Date   

Re: More on my ultralight experience

Rik
 

I still suspect there is a way to shield a loop or ferrite antenna with a grounded grid or solid 'screen'. I was hoping an engineer here would have already done this or at least give me ideas for experiments. Use of my hands and arms is pretty limited, but after awhile I can build some crude things. I do get less interference from computer equipment by hanging small loops close to the ceiling. If a shielding screen could be rigged under and behind a loop, it might become unidirectional. I am relatively near the East coast myself, so most all DX domestic targets are to my West, but there are locals to my East. If you have room for a Beverage, they can be unidirectional with a distal ground. - FARMERIK

--- In ultralightdx@..., "neilbellgroups" <neil.bell@...> wrote:

As a friend (Mike Maghakian) pointed out to me, our location on the extreme west coast of California near SF presents a major issue for MW DXing.

To the west we have nothing but ocean, many, many hundred miles of ocean, with only infrequent TP DX possible. If you are a few miles inland, (in my case 30 plus miles), TPs are very difficult.

To the east we have large deserts with sparsely populated areas like Nevada, Utah, Arizona, New Mexico etc. Compounding this there is
the large and high Sierra mountain range running the length of eastern California!

This means many MW stations lie either to the north or to the south. Using loops or loopsticks means that trying to null out a station to the north also nulls stations to the south. Obviously, this complicates DXing to the north or south. Using loops in this situation requires very careful positioning of the antenna/radio, sometimes working just the edge of the lobes of the antenna pattern.

I assume that DXers in Oregon and Washington face the same sorts of issues as do those on the extreme east coast.

Receiving a co-channel station when the other station on the same frequency is about 180 degrees opposite is a challenge requiring favorable propagation and close attention to the grey line. in this situation using my Phaser and paired random-wires is the best option.

Makes me envy the people living in middle parts of the country with DX opportunities in all directions or even people on the east coast with many more stations to chase and less challenging topography!

Despite the lack of a keypad for tuning, the PL360, when combined with Gary's 7.5 inch loop-stick works quite well even considering my arthritic hands. I have rigged a nice stand to hold the radio and still give free access to the loop-stick.

Neil Bell
KJ6FBA


More on my ultralight experience

neilbellgroups <neil.bell@...>
 

As a friend (Mike Maghakian) pointed out to me, our location on the extreme west coast of California near SF presents a major issue for MW DXing.

To the west we have nothing but ocean, many, many hundred miles of ocean, with only infrequent TP DX possible. If you are a few miles inland, (in my case 30 plus miles), TPs are very difficult.

To the east we have large deserts with sparsely populated areas like Nevada, Utah, Arizona, New Mexico etc. Compounding this there is
the large and high Sierra mountain range running the length of eastern California!

This means many MW stations lie either to the north or to the south. Using loops or loopsticks means that trying to null out a station to the north also nulls stations to the south. Obviously, this complicates DXing to the north or south. Using loops in this situation requires very careful positioning of the antenna/radio, sometimes working just the edge of the lobes of the antenna pattern.

I assume that DXers in Oregon and Washington face the same sorts of issues as do those on the extreme east coast.

Receiving a co-channel station when the other station on the same frequency is about 180 degrees opposite is a challenge requiring favorable propagation and close attention to the grey line. in this situation using my Phaser and paired random-wires is the best option.

Makes me envy the people living in middle parts of the country with DX opportunities in all directions or even people on the east coast with many more stations to chase and less challenging topography!

Despite the lack of a keypad for tuning, the PL360, when combined with Gary's 7.5 inch loop-stick works quite well even considering my arthritic hands. I have rigged a nice stand to hold the radio and still give free access to the loop-stick.

Neil Bell
KJ6FBA


Re: Tecsun PL-390 2 speaker SW radio on eBay

dave_m1ctk
 

Thanks, hmm nice but not much point for it somehow....like to know what has happend to the proposed PL-750

2010/7/6 Moisés Knochen <moises.knochen@...>

 

These are the links Ms Joyce sent me for the PL-390:

SILVER : http://cgi.ebay.com/TECSUN-New-PL390-PLL-World-Band-w-Dual-Speaker-Radio-/120592182930?cmd=ViewItem&pt=Shortwave_Radios&hash=item1c13daae92

GREY: http://cgi.ebay.com/TECSUN-New-PL390-PLL-World-Band-w-Dual-Speaker-Radio-/120592192434?cmd=ViewItem&pt=Shortwave_Radios&hash=item1c13dad3b2

Regards,

Moises


At 11:34 06/07/2010, you wrote:
 

What is the link for it on ebay please ?

On 6 July 2010 15:33, sjb92338 <sbass@...> wrote:
 



Joyce emailed me that the PL-390 has the 5 bandwidths like the PL-380, but that the internal ferrite is only 2.4 inches long.

Steve Bass

--- In ultralightdx@..., "thinkdx" wrote:
>
> I saw this model earlier today, George. It looks like a mini boombox!
>
> The auction copy does not mention DSP or multiple bandwidths, but the front panel clearly says "DSP" and there is an "AM BW" button.
>
> Guy Atkins
> Puyallup, WA
> http://fivebelow.squarespace.com
>
>
> --- In ultralightdx@..., "georgesmn" wrote:
> >
> > From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN
> >
>


Moises Knochen
Montevideo, Uruguay



Re: Deciphering the Kchibo Radio DSP-chip Puzzle

Gary DeBock
 

Hi Scott,
 
The reverse side of the KK-D6110 digital board (pictured below) apparently only has digital switches, the digital display housing, and the male 8-pin connector to the RF board. A higher resolution photo of this will be uploaded to the album, but nothing like a DSP chip is in evidence.
 
73, Gary
 
                                                               
 
In a message dated 7/6/2010 9:31:59 A.M. Pacific Daylight Time, sdwillingham@... writes:

 

Gary,

Do you have any pictures of the other side of the PCB? I suspect the radio chip is on that side.

Thanks,
Scott


Hopalong Cassidy at the Dials?????............

robert ross
 

HI Guys:

Well...after a trip to see the Surgeon yesterday, it looks like I'm gonna have some Extra DXing time after Aug/10th!! They are gonna fix my Knee for me .....hopefully, and with Holidays and sick time I will be off for 5 Weeks from Aug/10 to Sept/13. With any luck the AM BCB will be back to DX quality by then....and if I'm really lucky, there will be a 5 week TROPO opening on the FM Band at the same time. With a Bunged up knee....and nowhere to go, I will mercifully be TRAPPED in my Radio Room!! HAHHAHAHHA

Actually....can't think of a better place to be trapped for 5 weeks...as long as conditions are good...and the Central Air doesn't fail!! Man it was HOT here yesterday.....Peaked out at 35 Degrees C.

So......after Aug/10th, I should be in here buggin' everyone for 5 weeks or so.....

Salute...ROB VA3SW

Robert S. Ross
London, Ontario CANADA


Re: Tecsun PL-390 2 speaker SW radio on eBay

Moisés Knochen
 

These are the links Ms Joyce sent me for the PL-390:

SILVER : http://cgi.ebay.com/TECSUN-New-PL390-PLL-World-Band-w-Dual-Speaker-Radio-/120592182930?cmd=ViewItem&pt=Shortwave_Radios&hash=item1c13daae92

GREY: http://cgi.ebay.com/TECSUN-New-PL390-PLL-World-Band-w-Dual-Speaker-Radio-/120592192434?cmd=ViewItem&pt=Shortwave_Radios&hash=item1c13dad3b2

Regards,

Moises

At 11:34 06/07/2010, you wrote:
 

What is the link for it on ebay please ?

On 6 July 2010 15:33, sjb92338 <sbass@...> wrote:
 



Joyce emailed me that the PL-390 has the 5 bandwidths like the PL-380, but that the internal ferrite is only 2.4 inches long.

Steve Bass

--- In ultralightdx@..., "thinkdx" wrote:
>
> I saw this model earlier today, George. It looks like a mini boombox!
>
> The auction copy does not mention DSP or multiple bandwidths, but the front panel clearly says "DSP" and there is an "AM BW" button.
>
> Guy Atkins
> Puyallup, WA
> http://fivebelow.squarespace.com
>
>
> --- In ultralightdx@..., "georgesmn" wrote:
> >
> > From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN
> >
>


Moises Knochen
Montevideo, Uruguay


Re: Tecsun PL-390 2 speaker SW radio on eBay

dave_m1ctk
 

What is the link for it on ebay please ?

On 6 July 2010 15:33, sjb92338 <sbass@...> wrote:

 



Joyce emailed me that the PL-390 has the 5 bandwidths like the PL-380, but that the internal ferrite is only 2.4 inches long.

Steve Bass

--- In ultralightdx@..., "thinkdx" wrote:
>
> I saw this model earlier today, George. It looks like a mini boombox!
>
> The auction copy does not mention DSP or multiple bandwidths, but the front panel clearly says "DSP" and there is an "AM BW" button.
>
> Guy Atkins
> Puyallup, WA
> http://fivebelow.squarespace.com
>
>
> --- In ultralightdx@..., "georgesmn" wrote:
> >
> > From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN
> >
>



Re: Tecsun PL-390 2 speaker SW radio on eBay

sjb92338 <sbass@...>
 

Joyce emailed me that the PL-390 has the 5 bandwidths like the PL-380, but that the internal ferrite is only 2.4 inches long.

Steve Bass

--- In ultralightdx@..., "thinkdx" <dx@...> wrote:

I saw this model earlier today, George. It looks like a mini boombox!

The auction copy does not mention DSP or multiple bandwidths, but the front panel clearly says "DSP" and there is an "AM BW" button.

Guy Atkins
Puyallup, WA
http://fivebelow.squarespace.com


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

From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN


Re: Deciphering the Kchibo Radio DSP-chip Puzzle

cadcoast <jm392c@...>
 

I transplanted a 7.5" loopstick wound with Litz onto the KK-D6110 and it does give it a substantial boost. The stock loopstick is easy to access, as are the solder terminals. It's disappointing, but not surprising, that this model does not contain the si4734 chip. My question to the group is: is there any way for a layman, other than trial and error, to determine the best number of turns of Litz wire?

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

Hello All,

Those DXers (including me) who had thought that the new KK-D6110 model was
a serious attempt by Kchibo to upgrade the D96L model now have serious
evidence to the contrary. After multiple reports of lackluster performance on
both the AM and FM bands, a detailed investigation and disassembly of the
KK-D6110 model has revealed that the new radio is not an Si4734 DSP chip
radio after all, but apparently uses the same DSP chip powering the Kchibo
KK-D680, KK-210B, KK-D202 and KK-D220 models. This certainly explains the drop
off in AM performance relative to the D96L model, a true Si4734 DSP chip
receiver.

The KK-D6110's lower AM sensitivity specification and much lower eBay
selling price (relative to the D96L) created doubts about this from the
beginning, but the sole eBay seller's KK-D6110 listing (obviously translated by
Google from the original Chinese on the Kchibo web site) certainly doesn't
make the DSP chip identity very clear.

The KK-D6110 has a DSP filter selection switch which mimics the Si4734
models quite well (although the filtering selections are backward, like in the
D92L), and other functions also are apparently designed to resemble the
D96L, such as the green display light and memory operations. But AM-DXing
performance falls well short of the D96L, and full disassembly of the KK-D6110
brought the truth to light.

The stock loopstick has a single coil with an inductance measured at 630
uh, which would certainly be an unusual value for an Si4734-chip radio with
no LW-band responsibility. Subtracting coil turns on the stock loopstick
did not significantly improve X-band performance on the KK-D6110, as it would
with a true Si4734-chip radio having a 630 uh loopstick coil. The digital
board copper shield was simply tack-soldered at a few places, resulting in
a slight digital whining noise bleeding through to the loopstick (which
also affected all upgrade loopsticks, both internal and external). Removal of
the copper shield (photo at _http://www.mediafire.com/?xy2u3wnjvyn_
(http://www.mediafire.com/?xy2u3wnjvyn) ) revealed various IC's, but certainly no
Si4734 DSP chip. After the earlier indications, it wasn't a big surprise.

The Kchibo model numbering system apparently gives an indication whether
the Radio is a true Si4734 DSP chip model, or not. Those models with a DxxL
numbering system (D92L, D95L, D96L, etc.) are the true Si4734 chip radios,
while those with the KK-Dxxx numbering system (KK-D6110, KK-D680, KK-D220,
etc.) are not. Kchibo advertises both types as DSP radios, and the Chinese
documentation (with rough English translations) is confusing at best. Sorry
for any inconvenience because of this, but those DXers who had planned to
order the new KK-D6110 model as a upgraded replacement for the D96L should
not proceed. The KK-D6110 is a decent radio for the money, but should not
be confused with true Si4734 DSP receivers like the D96L, PL-310, PL-380,
PL-360 etc. The detailed disassembly photos will be uploaded to the KK-D6110
photo album on the Ultralightdx site.

73, Gary DeBock (in Puyallup, WA, USA)


Question about ultralight and loops for MW

sarmento2k
 

Hi

After have seen info about these new DSP receivers (like PL310/380) :

http://bbs.tecsun.com.cn/0002.asp?open=186695

I wonder if it would support loop antennas, like square air coil or even ferrite loops.

If one issue to add : living near big power MW stations.

Have anyone tried MW dx in this conditions ?

Regards
Sarmento - Rio de Janeiro - Brazil


One New Station

Kirk <kirk74601@...>
 

As you know, 1560 has been a target freq of mine for about the last week and yielded one new sta during that time. Overnight I managed to ID a second new station there. Interestingly for the last two nights there's been no sign whatsoever of the black gospel mx sta I reported as an UNID last week on the same freq. The new sta below was logged on the trusty Eton E-100 w/ SAT.

1560, KZQQ, Abilene, TX, 0620 UTC, 7/6/10, classic rock mx including Pink Floyd, Black Sabbath, The Animals, etc. IDs as "Classic Rock Radio" and "1560, KZQQ". Vy nice sig peaks. 45 watts night pwr. 332 miles/535 km, ULR Sta #671. By the way, according to an article I found online, this is a format change from their former ESPN format. Topaz has this listed as their antiquated Adlt Stnds format. Topaz badly needs to be updated.

That's it from the flatlands of Oklahoma.
73!

Kirk Allen
Ponca City, OK


Re: Tecsun PL-390 2 speaker SW radio on eBay

Guy Atkins
 

I saw this model earlier today, George. It looks like a mini boombox!

The auction copy does not mention DSP or multiple bandwidths, but the front panel clearly says "DSP" and there is an "AM BW" button.

Guy Atkins
Puyallup, WA
http://fivebelow.squarespace.com

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

From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN


Deciphering the Kchibo Radio DSP-chip Puzzle

Gary DeBock
 

Hello All,
 
Those DXers (including me) who had thought that the new KK-D6110 model was a serious attempt by Kchibo to upgrade the D96L model now have serious evidence to the contrary. After multiple reports of lackluster performance on both the AM and FM bands, a detailed investigation and disassembly of the KK-D6110 model has revealed that the new radio is not an Si4734 DSP chip radio after all, but apparently uses the same DSP chip powering the Kchibo KK-D680, KK-210B, KK-D202 and KK-D220 models. This certainly explains the drop off in AM performance relative to the D96L model, a true Si4734 DSP chip receiver.
 
The KK-D6110's lower AM sensitivity specification and much lower eBay selling price (relative to the D96L) created doubts about this from the beginning, but the sole eBay seller's KK-D6110 listing (obviously translated by Google from the original Chinese on the Kchibo web site) certainly doesn't make the DSP chip identity very clear. 
 
The KK-D6110 has a DSP filter selection switch which mimics the Si4734 models quite well (although the filtering selections are backward, like in the D92L), and other functions also are apparently designed to resemble the D96L, such as the green display light and memory operations. But AM-DXing performance falls well short of the D96L, and full disassembly of the KK-D6110 brought the truth to light.
 
The stock loopstick has a single coil with an inductance measured at 630 uh, which would certainly be an unusual value for an Si4734-chip radio with no LW-band responsibility. Subtracting coil turns on the stock loopstick did not significantly improve X-band performance on the KK-D6110, as it would with a true Si4734-chip radio having a 630 uh loopstick coil. The digital board copper shield was simply tack-soldered at a few places, resulting in a slight digital whining noise bleeding through to the loopstick (which also affected all upgrade loopsticks, both internal and external). Removal of the copper shield (photo at http://www.mediafire.com/?xy2u3wnjvyn) revealed various IC's, but certainly no Si4734 DSP chip. After the earlier indications, it wasn't a big surprise.
 
The Kchibo model numbering system apparently gives an indication whether the Radio is a true Si4734 DSP chip model, or not. Those models with a DxxL numbering system (D92L, D95L, D96L, etc.) are the true Si4734 chip radios, while those with the KK-Dxxx numbering system (KK-D6110, KK-D680, KK-D220, etc.) are not. Kchibo advertises both types as DSP radios, and the Chinese documentation (with rough English translations) is confusing at best. Sorry for any inconvenience because of this, but those DXers who had planned to order the new KK-D6110 model as a upgraded replacement for the D96L should not proceed. The KK-D6110 is a decent radio for the money, but should not be confused with true Si4734 DSP receivers like the D96L, PL-310, PL-380, PL-360 etc. The detailed disassembly photos will be uploaded to the KK-D6110 photo album on the Ultralightdx site.
 
73, Gary DeBock (in Puyallup, WA, USA) 
 
                  


Tecsun PL-390 2 speaker SW radio on eBay

George Sherman
 

From Ms. Joyce Anon-co for just a couple dollars more we can have a 2nd speaker which I guess means it won't fit in pocket or will at least stick out more. Where it says features the ad goes into Chinese, no obvious specs. Anyone know more? Guess it's the first day listed. Sorry for mentioning something that's not an ultralight but someone might be interested? 73, George S., MN


Tecsun PL-390

Rick Robinson <w4dst@...>
 

I just noticed that anon-co on ebay has listed the new Tecsun PL-390. It appears to be a repackaged PL-380 in a wider case with 2 speakers. The whip antenna is also longer and with the wider case, I'm hoping that maybe a 20cm, 7 7/8", ferrite bar antenna might be inside. This will be too large for an ULR, but it is an interesting radio. From the pictures it looks like the selectable band width is retained from the PL-380.

Does anyone have one in hand or on order? I hope they've replaced the anemic bar antenna in the PL-380 with a larger one.

Rick W4DST


Re: Tecsun PL-380 vs Panasonic RQ-SW20

Rik
 

YES! Mail all your ULR radios to me! Ha! I'll use them outdoors, and when the power is out. - FARMERIK

--- In ultralightdx@..., "Stephen" <pianoplayer88key@...> wrote:

Hi all....

I got a Tecsun PL-380 several months ago after reading some reviews & reports, hoping it would replace my Panasonic RQ-SW20, as there were many stations I wanted to hear that were buried under noise or other stations on the Panasonic. One of my reasons for selecting the PL-380 was reports of absolutely superb selectivity, with TPs being received barefoot within a few kHz of strong locals. (BTW, were any of those strong locals at least 63dBu on-channel? If so, then either the TP propagation was superb, or I have a defective PL-380, In 1kHz BW mode, I still hear chatter 10kHz away from signals approximately 50dBu, maybe a little lower.) Also I understood the sensitivity was fairly good, although I do realize it DOES have room for improvement.

Well... upon testing it, I discovered that the sensitivity IS somewhat better than my Panasonic, like I had expected.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/inside%20vehicle%20^5to%20attenuate%20strong%20signals^6

Also, the selectivity, at least at first, APPEARED to be MUCH better. HOWEVER, a few months ago I was visiting my grandparents in San Gabriel, CA, who live 0.5km from a diplexing 23kW on 1300 and 50kW on 1430, and 8km from a 50kW IBOC on 1110. I noticed that the PL-380 was indicating 50dBu on "empty" channels across most of the band, and stations that should have been "loud and clear" / "armchair copy" (or whatever phrase would mean a signal so strong that there is NO audible static, has the same SNR as HD or a CD, etc) were barely detectable.

About a week and a half ago, I took my PL-380 and RQ-SW20 to a place near 1450 KFSD's transmitter.....

http://picasaweb.google.com/PianoPlayer88Key/20100702Sx10Kfsd1450?authkey=Gv1sRgCKCI3rqB6LGpGA#5490231041595079410

and recorded comparisons on several stations. (I was just on the near side of the wooden fence sitting on those light pink cover things.) The PL-380 was set in the 1kHz mode, and the RQ-SW20, which I believe (I'm posting from my phone) appears first in the comparisons, has no BW control, so is a fairly wide bandwidth.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/near%20KFSD%201450%20transmitter

For those of you that would expect the PL-380 would wipe the floor with the RQ-SW20, considering the Panasonic's SRF-M37W-like selectivity, I think you will be quite surprised. There were several stations that I could hear quite well on the Panasonic that were completely buried under the Tecsun's 50dBu noise floor.

So, it looks like the PL-380 isn't cutting it for me. :( Also the tuning knob has broken more than once, AND I would like a sensitive AND selective vertically-oriented radio with multiple bandwidths. Also I want to listen to stations that are virtually impossible to receive with my Panasonic... and some places that's because it's within a couple 10kHz channels of a strong local that on the SRF-M37 would be heard +/-500kHz just as strong as on its channel.

Any ideas what else I should look for? I don't want to use a plug-in loopstick for walk-about listening, and I would like multiple bandwidths (so I can select narrow like 1kHz for a weak TA (I'm about 10-15 mi from the Pacific) 1kHz away from a 50kW IBOC local 0.1km away, or wide like 10kHz for listening to a C-Quam Stereo local when I happen to be near one. Also I would want good sensitivity, but it would need to be with as efficient of a loopstick for its size as possible, as I really can't put a radio more than about 4" wide, 5" tall, 1" thick or so in my pocket. The PL-380 will fit in there, but it will either be awkward, or the antenna will be oriented wrong.

I'm hoping I can use the PL-380 as a bedside clock radio, though... BUT... one station I would want to wake up to is almost buried under a 39dBu noise floor from a strong 10kW local 6 miles away on 1130 (it's there, but very faint, well under the soft mute threshold even in 1kHz mode, indicating 0dB SNR), AND the tuning knob is broken (again!). :(

Should I just give up on ULR or radio in general? :|


MI LOG - FM

wa8lcz
 

4JUL2010 SUN SFI=72-8-1 DUCTING 0730-0930, E-SKIP 0900-1300

099.1 WFMK E.LANSING MI LITE ROCK 0816EDT 28K 75 MI (MI41)
101.3 CKOT TILLSONBURG ONT SOFT ADULT 0917EDT 50K 115 MI (ONT24)



TOTALS: 81
RCVR: SONY MHC-C33
ANT: FULL wavelength loop cut for 88 mhz
Byron WA8LCZ nr Detroit


Re: Tecsun PL-380 vs Panasonic RQ-SW20

huelbe_garcia@fastimap.com <huelbe_garcia@...>
 

Hi Stephen!

Here's my guess: as PL-380 uses a tuned-tank circuit, the "de-sensitizing" effect is, perhaps, coming from the telescopic antenna, headphone wire, or poor shielding.

Just my $0.02! :)

--hg

On Jul 5, 2010, at 12:18 AM, Stephen wrote:

Hi all....

I got a Tecsun PL-380 several months ago after reading some reviews & reports, hoping it would replace my Panasonic RQ-SW20, as there were many stations I wanted to hear that were buried under noise or other stations on the Panasonic. One of my reasons for selecting the PL-380 was reports of absolutely superb selectivity, with TPs being received barefoot within a few kHz of strong locals. (BTW, were any of those strong locals at least 63dBu on-channel? If so, then either the TP propagation was superb, or I have a defective PL-380, In 1kHz BW mode, I still hear chatter 10kHz away from signals approximately 50dBu, maybe a little lower.) Also I understood the sensitivity was fairly good, although I do realize it DOES have room for improvement.

Well... upon testing it, I discovered that the sensitivity IS somewhat better than my Panasonic, like I had expected.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/inside%20vehicle%20^5to%20attenuate%20strong%20signals^6

Also, the selectivity, at least at first, APPEARED to be MUCH better. HOWEVER, a few months ago I was visiting my grandparents in San Gabriel, CA, who live 0.5km from a diplexing 23kW on 1300 and 50kW on 1430, and 8km from a 50kW IBOC on 1110. I noticed that the PL-380 was indicating 50dBu on "empty" channels across most of the band, and stations that should have been "loud and clear" / "armchair copy" (or whatever phrase would mean a signal so strong that there is NO audible static, has the same SNR as HD or a CD, etc) were barely detectable.

About a week and a half ago, I took my PL-380 and RQ-SW20 to a place near 1450 KFSD's transmitter.....

http://picasaweb.google.com/PianoPlayer88Key/20100702Sx10Kfsd1450?authkey=Gv1sRgCKCI3rqB6LGpGA#5490231041595079410

and recorded comparisons on several stations. (I was just on the near side of the wooden fence sitting on those light pink cover things.) The PL-380 was set in the 1kHz mode, and the RQ-SW20, which I believe (I'm posting from my phone) appears first in the comparisons, has no BW control, so is a fairly wide bandwidth.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/near%20KFSD%201450%20transmitter

For those of you that would expect the PL-380 would wipe the floor with the RQ-SW20, considering the Panasonic's SRF-M37W-like selectivity, I think you will be quite surprised. There were several stations that I could hear quite well on the Panasonic that were completely buried under the Tecsun's 50dBu noise floor.

So, it looks like the PL-380 isn't cutting it for me. :( Also the tuning knob has broken more than once, AND I would like a sensitive AND selective vertically-oriented radio with multiple bandwidths. Also I want to listen to stations that are virtually impossible to receive with my Panasonic... and some places that's because it's within a couple 10kHz channels of a strong local that on the SRF-M37 would be heard +/-500kHz just as strong as on its channel.

Any ideas what else I should look for? I don't want to use a plug-in loopstick for walk-about listening, and I would like multiple bandwidths (so I can select narrow like 1kHz for a weak TA (I'm about 10-15 mi from the Pacific) 1kHz away from a 50kW IBOC local 0.1km away, or wide like 10kHz for listening to a C-Quam Stereo local when I happen to be near one. Also I would want good sensitivity, but it would need to be with as efficient of a loopstick for its size as possible, as I really can't put a radio more than about 4" wide, 5" tall, 1" thick or so in my pocket. The PL-380 will fit in there, but it will either be awkward, or the antenna will be oriented wrong.

I'm hoping I can use the PL-380 as a bedside clock radio, though... BUT... one station I would want to wake up to is almost buried under a 39dBu noise floor from a strong 10kW local 6 miles away on 1130 (it's there, but very faint, well under the soft mute threshold even in 1kHz mode, indicating 0dB SNR), AND the tuning knob is broken (again!). :(

Should I just give up on ULR or radio in general? :|








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Yahoo! Groups Links



Re: My ultralight dilemma and thoughts

Rick Robinson <w4dst@...>
 

On 7/4/2010 6:18 PM, neilbellgroups wrote:
I find the ULRs work fine with strong signals but the weak ones get submerged in the RF noise in my radio room. When I take the radios outside well away from my house, things improve greatly.
Ferrite bar antennas are notorious for their susceptibility to electrical noise. The decrease in noise away from your house is normal and shows how much noise the ferrite bar antenna in the ULR picks up around your indoor noise sources.
The ultralights performance on the SW bands is pretty poor in my opinion. Compared with my Palstar they are just pathetic with their whips.
Try disconnecting your outside antenna system and connect a telescopic whip antenna to your Palstar and see how well it works. I would imagine the Palstar would also exhibit a very noticeable decrease in performance. Vertical antennas are also notorious for increased noise reception. That is why many MW DXers, myself included, sometimes use a vertical antenna as a source of noise for nulling out noise with a phasing system . See the superb website of Mark Connelly, WA1ION, for articles on noise reduction and antenna phasing systems by Mark, John Bryant, Dallas Lankford and other DXers. I also highly recommend the website of Tom Rauch, W8JI, for more information on antennas and impedance matching toroid transformers.
I fed the output of the Phaser-random wire combo into the ULRs and obviously things improve quite a bit. Nevertheless, with no SSB, avoiding adjacent signals is difficult. Even with the "bandwidth" options on the 380 set to 1 kHz, the adjacent signals are still a problem. Obviously with no SSB, listening to hams is no option!
I have no problem with the DSP filters in my PL-380 for both MW and SW listening. In fact, I use the 3kHz bandwidth and tune 2 kHz off frequency when MW DXing. This improves reception quite a bit. I use the same technique with my Drake R8A and AR-7030+ to pull out weak stations. I am too far inland to be DXing the 9kHz splits and don't worry about stations 1kHz away.

I really wonder how "real" the bandwidth setting is compared with a genuine communications receiver's bandwidth options in receiving shortwave HF signals.
Somewhere I have seen the results of an UL owner measuring the DSP bandwidth using commonly available software. It may have been John Bryant or someone else who published their findings. A "genuine" communications receiver will have passband tuning, a feature that a Palstar lacks and that adds greatly to the rejection of adjacent signals.

It seems to me that connecting outside antennas to a ULR sort of defeats the main purpose of these small radios which, in my opinion, is barefoot use.
To some extent, but it can also open up other possibilities for DXing. Using an ULR with an outside antenna can demonstrate its strong signal handling and selectivity. The same defeating of purpose can be said of attaching a 7 1/2" ferrite bar antenna, but again with other possibilities such as trans-oceanic DXing. I use a Radio Shack closed loop antenna with my G8 and PL-380 for the unlimited class. The closed loop is much quieter than the 20cm ferrite bar antennas that I have. I have 4 325' noise reduced beverage-on-ground antennas that I can connect directly to my G8 via an internally mounted binocular core toroid impedance matching transformer. I have yet to see the G8 overload with any of the SW powerhouses.
Certainly, demonstrating the remarkable technology of these tiny radios is interesting and this improving DSP technology will find itself showing up increasingly in other higher-end radios.
I once owned a JRC NRD-545 DSP receiver, one of the first DSP communications receivers. The DSP filters in the PL-380 are as good as, if not better, than the DSP filter implementation in the '545. We're talking 2010 technology in the ULRs vs. 1997 technology in the JRC. It is amazing how far DSP has come in the last 15 years. At times, the '545 DSP circuitry was an amazing receiver, at other times very disappointing. I can't wait to see the first implementation of current generation DSP technology in a communications receiver. Like the '545, AM sync, passband tuning, BFO, selectable SSB, noise reduction and notch filtering can all be implemented via DSP.
So my dilemma is since I want to listen to my radios in my radio room and not outside, have no desire to just connect my existing antenna-Phaser to an ultralight, how much will I really use these radios?? Do I keep them or sell them to someone with different goals than I have? Make no mistake, they are great little radios with amazing technology, but I am beginning to doubt they are my cup of tea.
I'd suggest anyone with this dilemma should go to the nearest Radio Shack and buy the latest version of their MW loop antenna. It costs in the neighborhood of $30 and if it doesn't work RS with take it back within 30 days no questions asked. Closed loops are much quieter and you'll be surprised at how well they work. BTW, from my experimentation, they work best when the radio is inside the loop. I have a small platform that my ULRs sit on and I rotate the antenna and ULR on a $3 plastic "lazy susan".

Good ULR DXing,

Rick W4DST


Tecsun PL-380 vs Panasonic RQ-SW20

pianoplayer88key
 

Hi all....

I got a Tecsun PL-380 several months ago after reading some reviews & reports, hoping it would replace my Panasonic RQ-SW20, as there were many stations I wanted to hear that were buried under noise or other stations on the Panasonic. One of my reasons for selecting the PL-380 was reports of absolutely superb selectivity, with TPs being received barefoot within a few kHz of strong locals. (BTW, were any of those strong locals at least 63dBu on-channel? If so, then either the TP propagation was superb, or I have a defective PL-380, In 1kHz BW mode, I still hear chatter 10kHz away from signals approximately 50dBu, maybe a little lower.) Also I understood the sensitivity was fairly good, although I do realize it DOES have room for improvement.

Well... upon testing it, I discovered that the sensitivity IS somewhat better than my Panasonic, like I had expected.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/inside%20vehicle%20^5to%20attenuate%20strong%20signals^6

Also, the selectivity, at least at first, APPEARED to be MUCH better. HOWEVER, a few months ago I was visiting my grandparents in San Gabriel, CA, who live 0.5km from a diplexing 23kW on 1300 and 50kW on 1430, and 8km from a 50kW IBOC on 1110. I noticed that the PL-380 was indicating 50dBu on "empty" channels across most of the band, and stations that should have been "loud and clear" / "armchair copy" (or whatever phrase would mean a signal so strong that there is NO audible static, has the same SNR as HD or a CD, etc) were barely detectable.

About a week and a half ago, I took my PL-380 and RQ-SW20 to a place near 1450 KFSD's transmitter.....

http://picasaweb.google.com/PianoPlayer88Key/20100702Sx10Kfsd1450?authkey=Gv1sRgCKCI3rqB6LGpGA#5490231041595079410

and recorded comparisons on several stations. (I was just on the near side of the wooden fence sitting on those light pink cover things.) The PL-380 was set in the 1kHz mode, and the RQ-SW20, which I believe (I'm posting from my phone) appears first in the comparisons, has no BW control, so is a fairly wide bandwidth.

http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/near%20KFSD%201450%20transmitter

For those of you that would expect the PL-380 would wipe the floor with the RQ-SW20, considering the Panasonic's SRF-M37W-like selectivity, I think you will be quite surprised. There were several stations that I could hear quite well on the Panasonic that were completely buried under the Tecsun's 50dBu noise floor.

So, it looks like the PL-380 isn't cutting it for me. :( Also the tuning knob has broken more than once, AND I would like a sensitive AND selective vertically-oriented radio with multiple bandwidths. Also I want to listen to stations that are virtually impossible to receive with my Panasonic... and some places that's because it's within a couple 10kHz channels of a strong local that on the SRF-M37 would be heard +/-500kHz just as strong as on its channel.

Any ideas what else I should look for? I don't want to use a plug-in loopstick for walk-about listening, and I would like multiple bandwidths (so I can select narrow like 1kHz for a weak TA (I'm about 10-15 mi from the Pacific) 1kHz away from a 50kW IBOC local 0.1km away, or wide like 10kHz for listening to a C-Quam Stereo local when I happen to be near one. Also I would want good sensitivity, but it would need to be with as efficient of a loopstick for its size as possible, as I really can't put a radio more than about 4" wide, 5" tall, 1" thick or so in my pocket. The PL-380 will fit in there, but it will either be awkward, or the antenna will be oriented wrong.

I'm hoping I can use the PL-380 as a bedside clock radio, though... BUT... one station I would want to wake up to is almost buried under a 39dBu noise floor from a strong 10kW local 6 miles away on 1130 (it's there, but very faint, well under the soft mute threshold even in 1kHz mode, indicating 0dB SNR), AND the tuning knob is broken (again!). :(

Should I just give up on ULR or radio in general? :|