Re: early afternoon DX with PL-380 & SAT this (and last) week


Gary DeBock
 

"And, even if I am able to fix some of the barefoot deficiencies, there are times when I will want the extra boost of a larger loop antenna than the SAT, which just isn't cutting it anymore.   How much of an improvement would a 5.5" PVC loop be (or is the 4' one the largest that can be built without requiring a jumper to enable tuning the entire band) over the SAT?  (I mainly would like to, as much as possible, improve the barefoot performance, as I will not be able to use any type of external antenna for the vast majority of my casual listening  (for example, walking / biking around town, walking into a local mall, yogurt shop, etc."
 
Hello Stephen,
 
The 4' and 5.5' PVC loops will give you a very major DXing signal boost over the SAT (or any similar-sized tuned passive loop) without the need to perform any surgery on your barefoot PL-380. Both indoors and outdoors, collapsible-frame versions of these sizable loops offer a rare combination of portability and convenience. You can use your barefoot PL-380 for the majority of listening, then quickly assemble a sizable PVC Loop whenever and wherever you wish to give you a major DXing boost (by inductive coupling). A photo album describing this system (my next project article) is at  http://www.mediafire.com/?hqyzzu1mvyt .
 
Although this portable PVC box loop system was designed for ocean beach runs (where a disassembled 5.5' loop and base can fit easily in a compact car), it works equally well indoors, where it can be quickly assembled for DXing in a bedroom, living room, etc. My own 36" version stays bedside during the TP season, and provided 15 new TP's last year.
 
73, Gary DeBock (in Puyallup, WA)  
 
In a message dated 3/18/2010 3:48:35 A.M. Pacific Daylight Time, pianoplayer88key@... writes:

 

Hi all... I took my PL-380, SAT & Zoom H2 outside this past week and recorded a few stations.  Most were recorded yesterday (2010-03-17) at around 3pm, but one was recorded a little over a week ago (2010-03-08), also at around 3pm.

All the ones recorded yesterday were in the 1 kHz bandwidth position.

530 - WNHV296 Los Angeles, CA (LAX TIS) - 33°56'43.0"N, 118°22'46.3"W
distance = 116.371 mi, heading = 315.08° (reference (from my location): 360°,0° = north, 180° = south)

680 KNBR San Francisco, CA - 37°32'50"N, 122°14'0"W
distance = 445.415 mi, heading = 319.41°
QRM was from a local - 690 XEWW (may be listed as XETRA), 77kW directional day, distance 32.355 mi, heading 188.75°,  barefoot PL-380 signal usually 63dBu RSSI (btw what does that stand for?), 25dB S/N

810 KGO San Francisco, CA - 37°31'35"N 122°6'2"W
distance = 439.377 mi, heading = 319.97°
QRM is from 800 XESPN, listed as 1kW, distance 17.532 mi, heading 192.93°

1230 KXO El Centro, CA - 32°46'34"N 115°32'58"W
distance = 81.117 mi, heading = 88.87°
QRM is from 1240 KNSN, 1kW non-directional, distance 11.188 mi, heading 245.90°

1570 KPRO Riverside, CA - 33°55'54"N 117°23'47"W
distance = 84.973 mi, heading = 342.30°
note the antenna pattern per FCC  and Radio-Locator .

distance = 14.373 mi, heading = 209.25°
This was recorded with the SAT, but can be heard fairly well barefoot (a little above the soft mute threshold if I remember correctly, although it's night right now and the QRM prevents me from checking)

The one recorded on the 8th was mostly in the 1kHz, but I did attempt to switch to 2kHz and tune 2kHz off in an attempt to get away from local QRM.  Also I'm not sure I have positively ID'd it, though.   I attempted to DX it today and couldn't get any trace of it.

(maybe?) 700 KALL North Salt Lake City, UT - 40°53'29"N 111°56'29"W
distance = 625.882 mi, heading = 24.76°
heavy QRM from 690 XEWW (or is it still XETRA?) - 77kW directional day, distance 32.355 mi, heading 188.75°,  barefoot PL-380 signal usually 63dBu RSSI, 25dB S/N.

Listening post is close enough to 32°45'40"N 116°56'50"W so that a legal part-15 FM station transmitting at that spot (although there is none that I'm aware of) would be receivable barefoot at my actual location.  As mentioned before, equipment used was:
radio: PL-380, unmodded (except for repair of a broken tuning knob which, after a few hiccups, was successful, although it did require repairing a trace on the PCB)
antenna: Select-A-Tenna
recorder: Samson Zoom H2, using direct audio cable connection

In many cases, in spite of using the 1kHz bandwidth and tuning 1kHz away from the QRM on the far side of the desired station, local stations 10 (or 11) kHz away were all but wiping out the stations I was trying to receive.  Is there anything that can be done to help alleviate that, short of relocating?

Also, I'm having some difficulty around the middle of the band.  There's a 50kW local (1170 KCBQ) that's 9.354 miles away at a heading of 7.28°, with a directional antenna pattern basically aimed toward me .  For about a few hundred kHz either way, the RSSI is about 30dBu in "blank spots" on the dial.  (In more rural areas it's more like about 15dBu or so.)   Can anything be done (for example, rewinding or replacing the internal loopstick) to alleviate that?  The apparent desensitization makes it difficult, if not impossible, to receive a few stations I would like to be able to listen to - 1110 KDIS Pasadena, CA (would possibly almost be strong enough to stop on while scanning, but with the desensitization is somewhat below the soft mute threshold), 1150 KTLK Los Angeles, CA, 1180 KERI Wasco-Greenacres, CA, and, if possible, 1160 KSL Salt Lake City (hey, if 700 from north of there can be heard here, why not 1160, even if it requires a SAT)?  Also, 10kW 1130 KSDO, 6.337 mi, directional , 350.28°, isn't making things any easier.

And, even if I am able to fix some of the barefoot deficiencies, there are times when I will want the extra boost of a larger loop antenna than the SAT, which just isn't cutting it anymore.   How much of an improvement would a 5.5" PVC loop be (or is the 4' one the largest that can be built without requiring a jumper to enable tuning the entire band) over the SAT?  (I mainly would like to, as much as possible, improve the barefoot performance, as I will not be able to use any type of external antenna for the vast majority of my casual listening  (for example, walking / biking around town, walking into a local mall, yogurt shop, etc).)  Anyone know of a way to put a loopstick in the battery compartment, and somehow figure out another way to get a 3.6V supply, while maintaining the barefoot appearance?  I don't really care about LW all that much, as I am unable to detect any LW stations near me.  It seems there should be plenty of room for a semi-decent stick there (I thought a month or two ago someone mentioned that they wanted to experiment with that, but I haven't heard anything since then), and I'd be willing to deal with somewhat of a reduction of battery life (I have plenty of Sanyo Eneloop 2000mAh AAs.)  Also I would be interested in learning more about sdwillingham's method of defeating soft mute (although I do want to retain an internal speaker).  

P.S. anyone know how to embed images in a group message using the web interface?

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