Your DSP radio readings on/±20kHz strongest midday signals (incl. nulls)?


I would, if so many of the stations I wanted to listen to in the daytime (560-KBLU, 580-KSAZ, 660-KTNN or 660-KWVE, 680-KNBR, 700-KALL (as for last 2, 77kW 690-XEWW 32 miles distant could be a challenge), 720-KDWN, 770-KCBC or 770-K780-KAZM, 810-KGO, 840-KXNT, 870-KRLA, 890-KLFF, 920-KPSI (5kW 910-KECR at 9.3 miles is probably a challenge here), 960-KIXW, 970-KNWZ- 980-KFWB, 1010-KXPS, 1100-KFNX, 1110-KDIS, 1140-KNWQ (being 6.3 miles from 10kW 1130-KSDO probably doesn't help), 1150-KTLK, 1180-KERN (being 9.3 miles from 50kW 1170-KCBQ I'm sure doesn't help), 1200-KYAA, 1230-KXO, 1260-KGIL, 1290-KZSB, 1300-KROP, 1320-KKSM, 1340-KCLU, 1350-KTDD (5kW 1360-KLSD splatters and covers the desired signal on my PL-380 from 8.3 miles away even in 1kHz BW mode, like the previously mentioned pests also do to their nearby desired signals), 1380-KLPZ, 1400-KESQ or 1400-KKZZ, 1430-KWST, 1440-KFNY, 1460-KTYM, 1490-KGBA or 1490-KSPE, 1510-KSPA, 1520-KVTA, 1560-KNZR) weren't so badly obliterated by desense, or in some cases, splatter. Most of the listed stations, except a few, are completely unreadable on my Panasonic RQ-SW20 in the daytime, my previous radio for which I've been trying to find a replacement that will hear at least most of those stations as strong as possible without any side splatter. I would have added a few more stations to the list, but IBOC from some stations 10kHz away would have covered them up anyway, and only 1 or 2, IIRC, were barely readable before the stations started using IBOC.
I'm basically wondering if my PL-380 is the only one that desenses so badly near strong signals. For example, 1170-KCBQ (non-IBOC) reads 77,25 on the G8 (which is going back to the store today), and on my PL-380 reads 45,00 on 1150 and 43,00 on 1190. The manual for the PL-606 states selectivity as >60dB at +/-9kHz in 3kHz BW mode, and therefore I'd expect to see 17,00 on 1161 and 1179 kHz on that radio (I don't have one) without any trace of audible splatter at all (which is audible to some degree from 1155 to 1185 on my PL-380 in 3kHz BW mode).

I've already proven that the elevated RSSI readings is actually desense and not just high ambient noise, by the reduced readings when the strong signal is nulled. Interestingly, the audible noise is actually LOUDER on the signals that aren't desensed so bad (for example, noise on a 15,00 sounds considerably louder than on a 45,00 channel). This seems to indicate to me that although there's no audio splatter heard very far beyond a channel, there could still be some form of side signal in there somewhere that's made it through the radio's filters. Also, I've noticed at least one, if not more cases, where a signal was noticeably more readable at a location farther away from a nearby pest, even though it was also farther away from the desired signal. For example, KDIS-1110 indicates about 43dBu RSSI, 0dB SNR a couple miles south of El Cajon, CA (112 miles to KDIS, 10kW pest 1130-KSDO is 72,25 on the G8 from 6.3 miles away), and is about 15dBu RSSI, 10dB SNR at Cameron Corners, CA (135 miles to KDIS, KSDO's directional signal reads 25,25 here on the PL-380).

I'm looking forward to learning more about the PL-606's performance, for example to see if it measures up to the specs in the manual. If it does, then maybe that radio might at least enable me to hear some of the stations I want to hear. (I didn't originally come here to participate in contests, I originally came to see about finding a radio with which I could hear several stations I wanted to listen to that were usually inaudible on my Panasonic RQ-SW20, and I knew I wanted to keep it in the ultralight size and price range, as I was looking for a not-too-expensive pocket AM radio.)

--- In ultralightdx@..., James McWain <bcs961@...> wrote:

Stephen, Just forget all of your number..listen to your radio!   James

From: Stephen <pianoplayer88key@...>
To: ultralightdx@...
Sent: Tue, November 2, 2010 4:36:12 PM
Subject: [ultralightdx] Your DSP radio readings on/±20kHz strongest midday
signals (incl. nulls)?


1110      43,00 | 30,00 | 20,00
1130-KSDO 72,25 | 43,25 | 19,00
1150      45,00 | 34,00 | 19,00
1170-KCBQ 77,25 | 54,25 | 15,00
1190      43,00 | 29,00 | 15,00

First is when facing the transmitter, second is when rotating for a null (radio
is still horizontal) and third is when tilting for maximum null.  In my case, I
have two strong stations 40 kHz apart, both basically north of me.  The
strongest one, 50kW 1170-KCBQ, is 9.3 miles away, heading 7°, and the runner-up,
10kW 1130-KSDO, is 6.3 miles away, heading 350°.  The difference in heading, and
the fact that the tilt null is extremely narrow, accounts for why the 1110 tilt
reading is higher than the 1130 reading, which was higher than that of 1170 -
KCBQ's signal was upwards of 50-something dBu IIRC (I didn't take a note of it
though) when 1130 was tilt-nulled.
On 1110, KDIS is faintly audible, but doesn't come anywhere near pushing through
the 0dB barrier.  On 1190, I can barely make out KXMX, but I think KTLK is too
far under the desense on 1150 to be heard.

Now... how do your DSP radios behave?  I'd like to know the readings on the
strongest station, and the readings +/-20kHz.  (If your radio has selectable
bandwidths, set it to 3kHz to level the playing field.)  If there are audible
stations on those frequencies, either post only the one that doesn't have any
audible station (unless the SNR is 0dB), or post the +/-15kHz readings, unless
it's an IBOC station.  Also, like I posted, I'd like to see the numbers when the
strong station is nulled.  (You don't have to do the tilt null, unless you want
to.)  If your strongest station is such that you're getting 49,00 or 50,00
readings, then post over what range of frequencies you get those readings.  For
example, at my grandma's house in San Gabriel I get somewhere around 85-90dBu if
not more on 23kW 1300-KAZN and 50kW 1430-KMRB, both of which are diplexing from
1/3 mile away and visible from her front yard.  There, I get 50,00 readings from
about 1200-1550 and 49,00 from about 960-1710.

Is my PL-380 and the G8 (which is going back to Radio-Shack tomorrow, although I
may buy another one later as I didn't get to finish some comparisons I wanted to
do) the only radios that show high RSSI levels on channels around strong
signals?  I'm hoping to see some data, and compare to my own PL-380.  I
especially would like to know if the PL-606 lives up to spec.  The manual states
60dB selectivity in 3kHz BW when tuned +/-9kHz.  If that's true, should I
expect a 75dBu station to be reading 15dBu at +/- 9+ kHz, or a 90dBu station to
be reading 30dBu at 9kHz (and lower when tuned farther off at a rate of
9.5dB/kHz, calculated by assuming the BW is +/-3dB, and dividing the dB
difference (60-3=57) by the frequency difference (9-3=6) - 57/6 = 9.5)?