater, I think it will cause severe multipath distortion in many areas around greater Boston and metro-west when between repeaters, or where the strength of a repeater is not stronger than the much more powerful (but distant) parent signal from Haverhill.

    That’s the $64,000 question, isn’t it? Like I said, there’s been a ton of really interesting work done on SFN’s in the last ten years. Allegedly they’ve found ways to largely eliminate the multipath problems you describe. I’ve seen white papers on prototype systems with boosters they’ve done outside of San Diego and it worked surprisingly well. Like, way better than the conventional wisdom on boosters would suggest. But I don’t think it’s ever been tried where the stakes would be THIS high: where the boosters are covering the biggest money demo areas, and in a Top 10 market.

    FWIW, HD Radio performs EXCELLENTLY in high multipath areas. In fact, it works better in high multipath because (thanks to the digital delay) it can aggregate the bits from whatever the strongest RF source is, and sometimes that’s a multipath reflection. But even if WXRV ran HD Radio, and was willing to spend the significant $$$ to make all the boosters be in HD Radio as well (AND be synchronized to each other)…it wouldn’t help one bit about dealing with self-interference on the ANALOG side of things. All the technology about reducing self-interference on the analog side is the “black art” stuff that I was talking about above. Supposedly it works, but I don’t know if it works well enough for WXRV to avoid causing HEFTY swaths of self-interference around the boosters. I guess we’ll see.

    This all assumes that WXRV is buying the latest and greatest technology for their boosters, too. For all we know, they’re just buying regular transmitters and piping the content to them over landlines and they don’t care one whit about self-interference. That in and of itself would also be interesting; that a station would intentional sacrifice a lot of coverage area to zero in on four key locations.

    Also FWIW, assuming for a moment that WPLM wanted to sell, I don’t think WXRV would want to buy. Not if the point is to get better Boston-area coverage which, presumably, is what they care about (just basing that on the fact that they applied for those boosters). Neither signal gets into Boston all that great. If WXRV really wanted Boston coverage, I’d imagine they would’ve ponied up for 101.7FM before iHeart got it. Considering that was a $14mil purchase (IIRC) I would guess it was more than they could afford…and presumably WPLM would sell for at least that much, too, and thus also be unaffordable.


    Participant
    #140489

    FWIW, HD Radio performs EXCELLENTLY in high multipath areas. In fact, it works better in high multipath because (thanks to the digital delay) it can aggregate the bits from whatever the strongest RF source is, and sometimes that’s a multipath reflection. But even if WXRV ran HD Radio, and was willing to spend the significant $$$ to make all the boosters be in HD Radio as well (AND be synchronized to each other)…it wouldn’t help one bit about dealing with self-interference on the ANALOG side of things. All the technology about reducing self-interference on the analog side is the “black art” stuff that I was talking about above. Supposedly it works, but I don’t know if it works well enough for WXRV to avoid causing HEFTY swaths of self-interference around the boosters. I guess we’ll see.

    The HD receivers that I have, of various makes, just lose HD and default to analog when encountering a signal with multipath even when overall station signal strength is pinning the “bars” on the display, and any HD2 or HD3 signals just go silent because they don’t have analog backups. This happens only a few miles from the Class B HD transmitters in Boston in areas where there are any reflected signals from terrain, buildings, etc… reaching the receiver at slightly different times.


    Participant
    #140510

    The HD receivers that I have, of various makes, just lose HD and default to analog when encountering a signal with multipath even when overall station signal strength is pinning the “bars” on the display, and any HD2 or HD3 signals just go silent because they don’t have analog backups. This happens only a few miles from the Class B HD transmitters in Boston in areas where there are any reflected signals from terrain, buildings, etc… reaching the receiver at slightly different times.

    “In this, thou hast answered rightly.”


    Member
    #140539

    We should all try and be civil and respect others opinions. I have been guilty on more than one occasion of posting snarky replies. However, when someone posts an idea or speculates on something that defies, reason, logic or common sense are we expected to stay silent or post gee that would be a good idea.

    WXRV’s signal problems would be solved if they bought 98.5FM but there is no indication that it is for sale. Laurie Campbell has shown no interst in selling WPLM and is actually taking more interest in the station than she has in the past.


    Member
    #140617

    I’d be curious to know more details, because I know the engineering behind HD Radio and I’ve seen the test results with my own eyes: HD Radio works BETTER in high-multipath situations than low- or no-multipath. This is typical for most OFDM transmission methods like HD Radio, among many others. See: http://www.eetimes.com/document.asp?doc_id=1225472

    Plus there’s also empirical evidence from guys I trust. I know WBUR has seen night and day differences with multipath problems on their signal, which are not trivial on their analog signal. And their listeners notice it, too, they have several hundred that immediately start calling/emailing if the HD goes down, hollering about why suddenly there’s all this static on 90.9 as they drive around town.

    Without knowing any details, I’d be inclined to think your experience is not due to multipath but instead something else. Co-channel or especially adjacent-channel interference comes to mind. Certain early-gen HD Radio receivers were also deaf as posts, or (like the Boston Acoustics Receptor HD) had huge problems with self-interference from poorly-designed displays and/or power supplies. The BA Receptor was so bad that just adding 1ft of coax cable to the antenna jack…to get your antenna physically more distant from the display…could make a world of difference.

    Can you give any more deets? Specific stations/frequencies? Makes/models of receivers? Types of antennas?


    Member
    #140624

    Laurie Campbell has shown no interst in selling WPLM and is actually taking more interest in the station than she has in the past.

    That AM on 1390, with 4 towers has got to be draining her. I don’t think its being rented out now.

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