Someone on 1190 off frequency?

Viewing 15 posts - 1 through 15 (of 18 total)
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  • #10743
    Scott Young
    Participant

    I’ve noticed over the last several months that whenever I tune to 1190 at night outside the Portland area it sounds like either KEX or another 1190 station (usually CFSL in Weyburn, Saskatchewan) is slightly off frequency. The two stations combine into a very low frequency beat note that’s really annoying. I noticed it during a trip to Astoria in March, and again a couple weeks back in the Boise area. Anyone else ever notice the same thing out in the hinterlands?

    By the way, KEX was much stronger in Boise at night than I expected. They didn’t sound much like I was in the middle of a Fort Wayne, Indiana null, which I think should have been.

    #10744
    Alfredo_T
    Participant

    A while ago (perhaps 2 years), I measured KEX around 30 Hz off frequency. I will try to remember to measure their frequency again tonight.

    #10745
    W7PAT
    Participant

    I have wondered if the station on 1200 in Vancouver, BC is on frequency or is just really wide band. They splatter all over KEX up north and even in Astoria at night.

    I am currentlyat Sunriver and can hear KEX day and night.Right the nearby lightning storms are taking them out though.

    #10747
    Alfredo_T
    Participant

    CJRJ 1200 broadcasts music in AM stereo, so their sidebands 7-10 kHz away from the carrier might just be really strong. I will attempt to do a frequency measurement on them tonight, though I can’t guarantee its accuracy.

    #10749
    jr_tech
    Participant

    Too bad some of the old threads are gone, I think that we have posted about KEX being off frequency for several years.
    As close as I determine, KEX is about 1187.97 on the dial, right now. Alfredo can supply a much more precise number.

    #10751
    Dan Packard
    Keymaster

    What’s the frequency, Kenneth?

    Weird, the search box disappeared that was here last week. Working on getting it back . . .

    #10755
    jr_tech
    Participant

    Woops! I made a typo above…I really read KEX at about 1189.97 kHz.
    Sorry!

    #10769
    semoochie
    Participant

    Scott, quite a few years ago, WOWO gave up its clear channel rights and decreased nighttime power, in order to increase nighttime power on its sister station in New York. This may be why KEX switched to non-directional during the daytime. I had asked previously if it was now possible for KEX to go ND at night but apparently it’s a case of too much water under the bridge.

    #10774
    Alfredo_T
    Participant

    I ran frequency measurements on a variety of broadcast band stations, using a Rycom 6040 selective level meter. The IF bandwidth on this receiver is 50 Hz, which eliminates the possibility of modulation causing frequency measurement errors. The first station I measured was WWV, in order to confirm accuracy of the measurements.

    Frequency   Station   Error
    2500 kHz    WWV         0 Hz
    
     550 kHz    KOAC       -2 Hz
     620 kHz    KPOJ       +7 Hz
     640 kHz    KFI        -1 Hz
     670 kHz    KBOI      -10 Hz
     710 kHz    KIRO       -1 Hz
     750 kHz    KXTG        0 Hz
     780 kHz    KKOH        0 Hz
     800 kHz    KPDQ       +5 Hz
     810 kHz    KGO        -2 Hz
     860 kHz    KPAM       +3 Hz
     880 kHz    KWIP       +2 Hz
     970 kHz    KUFO       -5 Hz
    1000 kHz    KOMO       -1 Hz
    1010 kHz    CBR         0 Hz
    1040 kHz    KXPD       -1 Hz
    1080 kHz    KFXX       -2 Hz
    1120 kHz    KPNW      +13 Hz
    1190 kHz    KEX       -30 Hz
    1200 kHz    CJRJ       -1 Hz
    1330 kHz    KKPZ        0 Hz
    1360 kHz    KUIK       -6 Hz
    1480 kHz    KBMS       -5 Hz
    1520 kHz    KQRR       +1 Hz
    1550 kHz    KKOV       -6 Hz
    1640 kHz    KDZR       +2 Hz

    My measurement confirms Jr_tech’s. KEX is indeed at 1189.970 kHz. Note that some of the stations are dead-on with their carrier frequencies. It was mentioned on this board several years ago that some AM stations, particularly those that broadcast IBOC, have their carriers locked to a GPS frequency reference. In my recollection, KEX was on-frequency when they were broadcasting IBOC, and the frequency error showed up when they discontinued IBOC operations.

    #10776
    Scott Young
    Participant

    The frequency check chart is really interesting. I think that 30Hz error could be costing KEX some listeners fairly close in on the back side of their night pattern. My listening experience was that the co-channel interference was not very noticeable except that the carriers were beating, which drove me nuts. If not for that the co-channel interference would have been pretty negligible most of the time.

    Semmochie, if this pattern is still in use then KEX’s easterly null is still pretty deep.

    https://transition.fcc.gov/ftp/Bureaus/MB/Databases/AM_DA_patterns/618571-77798.pdf

    #10782
    nosignalallnoise
    Participant

    I must have been asleep. When did KEX discontinue its Ibiquity service?

    #10792
    jr_tech
    Participant

    Thanks for the measurements, Alfredo… My estimate was based only on comparing “beat” notes of the preset Portland stations on my Icom (in CW mode), noting that most were fairly close to the same, with some running a little “sharp” and others a little “flat”, while KEX was very “sharp”. I then tuned the receiver downward (10Hz steps only available) until by ear it “matched” the “average” and read 1189.97.
    Thanks again for the real measurement.

    #10794
    Alfredo_T
    Participant

    I must have been asleep. When did KEX discontinue its Ibiquity service?

    It has been at least three years, in my recollection.

    #10803
    Dan Packard
    Keymaster

    Well maybe KEX will have to amend their liners to now say “1189 KEX” 🙂 Great work measuring the AM frequencies Alfredo!

    Regarding searching for old threads. I’m working on making that easier. Some of the old Google search code has deprecated. (Part of the problem when you run a 20 year old web site).

    Best way for comprehensive search right now is from home page, pdxradio.com and using the custom search at top right of page.

    It’s where I found this old thread about KEX and HD, http://archive.pdxradio.com/2009-14/topic/hd-radio-happenings/page/9

    #10808
    jr_tech
    Participant

    Thanks for the tip on searching… found this old thread about KEX being off frequency enough to produce some “stereo” effects:
    http://archive.pdxradio.com/2009-14/topic/kex-am-stereo

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