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Electricity out (4am), suggestions for TPs 2 try w/PL-...

Gary DeBock
 

Hi Gil,
 
Thanks for sharing your interesting suggestions about further PL-310 and PL-380 stealth mods.
 
Your comments remind me of the Words of Wisdom a fellow tinkering fanatic shared with me during my Navy days: "You can do almost anything you want to boost up the performance of a circuit, depending upon how much time and money you are willing to invest." :-)  Since you have been in the ULR group since the very beginning, no doubt you have been amazed (and amused) as various innocent Ultralights have had their IF filters and loopsticks ripped out and discarded, in favor of bizarre modifications to increase transoceanic reception. Having been the culprit primarily responsible for this demolition-related activity, I take full responsibility for my actions.
 
If any wisdom can be obtained by violating the warranties on about 38 Ultralights, it is that you need to have a clear objective before you start the demolition work. In the case of the PL-380 stealth mod already developed, the ambitious objective was to provide a significant sensitivity boost on all AM frequencies by recycling the stock bar, and using superior 40/44 Litz wire. Where did I get the idea to use 40/44 Litz wire? From an attorney in Georgia, two years ago (who, presumably, is prepared to defend the superiority of this material in court). The current PL-380 stealth mod exceeded my expectations, but it certainly will not compete with a Slider E100, or any other 7.5" loopstick Ultralight coming out of the local Demolition Derby. 
 
Your suggestion to ditch the cylindrical batteries and install a 5" rod of 1/2" diameter type 61 ferrite (in the empty slot) potentially could work quite well, but you would still need to ensure that the coil inductance was acceptable to the Si4734 chip varactor (without any lock-up issues on the high band), and that no major side effects would occur from the "plastic surgery." Having been through these adventures before, I would strongly recommend that you set a time and $$ limit before starting the project, and define your objective in the sensitivity boost you will consider successful. I recommend that you keep in mind that any internal-cabinet loopstick is unlikely to compete with the 7.5" external designs, and that you may prefer to obtain even greater AM sensitivity boosts by using external inductively-coupled loops, without any surgical procedures at all. But to be perfectly honest, the thrill of replacing the stock loopstick with a greatly superior in-cabinet design of your own creation is like no other in the hobby, and could become habit-forming, Gil. Consider yourself forewarned :-)
 
73, Gary           
 
In a message dated 1/20/2010 1:41:47 P.M. Pacific Standard Time, gilstacy@... writes:

 


Gary,

One semi-stealth mod to the 310 or 380 that I have been contemplating is to ditch the cylinderical batteries and install a 4" Amidon 61 rod where the two batteries lie side by side. The batteries are .5". With a little surgery, the battery side tabs could be ditched and a 5" rod would fit snugly in the case. A lipoly battery, similar to what is used in the D96L could be secured on the battery compartment door and the power input rewired Or it could be secured where the kick stand sits. It doesn't quite fit in the recess. I don't know if the internal charging circuit is compatible with the lipos, however. Don't see why not, but would be cautious here. One way to see if the 4" Amidon is worthwhile, would be to leave the factory loopstick in place and just disconnect the leads; a temporary power source can be connected via the USB port. The 380 works without batteries if a power source is connected to the port. Just kicking this around in my head...
73 Gil
Gil Stacy
 

Gary,
There is no doubt that the 7.5" external would be superior to any internal loopstick, but I am more intrigued with the "wolf in sheep's clothing" look of an outwardly appearing stock radio with measurably improved performance exceeding the stock loopstick with new wire and higher inductance. The discovery of the upband varcator lock-out phenomenon will make a huge difference in how I approach this task with the speed of a Siberian glacier as contrasted with yours and Kevin-U-Know-Who "just do it" attitudes. ;)
73 Gil
pianoplayer88key
 

Ok... lol... seems that this thread kinda got a bit disorganized :) so my "replies" may be likewise a bit out of order.


So apparently you can use a ceramic tile saw to cut a ferrite rod. Would it be possible to cut a rod down its length so I could put a 4" (or 5") Amidon-61 rod in the spot where the normal loopstick is?

Or, would it be better to consider putting Eneloop (or other slow-discharge) AAA batteries in the spot where the loopstick now is, and putting the 5" (after it's cut to size) 0.5" Amidon bar in the spot where the 2 batteries in line are (while leaving the 3rd AA there)? Also, considering I don't really want to have to unscrew the back of the radio every time I need to charge the batteries (normally I pull the dead set out and put a new one in, then charge the flat ones), is the built-in charger hardware smart enough to charge those different types of batteries (different capacity, etc)?


Jim_kr1s, no, I didn't need the heat. :) We have a wood-burning stove, and before I went to bed (around 5am) the temp on my PL-380 was showing 70°F.
I just have trouble hearing ANY hets at all - am I just trying at the wrong time, or using the wrong techniques or something.... or should I give up on trying to get a TP sandwiched between a local station's main signal and its IBOC carrier, when that local station is 63dBu and 25dB S/N?


(Gary Debock:) "Your comments remind me of the Words of Wisdom a fellow tinkering fanatic shared with me during my Navy days: "You can do almost anything you want to boost up the performance of a circuit, depending upon how much time and money you are willing to invest." :-) Since you have been in the ULR group since the very beginning, no doubt you have been amazed (and amused) as various innocent Ultralights have had their IF filters and loopsticks ripped out and discarded, in favor of bizarre modifications to increase transoceanic reception. Having been the culprit primarily responsible for this demolition-related activity, I take full responsibility for my actions."

LOL. :)

I do have a $$ limit (getting the 7.5" Amidon rod would be a stretch, but a 4" or 6" might be doable, plus the Litz wire), but I'm much more flexible on time.


I don't really care much about any longwave boost (in fact I don't think I even have anything close to me that would even be detectable WITH a 7.5" Slider loopstick -- anyone have a suggestion for a website for me to check? btw I'm within about a mile of 32°46'N 116°57'W), but I do want a sizeable boost on MW if at all possible. At minimum, I'd like an improvement comparable to what you got, Gary, on longwave. (I really didn't notice much of a boost on mediumwave in the examples you posted.)
If I could get a boost like the one in the link below, that would be nice.
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/SW20^JSAT%20compare%20-%20670^J%20930^J%20970^J%20980.mp3
That's my previous radio (Panasonic RQ-SW20), barefoot then with the Select-A-Tenna, on 670, 930, 970 and 980.


I'll eventually want to build one of those several-foot-diameter loops to inductively couple with the PL-380, though. My Select-A-Tenna just doesn't cut it anymore. Would it be possible, say, with a 6' diameter loop (or should I keep it to 4'?), to have a sizeable boost -- say, take a signal from completely undetectable on the stock barefoot PL-380 (and maybe only just barely hetting on Gary's stealth PL-380), to a full 63dBu, 25dB S/N signal with the loop? Another way to put it, I guess, is with a multi-foot external loop, I'd want performance comparable to what Bruce Carter (he posts as rbrucecarter5 on the radio-info.com board) gets with his antennas, or better if possible.


Also, when I do the loopstick mod, I don't have a (LCR/inductance/?) meter, so anyone have suggestions for how to do it without one? Also, I understand you usually will check 1700kHz to make sure you don't get the lockup on the high end of the band with the coil winding. I have a local on 1700 that is right now (2:10am) showing about 33dBu and 15dB S/N - is that too strong of a signal already to use as a test signal? Or should I use the weak TIS from about 15 miles away on 1620 that is next to a semi-local (comparable signal to 1700, or maybe a bit weaker) on 1630? Or, what about the one from about 85-95 miles away on 1670 that in the daytime is basically undetectable most of the time, but at night is about as strong as 1700? (Or, what about the San Diego Airport TIS on 1690, that even before 1700 was on the air, was barely detectable on my previous radio even WITH the Select-A-Tenna?)
Gil Stacy
 

Stephen,
Gary has pointed out in previous posts that the Amidon's thickness, .5" OD, prevents it from being used where the stock ferrite lies. Major plastic trimming to allow a fit looks risky in that it appears trimming would have to be done on a circuit board as well. The risk would be cutting board traces that interconnect components.
I have ordered some flat lipoly batteries that will fit in a vacant spot in the radio. I plan on checking the charging circuit in the rx to see if that will work with these batteries. I don't forsee a problem. I will alligator clip them to the correct spots in the existing battery box for testing the charging circuit.
The plan is to then use a 4" Amidon .5 OD rod where the two batteries lie inline. With a minimum amount of surgery, a 5" Amidon work could fit inside the cabinetry. No circuit boards are at risk. I have a 6" rod that I can trim.
It will probably be next week before I do the work.
Once again, I try to "fix" a radio that isn't broken. ;)
73 Gil
Gary DeBock
 

Hi Stephen,
 
Thanks for your comments, and I'll try to answer your questions one by one.
 
"I don't really care much about any longwave boost (in fact I don't think I even have anything close to me that would even be detectable WITH a 7.5" Slider loopstick -- anyone have a suggestion for a website for me to check? btw I'm within about a mile of 32°46'N 116°57'W), but I do want a sizeable boost on MW if at all possible. At minimum, I'd like an improvement comparable to what you got, Gary, on longwave. (I really didn't notice much of a boost on mediumwave in the examples you posted.)
If I could get a boost like the one in the link below, that would be nice.
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/SW20^JSAT%20compare%20-%20670^J%20930^J%20970^J%20980.mp3
That's my previous radio (Panasonic RQ-SW20), barefoot then with the Select-A-Tenna, on 670, 930, 970 and 980."
 
Well, Stephen, it would be nice to get an AM sensitivity boost on the "Stealth PL-380" just like the huge LW enhancement, but trying out any new loopstick design is something like opening a Christmas present-- the result could be anything from phenomenal to abominable. My goal in the $5 modification project was simply to achieve a significant boost in AM sensitivity from 530-1700 kHz, and although the "significant" part is open to debate, I'm pretty satisfied with the AM results. Someone with more time could experiment with different Litz wire in attempts to get a greater boost, but my own impression is that the AM sensitivity in the "Stealth" model is fairly close to the maximum, when the stock ferrite bar is recycled.
 
  "I'll eventually want to build one of those several-foot-diameter loops to inductively couple with the PL-380, though. My Select-A-Tenna just doesn't cut it anymore. Would it be possible, say, with a 6' diameter loop (or should I keep it to 4'?), to have a sizeable boost -- say, take a signal from completely undetectable on the stock barefoot PL-380 (and maybe only just barely hetting on Gary's stealth PL-380), to a full 63dBu, 25dB S/N signal with the loop? Another way to put it, I guess, is with a multi-foot external loop, I'd want performance comparable to what Bruce Carter (he posts as rbrucecarter5 on the radio-info.com board) gets with his antennas, or better if possible"
 
Stephen, in answer to your question, a 6' sided PVC tuned passive loop does have the ability to boost the PL-380's AM sensitivity to enable reception of many DX stations completely inaudible on the barefoot unit, but not up to the 63 dBu, 25dB level. That level is unnecessary in actual DXing, anyway. Most of the time the 6' loop will take a station completely inaudible on the barefoot unit and boost it up to a moderate level, such as this recording of 1575-Radio Farda here in December:  http://www.mediafire.com/?jji22kjj0q1  Radio Farda was completely inaudible on any of the stock Ultralights at the time. You can use larger loops for better DX signal quality, but none of them will boost inaudible stations up to the 63 dBu level.
 
   Also, when I do the loopstick mod, I don't have a (LCR/inductance/?) meter, so anyone have suggestions for how to do it without one? Also, I understand you usually will check 1700kHz to make sure you don't get the lockup on the high end of the band with the coil winding. I have a local on 1700 that is right now (2:10am) showing about 33dBu and 15dB S/N - is that too strong of a signal already to use as a test signal? Or should I use the weak TIS from about 15 miles away on 1620 that is next to a semi-local (comparable signal to 1700, or maybe a bit weaker) on 1630? Or, what about the one from about 85-95 miles away on 1670 that in the daytime is basically undetectable most of the time, but at night is about as strong as 1700? (Or, what about the San Diego Airport TIS on 1690, that even before 1700 was on the air, was barely detectable on my previous radio even WITH the Select-A-Tenna?)

"Also, when I do the loopstick mod, I don't have a (LCR/inductance/?) meter, so anyone have suggestions for how to do it without one? Also, I understand you usually will check 1700kHz to make sure you don't get the lockup on the high end of the band with the coil winding. I have a local on 1700 that is right now (2:10am) showing about 33dBu and 15dB S/N - is that too strong of a signal already to use as a test signal? Or should I use the weak TIS from about 15 miles away on 1620 that is next to a semi-local (comparable signal to 1700, or maybe a bit weaker) on 1630? Or, what about the one from about 85-95 miles away on 1670 that in the daytime is basically undetectable most of the time, but at night is about as strong as 1700? (Or, what about the San Diego Airport TIS on 1690, that even before 1700 was on the air, was barely detectable on my previous radio even WITH the Select-A-Tenna?)"
 
Stephen, the loopstick coil turn-subtracting strategy (to solve an Si4734 varactor lock-up issue on the X-band frequencies) during the PL-380 "Stealth Mod" loopstick tuning was a new method that worked great for me, but then I don't have any locals around 1700 kHz. I was tuned to that frequency when subtracting the turns, when suddenly the San Diego (actually Tijuana, Mexico) station on that frequency boomed in like a local, when I subtracted the last coil turn. During the entire process I didn't rely on the LCR meter at all, but I did record the coil inductance after the process was successful (433 uh). This was done on two different PL-380 "Stealth" models (and Steve Ratzlaff also presumably used this method, to tune his own modified PL-380 loopstick coil), so the procedure certainly seems to work. If you have locals around 1700 kHz, go down in frequency until you have "00" showing on the PL-380's S/N reading, and subtract coil turns one by one until the radio has a great sensitivity boost on that frequency. Such a strategy will probably provide adequate coil tuning, but if an LCR meter is available, simply winding a 40/44 Litz wire coil on the stock ferrite bar for an inductance of 433 uh should work just as well (assuming that Tecsun and Silicon Labs don't change anything on us :-)
 
73, Gary        


 
In a message dated 1/22/2010 2:43:26 A.M. Pacific Standard Time, pianoplayer88key@... writes:

 

Ok... lol... seems that this thread kinda got a bit disorganized :) so my "replies" may be likewise a bit out of order.

So apparently you can use a ceramic tile saw to cut a ferrite rod. Would it be possible to cut a rod down its length so I could put a 4" (or 5") Amidon-61 rod in the spot where the normal loopstick is?

Or, would it be better to consider putting Eneloop (or other slow-discharge) AAA batteries in the spot where the loopstick now is, and putting the 5" (after it's cut to size) 0.5" Amidon bar in the spot where the 2 batteries in line are (while leaving the 3rd AA there)? Also, considering I don't really want to have to unscrew the back of the radio every time I need to charge the batteries (normally I pull the dead set out and put a new one in, then charge the flat ones), is the built-in charger hardware smart enough to charge those different types of batteries (different capacity, etc)?

Jim_kr1s, no, I didn't need the heat. :) We have a wood-burning stove, and before I went to bed (around 5am) the temp on my PL-380 was showing 70°F.
I just have trouble hearing ANY hets at all - am I just trying at the wrong time, or using the wrong techniques or something.... or should I give up on trying to get a TP sandwiched between a local station's main signal and its IBOC carrier, when that local station is 63dBu and 25dB S/N?

(Gary Debock:) "Your comments remind me of the Words of Wisdom a fellow tinkering fanatic shared with me during my Navy days: "You can do almost anything you want to boost up the performance of a circuit, depending upon how much time and money you are willing to invest." :-) Since you have been in the ULR group since the very beginning, no doubt you have been amazed (and amused) as various innocent Ultralights have had their IF filters and loopsticks ripped out and discarded, in favor of bizarre modifications to increase transoceanic reception. Having been the culprit primarily responsible for this demolition-related activity, I take full responsibility for my actions."

LOL. :)

I do have a $$ limit (getting the 7.5" Amidon rod would be a stretch, but a 4" or 6" might be doable, plus the Litz wire), but I'm much more flexible on time.

I don't really care much about any longwave boost (in fact I don't think I even have anything close to me that would even be detectable WITH a 7.5" Slider loopstick -- anyone have a suggestion for a website for me to check? btw I'm within about a mile of 32°46'N 116°57'W), but I do want a sizeable boost on MW if at all possible. At minimum, I'd like an improvement comparable to what you got, Gary, on longwave. (I really didn't notice much of a boost on mediumwave in the examples you posted.)
If I could get a boost like the one in the link below, that would be nice.
http://cid-6bdd1917662288cb.skydrive.live.com/self.aspx/AM%20radio%20files/SW20^JSAT%20compare%20-%20670^J%20930^J%20970^J%20980.mp3
That's my previous radio (Panasonic RQ-SW20), barefoot then with the Select-A-Tenna, on 670, 930, 970 and 980.

I'll eventually want to build one of those several-foot-diameter loops to inductively couple with the PL-380, though. My Select-A-Tenna just doesn't cut it anymore. Would it be possible, say, with a 6' diameter loop (or should I keep it to 4'?), to have a sizeable boost -- say, take a signal from completely undetectable on the stock barefoot PL-380 (and maybe only just barely hetting on Gary's stealth PL-380), to a full 63dBu, 25dB S/N signal with the loop? Another way to put it, I guess, is with a multi-foot external loop, I'd want performance comparable to what Bruce Carter (he posts as rbrucecarter5 on the radio-info.com board) gets with his antennas, or better if possible.

Also, when I do the loopstick mod, I don't have a (LCR/inductance/?) meter, so anyone have suggestions for how to do it without one? Also, I understand you usually will check 1700kHz to make sure you don't get the lockup on the high end of the band with the coil winding. I have a local on 1700 that is right now (2:10am) showing about 33dBu and 15dB S/N - is that too strong of a signal already to use as a test signal? Or should I use the weak TIS from about 15 miles away on 1620 that is next to a semi-local (comparable signal to 1700, or maybe a bit weaker) on 1630? Or, what about the one from about 85-95 miles away on 1670 that in the daytime is basically undetectable most of the time, but at night is about as strong as 1700? (Or, what about the San Diego Airport TIS on 1690, that even before 1700 was on the air, was barely detectable on my previous radio even WITH the Select-A-Tenna?)
pianoplayer88key
 

I'm definitely interrested in learning more about the mod you're speaking of. Also, would it possibly have the added benefit of getting the loopstick away from the LCD, DSP chip, CPU, etc, and cutting down on some internal noise, or would it either not make a difference, or, introduce some new noise due to nearby componnents at the new location?

Also, what about powering the radio when it's not plugged in, and replacing batteries as necessary? I don't want to take the back stand off and put a D96L battery there, as I've seen referenced in another post.

If I was going to use the same spot as the original loopstick to put the modded stick, would a 0.25" OD 4" (longest in that size) stick work there, or would it need to be cut down its length? Or what about a bunch of 0.03" OD 0.3" long sticks together, like a mini version of some of the fancy outdoor loopsticks I've seen in a loopstick article (one of which is like a 6-8' stick)?

--- In ultralightdx@..., "nn4cw" <gilstacy@...> wrote:



Stephen,
Gary has pointed out in previous posts that the Amidon's thickness, .5" OD, prevents it from being used where the stock ferrite lies. Major plastic trimming to allow a fit looks risky in that it appears trimming would have to be done on a circuit board as well. The risk would be cutting board traces that interconnect components.
I have ordered some flat lipoly batteries that will fit in a vacant spot in the radio. I plan on checking the charging circuit in the rx to see if that will work with these batteries. I don't forsee a problem. I will alligator clip them to the correct spots in the existing battery box for testing the charging circuit.
The plan is to then use a 4" Amidon .5 OD rod where the two batteries lie inline. With a minimum amount of surgery, a 5" Amidon work could fit inside the cabinetry. No circuit boards are at risk. I have a 6" rod that I can trim.
It will probably be next week before I do the work.
Once again, I try to "fix" a radio that isn't broken. ;)
73 Gil

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