upcoming shootout - DSPs immune to overload or not? (Re: K...


There's more comments below... but I was curious about something.
I don't remember what you said the indicated dBu on the 3 stations were on your PL-380, but I do remember they were all higher than my PL-380's max cap of 63dBu, with 1450 I think showing 79dBu if I remember correctly.

I was wondering... what are the dBu readings on your PL-380 in some of the blank channels across the band? I almost bet that yours, unless it's much better than mine, will be showing 50dBu across much of the 1400s or so, for example.
Also, when you go to Grayland, what are some readings there, either from a few stations you can hear from there, or in the blank channels? My PL-380's minimum is 15dBu when not swamped by RF... and sometimes I've heard stations indicating 15dBu RSSI, 18dB S/N. That same signal would be completely undetectable when swamped by the 50dBu noise floor courtesy of a very strong station 100-200kHz away on my PL-380.

Also, I looked at radio-locator for 47°10'0"N 122°19'45"W, which I guess is probably within a few miles of you or so... and came up with a comparison I wouldn't mind if you could do. You're fairly close to 850 KHHO if I remember correctly, and 860 KPAM Troutdale, OR, shows as having a fringe signal, with you about halfway between the fringe and distant contour. Also, Grayland is in about the same signal range as KPAM, and has no nearby pests. Could you do a comparison of KPAM's reception quality from Puyallup vs. Grayland? Or would KHHO's IBOC wipe it out even on the PL-380?
I will say, though, that your reception of KARR, based on Radio-Locator's maps, is impressive in the face of KSUH, considering how wide you say they spread on the SRF-M37V! I'm wondering... if I had a properly working PL-380... would I be able to hear 1290 KKDD from my grandparents' house in San Gabriel, about 1/3 mile from 23kW 1300 KAZN and 50kW 1430 KMRB? That location is right near KKDD's fringe. KAZN does have a minor lobe toward that location if I remember correctly, but it helps that neither station is IBOC (although there is a 50kW IBOC pest on 1110 5 miles to the east), and KMRB has a null in that direction. Also I believe the ground conductivity is considerably higher here in southern CA than it is there in western WA, not counting the salt water.

--- In ultralightdx@..., D1028Gary@... wrote:

Hi Stephen,

All of the Shootouts are conducted in my generous back yard in the valley
part of Puyallup, WA, a location about 6 miles from salt water Puget Sound.
This is a typical suburban RF environment, with the usual mix of a few
local mega-pests combined with many moderately irritating urban (Seattle)

KSUH-1450 (a Korean-language station cited by the FCC for poor tower
maintenance) is about 3 miles away, and covers a huge part of the AM band on
Ultralights with poor selectivity (SRF-M37V, etc.). In the very early days of
the ULR boom, I was sure I had logged 1566-HLAZ (Korea) on the barefoot
SRF-M37V shortly after local midnight... until I followed the Korean-language
program all the way back to KSUH-1450 :-) The station can be nulled at
night, however, on ULR's with 1 kHz DSP selectivity like the PL-380. The same
ULR's can receive 1460-KARR in Kirkland, WA during the daytime-- a superb
show of sharp selectivity.
Wow... that's quite a spread. I can get signals on my PL-380 to spread that much, too, and farther... IF I'm close to their transmitter like in the photo at the link.
The frequency indicated on the PL-380 is the 18th harmonic of one of the stations broadcasting from the towers in the background, and I was right in the middle of 50kW 1170 KCBQ's main lobe. (The other station is 5kW 910 KECR which is basically the ONLY other station I can hear there (and MAYBE 600 KOGO or 760 KFMB but that's doubtful), other than 89.5 KBPS and maybe a couple other FMs that I didn't check.)

There is a 10kw IBOC monstrosity in Tacoma only about 5 miles from here
(KHHO-850) which covers 830-870 kHz in the daytime, but is not bad at night
(apparently protecting Denver, which is in the same SE direction as my
location). KKOL-1300 is a major 50 kw daytime pest only about 7 miles from here,
and usually wipes out 1290-1310 kHz, except on the 1 kHz DSP Ultralights.
My local IBOC monstrosity is a 5kW on 600, KOGO, about 7.5 miles west. On my PL-380 it's 40dBu from about 585 to 615 kHz or so in 1kHz mode, and 63dBu on the 600kHz main carrier.
My major 50kW daytime pest is 1170 KCBQ, 9 miles away. It is 63dBu on 1170, 43dBu with slight chatter on 1160 and 1180, and 41dBu with just static (but quieter static than normal) on 1150 and 1190. 1130 KSDO, despite being only 10kW, is about 6 miles away in the same direction as KCBQ, and is 63dBu on 1130, 40-41dBu on 1120 and 1140, and about 39-40dBu on 1110, nearly blocking reception of KDIS, a station I wanted to listen to without having to use an external antenna, and one of the original reasons I sought a different radio than what I had before.

It would be nice to run a few comparison tests close to the 50 kw pests,
Stephen, but the Shootouts are really only designed to give "relative"
performance information on how the ULR's compare with each other. Here in the
Puyallup suburban environment, all the models are tested for relative AM
sensitivity, selectivity, nulling ability, spurs/defects, etc., and the top
models always have a decent opportunity to excel in each category. The
relative performance results would probably not change, even adjacent to 50 kw
sloppers. Regarding your individual PL-380 unit's adjacent-channel rejection,
my own impression (along with that of Scott, and others who have analyzed
your situation) is that the model is probably defective. A normal PL-380
should provide excellent 1 kHz DSP selectivity to limit the splatter from
local pests, and if you are not satisfied, I would certainly recommend
replacement of the model.
Yeah... I've been thinking mine's probably defective. I can understand having signals spread all over the place when I'm near a transmitter site like in the picture linked above, but not when the nearest transmitter is 6 miles away! How would you suggest going about replacing it? I don't know that I can really afford to buy another one right now... and last time (a few months or so ago - would need to check my sent folder) I emailed Joyce about something else semi-related I don't recall getting a response.

For those interested in the detailed Shootout radio reviews from previous
seasons, links are provided below.

73, Gary DeBock (in Puyallup, WA)

December 2007 "Round One" Shootout
(http://www.dxer.ca/latest/56-ultralight-radio-am-dx-shootout-round-one) (SRF-59, SRF-M37V, DT-200VX, ICF-S10Mk2)

2008 Spring Shootout _http://www.mediafire.com/?zijl1lqtznn_
(http://www.mediafire.com/?zijl1lqtznn) (SRF-T615, SRF-39FP, DT-180V, DT-210V, C.Crane

2008 Summertime Shootout _http://www.mediafire.com/?2t5godzzyaw_
(http://www.mediafire.com/?2t5godzzyaw) (SRF-M97, SRF-S84, E100, DT-400W, SRF-M37W

2009 Shootout _http://www.mediafire.com/?nokcjzwtyzt_
(http://www.mediafire.com/?nokcjzwtyzt) (DE1123, R911, R9012, PL-300WT/ G8, D92L, D96L,
C.Crane SWP)

Tecsun PL-310 _http://www.mediafire.com/?yennzd1iu0i_

Tecsun PL-380 _http://www.mediafire.com/?w4yuzhj2kyz_

In a message dated 6/18/2010 3:03:02 A.M. Pacific Daylight Time,
pianoplayer88key@... writes:

Gary, when you do the shootouts, where approximately do you do them? From
your home in/near Puyallup, or near Grayland, or somewhere else?
Also besides testing adjacent-channel selectivity, do you test for other
evidence of overloading on radios, like desensitization or blocking, besides
just harmonics and spurious/mixed images/intermodulation? On my own
PL-380, I live in a place where the RSSI on some stations exceeds 35-40dBu even
20-30kHz away from a strong station's frequency, and is generally at least
30dBu in blank channels over most of the band. Also I'm often in places
where the RSSI in the blank channels can touch 50dBu over a portion of the band
due to a very strong local. (By comparison, in rural areas, or if the
radio is in a shielded enclosure, the RSSI is 15dBu on the blank channels, and
I've often had readable stations indicating up to a 1 or 2 dB HIGHER SNR
than the RSSI indicated.) I'm wondering how well your Tecsuns and other DSP
and other radios perform in similar environments, for example about 0.5km
from a 50kW stick?
Also, I was just reading your PL-380 review, and you say KARR has no KSUH
slop, in spite of it being only 10kHz away. Also, if I remember correctly,
you are a mile or two away from KSUH's transmitter, and I think I saw you
mention their RSSI in another post as being somewhere in the upper 70s to
low 80s dBu... but my own PL-380 caps it at 63dBu. Also I notice some slop
+/-10kHz away from 63dBu stations, even in 1kHz mode.
It does seem that my PL-380 is a good 12-15dB more sensitive than my
previous radio... that is, when it's not overwhelmed by not-so-strong
semi-locals, like, for example, a 50kW 9 miles away, a 5kW IBOC 7 miles away, a 10kW
6 miles away, just to name a few. However, due to the elevated RSSI from
the strong stations, it seems to negate the effect somewhat.
Is it possible I got a dud PL-380 (not to mention the tuning knob has
broken TWICE), or do they all perform like that? When I originally was looking
into getting another portable AM radio to replace one I had (and still
have), and ordered the PL-380, one of my goals was to bring in some stations
that on my previous radio (a Panasonic RQ-SW20, ~15dB less sensitive than
PL-380, comparable selectivity to Sony SRF-M37W, and possibly worse due to the
splatter being just as wide, if not wider on the SW20, even though it's
less sensitive than the M37W) would just basically not exist. Occasionally
the SW20 just wasn't sensitive enough to pull in the stations I wanted to
hear, but usually even if it WAS sensitive enough, chances are a local pest
10kHz would completely wipe it off the face of the dial, and would ITSELF be
heard over a +/- 50-200kHz swath of the dial, while still being a strong,
low-noise signal (and strong enough to light the tuning indicator LED),
except for a little distortion and slightly higher audio fidelity while tuned
off frequency. (The Donald Duck effect is typically only noticeable at
+/-10kHz, then at +/- 20-30kHz (except on exceptionally strong signals, like in
the example below) it cleans up quite a bit on that Panasonic. Also, on
that radio, it's interesting to note that when you're tuned close to, but not
on, a very strong local station (typically one where the tuning indicator
is still lit at least 30kHz off), not only do you get the Donald Duck
distortion close in, the audio level drops considerably compared to when you're
tuned on the frequency. That effect can be heard in this audio clip recorded
a couple months ago -
%20to%201710%20-%20SAT%20@%20Power%20Pole.mp3) - that's my RQ-SW20 with the Select-A-Tenna at a power pole
tuning in 50kW 1170 from 9 miles away, then going up to 1710kHz in 10kHz
increments. My PL-380 in the same situation actually overloads (distorted
audio on channel):

Another thing... any chance that you could give the radios in the shootout
a bit more of a challenge in the selectivity and overload sections of the
shootout? Here's a picture of one idea, although I would have liked to have
been about 86 meters or so closer to the source of the QRM to increase the
difficulty of the test.
In that picture, the PL-380 is tuned to the 18th harmonic of 1170 KCBQ,
one of the stations broadcasting from the towers in the background (the other
is 910 KECR), and showing a signal strength of 62dBu!
I did record a bandscan at that location, but unfortunately I didn't keep
very good track of what was what in the recording (partially due to the
PL-380's beep function being turned off)... but I did note the readings on
some frequencies.... I should note that that location in the photo is in the
main lobes of the directional patterns of both stations (50kW 1170 KCBQ and
5kW 910 KECR).

1170 KCBQ vs. Tecsun PL-380 - near-field experiment.

PL-380 held up to power pole outside transmitter property

1170 = 63dBu RSSI, 25dB SNR
1171 = 63dBu RSSI, 0dB SNR
1180 = 63dBu
1190 = 50-63dBu
1210 = 50dBu
1300 = 56-57dBu
1400 = 50dBu
1710 = 56dBu

SW, whip antenna stored
3510 = 63dBu (KCBQ's 3rd harmonic)
2300 = 50dBu (lowest SW tune)
2340 = 63dBu (KCBQ's 2nd harmonic)
2300 = 52dBu (repeat?)
4680 = 63dBu (KCBQ's 4th harmonic)
11700 = 63dBu (KCBQ's 10th harmonic)
18720 = 60dBu (KCBQ's 16th harmonic)
15210 = 63dBu (KCBQ's 13th harmonic)
17550 = 61dBu (KCBQ's 15th harmonic)
21060 = 59dBu (KCBQ's 18th harmonic)

153 = 63dBu
200 = 57dBu
300 = 50dBu
400 = 54-58dBu
513 = 50-57dBu

520 = 63dBu
600 = 53-56dBu - some kogo audible
760 = 53-57dBu - some kfmb audible
910 = 63dBu RSSI,20dB SNR - KECR (with whom KCBQ diplexes)

SW: 21060 = 59-63dBu - whip antenna extended

64.0 = 10dBu - whip antenna stored
80.0 = 4dBu
108.0 = 0dBu
89.5 = 8dBu RSSI, 1dB SNR - KPBS

As for how much amplification I'm getting from the power pole.... I have
previously posted examples recorded at my house, 9 miles away, of tuning the
same station using the Select-A-Tenna and a ground wire on a power pole
outside my house. This is a picture of where I would be to approximately
match that signal level on the barefoot PL-380 (approximate location
32°53'35.4"N, 116°55'39.7"W):
In a nutshell, it overloads on the frequency, which can be heard starting
at about 0:22 in this recording:
RSSI was 45dBu at 153kHz, 50dBu across most of the AM band, 63dBu at
2340kHz (2nd harmonic), ~50dBu at 3510kHz (3rd harmonic), just to summarize a
few points.

Any chance that you could conduct a portion of the 2010 shootout in a
similar strong-signal environment? ;)

--- In _ultralightdx@... (mailto:ultralightdx@...)
, D1028Gary@ wrote:


One of these Kchibo KK-D6110 radios (the official name) has been ordered
for the upcoming 2010 Shootout, which will also feature the PL-310,
and PL-360 models. I'm kind of curious myself whether Kchibo has
the digital "chuffing noise" of the D96L model.

73, Gary DeBock (in Puyallup, WA)

In a message dated 6/16/2010 5:42:37 P.M. Pacific Daylight Time,
schuster@ writes:

There's a thread from 2009 on the Chinese "leowood.net" BBS on this
Google Translate says it's the "battery version of ordinary D-96L". They
also say it's very ugly.

I parted company with my D-96L over the DSP/display noise problem.
if this is any better. Not willing to invest to find out - Kchibo's
control seems to be worse than Tecsun.

--- In __ultralightdx@...
(mailto:_ultralightdx@...) _ (mailto:_ultralightdx@...
(mailto:ultralightdx@...) )
, "DiamJ" <jm392c@> wrote:

The Kchibo KK-6110 is available on e-bay from hygt369 for about 51.99
US$. If it won't come up directly on e-bay then google the name and
the link to e-bay. Unlike the DL-96 this one uses AA batteries.
I don't know if there is an English manual.

Jim Z

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