Hi Stephen,

To be honest, despite your apparent impressions, the PL-380 (and the other
Si4734 chip based ULR's) actually have above average AM-band overload
resistance among the Ultralight radio class. The reason for my conclusion is
detailed testing with various ULR's inductively coupled to the 9' PVC loop,
which will seriously overload any pocket radio which is not "crunch
resistant." The 9' loop overloads the analog design Ultralights (SRF-39FP, R9012,
R911, etc.) so badly that whenever the radio is brought within inductive
coupling range of the loop, the loop's tuning capacitor can actually tune the
radio from 530-1700 kHz (regardless of where the radio's tuning capacitor is
set).

The SWP Slider model has outstanding resistance to overload, which makes
it ideal for use with the 9' loop. In this respect, it's probably a shade
more impressive than the Si4734 models. The fact that the SWP Slider has its
own tunable loopstick contributes to this stability, and when the tunable
Slider loopstick is combined with the 9' loop's tuning capacitor, the
ultimate selectivity of the system is probably close to optimum in the Ultralight
class.

Anyway, Stephen, even though there are no more SWP Sliders being made,
it's always possible to boost up your TP-chasing ability by going with a
larger tuned passive loop (than your SAT), or with a 7.5" loopstick PL-380
(which can partially null out some of your pests, if their bearing is about 90
degrees off of the NW direction). The only way you will know which TP's are
possible in your "RF Zoo" is to get up early, and try chasing them before
sunrise. Nobody has a perfect location, or a perfect radio. The most
successful TP-DXers (or TA DXers) are the ones who push their luck constantly, no
matter what handicaps they may face. Optimism, persistence and
determination are the main ingredients for success-- even if your radio, antenna or
location has some limitations. Keep trying, and I'm sure that you will
receive many more TP's this season.

73, Gary






In a message dated 10/18/2010 10:42:54 P.M. Pacific Daylight Time,
pianoplayer88key@... writes:




CQ CQ Calling N7EKX...

I'd be interested in finding out how they compare with separating a very
strong signal from a very weak one (even if it is 10kHz away) when nulling
the strong signal isn't an option. With my PL-380, even in the 1kHz mode, I
can hear some of my strong locals 12kHz away. Across town I was trying to
listen to KDIS-1110 yesterday on my way to a Bible study service.
Unfortunately, their faint 41/00 signal was being stepped on by residual
chirps/chatter from XEPRS-1090, which was booming in at a solid 63/25. (I didn't have
the G8 with me, but I would guess XEPRS probably would have been around
72-76/25 or thereabouts.) However, I was almost right on KDIS's 2mV/m "local"
contour according to Radio-Locator, or possibly just slightly outside it at
the time, in Ocean Beach (a few miles northwest of San Diego airport). When
I have been in rural areas, though, I've been able to get listenable audio
on weaker signals, including some for which I was well outside Radio-Locat
or's estimated 0.15mV/m "fringe" contour - in a few cases even twice as
far, maybe more.
I was wondering how well the Slider+Murata'ed SWP would do in a test which
my PL-380, even in 1kHz BW mode, fails miserably. In a place where (I'm
guessing, as I don't own one to know its actual sensitivity) the PL-360 would
be indicating somewhere around 93/25 to 96/25 WITHOUT an antenna plugged
in... how well would the SWP (and if you want to check it with your
7.5-inched PL-380 (mine's stock) that's fine too) hear a signal 10kHz away coming
from the same direction as the strong pest, for which you are about 1.5 to
2x past Radio-Locator's predicted 0.15mV/m "fringe" contour? My PL-380
utterly fails that test. If it passed it, I'd be able to hear one of the
stations I originally wanted to be able to hear in the daytime, KERN-1180
Wasco-Greenacres, CA, for which I'm about 2x past the 0.15mV/m contour.
Unfortunately, KCBQ-1170's 77/25 signal still has significant splatter audible on 1180
(which does die out by around 1182 or 1183 or so), and even KXMX Anaheim
's 43/00 signal is only barely audible.

73... Stephen (No, I haven't gone past the no-turning-back point and
gotten a Ham license.)

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

Hi Rick,

Thanks for your generous comments on the SWP Slider models. Only about 5
of these models were ever made (in cooperation with Steve Ratzlaff, who
installed the Murata CFJ455K5 filters), including the one that I am

currently

using for TP-DXing each morning. Far more Eton E100 Slider models were

made

and sent out, including several by John Bryant (with his plywood frame
mounting style).

When the first Si4734 chip 1 kHz DSP model (the Kchibo D96L) was

released

in August of last year, there was intense interest in whether or not the
model's stock 1 kHz DSP selectivity would be competitive with the

premium

Murata CFJ455K5 IF filters transplanted into our modified SWP and E100

models.

That month I took a new Kchibo D96L to a famous Pacific beach DXpedition
site here in Washington state (Grayland), and made comparison MP3's

during

the reception of two South Pacific stations. A 3' portable PVC loop was
used to boost signals, and the SWP was tuned 1 kHz off the DX station's
frequency (away from domestic splatter) to provide crisper audio (this

could not

be done with the D96L, because of the "soft mute" issue). In the first

15

seconds, the D96L (with its 1 kHz Si4734 DSP filtering) receives the

South

Pacific split-frequency station, and in the last 15 seconds the SWP

Slider

(with a Murata CFJ455K5 filter) receives the same signal:

567-2YA Wellington, New Zealand 1250 UTC 8-9-09
__http://www.mediafire.com/?8n4ce5j2y1hfw6c__

(http://www.mediafire.com/?8n4ce5j2y1hfw6c_) (_http://www.mediafire.com/?8n4ce5j2y1hfw6c_
(http://www.mediafire.com/?8n4ce5j2y1hfw6c) )

738-Tahiti Mahina, Tahiti 1215 UTC 8-9-09
__http://www.mediafire.com/?l02marixc0xvhuh__

(http://www.mediafire.com/?l02marixc0xvhuh_) (_http://www.mediafire.com/?l02marixc0xvhuh_
(http://www.mediafire.com/?l02marixc0xvhuh) )

Of course the receivers' audio sections also influenced the quality of

the

received signals, but at the time I reported to the group that the

D96L's 1

kHz DSP selectivity (from its Si4734 chip) was fairly competitive with
that provided by the transplanted Murata K filter in the SWP. The

consensus

among the group, however, was that the Murata filter SWP had somewhat

more

"mellow" audio than that provided by the Si4734 chip's 1 kHz DSP

setting.

The Si4734 chip's 1 kHz DSP filtering is a tremendous breakthrough for
inexpensive stock Ultralights, though, and I've used both the 7.5"

loopstick

PL-380 and the 7.5" loopstick SWP Slider for South Pacific DXpeditions

this

past summer.

73, Gary DeBock (in Puyallup, WA)




In a message dated 10/18/2010 8:13:45 A.M. Pacific Daylight Time,
w4dst@ writes:




My Thanks to Gary for the CCrane SWP Slider that is now a fine
addition to my shack. Now that it is DXing season, I hope to be able to
give it a good workout with some new DX and hopefully some TA loggings.
I have been comparing it to some of the other receivers in the shack and
I thought I'd pass along my observations. These are not scientific,
just objective but I've tried to be impartial. Some of the results are
surprising.

One of my receivers is a Sangean ATS-803A that I picked up at a hamfest
over the Labor Day weekend and have given it a good alignment. The
ATS-803A/Radio Shack DX-440 and the Sony 2010 were considered 2 of the
best MW radios of their day and are still excellent performers. I am
fortunate to own both and thought I'd see how the slider stood up to
these 2 classics. My 2010 has 2 Kiwa filters in it, the CCrane has a
2.5kHz MuRata 6 element ceramic filter replacing the stock filter and
the Sangean has both stock filters. Selectivity wise, the CCrane's
MuRata filter is even better than the narrow Kiwa filter in the Sony,
which was surprising, and as good as, or better than the Sangean narrow
filter. The filters in the Sangean surprised me at how good they are
and the audio in the Sangean easily beats the others hands down.

When testing the sensitivity during the day, the slider came out the
winner over both receivers due the nice job Gary did on the slider
antenna. Being able to tune the antenna to the receiver is a very
valuable asset for DXing as others have noted. The Sangean, Sony and
the slider ferrite bars are all very close in length, 7.5" and all are
wound in much the same method with the windings closely wound on the
left end as you face the bar. The slider is slightly better than the
Sangean in nulling and equal to the Sony.

The only radio I have that takes on the slider and comes out ahead in
any way is my classic Radio Shack 12-655. This is a TRF design from the
early 1980s with a similar size ferrite bar. It is a analog radio, very
simple in operation and is legendary in MW DXing circles for its
outstanding sensitivity and nulling ability. During the day, I can
twist and turn my 12-655 and completely null out local WHKP 1450 6 miles

away, and hear WATA in Boone, NC, 140 miles to my north with full
audio. No other radio or my Quanum loop antenna is capable of this,
only my antenna phasing system can duplicate this feat. I have no
idea what contributes to it's amazing nulling quality since the antenna
looks to be wound just like the other 3 bars. As we say in the QRP
community, the 12-655 just has mojo. The slider and the 12-655 are very
close in sensitivity and it would be difficult without test equipment
measurements to determine which is the more sensitive. My 12-655 has
always been my benchmark for sensitivity and nulling capabilities and
will continue to be.

I have also experimented with a 280uH fixed coil ferrite bar antenna
that I wound on a 20cm, 7 7/8", bar from a junked Grundig S350L. It
has a 1/8" stereo plug on the end to interface with my PL-310 with its
"Laurie" mod. It and the slider seem to be equal in sensitivity.
However, the digital filter in the Si4734 has the edge on the MuRata
filter in the CCRane. Once again, I am impressed with Scott and the
rest of the folks at Silicon Labs and the design of this fantastic
chip. It's amazing so much can be packed into this tiny chip.

Good DXing in the upcoming season to everyone.

Rick W4DST
Hendersonville, NC