The FM DX thread

Viewing 15 posts - 1 through 15 (of 25 total)
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  • #4567
    Alfredo_T
    Participant

    I was recently surprised to learn that reception of KMUZ is possible from my location in Hillsboro. I am using a 10 element Yagi pointed south (to null KBVM). Because KBVM runs mostly spoken word programs with low average modulation levels, the interference is not too severe. The receivers so far that work are an Onkyo T4150 in narrow IF mode (two 150 kHz filters cascaded with two 230 kHz filters) and a modified Technics SA-929 (two 180 kHz filters). Tuners with stock filters (typically 230 kHz) do not provide adequate selectivity.

    In my attic, I have an old 1978 vintage Sony tuner that I believe uses SIX IF filters and has three RF tuned circuits. (I have the block diagram but have not looked at it in a while.) I bet that this would be a killer FM DX radio if the ceramic filters were replaced with 180 kHz filters!

    #4568
    jr_tech
    Participant

    I’m guessing that the older Sony (with only 3 gangs of RF tuning) will not do as well as the modified Onkyo or Technics, but I have been wrong before. Interesting experiment! So far, my little Sony XDR-F1HD remains as the tuner of choice for FM DX, far surpassing my mid 70s vintage Pioneer 9100, which has 5 FM tuning gangs and fairly narrow IFs. For a ton of info on vintage tuners check out: http://www.fmtunerinfo.com/

    #4574
    Boss_Radio_1550
    Participant

    Nice website. Thanks! I had no idea this site existed. Unfortunately, it doesn’t have some of the boat-anchor tuners that I have. No biggie. Granted, there have been a lot of tuners manufactured over the years. Do you feel that the Sony (in Analog mode) that you have now is selective enough for use in the crowded metro Portland area weeding out the signals from translators, LPFM’s, DX stations? I know my 3 stage IF receivers work a lot better than the 2 stage, due to their better selectivity.

    #4581
    jr_tech
    Participant

    Which Sony? If you are asking about my F1HD, it is the most selective tuner that I have ever used. Check out the specs and info from Brian B. (K6STI) here:
    http://www.ham-radio.com/k6sti/xdr-f1hd.htm
    It does overload a bit when my antenna is pointed at the Portland towers, obscuring weaker signals to the East. In this *one* performance parameter, my number 2 DX tuner, a modified Yamaha TX-950 wins.
    Unfortunately, Sony has discontinued this little $100 gem and the price of used and NIB examples has sky-rocketed 🙁

    #4605
    Alfredo_T
    Participant

    I had started a reply to Boss_Radio_1550’s questions yesterday, but I did not post it, assuming that he was asking exclusively about the XDR-F1HD.

    What I am expecting of the old tuner is that it would have an IF passband on the order of 230-280 kHz, but that the skirts would be very steep. I am curious to see how the front end performs. It has the benefit of using a mechanical variable capacitor, instead of varactor diodes. However, I don’t know how resistant to overload the RF amplifiers and mixer will be.

    For more fun, yesterday, I was up late into the night sweep aligning the FM side of a 1962 vintage Knight KF-90. After hours of carefully moving slugs back and forth, I had a symmetric IF response with a flat top, very likely as the radio’s designers had intended (it was badly misaligned when I bought it).

    The front end of the Knight is a triode tube cascode design that seems bulletproof (I cannot overload it, even with a 10 element Yagi pointed toward the West Hills). However, the IF selectivity is not good enough to make this a DX radio (KPDQ bleeds over into 2nd adjacent K228EU and KZZR).

    #10877
    Alfredo_T
    Participant

    Lately, I have been listening to KYTE 102.7. The signal strength varies quite a bit, and I hear the occasional airplane flutter.

    I’ve noted that:

    1) They seem to play a fair number of 1980s “forgotten hits” that I remember hearing on the radio growing up but that one would not hear on commercial stations in Portland (examples: “All Cried Out” by Lisa Lisa & Cult Jam, “On Our Own” by Bobby Brown).

    2) The audio processing is very light, compared to commercial stations in Portland. (The same can be said of KZEL.)

    When I heard the forgotten 1980s songs, they sounded very different than how I remembered them. Perhaps some of this was due to the long term unreliability of my bunny brain, but I think that the other reason was that when I first heard these songs, they played on stations with very aggressive processing (both AM and FM).

    #14528
    Alfredo_T
    Participant

    I tried to see if I could pull in the 98.5 station that was reportedly playing Christmas music. I was not able to sufficiently null out KUPL to hear anything on 98.5 MHz. However, I only tried one radio (with two 180 kHz ceramic filters). I’ll do some more experimenting tonight.

    About a week ago, I briefly heard, on the car radio, a station playing Reggaeton music on 107.1 MHz. This was not KLVU or K296FT (X-ray), which were running different programming. What I heard as I was driving was KLVU and K296FT fighting for control of 107.1, and both stations were very briefly overridden by the Reggaeton music. I unsuccessfully tried to receive the Reggaeton-playing station from my house, using a 10 element log-Yagi. This could mean any one of the following:

    • The Reggaeton station is using vertical polarization.
    • The Reggaeton station appeared because of a very short-lived skip condition (such as an ionization trail from a meteor).
    • The Reggaeton station was an extremely low powered pirate station.
    #27148
    Alfredo_T
    Participant

    Yesterday, I heard a surprisingly strong signal from KIEV-LP 102.7 from my location in downtown Hillsboro. The signal strength peaked (subtle pun) with the antenna pointed south. KIEV’s signal was strong enough to cover up KYTE.

    The pun is that on a previous evening, I was getting a reflected signal on 98.3 (KPPK) by pointing my antenna south. What is causing the reflection–Bald Peak? However, that would not explain my hearing KIEV-LP, as KYTE usually dominates 102.7 here.

    #27163
    KXRU-ED
    Participant

    KYTE usually dominates 102.7 here

    Do you think what you hear is KYTE from their new location?
    http://radio-locator.com/cgi-bin/finder?call=kyte&x=0&y=0&sr=Y&s=C

    #27193
    Alfredo_T
    Participant

    I think that I must have been hearing the old transmitter site. I say this because I just found an old posting from me (dated 2016) in which I said that I had noted that I could no longer receive KYTE.

    #27199
    e_dawg
    Participant

    I used to live in inner southeast Portland. I can tell you it’s really hard to Dx fm stations in the area due to translators and lpfm taking over 2nd adjacent channels

    #28006
    Alfredo_T
    Participant

    Today, I went up to the top of the Kaiser Permanente parking garage in Hillsboro and took a spin around the dial. The garage is eight stories high.

    To my surprise, I could not hear as much as a peep from KFFD 98.3. All that I heard was a weak signal from KPPK; the reception was no better than that at street level. I did note that on 91.1, I heard KTJC, not KWAX.

    I noted some differences in AM reception, which I had not expected. KBAM was significantly stronger than it is at my home (where it is very weak). KDZR was surprisingly strong. I experienced some problems with overloading, as KUFO and KUIK have fairly strong signals in that area.

    #28008
    mwdxer1
    Participant

    Out here North of Seaside, I have a Sony HD Radio and a Korner 9.2 German FM Yagi (9 elements), and so far I have not received any LPFM’s out of the Portland or Valley area. At least not that I could ID. I do hear several FM translators out here relaying AM’s, the two local, one out of Aberdeen and two out of Longview. Those are quite good running 100-250w ERP. This Summer I plan to raise the Yagi up 20 feet and ad a rotor. Hopefully that will help with DX. I regularly get Vancouver.Victoria BC to the North.

    Patrick

    #28010
    semoochie
    Participant

    The other day, I was listening to KFFD on US26 by the Cornell exit. The signal quickly turned into hash and I got off at the Brookwood Parkway exit and could only hear KPPK. I’m not surprised that you couldn’t hear it.

    #30331
    lastday
    Participant

    So I was in Oakridge again on 6/30. On all my trips there I’ve never been unable to receive KRVM in the car on 91.9. It’s usually fuzzy but once in a while I can get an HD lock.

    But on this visit there were two (and possibly three) other stations fading in and out on 91.9.

    In the videos when the car is tuned to 88.5 that’s KAVE/KRVM. 91.9 should be the same.

    In this video you can hear 91.9 flipping back and forth between two stations, but neither of them is KRVM.

    One of them positively ID’d as 91.9 KLKI, a K-Love station in Dolan Springs AZ.* That’s 900+ miles from Oakridge.

    https://radio-locator.com/info/KLKI-FM

    I couldn’t ID the other station that’s playing Suzie Q.

    Later there was a Mexican-music station flipping back and forth with KLKI. The host was speaking English but playing Mexican type music. Couldn’t ID that station either. Seems unlikely to be the same as the Suzie Q station but maybe.

    Both samples are in Oakridge proper, not high up in the hills.

    Sporadic e? Tropospheric ducting? 🙂

    Anyway luckily for KRVM & KAVE their Sony XDR-F1HD that receives KRVM-HD1 via a high-mounted directional antenna and rebroadcasts it on 88.5 did not seem to be affected.

    Dave

    *EDIT: I suppose it could be a translator or something rebroadcasting KLKI on 91.9 but I can’t find a likely candidate in an interwebs search for stations on 91.9.

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