Date   

Graham Maynard's Tecsun PL-380 Modification Article

Gary DeBock
 

Hello All,
 
Noted UK experimenter Graham Maynard has published an excellent PL-380 modification article in the April edition of Medium Wave News (Europe's premier MW hobbyist club bulletin). He details an effective "stealth" loopstick modification (with some minor plastic removal) and simple component changes to greatly improve audio fidelity.
 
Reprinted with Graham's permission, the article has been uploaded to the Ultralightdx file site at  http://f1.grp.yahoofs.com/v1/0JHKSyBSe64gJsKLlKJxajGvyDP8imUye-iNYa32zQ_OI350X_pXOaqxuX_6omKENZyVBfJjibSAcarJn_Faqq0PGjemBgc/6%20Alignment%20%26%20Modification/The%20Tecsun%20PL380mod.doc ,                      
and is also available at  http://www.mediafire.com/?oy4cqzungkz .
 
Graham has been an active UK experimenter for many years, and his fine technical articles are posted on his website at http://www.gmweb2.net/ . Thanks to Graham (and MWC) for making this article available.
 
73, Gary DeBock (in Puyallup, WA, USA)


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

Rik
 

Very hard to get WTIC well here, I think there antenna must point north. I get it better during the day well into VT. WHYN from Springfield MA is much clearer with far less power at my house. Right now on my PL-600, 1090 [WBAL?] pegs the meter at 5, and WTIC on 1080 is bouncing between 0-1-2 sometimes. No signal at all on 1070. - FARMERIK

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

Actually, Farmerik, WTIC is quite close to both you and me in different directions. Try tuning in 1090 or 1070 kHz... all you should get is a iBOC hurricane, with weak WBAL 1090 and CHOK on 1070, both rather unusable. Though not technically an overload, it should be the strongest signal on your dial, except for Vernon and Manchester maybe. Down here, WELI 960 and WXCT 990 are VERY strong daytimers (5kw-20km and 2.5kW-10 km respective).

Paul S. in CT


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

Scott - I have the opposite conditions in my area [CT]. There are no nearby 50kW stations, but there are signals on almost every AM channel, and many with more than one on the same frequency. I am enjoying the radios with highly directional ferrite rod antennas, but I am also interested in making a large [perhaps 3-4 foot] air loop, and wondered what factors would make it more directional for DXing, and LESS directional for regular listening? I am asking for an opinion, and I am sure experts will disagree. - FARMERIK


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

ferrite61 <dxrx@...>
 

Actually, Farmerik, WTIC is quite close to both you and me in different directions. Try tuning in 1090 or 1070 kHz... all you should get is a iBOC hurricane, with weak WBAL 1090 and CHOK on 1070, both rather unusable. Though not technically an overload, it should be the strongest signal on your dial, except for Vernon and Manchester maybe. Down here, WELI 960 and WXCT 990 are VERY strong daytimers (5kw-20km and 2.5kW-10 km respective).

Paul S. in CT

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

Scott - I have the opposite conditions in my area [CT]. There are no nearby 50kW stations, but there are signals on almost every AM channel, and many with more than one on the same frequency. I am enjoying the radios with highly directional ferrite rod antennas, but I am also interested in making a large [perhaps 3-4 foot] air loop, and wondered what factors would make it more directional for DXing, and LESS directional for regular listening? I am asking for an opinion, and I am sure experts will disagree. - FARMERIK


Re: Spanish Sports heard on 1510 kHz

ferrite61 <dxrx@...>
 

I thought it might be WWZN (already logged) but wasn't sure. They have a lot of brokered time on wkends. Brother Stairs (aka Brother Scare) is also heard on-channel.

In other news WDEL 1150 kHz from Wilmington DE is putting in a good twilight signal up here between 1900 and 2030 EDT, wiping out local WMRD at 46 Watts 20 km. If you need DE as a state heard, this one offers the best opportunity IMHO.

Paul S. in CT

--- In ultralightdx@..., "D" <jm392c@...> wrote:



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

Right now at 2000 EDT I am clearly hearing Spanish Sports on 1510 kHz, I believe this is baseball. Signal is 35: 12 on the pl310 Hearing mentions of Carl Crawford. This could be WWZN out of Boston, but I am not aware of Spanish Broadcasting on this station. Its not tuning normally, indicating a direction almost due North for best reception. This is def. A Tampa Bay vs. Boston baseball game and English is availible on WTIC 1080. Itws 2005 EDT and will report if I hear a call sign... so far none yet.

Paul S. in CT
WWZN Boston recently started carrying Red Sox games in Spanish. The rest of the time they broadcast in English, a combination of progressive talk and sports.

Jim
Milford, Massachusets


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

sdwillingham
 

Farmerik,

For nulling, I recommend starting with Jim K's hoop-loop design. I think that further experimentation may improve upon his balun transformer design, but clearly, Jim's already getting great results. I'm no expert in AM antenna design, but I think a reasonable air loop will be mostly limited in nulling by the transformer design and by keeping the loop away from nearby metal.

According to results in this very interesting article, http://www.kongsfjord.no/dl/Antennas/Loop%20Antenna%20Sensitivity.pdf , I would stick with a maximum of a two-foot loop to start, maybe even one-foot. Bigger loops are unlikely to give better signal-to-noise, and will be harder to manipulate for nulling.

Again, I don't have a lot of experimental experience with AM antennas, so my opinions should be taken as informed, but not authoritative. It seems to me the big-loop with inductive coupling is just as viable for catching difficult signals. The excess size doesn't give more SNR, but adds some signal strength that compensates for weaker inductive coupling. Clearly, Gary gets strong results using his big loops. The reason I recommend Jim's loops is for operational convenience. They are easily manipulated and tuning is automatic.

-Scott-

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

Scott - I have the opposite conditions in my area [CT]. There are no nearby 50kW stations, but there are signals on almost every AM channel, and many with more than one on the same frequency. I am enjoying the radios with highly directional ferrite rod antennas, but I am also interested in making a large [perhaps 3-4 foot] air loop, and wondered what factors would make it more directional for DXing, and LESS directional for regular listening? I am asking for an opinion, and I am sure experts will disagree. - FARMERIK

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




Stephen,

Thanks for posting your thorough band-scan data. It is very interesting
and helpful.

It is always possible to overload the front-end of any radio (except
possibly a crystal set). So the lesson from that is: avoid doing it --
excess gain is unneeded and unproductive. Most of the time, and
especially in urban situations, you cannot improve the noise floor
by elevating all signals.

Sometimes, you can get a marginal signal by more selective antenna gain.
But this involves raising the desired signal while reducing a pest. Two
methods are viable: a tuned, frequency-selective antenna or a directional
antenna.

The tuned approach is very helpful, and the Si4734's automatic tuning
takes full advantage. Like all methods, there are limits. Frequency
selectivity will not help by more than a couple dB when a pest is only
a channel or two separated from the desired. Technically, the Si4734
should support antenna resonances with a maximum Q of roughly 100. In
the stock PL-380, the Q is around 25. This means you will get only
about 3 dB reduction of a pest 40 kHz away. But pests further away
are attenuated more, and in an urban environment, chopping down several
pests will help a lot. The resonance will also help a lot at the
upper end of the band, reducing 2nd harmonic problems from pests low
in the band.

External antennas, like the SAT or Q-Stick+, can also help with frequency
selectivity. These can achieve higher Q resonance and that resonance is
added to the resonance already in you radio. My experience, however, is
that a Q-Stick+ does not couple well to the stock PL-380 antenna. I
don't have a SAT to compare to. I am currently experimenting with
transformer-coupled loops (like Jim K's hoop-loop, but smaller). My loop
couples great to the Q-Stick+ and I see excellent results, usually in the
form of greatly improving the SNR of a station. What is really interesting
is that the improved SNR happens simultaneously with _lowering_ the RSSI
strength! This is consonant with the idea that we don't always need
more signal, but we often need less of an undesired signal.

Directional antennas can help you sort desired stations from pests that
are close in frequency. So in an urban environment, your best friend is
an antenna with good nulling. So concentrate on nulling setups and stay
away from power poles! Unfortunately, directional antennas will not help
you in your desired "walking around" operation.

In examining your band scans, I don't really see any anomalies with your
radio's operation. It's unfortunate that the PL-380's display puts a
63 dB ceiling on RSSI measurements. I was hoping to get a better idea
of the magnitude of your locals. But in the situations where your radio
is not overloading, the RSSI at frequencies adjacent to strong stations
looks normal in my opinion. That is, seeing 30-35 dB RSSI in the slot
adjacent to a 63+ dB station is normal. I generally see 30-35 dB noise
floor during the day with 4-5 stations that are between 60 and 70 dBu.
At night, the noise floor can get higher. In more rural areas, the noise
floor will drop.

A good deal of the noise floor is just the RF environment. Some call it
"splatter", but that's a bit unfair (IMO). A 30 dB drop in signal strength
means that 0.1% of a transmitter's power is "escaping" out of band. At
40 dB, you're talking about 0.01%. Again, probably the most fruitful
method of working near a pest is a sophisticated nulling setup and skillful
operation.

Regarding your question about my location, I'm in Austin Texas, about
two miles from downtown. There are transmitter towers in all directions,
but power levels are not super high. I see about eight stations between
50 and 70 dBu during the daytime, and a "noise level" of 30 to 35 dBu.

I got my graduate degrees at UCLA, so I'm familiar with So Cal and have
been to San Diego many times. It's a wonderful place to live, except
for the politics, which I'll avoid commenting on further!

-Scott-


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

Rik
 

Scott - I have the opposite conditions in my area [CT]. There are no nearby 50kW stations, but there are signals on almost every AM channel, and many with more than one on the same frequency. I am enjoying the radios with highly directional ferrite rod antennas, but I am also interested in making a large [perhaps 3-4 foot] air loop, and wondered what factors would make it more directional for DXing, and LESS directional for regular listening? I am asking for an opinion, and I am sure experts will disagree. - FARMERIK

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




Stephen,

Thanks for posting your thorough band-scan data. It is very interesting
and helpful.

It is always possible to overload the front-end of any radio (except
possibly a crystal set). So the lesson from that is: avoid doing it --
excess gain is unneeded and unproductive. Most of the time, and
especially in urban situations, you cannot improve the noise floor
by elevating all signals.

Sometimes, you can get a marginal signal by more selective antenna gain.
But this involves raising the desired signal while reducing a pest. Two
methods are viable: a tuned, frequency-selective antenna or a directional
antenna.

The tuned approach is very helpful, and the Si4734's automatic tuning
takes full advantage. Like all methods, there are limits. Frequency
selectivity will not help by more than a couple dB when a pest is only
a channel or two separated from the desired. Technically, the Si4734
should support antenna resonances with a maximum Q of roughly 100. In
the stock PL-380, the Q is around 25. This means you will get only
about 3 dB reduction of a pest 40 kHz away. But pests further away
are attenuated more, and in an urban environment, chopping down several
pests will help a lot. The resonance will also help a lot at the
upper end of the band, reducing 2nd harmonic problems from pests low
in the band.

External antennas, like the SAT or Q-Stick+, can also help with frequency
selectivity. These can achieve higher Q resonance and that resonance is
added to the resonance already in you radio. My experience, however, is
that a Q-Stick+ does not couple well to the stock PL-380 antenna. I
don't have a SAT to compare to. I am currently experimenting with
transformer-coupled loops (like Jim K's hoop-loop, but smaller). My loop
couples great to the Q-Stick+ and I see excellent results, usually in the
form of greatly improving the SNR of a station. What is really interesting
is that the improved SNR happens simultaneously with _lowering_ the RSSI
strength! This is consonant with the idea that we don't always need
more signal, but we often need less of an undesired signal.

Directional antennas can help you sort desired stations from pests that
are close in frequency. So in an urban environment, your best friend is
an antenna with good nulling. So concentrate on nulling setups and stay
away from power poles! Unfortunately, directional antennas will not help
you in your desired "walking around" operation.

In examining your band scans, I don't really see any anomalies with your
radio's operation. It's unfortunate that the PL-380's display puts a
63 dB ceiling on RSSI measurements. I was hoping to get a better idea
of the magnitude of your locals. But in the situations where your radio
is not overloading, the RSSI at frequencies adjacent to strong stations
looks normal in my opinion. That is, seeing 30-35 dB RSSI in the slot
adjacent to a 63+ dB station is normal. I generally see 30-35 dB noise
floor during the day with 4-5 stations that are between 60 and 70 dBu.
At night, the noise floor can get higher. In more rural areas, the noise
floor will drop.

A good deal of the noise floor is just the RF environment. Some call it
"splatter", but that's a bit unfair (IMO). A 30 dB drop in signal strength
means that 0.1% of a transmitter's power is "escaping" out of band. At
40 dB, you're talking about 0.01%. Again, probably the most fruitful
method of working near a pest is a sophisticated nulling setup and skillful
operation.

Regarding your question about my location, I'm in Austin Texas, about
two miles from downtown. There are transmitter towers in all directions,
but power levels are not super high. I see about eight stations between
50 and 70 dBu during the daytime, and a "noise level" of 30 to 35 dBu.

I got my graduate degrees at UCLA, so I'm familiar with So Cal and have
been to San Diego many times. It's a wonderful place to live, except
for the politics, which I'll avoid commenting on further!

-Scott-


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

sdwillingham
 

Stephen,

Thanks for posting your thorough band-scan data. It is very interesting
and helpful.

It is always possible to overload the front-end of any radio (except
possibly a crystal set). So the lesson from that is: avoid doing it --
excess gain is unneeded and unproductive. Most of the time, and
especially in urban situations, you cannot improve the noise floor
by elevating all signals.

Sometimes, you can get a marginal signal by more selective antenna gain.
But this involves raising the desired signal while reducing a pest. Two
methods are viable: a tuned, frequency-selective antenna or a directional
antenna.

The tuned approach is very helpful, and the Si4734's automatic tuning
takes full advantage. Like all methods, there are limits. Frequency
selectivity will not help by more than a couple dB when a pest is only
a channel or two separated from the desired. Technically, the Si4734
should support antenna resonances with a maximum Q of roughly 100. In
the stock PL-380, the Q is around 25. This means you will get only
about 3 dB reduction of a pest 40 kHz away. But pests further away
are attenuated more, and in an urban environment, chopping down several
pests will help a lot. The resonance will also help a lot at the
upper end of the band, reducing 2nd harmonic problems from pests low
in the band.

External antennas, like the SAT or Q-Stick+, can also help with frequency
selectivity. These can achieve higher Q resonance and that resonance is
added to the resonance already in you radio. My experience, however, is
that a Q-Stick+ does not couple well to the stock PL-380 antenna. I
don't have a SAT to compare to. I am currently experimenting with
transformer-coupled loops (like Jim K's hoop-loop, but smaller). My loop
couples great to the Q-Stick+ and I see excellent results, usually in the
form of greatly improving the SNR of a station. What is really interesting
is that the improved SNR happens simultaneously with _lowering_ the RSSI
strength! This is consonant with the idea that we don't always need
more signal, but we often need less of an undesired signal.

Directional antennas can help you sort desired stations from pests that
are close in frequency. So in an urban environment, your best friend is
an antenna with good nulling. So concentrate on nulling setups and stay
away from power poles! Unfortunately, directional antennas will not help
you in your desired "walking around" operation.

In examining your band scans, I don't really see any anomalies with your
radio's operation. It's unfortunate that the PL-380's display puts a
63 dB ceiling on RSSI measurements. I was hoping to get a better idea
of the magnitude of your locals. But in the situations where your radio
is not overloading, the RSSI at frequencies adjacent to strong stations
looks normal in my opinion. That is, seeing 30-35 dB RSSI in the slot
adjacent to a 63+ dB station is normal. I generally see 30-35 dB noise
floor during the day with 4-5 stations that are between 60 and 70 dBu.
At night, the noise floor can get higher. In more rural areas, the noise
floor will drop.

A good deal of the noise floor is just the RF environment. Some call it
"splatter", but that's a bit unfair (IMO). A 30 dB drop in signal strength
means that 0.1% of a transmitter's power is "escaping" out of band. At
40 dB, you're talking about 0.01%. Again, probably the most fruitful
method of working near a pest is a sophisticated nulling setup and skillful
operation.

Regarding your question about my location, I'm in Austin Texas, about
two miles from downtown. There are transmitter towers in all directions,
but power levels are not super high. I see about eight stations between
50 and 70 dBu during the daytime, and a "noise level" of 30 to 35 dBu.

I got my graduate degrees at UCLA, so I'm familiar with So Cal and have
been to San Diego many times. It's a wonderful place to live, except
for the politics, which I'll avoid commenting on further!

-Scott-


Re: A few new ones tonight, and finally TWO new states!

Kirk <kirk74601@...>
 

--- In ultralightdx@..., Rick Garrett <IndyRick@...> wrote:

I FINALLY broke my new state drought tonight. :)
Rick, Congratulations on TWO new states!! I understand about getting "stuck". I've been stuck at 29 states for quite a while.
73,
Kirk Allen
Pasadena, TX


Re: A few new ones tonight, and finally TWO new states!

wa8lcz
 

hi rick,

so you copied salem oregon KPJC that runs 1000 watts day and 171 watts nighttime ????? from indiana ?? 1976 mi from MI. that has to be some kind of record.

i find that hard to believe. what time did you hear them, and what was the programming ? how long did you hear them ? how sure are you that it was Oregon ?

byron nr Detroit

--- In ultralightdx@..., Rick Garrett <IndyRick@...> wrote:

I FINALLY broke my new state drought tonight. :)

1370, WCOA, Pensacola, FL. Really nice signal into Indianapolis for about
15 minutes tonight at 8:20 local, till fade out about 8:38

1220 KPJC, Salem, Oregon. I had high hopes for this one, as a friend had
picked them up about a week ago in Indy. Tickled to death with this one.

Also logged tonight:

600 WSNL, Memphis, TN

1160 WYLL, Chicago, IL.

Happy weekend, all!


Re: A few new ones tonight, and finally TWO new states!

Rick Garrett <IndyRick@...>
 


 

Hi Rick,

Just a small correction - 600 WSNL would be Flint, MI. 600 WREC is in Memphis, TN.

Tim C.





Tim, thank you for the correction!


Re: A few new ones tonight, and finally TWO new states!

osage_archer
 

Hi Rick,

Just a small correction - 600 WSNL would be Flint, MI. 600 WREC is in Memphis, TN.

Tim C.

--- In ultralightdx@..., Rick Garrett <IndyRick@...> wrote:

I FINALLY broke my new state drought tonight. :)

1370, WCOA, Pensacola, FL. Really nice signal into Indianapolis for about
15 minutes tonight at 8:20 local, till fade out about 8:38

1220 KPJC, Salem, Oregon. I had high hopes for this one, as a friend had
picked them up about a week ago in Indy. Tickled to death with this one.

Also logged tonight:

600 WSNL, Memphis, TN

1160 WYLL, Chicago, IL.

Happy weekend, all!


Re: Spanish Sports heard on 1510 kHz

D <jm392c@...>
 

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

Right now at 2000 EDT I am clearly hearing Spanish Sports on 1510 kHz, I believe this is baseball. Signal is 35: 12 on the pl310 Hearing mentions of Carl Crawford. This could be WWZN out of Boston, but I am not aware of Spanish Broadcasting on this station. Its not tuning normally, indicating a direction almost due North for best reception. This is def. A Tampa Bay vs. Boston baseball game and English is availible on WTIC 1080. Itws 2005 EDT and will report if I hear a call sign... so far none yet.

Paul S. in CT
WWZN Boston recently started carrying Red Sox games in Spanish. The rest of the time they broadcast in English, a combination of progressive talk and sports.

Jim
Milford, Massachusets


Puyallup, WA TP's for 4-17

Gary DeBock
 

Hello All,
 
Asiatic conditions here this morning were similar to those reported by Dennis, with several "big gun" TP's managing to produce audio, although not at booming levels. The following were heard during a short listening session in the back yard, from 1248-1320 on the modified Tecsun PL-380 (and 7.5' PVC box loop):
 
 594- JOAK   Moderately strong with Japanese news at 1303
 666- JOBK   Unusually good signal around 1315 in KBOI splatter; best of the Japanese
 738-            Mix of two good carriers at 1305, from SW (Tahiti) and NW (probably Taiwan)
 747-JOIB     Decent audio at 1309, but didn't last for long
1134-KBS     In and out of Korean audio around 1307; no competition from Japan or China
1557-           Strong carrier (presumably Taiwan) here around 1313, but way too much KZIZ-1560
1566-HLAZ   Fair to good audio with religious program at 1258
1575-VOA    In and out of Asiatic-language audio from 1300-1320; no sign of AFN music
 
73, Gary DeBock (in Puyallup, WA)
 
Spotting receiver:  Modified ICF-2010 (30" loopstick)
Main receiver:  Modified Tecsun PL-380 DSP Ultralight (7.5" loopstick)
7.5' (side) PVC-framed tuned passive loop
 
   


Re: 1629 3ABN Busselton heard in South Africa

freetodx
 

Thanks Richard, Gary and Jim

It was also interesting to compare the evening trans-oceanic reception from the two coastal locations : Steenbras River Mouth was suited to evening reception from Europe while Betty's Bay, only 20 kilometres towards the south-east on the other side of the mountain range, favoured Western Australia. 

73

Gary

Gary Deacon

Fish Hoek

Cape Province

South Africa

www.capedx.blogspot.com 


Re: Return of the Ultralight TP's

jim_kr1s <jkearman@...>
 


--- In ultralightdx@..., D1028Gary@... wrote:
>
> My own preference is to
> avoid hard-wiring any large external accessories to Ultralight radios, in
> order to keep them as portable as possible.

Gary,

I think you must own more ULRs than the rest of us combined. Dedicate one to plug-in toroids! It's good to know you're hearing the Russians on those frequencies. I had a sunrise grayline to the 180 a few days ago. Sunrise in Siberia the same time as in Florida -- how weird is that? But conditions weren't favorable.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


KCBQ overloads PL-380 (Re: Tecsun PL-360 3" Loopstick Testing)

pianoplayer88key
 

Ok, I went outside a little while ago and did the best crunch test I could come up with for where I am. Locally, the strongest station here is 1170 KCBQ daytime, which, even without any external antenna aid, loudly splatters several channels each way (limited to about 2 or 3 due to an almost-as-strong local on 1130) on my Panasonic RQ-SW20, a radio with selectivity comparable to the Sony SRF-M37W with sensitivity a few dB less. (A station that may have weak, but recognizable audio on the SRF-M37W just will not be there at all on the RQ-SW20).

Now, while KCBQ is strongest in the daytime (50kW, 9 miles), at night KCBQ powers down to 2.9kW, and 760 KFMB, 7 miles away, powers UP from 5kW to 50kW at night. Interestingly, though, KCBQ is stronger daytime than KFMB is nighttime, even though KFMB is closer. (This is judged by reading how wide the splatter is on my not-so-selective RQ-SW20.)
Just checked with the FCC calculator, and actual distance/heading to KCBQ's transmitter is approximately 15.031km (9.34mi), 7.08°.

Well, anyway, I took my Select-A-Tenna and PL-380, and put it up to a power pole...
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/Me^J%20PL-380^J%20SAT%20@%20Power%20Pole.jpg
See the thin wooden piece running down the pole? If I put my radio and SAT up to that (like in the pic), it gives the signal some serious gain. (For example, a TIS on 1620 which is normally 24dBu barefoot is about 57dBu with the SAT at the power pole, and 41dBu with the SAT alone. Also 570 KLAC reads 60dBu at the pole w/SAT, 51dBu with SAT alone, and 31dBu barefoot.) There's another way to put it... I can't get it to overload like this, barefoot, as we're driving right by their transmitter site!
(pic of power line from one pole to the next): http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/PowerLine.jpg

...and made some recordings:

First, a quick comparison. First part of the recording is KCBQ barefoot, with the PL-380 held a few feet away from the SAT and power pole. About halfway through this recording, I bring the PL-380 to rest on top of the SAT (which is tuned to 1170) like in the picture above. http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20PL-380%20-%20overload%20demo%20-%202nd%20half%20SAT%20@%20PowerPole.mp3
Now if you don't call that audio distortion overload when it's tuned to 1170, what do you call it?

Next, a partial harmonic series, with the SAT + power pole. I think I stopped at about the 7th or 8th harmonic. http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20PL-380%20-%20partial%20harmonic%20series%20-%20SAT%20@%20PowerPole.mp3
Just to give you a little bit of an idea, the 2nd harmonic (2340kHz) was reading 63dBu, and the 3rd harmonic (3510kHz) was reading 49dBu.

Next two are the PL-380 with SAT @ Power Pole, tuning from 1170 up to 1710, then from 1170 down to 520.
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20PL-380%20-%201170%20to%201710%20-%20SAT%20@%20PowerPole.mp3
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20PL-380%20-%201170%20to%200520%20-%20SAT%20@%20PowerPole.mp3

For comparison, here's the Panasonic RQ-SW20 tuning from 1170 to 1710, then from 1170 down to 710 (stopped there), also with the SAT @ Power Pole.
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20RQ-SW20%20-%201170%20to%201710%20-%20SAT%20@%20Power%20Pole.mp3
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/1170%20KCBQ%20-%202010-04-16/KCBQ%201170%20-%20RQ-SW20%20-%201170%20to%200710%20-%20SAT%20@%20Power%20Pole.mp3

I should mention those are all done in the 6kHz bandwidth... but even so I shouldn't be hearing station audio from 1170 on almost every frequency, right?

With the antenna tuned to 1170 kHz, I was getting 45 to 50 dBu between channels throughout the longwave and mediumwave bands. I didn't check for 1170 daytime like I did for 760 nighttime, but I suspect I would have been nearing 50dBu at least somewhat into the shortwave bands.

In an earlier posting I posted a log of my signal strength readings barefoot (and some with the SAT) for the PL-380. Now here's some barefoot inside a car, which gives some attenuation. You may notice that most of the time, the signal level between channels is usually 15 dBu. (All were taken in the 1 kHz bandwidth mode.)

520 - 15,00
530 - 15,00 - slight XESURF chatter
540 - 36,25 sw - XESURF (null=15,06)
550 - 15,02 - slight XESURF chatter
560 - 15,00
570 - 18,08 NW - KLAC (null=15,00)
580 - 15,00
590 - 28,00 W - KOGO's IBOC (n=15,10)
600 - 52,25 W - KOGO (null=31,25)
610 - 27,00 W - KOGO's IBOC (n=15,00)
620 - 24,21 S - XESS (null=19,03-15)
630 - 15,00 (slight KFI IBOC?)
640 - 29,25 NW - KFI (null=15,10-16)
650 - 15,00 (slight KFI IBOC?)
660 - 15,00
670 - 15,04 WNW - KIRN (null=15,00-01)
680 - 17,00 S - XEWW splatter (null=15,00)
690 - 50,25 S - XEWW (null=35,25)
700 - 15,00 S - XEWW splatter
710 - 15,10 NW - KSPN (null=15,00-01)
720 - 15,00
730 - 17,05-08 WNW - KBRT IBOC (null=15,00)
740 - 34,25 WNW - KBRT (null=17,17-20)
750 - 17-24,00 NNW - KFMB splatter
760 - 53,25 NNW - KFMB
770 - 20-22,00 NNW - KFMB splatter
780 - 15,00
790 - 17,23-20 WNW - KABC (null=15,00)
800 - 37,25 SSW - XESPN (null=15,04-07)
810 - 15,00 - XESPN splatter
820 - 15,00
830 - 15,13-18 N - KLAA (null=15,00
840 - 15,00
850 - 15,00
860 - 38,25 SSW - XEMO (null=16,16-19)
870 - 15,00
880 - 15,00
890 - 15,00
900 - 17,00 NNE - KECR splatter (null = 15,00)
910 - 48,25 NNE - KECR (null=32,25)
920 - 15,00 - KECR splatter
930 - 15,07 NW - KHJ (null=15,00-01)
940 - 15,00 - slight XEKAM splatter
950 - 34,25 SSW - XEKAM (null=19,14-22)
960 - 15,00
970 - 15,00
980 - 15,00
990 - 15,00
1000 - 24,25 NNW - KCEO (null=15,00-01)
1010 - 15,00
1020 - 15,00 NW - KTNQ
1030 - 25,16-25 S - XESDD (null=15,00-01)
1040 - 34,25 WSW - KURS (null=16,16-18)
1050 - 15,00-02 E - XED
1060 - 15,00 (slight KNX IBOC?)
1070 - 30,25 NW - KNX (null=20,02-04)
1080 - 17,00 NW - KNX IBOC
1090 - 34,25 SSW - XEPRS (null=25,23)
1100 - 19,00 N/S , 17,00 E/W
I noticed that if I pointed the radio at my strongest pest, THEN tuned the radio, it would read something like 30dBu inside the car, from about 1100 to 1300 or so (pest being 1170). If I then turned the radio to null the pest, it would drop down to 15 or 17 dBu, then if I turned back to face the pest the signal level would stay down, or maybe gain 2 dB (17-19dBu).
1110 - 19,00 NW - KDIS
1120 - 19-31,00 N - KSDO splatter
1130 - 57,25 N - KSDO (null=31,24-25)
1140 - 22-38,00 N/S - KSDO splatter , 20,00 E/W
1150 - 24,00 N/S , 22,00 E/W
1160 - 24-29,00 N/S - KCBQ splatter , 22,00 E/W
1170 - 62,25 NNE - KCBQ (null=45,25)
1180 - 22,00 N/S - KCBQ splatter, 20,00 E/W
1190 - 20,00 NW - KXMX carrier (noise beating a couple pulses/second, but too weak for actual audio) (null=22,00)
1200 - 19,00 (slight KPRZ splatter?)
1210 - 38,25 NNW - KPRZ (null=24-25,04-12)
1220 - 20,00 (slight KPRZ splatter?)
1230 - 19,00
1240 - 40,25 WSW - KNSN (null=20,18-19)
1250 - 15,00
1260 - 17,00 (slight XEAZ splatter)
1270 - 31,25 SSW - XEAZ (null=17,10-13)
1280 - 17,01-05 WNW - KFRN (null=17,00)
1290 - 15,00
1300 - 17,00
1310 - 25-26,20-22 SSW - XEC (null=17,00)
1320 - 17,00
1330 - 17,00
1340 - 17,00
1350 - 17,00
1360 - 50,25 WSW - KLSD (null=17,14-19)
1370 - 17,00
1380 - 17,00
1390 - 25,25 SE - XEKT (null=15,00-02)
1400 - 15,00
1410 - 15,00
1420 - 29,25 S - XEXX (null=15,00)
1430 - 15,00
1440 - 15,00
1450 - 15,11-13 N - KFSD (null=15,00)
1460 - 15,00
1470 - 35,25 SSW - XERCN (null=19,19-23)
1480 - 15,00 (slight XERCN splatter?)
1490 - 15,00
1500 - 15,00
1510 - 15,00
1520 - 15,00
1530 - 15,00
1540 - 15,15 - unidentified carrier, no known local (unless it's a new TIS that's testing?) on that frequency (KMPC L.A. is barely detectable (if at all) outside the car, and this bandscan is done inside where it's more attenuated)
1550 - 15,17 S - XEBG (null=15,00-01)
1560 - 15,00
1570 - 15,00
1580 - 15,00 WNW - KBLA? (or could have been KMIK but it was too faint to ID)
1590 - 15,00
1600 - 15,00
1610 - 15,00
1620 - 15,00 SSW - WNSB415 (very weak, but could ID)
1630 - 30,25 S - XEUT (null=15,12-16)
1640 - 15,00
1650 - 15,00
1660 - 15,00
1670 - 15,00
1680 - 15,00
1690 - 15,00
1700 - 32,25 S - XEPE (null=15,00-01)
1710 - 15,00

Now that I've posted a few of my local bandscan readings with my DSP radio... I'm curious as to what some of your daytime bandscans look like on your DSP radios, barefoot, and with various antennas. (They should probably be put in a separate topic, btw.)


So I may have a defective PL-380, you say, right? Does your PL-380 manage just fine, Gary? :) For example, if you go close enough to 570 KVI so that on the SRF-M37W it splatters all the way up to 1710, can you still hear 560 KPQ and TPs/TAs on 567 kHz just fine in the 1kHz bandwidth mode with no splatter from KVI, for example?

--- In ultralightdx@..., "jim_kr1s" <jkearman@...> wrote:


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

With analog models like the SRF-59
and the R9012 you can actually tune the radio simply by tuning the 9'
loop
(when their distance is within 5 feet), but the DSP Ultralights
typically
receive only on their tuned frequency, no matter what frequency the
huge
loop selects.
Analog radios borrow part of the ferrite rod for the local-oscillator
(LO) inductor. You are tuning the radio with the antenna, by "pulling"
the LO. DSP radios digitally synthesize the LO; there are no tuned LO
circuits. You could use a separate inductor for the LO, but that only
moves another weak link into position, the front-end circuitry.
Portables are designed to have gain commensurate with their antennas,
and will "saturate" on strong signals.

DSP radios will overload too,. The effect is hard to discern from the
usual splatter by adjacent stations. You can demonstrate it with some
simple test equipment (two signal generators and calibrated
attenuators). Where several strong signals are close together, the radio
may sound noisy between stations, because of intermodulation
<http://en.wikipedia.org/wiki/Intermodulation> . Shielding the radio in
such a way that you can still read the meters (screen wire) or simply
taking the radio farther away from the location, will eliminate those
stations as possible causes of the problem. Location location location.
This article
<http://www.radio-electronics.com/info/receivers/overload/cross-modulati\;
on-intermodulation-intercept-point.php> simply explains the causes.

This PDF <http://neazoi.com/arrl/020708qex046.pdf%20> explains how
ARRL <http://www.arrl.org/> measures intermodulation distortion
<http://en.wikipedia.org/wiki/Intermodulation> (IMD). It's more easily
done when you can disable AGC, but the article further explains what's
happening in our radios in the presence of multiple strong signals.
Intermodulation is the product of two or more strong signals. If you
can reduce the strength of one or more of them, you may eliminate the
problem.

One of the most-effective ways to reduce the problem is to have as much
selectivity as possible before any amplifying stages. That's one reason
I persistently insist the antenna should resonate across the band. A
higher-inductance but non-resonant antenna may increase indicated signal
levels, but lead to IMD problems in areas where there are multiple
strong, nearby stations. They might work great where there aren't many
strong stations, but crash and burn in places where there are.

73,

Jim, KR1s
http://kr1s.kearman.com/ <http://kr1s.kearman.com/>


A few new ones tonight, and finally TWO new states!

Rick Garrett <IndyRick@...>
 


I FINALLY broke my new state drought tonight. :)

1370, WCOA, Pensacola, FL.  Really nice signal into Indianapolis for about 15 minutes tonight at 8:20 local, till fade out about 8:38

1220  KPJC,  Salem, Oregon.  I had high hopes for this one, as a friend had picked them up about a week ago in Indy.  Tickled to death with this one.

Also logged tonight:

600  WSNL, Memphis, TN

1160 WYLL, Chicago, IL.

Happy weekend, all!









Re: Return of the Ultralight TP's

Gary DeBock
 

Jim,
 
Actually the 7.5" loopstick PL-380 has already received multiple LW TP's in its current configuration, including Radio Rossii on 180 and 279 kHz. The model could probably receive several more LW TP's without further changes, if I were motivated to go after them.
 
There is a 6.5' (side) LW-optimized PVC box loop already in the back yard also, in case there was a need for any more LW gain. My own preference is to avoid hard-wiring any large external accessories to Ultralight radios, in order to keep them as portable as possible. Inductively coupling the large PVC loops to Ultralights provides the maximum gain, freedom and convenience, in my opinion. But I respect other ideas.
 
73, Gary   
 

In a message dated 4/16/2010 10:45:45 A.M. Pacific Daylight Time, jkearman@... writes:
 

Gary,

That reminds me. I was looking up LW stations in WRTH. There are a bunch in Siberia, running about 100 kW. You'll be able to hear them. Not sure you can get enough wire onto a 7.5-inch rod and still have an effective antenna, but you might toss a toroid onto a PL-380 you've already hacked, and couple a loop into it. Make the winding 2700-3500 uH, measure the inductance of the loop (no tuning cap) and make another winding of the same inductance. Hook it up with speaker wire. LW BC is a lot of fun. Signals tend to remain steady for 30 minutes or more, and can be quite strong. Plus, you don't have as much interference from adjacent stations! The PL-380 works just as well at LW as MW, and I'd like to see more LW ULR activity.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Tecsun PL-360 Survives Full Disassembly

Gary DeBock
 

Hello All,
 
Prompted by an interest in the Si4734 chip firmware in the Tecsun PL-360 model (along with Scott), a full disassembly of the compact model was undertaken today. Tecsun's reputation for engineering technician-friendly disassembly methods played a large part in the decision, which would have been much tougher to make with a Kchibo or Degen model (neither of which have Tecsun's high reputation).
 
The compact model did indeed prove to be quite technician-friendly, and although the Si4734 chip itself was located under a 4-tab soldered shield on the back of the digital board, it was not too much trouble to remove the shield and take a photo of the Si4734 chip, posted below.
 
For those interested, and 8-photo album of the PL-360 disassembly has been uploaded to the Ultralightdx photo site, along with descriptions of the various components. The PL-360 has now been fully reassembled and checked out, having managed to survive the adventure. Tecsun's high-quality construction has once again saved the day :-)
 
73, Gary DeBock (in Puyallup, WA, USA) 
 
                                        


Re: Spanish Sports heard on 1510 kHz

robert ross
 

ferrite61 wrote:
 

Right now at 2000 EDT I am clearly hearing Spanish Sports on 1510 kHz, I believe this is baseball. Signal is 35: 12 on the pl310 Hearing mentions of Carl Crawford. This could be WWZN out of Boston, but I am not aware of Spanish Broadcasting on this station. Its not tuning normally, indicating a direction almost due North for best reception. This is def. A Tampa Bay vs. Boston baseball game and English is availible on WTIC 1080. Itws 2005 EDT and will report if I hear a call sign... so far none yet.

Paul S. in CT


Paul.......Most likely 1510 WRRD Waukesha, WISCONSIN with ESPN ESPORTES in Spanish......

73...ROB VA3SW

Robert S. Ross
London, Ontario CANADA