reception odities that make no sense

Hi everyone,
Can someone please explain this? I've had my mom take my CC Witness on two trips since I got it, and both trips have yielded some curious results.
The first trip, taken In February 2017, was to Orlando. The stations in question are WWKA, WJHM, WOMX, and WOCL. As many on this board will know, WWKA and WOMX are licensed to Orlando proper, while WJHM is licensed to Daytona Beach and WOCL is licensed to Deland, which appears to be closer to Daytona than to Orlando. From what I can understand, all of the above mentioned stations transmit from a big tower halfway between the two. So, why were WWKA and WOMX loud and clear, while it was hard to get a stereo signal on WOCL and you had to listen extremely carefully to pick out WJHM through all the static? In Tucson where my parents just got back from, I had them record among others KSZR an KOHT. They were staying with my aunt in Orrow Valley, KSZR's COL. KSZR, along with all the other stations recorded, was fine, as I expected. However, KOHT didn't come out at all, could barely make it out over all the static and overload from other signals. Would have been kind of cool to try and identify all the signals I got there, but didn't bother. The thing is, KOHT is actually closer to where they were than KSZR according to Radio Locator, though it rates both stations at a signal strength of 4. So, what gives? Also a local example though I've never taken a radio to experience this myself, driving up into the mountains along U.S. 2, apparently KUBE 93.3 is static-filled and mono, while KJR-FM 95.7 is full stereo. I can see no logical explanation for the vast signal difference there, as both stations are on the same tower, and as far as I know, there's no more interference to 93.3 than to 95.7 in that direction. In fact, I think the co-channel stations that even have a chance of causing problems for Seattle are also on the same tower, though I can't confirm that.

Sounds like classic examples of receiver multipath reception. You're getting reflections rather than a direct signal. The multiple reflected singals arrive at your radio at slightly different time, effectively cancelling each other out. Usually adjusting the length of your antenna or moving the radio/antenna will allow the receiver to lock onto one signal rather than several fighting it out.

But why would that happen on some frequencies but not others? Remember we're comparing the same or similar power levels here from the same site in all three cases, though as you know, KCMS also transmits from the Seattle antenna referenced in my original post, and depending on the day and radio, it seems to have a few more of what I'm going to call fractional bad spots than even KRWM or KLSW which are on an adjacent tower I believe.

In some of the cases, maybe because some of the signals null in a direction where there's few listeners? KKWF and KING-FM have nulls towards the Cascades (and if anything, 100.7 at Indian John Hill is a weak KHSS in Athena OR), but that's not the case with KZOK, KIRO-FM, etc. on Tiger Mountain. I can still get them at Cle Elum but multipathed.

If they are colocated with a TV transmitter, they may be on auxiliary facilities or low power due to the TV repack.

crainbebo said:

In some of the cases, maybe because some of the signals null in a direction where there's few listeners? KKWF and KING-FM have nulls towards the Cascades (and if anything, 100.7 at Indian John Hill is a weak KHSS in Athena OR), but that's not the case with KZOK, KIRO-FM, etc. on Tiger Mountain. I can still get them at Cle Elum but multipathed.

Click to expand...

Actually it was you who pointed out the differences in reception between KUBE and KJR, it was several years ago when you posted a bandscan from somewhere around Skycomish. Both those are non-directional, while KKWF and all the Entercom stations except KSWD are on the same directional antenna.

rfburns said:

If they are colocated with a TV transmitter, they may be on auxiliary facilities or low power due to the TV repack.

Click to expand...

I'm not sure if KOHT is co-located with a TV station or not. Also a correction, it appears WOCL and WQMP which I incorrectly referred to by its old WJHM calls are co-located, but are not at the same location as either WWKA or WOMX, which don't even appear to be co-located with each other. Even so, were they even doing repack work in February 2017 when those observations were made? Although I could be wrong, I was under the impression that that hadn't started yet at that time.

bobdavcav said:

But why would that happen on some frequencies but not others? Remember we're comparing the same or similar power levels here from the same site in all three cases, though as you know, KCMS also transmits from the Seattle antenna referenced in my original post, and depending on the day and radio, it seems to have a few more of what I'm going to call fractional bad spots than even KRWM or KLSW which are on an adjacent tower I believe.

Click to expand...

Because their antennas are in different physical locations and heights, reaching you at different angles and reflecting off equally different angles. Keep in mind too, that a physical object placed in a certain way will reflect radio signals better at one frequency than another. It's just physics. Sometimes a slight adjustment of the antenna is enough to null out a reflection.

rfburns said:

If they are colocated with a TV transmitter, they may be on auxiliary facilities or low power due to the TV repack.

Click to expand...

The stations he mentioned aren't involved with the TV repack. Okay rant time:

It chaps my hide that some listeners or OTA TV viewers automatically default to believing something is wrong with the radio/TV station. This is especially true with older (50+) who can't believe when the weather changes they have to move their stupid clock radio three inches to correct some multipath interference. Must be the station's fault!! There's no way it could be something wrong with my receiver, antenna or the fact I have my computer monitor spewing RF interference right next to my radio.

KOHT had a marginal signal when I lived in Tucson several years ago, and it probably has not improved much. It is a class-A FM on a short tower (<200 feet), far to the north of Tucson proper, and in the last few years it has probably suffered some adjacent channel issues with a Ted Tucker move-in on 98.5.

KSZR is on a much taller tower and probably has excellent line of sight to your aunt's residence.

Tucson can be a challenging market for FM transmission. The city is surrounded by mountain ranges that can block direct reception of some signals, or create reflections and multipath.

Kelly A said:

The stations he mentioned aren't involved with the TV repack. Okay rant time:

It chaps my hide that some listeners or OTA TV viewers automatically default to believing something is wrong with the radio/TV station. This is especially true with older (50+) who can't believe when the weather changes they have to move their stupid clock radio three inches to correct some multipath interference. Must be the station's fault!! There's no way it could be something wrong with my receiver, antenna or the fact I have my computer monitor spewing RF interference right next to my radio.

Click to expand...

Oh yeah, the unpredictable nature of signals sometimes is quite annoying, whatever the cause. Sometimes, usually around this time of year, KOMO's AM signal gets really noisey on my clock radio. Sometimes it sounds like electrical buzzing, other times, like the couple weeks around Christmas this year, it's just really loud static that sometimes makes the broadcast almost impossible to hear. The worst part? It would go from so much static the station wasn't audible to loud and clear, just like that. Then it would come back at random. Also since this thread has sort of veered into reception oddities in general, one that has annoyed me on several occasions on numerous stations, is when I reach up to turn on the radio, reception is loud and clear. Then I take my hand away and poof, reception fades to a semi-listenable static-filled signal. Another time, my dad and I were staying at a friend's beach house in Long Beach. I don't know what station it was on, but we were looking for, and found, the Mariners game. Dad finds it, and walks across the living room over to the kitchen table, where I think we were playing cards. He gets about halfway over to the table and the signal fades to almost nothing. He goes back over to the radio, and without doing anything, the signal comes back.

awsherrill said:

KOHT had a marginal signal when I lived in Tucson several years ago, and it probably has not improved much. It is a class-A FM on a short tower (<200 feet), far to the north of Tucson proper, and in the last few years it has probably suffered some adjacent channel issues with a Ted Tucker move-in on 98.5.

KSZR is on a much taller tower and probably has excellent line of sight to your aunt's residence.

Tucson can be a challenging market for FM transmission. The city is surrounded by mountain ranges that can block direct reception of some signals, or create reflections and multipath.

Click to expand...

Could KSZR have good line-of-sight to where they were but KOHT couldn't? To be honest, I was worried that KOHT wouldn't come out, but Radio Locator actually showed that that was the closest signal, although rating both signals at a strength of four out of five.

On the transmitting side, antenna type makes a difference too. In my area, I've listened to several different stations, and for stations with similar HAAT and ERP, a rototiller/slant-V style antenna seems to have a more solid signal up to the fringe of the coverage area compared to a ring-stub style, which seems to start dropping off earlier. Also, from my observations, ring-stub antennas seem to have a stronger horizontal component than vertical, while slant-V and rototillers are more uniformly circular. Stations running ring-stub antennas seem to have a bit more multipath closer to the transmitter than what the slant-V and rototillers do. Number of bays and spacing could play a role here too, if there is a large amount of power radiating downward and reflecting. Also, not all nondirectional antennas actually radiate truly omnidirectional. Tower to antenna spacing can distort the pattern, and location on the tower face relative to the populated area can end up throwing nulls where there are people listening.