Date   

Re: Battery testing on the PL-310

Rik
 

I have a large number of old Zenith portables, and I noticed in the SAMS transistor service books currant draw is listed. In the Zenith sales literature the number of hours of battery life is advertised. Many of my portable Zenith's are listed as 300 hours, whether they are mid size and powered by 6-C cells or quite large and powered by 12-D cells. I no longer can find my book with battery specs for the old carbon zinc cells sold in the 1960's, but close to 500 hours out of a pair of AA cells is amazing!

Rechargeable cells are rated in m Amp/hrs. but I have no idea of the rating for any brand of Alkaline AA cells. With carbon Zinc, you did get much larger total capacity with low rates of discharge. The same was true of Alkaline, but to a lesser extent. or so I have read or seen in tests. - FARMERIK

--- In ultralightdx@..., "ferrite61" <dxrx@...> wrote:

As you may remember, I do a battery test on all my radios. For those new here a quick review of others I own:

Tecsun R911 and Kaito WRX911: 480 hours Continuous: End of Life 0.95 to 1.0 Volts per cell. Very efficient use of alkalines. Great for camping trips, vacations, emergencies. 2 AA powered.

Grundig G6: Variable 72 to 80 hours Continuous. This set gets louder as the batteries weaken... unusual. Best I've managed to repeat was 80 hours. End of Life 1.20 to 1.25 Volts per cell... you must be kidding. 50% depletion causes termination of reception. in a word, "Wasteful". Gobbles up 2AA cells. There could be a fault in the "intelligent battery function" on this set... it is a first and early production before Buzz Aldrin sets appeared.

So how did the 3-cell Tecsun PL-310 do? Well, it gets 96 to 100 hours Continuous(4 days). Its the same as my PL-200 set. The End of Life Voltage is actually just a bit better at 1.05 Volts per cell, as opposed to the 1.10 Volts per cell for the PL-200. But since the PL-200 is consuming 2 cells, I'll call it a draw due to the increased demands of the DSP-style reception of the PL-310. Nonetheless, the PL200 if a few cents cheaper to operate with reviews here that indicate its performance is not worse than the PL-310. Above average battery consumption characteristics

In summation, most people would be astonished at the R911/WRX911 longevity, and I was no exception. When coupled with its other good receiving habits, I strongly recommend one just in case "stuff" happens. Seriously, one can take the depleted batteries from a Grundig G6 and still get 7-10 days Continuous in the R911/WRX911. Thats how different battery-wise these receivers are. The PL200 and PL310 earn my respect for not wasting battery power when using disposable cells. Four days continuous is very good for any receiver at any price. And to think of all those 9-Volts we went through in the "old days" when overnight was pretty good.

Paul S. in CT


MI LOG - FM

wa8lcz
 

27JUL2010 TUE
107.9 CJXY Burlington ONT Y108 Rock 2215EDT 26.1 KW 170 MI (ONT32)

28JUL2010 WEN
98.5 WNCX Cleveland OH Classic Rock 0640EDT 16K 94 MI (OH20)



TOTALS: 118, MI62,OH20,NC01,PA01,ONTARIO 32,TX01,NM01
46 new log entries in July
RCVR: Eton E10
ANT: Moxon 2 ele folded wire yagi 48" x 18" indoors

Byron WA8LCZ nr Detroit posted 28jul 1431edt


Re: PL-210???'s-FARMERIK

sdwillingham
 

Hi Paul,

--- In ultralightdx@..., "ferrite61" <dxrx@...> wrote:
I checked in at blog.sina.com.cn using G-Translate. Yup, the 3-step
attenuator is listed (anti-mirror reference) in a different translation
providing High/Med/Low signal strength. Meaning it will have the switch.
On the PL-200 this is left-end near top, and is functional on the SW and
FM bands. So my main point of contention has been removed (this one
function elevates the PL-200 above most other enthusiast grade radios
including UL's Re: PL310/380/300wt and most analog AM/SW/FM sets).
Note that in FM operation, the Si4734-based radios also have this
feature. It is not apparent as a switchable function to the user,
but FM inputs are automatically attenuated when they would otherwise
overload the input stage.

The AM and SW input has some safeguards against overload, but it is
not as robust as the FM input.

-Scott-


Re: Battery testing on the PL-310

Harold
 

Interesting. My G8 seems like it may have great battery life so far.
Unscientific but I've had it since early May and use it everyday. The battery life indicator in the display still shows a full charge. Still on the same Duracells.
By the way I'm in Western Mass.
Thanks, Harold

--- In ultralightdx@..., "ferrite61" <dxrx@...> wrote:

As you may remember, I do a battery test on all my radios. For those new here a quick review of others I own:

Tecsun R911 and Kaito WRX911: 480 hours Continuous: End of Life 0.95 to 1.0 Volts per cell. Very efficient use of alkalines. Great for camping trips, vacations, emergencies. 2 AA powered.

Grundig G6: Variable 72 to 80 hours Continuous. This set gets louder as the batteries weaken... unusual. Best I've managed to repeat was 80 hours. End of Life 1.20 to 1.25 Volts per cell... you must be kidding. 50% depletion causes termination of reception. in a word, "Wasteful". Gobbles up 2AA cells. There could be a fault in the "intelligent battery function" on this set... it is a first and early production before Buzz Aldrin sets appeared.

So how did the 3-cell Tecsun PL-310 do? Well, it gets 96 to 100 hours Continuous(4 days). Its the same as my PL-200 set. The End of Life Voltage is actually just a bit better at 1.05 Volts per cell, as opposed to the 1.10 Volts per cell for the PL-200. But since the PL-200 is consuming 2 cells, I'll call it a draw due to the increased demands of the DSP-style reception of the PL-310. Nonetheless, the PL200 if a few cents cheaper to operate with reviews here that indicate its performance is not worse than the PL-310. Above average battery consumption characteristics

In summation, most people would be astonished at the R911/WRX911 longevity, and I was no exception. When coupled with its other good receiving habits, I strongly recommend one just in case "stuff" happens. Seriously, one can take the depleted batteries from a Grundig G6 and still get 7-10 days Continuous in the R911/WRX911. Thats how different battery-wise these receivers are. The PL200 and PL310 earn my respect for not wasting battery power when using disposable cells. Four days continuous is very good for any receiver at any price. And to think of all those 9-Volts we went through in the "old days" when overnight was pretty good.

Paul S. in CT


Re: Battery testing on the PL-310

Rick Robinson <w4dst@...>
 

On 7/28/2010 6:28 AM, ferrite61 wrote:
As you may remember, I do a battery test on all my radios. For those new here a quick review of others I own:

Hi Paul,

Thanks for sharing your very interesting information. A couple of years ago I got a great deal on 2300mAh AA NiMh batteries that I use in all my AA applications. I was glad to get NiMhs supplied with my PL-380. I've found it to be very easy on the battery charge.

How do you test the battery life? I have an old Radio Shack digital meter with a serial interface and DOS logging software that should for this.

73,

Rick W4DST


Battery testing on the PL-310

ferrite61 <dxrx@...>
 

As you may remember, I do a battery test on all my radios. For those new here a quick review of others I own:

Tecsun R911 and Kaito WRX911: 480 hours Continuous: End of Life 0.95 to 1.0 Volts per cell. Very efficient use of alkalines. Great for camping trips, vacations, emergencies. 2 AA powered.

Grundig G6: Variable 72 to 80 hours Continuous. This set gets louder as the batteries weaken... unusual. Best I've managed to repeat was 80 hours. End of Life 1.20 to 1.25 Volts per cell... you must be kidding. 50% depletion causes termination of reception. in a word, "Wasteful". Gobbles up 2AA cells. There could be a fault in the "intelligent battery function" on this set... it is a first and early production before Buzz Aldrin sets appeared.

So how did the 3-cell Tecsun PL-310 do? Well, it gets 96 to 100 hours Continuous(4 days). Its the same as my PL-200 set. The End of Life Voltage is actually just a bit better at 1.05 Volts per cell, as opposed to the 1.10 Volts per cell for the PL-200. But since the PL-200 is consuming 2 cells, I'll call it a draw due to the increased demands of the DSP-style reception of the PL-310. Nonetheless, the PL200 if a few cents cheaper to operate with reviews here that indicate its performance is not worse than the PL-310. Above average battery consumption characteristics

In summation, most people would be astonished at the R911/WRX911 longevity, and I was no exception. When coupled with its other good receiving habits, I strongly recommend one just in case "stuff" happens. Seriously, one can take the depleted batteries from a Grundig G6 and still get 7-10 days Continuous in the R911/WRX911. Thats how different battery-wise these receivers are. The PL200 and PL310 earn my respect for not wasting battery power when using disposable cells. Four days continuous is very good for any receiver at any price. And to think of all those 9-Volts we went through in the "old days" when overnight was pretty good.

Paul S. in CT


Re: PL-210???'s-FARMERIK

ferrite61 <dxrx@...>
 

I checked in at blog.sina.com.cn using G-Translate. Yup, the 3-step attenuator is listed (anti-mirror reference) in a different translation providing High/Med/Low signal strength. Meaning it will have the switch. On the PL-200 this is left-end near top, and is functional on the SW and FM bands. So my main point of contention has been removed (this one function elevates the PL-200 above most other enthusiast grade radios including UL's Re: PL310/380/300wt and most analog AM/SW/FM sets). Everything else about the PL-210 specs out the same as the PL-200. 1000 more "open" memories and USB charge for the rechargeables are now offered "for free". The only question that remains is the low-AM band. Does it still need an alignment? I'm hoping dual-conversion isn't 450/455 kHz on AM... it should be 10.7MHz/455kHz on SW.

If you missed out on the PL200/E100 this one would be a second-chance.

Paul S. in CT

--- In ultralightdx@..., "farmerik" <farmerik@...> wrote:

Paul has cleared up some of the details, but I guess until someone has one of these radios in hand, we won't be certain exactly how it is set up. I don't think I could tell if dual conversion was used on AM BCB and LW myself though, from using one. - FARMERIK

--- In ultralightdx@..., "Kevin S" <satya@> wrote:

I see that the dual-conversion is listed as being for "AM". Since the
shortwave bands are AM, it could be that the dual conversion is only on
SW, as I've seen in other radios, including if memory serves the PL-200
(e100)?

Kevin S
Bainbridge Island, WA


Thanks. The 3 step antenna attenuator is listed in the translated specs,
it sounds like you didn't see the switch in the photos. Dual conversion on
AM BCB and hopefully LW might cut interference? I am guessing it would
lower sensitivity unless the design was markedly improved, but hopefully
improve S/N ratio.

My RP-2100 was supposed to be dual conversion, but it was full of AM and
SW false signals. I have an other dual conversion pocket radio which is
not as good as a slightly less expensive single conversion set. I am
talking about inexpensive radios, not expensive portables or
communications receivers.

-FARMERIK



--- In ultralightdx@..., "ferrite61" <dxrx@> wrote:

I took a look at the PL-210 over at 5bcl.cn There is a new twist to the
PL-200 in that the PL-210 now has Dual Conversion on AM. Meaning all
Amplitude Modulated frequencies. This is good. However i should temper
your enthusiasm in the following ways:
1) I do not see a local/Normal/DX switch
2) The tuning knob operates the same as a PL-310
3) Sensivity on all major bands did not improve: LW is 5mV/m (not good)
4) Of the 1700 memories 1200 are not dedicated... meaning you're free to
enter any frequency. However, there is a fixed style of 12 pages x 100
entries (24 pages of 50 would be ideal).
5) The Dual conversion frequencies are not specified.
6) No one knows yet of the quality, size, and windings of the ferrite
antenna. I presume it to be as good as a PL200/E100 with specs given.
7) FM stereo specs are low 24db vs a usual 30db (35 in high quality
sets).
8) Finally this: Although the S/N sensitivity is the same as the
PL200/E100, we do not know the ultimate noise floor of the PL-210. The
PL200/E100's are rather quiet with a trace of hiss at moderate volume
levels during electrical blackouts in my neighborhood over the years.
In comparison The WRX911/R911 has noticible hiss, and my Grundig G5 and
G6 are silent until you turn up the sound loud. Do not expect any iBOC
improvement.

My initial glances and impressions are that the PL-210 is a convienient
consumer product with a reduced functionality compared to a PL200/E100.
Its reception quality is on par with the PL200/E100. If your preference
is USB charging over Local/Normal/DX rf amplification, you'll like the
convienience. At a listed price of 300 Yuan its near equal to the PL200.

Paul S. in CT


--- In ultralightdx@..., "farmerik" <farmerik@> wrote:

I am interested in the soon to be available PL-210, and understand it
has dual conversion, which I thought was new. I also thought the
E-100 was supposed to be the same as the PL-200, but according to a
review in the files here, the E-100 already had dual conversion on
SW. So maybe I misread something along the way. Does the new PL-210
have dual conversion on the AM and LW bands? - FARMERIK


Re: rewinding a PL-380 antenna

Rick Robinson <w4dst@...>
 

On 7/27/2010 1:57 PM, gratiscomputer wrote:

Look here, a nice project, with 2 lines on LCD: s/n, db, RDS,

http://www.elektor.com/products/kits-modules/modules/100126-91-elektor-dsp-radio.1390232.lynkx
Hi Marc,

Thank you for posting the link to this most impressive radio. This is a Si473X hacker's dream and it looks like nothing has been left. Especially interesting to me is the BNC connector for SW/FM, the Atmel microcontroller, and the connection for an external S meter, which I assume is an analog voltage output.

Do you have one or can you point me to a review of it? I am seriously considering ordering one as it is similarly priced as Si473X development boards here in the US but with much more flexibility.

Best regards,

Rick W4DST


Adding another one to the log, but think I missed out on a new country.

pianoplayer88key
 

This morning a little after 4 am, I heard something different than normal on a particular frequency. It seemed there were possibly 2 stations fighting it out, but as I kept listening a religious program seemed to be triumphing. Judging from the frequency, direction, and the station's format, I am quite sure I heard KRDU-1130 Dinuba, CA, at a distance of 289.05mi (465.19km), heading 333.50°. According to FCC data, they put somewhere between a 24.89 and 34.76mV/m @ 1km F/S toward me.

Before I heard the religious station starting to show signs of dominance (although usually not by more than a few dB), I thought I heard snatches of a news station, but the signal was too marginal to be sure. Could I have possibly heard CKWX Vancouver, BC, from a distance of 1175.83mi (1892.31km), heading 346.22°, F/S toward me 1153.28 to 1201.27mV/m @ 1km? I don't think I'm quite ready to add it to the nental logbook yet, as I couldn't hear it well enough over the other stations to positively identify it.

The radio used was my Tecsun PL-380, barefoot.

Now... any suggestions on how to pull in CKWX (if it was that one) on my barefoot PL-380 from my location? I should mention that when I did bag KRDU, my local station, KSDO-1130, 10kW, 6.33mi (10.19km) distant, heading 350.06°, F/S 1233.96mV/m @ 1km toward me, was off the air at the time. Now that it's back on (and indicates 63/25 readings on-frequency, and somewhere around 41,00 on the 9khz-split-frequency 1116, for example), what can I do to snag CKWX from here with my barefoot PL-380?


Re: rewinding a PL-380 antenna

gratiscomputer <gratiscomputer@...>
 

Rick Robinson schreef:

I'll also offer a tip of the hat to the FM section of the Si4734 which
is also amazing. Is anyone using or planning to use the '4735 with RDS
decoding that you are aware of? I'd love to see this in a future ULR
although the increased size of the LCD to incorporate RDS data and the
cabinet to support it, would most likely take it out of ULR class.
Look here, a nice project, with 2 lines on LCD: s/n, db, RDS,

http://www.elektor.com/products/kits-modules/modules/100126-91-elektor-dsp-radio.1390232.lynkx


Size isn't that big!

Elektor is a magazine that is published in German, Dutch, French, English ...

I read some germans want to make a tuner for some 250 euros...

This is the author of the Elektor magazine article:
http://www.b-kainka.de/index.htm


Marc

--
What's on Shortwave guide: choose an hour, go!
http://shortwave.tk
700+ Radio Stations on SW http://swstations.tk
300+ languages on SW http://radiolanguages.tk


Re: Original pl-360 loopstick

Gary DeBock
 

Hello Marc,
 
Thank you for your information, comparing the PL-360 7.5" plug-in loopstick performance with the original loopstick + antenna tuner combination.
 
Also, I remember that you found a way to connect the PL-360 plug-in loopstick to the PL-380 model, and enjoy all the DXing benefits of the Si4734 DSP chip in the PL-380 using the 7.5" loopstick. This was also done here in a recent experiment, by adding a "docking port" to the PL-380 cabinet to accept the PL-360 7.5" plug-in AM and LW loopsticks. A photo of the modified PL-380 (with the PL-360 7.5" AM loopstick plugged in) is shown below.
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)
 
                                                                      
 
 
 
 

In a message dated 7/27/2010 12:29:38 A.M. Pacific Daylight Time, gratiscomputer@... writes:
 

Hello,

Compared with the original loopstick from the antenna tuner, the pl-360
loopstick gives an increase of

927kHZ +3dB
603kHz +8dB

The antenna tuner and its ferrite bar are here:
http://www.charly-hardt.de/eigen.html

Marc

--
What's on Shortwave guide: choose an hour, go!
http://shortwave.tk
700+ Radio Stations on SW http://swstations.tk
300+ languages on SW http://radiolanguages.tk


7.27.10

Antonios Kekalos <akekalos@...>
 

0739EDT, 89.3, WCMZ, Sault Ste. Marie, MI, 127 miles, 25K, NPR, G8
0750EDT, 93.3, WKQZ, Midland, MI, 102 miles, "Z93", G8
0754EDT, 99.7, WROE, Neenah-Menasha, WI, 147 miles, 13K, STN ID, G8


--
Tony, N4RNI
Traverse City, MI
EN74dq
FISTS #14949, SWLR-RN072

I'm apathetic, but I don't care



Original pl-360 loopstick

gratiscomputer <gratiscomputer@...>
 

Hello,

Compared with the original loopstick from the antenna tuner, the pl-360 loopstick gives an increase of

927kHZ +3dB
603kHz +8dB

The antenna tuner and its ferrite bar are here:
http://www.charly-hardt.de/eigen.html

Marc

--
What's on Shortwave guide: choose an hour, go!
http://shortwave.tk
700+ Radio Stations on SW http://swstations.tk
300+ languages on SW http://radiolanguages.tk


Re: Oregon Beach DXpedition Completed

pianoplayer88key
 

What RF hash issues are you talking about, Gary? Did someone build a multiplexing AM antenna farm right at the Grayland DX beach location with 50kW IBOC transmitters on each of 540, 630, 720, 810, 900, 990, 1080, 1170, 1260, 1350, 1440, and 1530? That too would absolutely give me fits if I was trying to DX around that on my barefoot PL-380, and I don't think I'd even try doing it with a SRF-M37W!

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

Hi Mark,

Thanks very much for your comments on the DX received during the Lincoln
City, Oregon DXpedition with Ultralight gear.

Chuck H., Bruce P., Patrick M. and my local friend Guy Atkins are helping
me go through some South Pacific UnID mysteries prior to drafting of the
DXpedition report, which I'm eager to complete. It will include links to
MP3's of several less common DU's, which seem to only occasionally show up at
Grayland with much more advanced equipment. I think there is a general
consensus that the Ultralight DXing results at Lincoln City were unusually good,
which may be related to the DXing location on top of a cliff (of about
100') adjacent to the ocean beach.

Whatever the reason for the great DX in Lincoln City, it seems like a nice
place to investigate, now that the Grayland Motel has fallen out of favor
because of recent RF hash issues.

73, Gary


In a message dated 7/26/2010 8:30:00 P.M. Pacific Daylight Time,
MarkWA1ION@... writes:




Gary, I'm looking forward to seeing your report. With what you've done at
the QTH in July with Ultralight gear, I'd like to see what you and some of
the other West Coast guys could do there in October with "big-gun" receivers
and antennas (Perseus or Excalibur receiver, QDFA or Beverage antenna).

Mark Connelly, WA1ION
Billerica, MA + South Yarmouth, MA, USA

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

Hello All,

We are now back home in Puyallup, WA now after a thrilling ULR
DXpedition
to an Oregon ocean beach at Lincoln City, primarily to chase South
Pacific
DX with the new 7.5" plug-in loopstick PL-380 and 3' portable PVC tuned
passive loop. Before leaving Oregon I had a chance to meet with Patrick
Martin,
one of the west coast's premier DU-chasing experts with decades of
experience. Patrick seemed to be quite fascinated with the new 7.5"
fixed-loopstick PL-380 that I left him as a gift, and hopefully he will
soon enjoy
chasing TP-DX with it, as an exciting way to rejuvenate his interest in
DXing at
his fantastic ocean beach location in Seaside, OR.

To give an indication of the incredible propagation during the recent
DXpedition in Lincoln City, I have uploaded the first of about 35 MP3's
of South
Pacific DX recorded last week. This link is for a bizarre snarl of two
S9+
stations mixing on 738 kHz-- Radio Tahiti (in French) and 2NR in
Grafton,
Australia, maxing out the PL-380's S/N reading at 25 (with an RSSI of
55).
This reception was obtained on the new 7.5" plug-in loopstick PL-380,
inductively coupled to a 3' portable PVC tuned passive loop. The amazing
signal
of these two DU's mixing together was also easily heard on a barefoot
Sony
SRF-T615, the first time I have ever heard two DU's fight it out on a
barefoot Ultralight! __http://www.mediafire.com/?eea954j14dmzalm__
(http://www.mediafire.com/?eea954j14dmzalm_)
(_http://www.mediafire.com/?eea954j14dmzalm_
(http://www.mediafire.com/?eea954j14dmzalm) )

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)


Re: Oregon Beach DXpedition Completed

pianoplayer88key
 

Considering how good some of your ultralights seem to be (although mine by comparison seems to be a dud - i'm getting 50,00 readings and severe desensitization across half the band right outside the fence surrounding a local 5kW IBOC AM site, but am getting 00,00 readings 2 channels on either side of an FM at the same site)... and considering that the "big guns" are even more awesome... I almost wonder if it would be possible to hear some of the TP transmitters over a DAYLIGHT PATH :) using that equipment (the big gun receivers and beverage antennas, for example) even in an area where an ultralight inductively coupled to Gary's 9-foot-per-side PVC loop would have NO chance whatsoever? I'm thinking, for example, you would be pulling in the TPs out from between the left and right sides of the structure of the tower of local blowtorches like KMPC, KFBK, KGDD, KMRB, KERN, KCBQ, KLOK, KPTK, KFXX, KNX, KOMO, KGNW, KTBI, KGO, KIRO, KSPN or KFI, while sitting at their 614,000mV/m contour.. and the TPs would be on the same frequency or 1kHz off. Or is that too much for even a beverage antenna (or are they not directional enough to pull in a distant station out from between the sides of the tower of a local on the same frequency?) and professional communications receiver to deal with? ;) Would the saltwater path STILL not be good enough to get a groundwave signal over several thousand miles of ocean? Of course I wouldn't expect an ultralight to be able to do that. :)

--- In ultralightdx@..., "MarkWA1ION" <MarkWA1ION@...> wrote:

Gary, I'm looking forward to seeing your report. With what you've done at the QTH in July with Ultralight gear, I'd like to see what you and some of the other West Coast guys could do there in October with "big-gun" receivers and antennas (Perseus or Excalibur receiver, QDFA or Beverage antenna).

Mark Connelly, WA1ION
Billerica, MA + South Yarmouth, MA, USA

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

Hello All,

We are now back home in Puyallup, WA now after a thrilling ULR DXpedition
to an Oregon ocean beach at Lincoln City, primarily to chase South Pacific
DX with the new 7.5" plug-in loopstick PL-380 and 3' portable PVC tuned
passive loop. Before leaving Oregon I had a chance to meet with Patrick Martin,
one of the west coast's premier DU-chasing experts with decades of
experience. Patrick seemed to be quite fascinated with the new 7.5"
fixed-loopstick PL-380 that I left him as a gift, and hopefully he will soon enjoy
chasing TP-DX with it, as an exciting way to rejuvenate his interest in DXing at
his fantastic ocean beach location in Seaside, OR.

To give an indication of the incredible propagation during the recent
DXpedition in Lincoln City, I have uploaded the first of about 35 MP3's of South
Pacific DX recorded last week. This link is for a bizarre snarl of two S9+
stations mixing on 738 kHz-- Radio Tahiti (in French) and 2NR in Grafton,
Australia, maxing out the PL-380's S/N reading at 25 (with an RSSI of 55).
This reception was obtained on the new 7.5" plug-in loopstick PL-380,
inductively coupled to a 3' portable PVC tuned passive loop. The amazing signal
of these two DU's mixing together was also easily heard on a barefoot Sony
SRF-T615, the first time I have ever heard two DU's fight it out on a
barefoot Ultralight! _http://www.mediafire.com/?eea954j14dmzalm_
(http://www.mediafire.com/?eea954j14dmzalm)

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)


Re: Oregon Beach DXpedition Completed

Rik
 

I hope you will still have time to wind some LW BCB versions for the PL-360-FARMERIK

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

Hi Norm,

The 7.5" plug-in loopsticks designed for the PL-360 (already sent out to
you, and 21 other DXers) are exactly the same as the 7.5" plug-in loopstick
that I used with a modified PL-380 last week, to chase South Pacific DX in
Oregon. The only difference is that I needed to attach a "docking port" to
the top of the PL-380 cabinet to accept the plug-in loopstick, since the
PL-380 doesn't have a loopstick plug-in jack like the PL-360.

Before the Oregon DXpedition, I rushed completion of the first PL-380
cabinet mod to accomplish this, and then plugged my "PL-360" 7.5" AM and LW
loopsticks into the PL-380 model to chase DX in Oregon. Both worked like
gangbusters in the PL-380, and the LW version easily received three LW TP's
despite the mediocre late July conditions. These were three Russian Far East
stations, which typically are the only LW-TP's available on the west coast in
summer --153-Radio Rossii _http://www.mediafire.com/?skaffgagzalo6ij_
(http://www.mediafire.com/?skaffgagzalo6ij) ,
180-Radio Rossi, and 279-Radio Rossii
_http://www.mediafire.com/?wes5amhcb3n5cqt_ (http://www.mediafire.com/?wes5amhcb3n5cqt) .

Before taking orders for more PL-380 cabinet modifications to accept the
7.5" plug-in loopsticks, though, it would probably be best to run a few more
experiments to refine the design and construction methods. My goal is to
have this PL-380 modification process ready for all 7.5" plug-in loopstick
owners to enjoy, in time for the fall DX season.

73, Gary


In a message dated 7/26/2010 6:47:38 P.M. Pacific Daylight Time,
ultralightdx@... writes:

Hi Gary,

I am the proud owner of one of your 7.5" fixed loopsticks and I am trying
to decide whether to purchase the PL-360 it was intended for, or to pursue
a modified PL-380?

Can you give me a brief opinion on which receiver might be the best for MW
DXing? Any other points to consider?

I know you are busy, so please don't feel like you have to answer right
away!

The best to you,
73, Norm Clark


Re: rewinding a PL-380 antenna

sdwillingham
 

Hi Stephen,

You bring up some good points to share with some of the list's newer
members.

The first is the "unpredictability" of very strong signals. All radios
can be overloaded with strong enough RF signals. When the front-end
circuits of a radio are overloaded, there are nonlinear effects that
produce a varied jumble of signals for the later stages of the radio
to handle. This jumble of signals, and the resulting RSSI readings,
can be quite unpredictable and counterintuitive in many cases. With
sufficient data, the effects can be sorted out, but it is usually
difficult and tedious.

Again, all radios suffer from this problem, just to different degrees.
There are a few ways to improve this performance. The first is to
reduce the antenna signal. DXers are highly resistant to this idea,
but many times it is quite effective. The "phantom" signals caused
by distortion reduce in magnitude at a faster rate than the desired
channels. Six decibels of attenuation can reduce the distortion
by 18 dB or more, for a net improvement in signal-to-distortion ratio
of 12 dB. Of course, one loses some sensitivity to very weak signals.
But very often, especially in urban environments where large signals
exist, your sensitivity (MW) is limited by noise external to the radio.
You often have "sensitivity" to burn, so to speak. Stephen: this
effect can also happen when you move further from the station. The
signal quality can improve, even though the signal power is weaker.

A second way to increase the distortion point of a radio is by changing
the circuit design of the radio. Obviously, there are tradeoffs, or
radio design would have been perfected decades ago. To achieve a net
improvement, one must increase the distortion point without reducing
gain or increasing noise. The bottom line is that to do this, the
power-consumption of the radio must increase. (Even if cryogenic
cooling of the circuits are used, that uses power.) To get 6dB better
dynamic range (ratio of distortion limit to noise floor), roughly
quadruples the required power consumption. In a ULR, the dynamic
range will always be more limited than for AC-powered radios.

A third way to remedy the problem is sharper passive filtering
(inductors and capacitors) before the active amplifiers. This also
is limited by practical components, cost, and size.

Getting back to RSSI readings, the strange variations for very strong
RF signals relates to distorted spurious signals generated in the radio's
front-end circuit. So in such an environment, only limited use can be
made of the RSSI readings.

--- In ultralightdx@..., "Stephen" <pianoplayer88key@...> wrote:
If I go a bit farther away, the RSSI on the weak or blank channels is
reduced. For example, there are some stations which range from 60 to
63dBu near here, and the RSSI on most of the band is 30dBu minimum in
most cases.

When I'm nowhere near a blowtorch, it's quite a different picture.
There, the RSSI on blank or weak stations will be 15dBu, absolute
minimum.
I think you are interpreting this as the radio's accuracy varying under
the stated conditions. But you need to be careful. As you go away from
a large-signal environment, you are also generally moving away from
man-made noise sources. In reality, the background RSSI *is* 30 dBuV
in one location and 15 dBuV in another. In MW operation, at least when
not using a low-noise antenna like a beverage, the noise floor is most
often limited by environment or antenna factors, not the radio circuits.

You've reminded me of another important caveat. The apparent 15 dBuV
floor on the AM RSSI readings is due to a technical tradeoff in a
firmware patch that Tecsun uses. So it is important to emphasize that
as signal levels dip to 15 dBuV and below, the RSSI is not reliable.
In my modified PL-380, I am able to disable this feature and then the
Si4734 reads RSSI accurately down to 0 dBuV.

Furthermore, the PL-380 limits the display of RSSI to 63 dBuV, even
when the SI4734 is indicating higher.

I've seen stations in rural areas with a 15dBu RSSI and 18dB SNR.
I even saw a 5dB greater SNR than RSSI at least a couple times when
I saw a 17,22 reading.
This indicates that the radio's internal noise floor is much lower
than the otherwise implied 15 dBuV floor.

Earlier today I visited the area near the site of a local 5kW IBOC
AM that also has an FM up on top of a tower.
Now that's a very complex situation, which I can't really analyze
without extensive data.

Cheers,
Scott


Re: rewinding a PL-380 antenna

pianoplayer88key
 

I'm not Scott, but I'll offer my thoughts and experiences with my PL-380. As an intro, I have seen wildly variable numbers in different cases.

For example, let's say I'm within a few miles or so of a high-powered (50kW for example) broadcast transmitter on a different frequency (possibly up to 100kHz apart) from the station I'm listening to.
One station that's otherwise a fairly strong local may have a RSSI of 50dBu and a SNR of maybe 4dB. The audio will be coming in fairly well, but will definitely have audible noise in it. The same station, when I go farther from the blowtorch pest so it isn't desensing my radio, may have a reading of 57dBu RSSI and 25dB S/N, for example, even if I've gone farther from the station, maybe. (I'm planning a couple semi-local trips to test this and other theories I have thought of.)
Another weaker station may still have easily understandable audio, but will be indicating 50dBu RSSI and 0dB SNR.

Iif I go a bit farther away, the RSSI on the weak or blank channels is reduced. For example, there are some stations which range from 60 to 63dBu near here, and the RSSI on most of the band is 30dBu minimum in most cases.

When I'm nowhere near a blowtorch, it's quite a different picture. There, the RSSI on blank or weak stations will be 15dBu, absolute minimum.
Remember what I said about the audio on a 50,00 signal still sometimes being perfecly understandable? In a less RF-saturated area, though, I may see indications of 15dBu RSSI and 1-2dB SNR on a station, and it is barely identifiable. (I suspect it may partially be the way the audio is done, though, notwithstanding the variable bandwidths which I usually set at or near 1kHz on weak/marginal signals. I have a Sony SRF-42 AM Stereo radio with almost a full response up to 10kHz, which is maybe a couple dB or so more sensitive than my Panasonic RQ-SW20. That radio's stereo decoder was (one of two things now: I've misplaced it, or it's non-functional) ALWAYS active, even on weak or non-stereo signals. A station that was completely unreadable on the RQ-SW20 was fairly easy to ID on the SRF-42.)
As for another station having a 50,04 reading in a high RF area... I've seen stations in rural areas with a 15dBu RSSI and 18dB SNR. I even saw a 5dB greater SNR than RSSI at least a couple times when I saw a 17,22 reading.

Scott, is that normal behavior for the Si4734 chip? Earlier today I visited the area near the site of a local 5kW IBOC AM that also has an FM up on top of a tower. The AM, 600 KOGO, caused a 50dBu RSSI to be spread over much of the band on the blank channels. One of the FMs up top, 106.5 KLNV, had a 63,43 reading on-channel, a 20dBu or so reading 1 channel (+/-200kHz) off, even though it wasn't an IBOC signal, and 0dBu 2 channels off. At 3 channels off both ways (+/-600kHz), I could hear clean images of 106.5 (which could also be heard around 93.3, 97.3, and 101.5, one of which also has an antenna on a KOGO tower, but all were under 52dBu - maybe I was in the null? The other 2 (all 3 I believe are IBOC) are on KLSD's tower about a mile away.

--- In ultralightdx@..., "mediumwavedx" <mediumwavedx@...> wrote:

Scott,

Could you tell us how and where the SNR figure is measured for display? Does the RSSI value work into it, or is it derived from audio output?

Thanks,

Bill

--- In ultralightdx@..., "sdwillingham" <sdwillingham@> wrote:

The comment about the dBuV reading is incorrect. The RSSI readings are referred to the pins of the chip, which are the inputs to the LNA. In the Tecsun radios operating in the MW band, this is also the voltage across the loopstick. In SW bands, the Tecsun ULRs use a preamp/LNA on the circuit board between the whip antenna and the Si4734. In that case, the RSSI readings reflect the signal at the output of Tecsun's external LNA.

Thanks for the complements about the Si4734. While Tecsun and others emphasize the chip's DSP features in marketing, the Si4734's performance is also enabled by considerable analog Kung Fu.

-Scott-


Re: rewinding a PL-380 antenna

sdwillingham
 

Hi Bill,

--- In ultralightdx@..., "mediumwavedx" <mediumwavedx@...> wrote:
Scott,

Could you tell us how and where the SNR figure is measured for
display? Does the RSSI value work into it, or is it derived
from audio output?
The SNR figure is calculated by a proprietary DSP algorithm, and
neither the RSSI nor audio output directly play a role. The
input to the algorithm is the filtered IF signal before audio
demodulation. It is really more of a carrier-to-noise ratio
than directly an audio noise measurement. Obviously, in AM it
is bounded between 0 and 25 dB. The motive for computing and
providing the number comes from implementing better station
search capabilities; the display is just a nice byproduct.

-Scott-


Re: rewinding a PL-380 antenna

sdwillingham
 

--- In ultralightdx@..., Rick Robinson <w4dst@...> wrote:
Thank you for clearing up my misunderstanding regarding the RSSI
readings being taken from the input not the output of the LNA. That
makes the radio almost a low cost selective voltmeter.
Yes, the RSSI readings are pretty accurate for most uses (especially
for relative readings). They could easily be calibrated with an
external attenuator for even more absolute accuracy. At very strong
RF levels, the readings may deviate for a couple of technical reasons.

I've noticed
that my PL-380 "updates" the RSSI/SNR info on the screen more frequently
than the G8. Is this my imagination or a programmable parameter in
firmware?
The screen in each radio is controlled by Tecsun's main application
processor. The processor sends query commands to the Si4734 to obtain
the RSSI numbers. The update rate is determined by Tecsun, probably to
reserve battery power and keep RF interference to a minimum. The Si4734
internally updates the RSSI and SNR parameters at much higher rates.

According to
the Si473X data sheet there are 7 different bandwidths. What are the 2
not implemented in the PL380?
The PL-380 uses the Si4734-B20 variant of the chip, which has version
2.0 of the Silabs' firmware. The C40 version of the chip adds 1.8 and
2.5 kHz filters. Although 1.8 kHz is very close to 2.0 kHz, I think
there are differences in the detailed filter response for better
intelligibility and adjacent channel rejection.

I'll also offer a tip of the hat to the FM section of the Si4734 which
is also amazing. Is anyone using or planning to use the '4735 with RDS
decoding that you are aware of? I'd love to see this in a future ULR
although the increased size of the LCD to incorporate RDS data and the
cabinet to support it, would most likely take it out of ULR class.
The FM section is the "bread-n-butter" of our revenue stream and is
highly refined. The RDS performance is the best in the industry in both
performance and ease of use. Many devices make use of this chip (minus
the AM functions), just in a different form factor than you are used to
looking for: Zillions of cell phones, "Personal Navigation Devices"
(GPS) which use the RDS decoding for traffic info, pre-HD versions of
the Zune mp3 player, Apple's FM radio accessory for iPods, the 5th-gen
iPod Nano, and many other mp3 players.

As for future "conventional" ULRs with RDS features, I don't have any
information about that.

-Scott-