Tecsun PL-360 Commercial 200mm Plug-in Upgrade Antenna


Gary DeBock
 

Hello All,
 
While checking the latest eBay listings I came across this 200mm plug-in upgrade loopstick for the Tecsun PL-360 model, sold for $35.00 (+ $9 shipping) from a company in Greece: 
 
A demonstration video of the 200mm plug-in loopstick's MW performance is posted at
 
Since this type of antenna is very similar to the 7.5" upgrade MW and LW loopsticks that I designed for the PL-360 model four years ago (the article posted at http://www.mediafire.com/view/2cqwsqj0bvajf6k/7.5_inch-LS.doc ) 
I thought that I would offer a couple of comments. The $35.00 price seems very reasonable, although no details are given of the loopstick's coil design or inductance. The design lacks any type of locking system like the rubber hose clamp on the 7.5" plug-in loopsticks, which means that the antenna will rotate around freely in the plug-in socket (similar to a ham radio antenna on a tower, with no brake). Finally, whoever shot the video apparently wasn't aware that whenever you change plug-in loopsticks on a PL-360 you must shift the frequency off slightly and then back on, in order for the Si4734 DSP chip to readjust to the different loopstick inductance, and provide maximum sensitivity. In any case, it will be interesting to see how many sales this company will end up with, and the ultimate performance of their 200mm loopstick design.
 
73, Gary DeBock (in Puyallup, WA, USA)


Peter Laws
 

On Sat, Oct 17, 2015 at 2:51 AM, D1028Gary@aol.com [ultralightdx]
<ultralightdx@yahoogroups.com> wrote:


Finally, whoever shot the video apparently wasn't aware that whenever you change plug-in loopsticks on a PL-360 you must shift the frequency off slightly and then back on, in order for the Si4734 DSP chip to readjust to the different loopstick inductance, and provide maximum sensitivity. In any case, it will be interesting to see how many sales this company will end up with, and the ultimate performance of their 200mm loopstick design.

Is power-cycling the receiver not sufficient to get the chip to
re-evaluate the antenna?

Also, let me add, that it's wicked cool that the chip can actually do that!! :)



--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


Rik
 

I was surprised how strong the signals were with out either ferrite antenna plugged in.

I also wondered if he just glues short ferrite to each side of the factory antenna. From the picture, it does not look exactly centered, but that could be camera angle.  How ever it was done, it certainly improved the RSSI numbers and audio. - FARMERIK


Tony Germanotta
 

I don't know how he did his, but I replaced the short ferrite in mine by opening the plastic cover and carefully unwinding the existing litz leaving it attached to the mini plug. 

Then I put a paper sleeve (reversed masking tape, sticky side up) on the end of a longer ferrite of the same width and rewrapped the original wire on this sleeve. 

Be careful not to do it too tightly, or you won't be able to slide the coil to the center once wound. When you finish, you slide the coil to the center (or off center if you prefer) and reassemble the plastic shell, which will include the plug. The end caps can either be drilled out to allow the longer ferrite to protrude, or you can do what I did: just use electrical tape to keep it all together. That also allows you to give a layer of protection to the protruding bare ferrite. 

The result is much more signal, and I like the ability to spin the antenna while holding the radio facing me. My ferrite is about 6 inches long. I had it in a parts box. I thought about using a longer one, but there is a law of diminishing returns at work here. Another 6 inches would be much more expensive, fragile and probably only a fraction more effective. Once you get beyond signal to noise floor, more antenna is just equal to adding volume. 

I also considered using better litz, but there isn't a lot of room inside the form for thicker wire. It's a compromise, but so is the radio. I use my PL 310 for more critical listening anyway. The band width selection helps so much. 

I did the antenna input jack mod on the PL 310, using the unused half of the stereo input to bypass the on board ferrite and allow the chip to tune outboard loops. So for tough conditions I use that radio and a series of air core MW and LW loops. 



On Oct 17, 2015, at 12:18 PM, farmerik@... [ultralightdx] <ultralightdx@...> wrote:

 

I was surprised how strong the signals were with out either ferrite antenna plugged in.

I also wondered if he just glues short ferrite to each side of the factory antenna. From the picture, it does not look exactly centered, but that could be camera angle.  How ever it was done, it certainly improved the RSSI numbers and audio. - FARMERIK


Guy Atkins
 

Hi Gary,

I remember seeing this Ebay seller from Greece with a similar posting in July, and it's what gave me the idea to try it out with the Countycomm GP-5/SSB (not an official Ultralight :^)

I don't know if this Ebayer winds a new Litz wire coil, but I used some larger Litz left over from a PL-380/Amidon rod project and matched the inductance with an LCR meter. The assembly barely fit underneath the Tecsun antenna's plastic housing; I had to do some gentle X-acto knife carving here and there. Fortunately the clever screw-on caps help hold things together, after drilling out the caps' centers for the longer rod of course.

It did give a major boost to the signal levels, but as you correctly suspected it was unwieldy due to the small 3.5mm headphones jack supporting all the weight. The lack of any "brake" or lock for the antenna's position was the reason I eventually stopped using this modification and went onto other things (like my current digital readout ICF-EX5MK2 project :^)

I think someone could optimize this larger rod antenna with some sort of friction clutch or "brake", perhaps using your own idea of the stiff, rubber tubing section to provide the friction. It may be best though to fix the antenna's position firmly in place, as it's easy enough to rotate the body of the entire, skinny PL-360 by hand.

Ah... I just remembered what my final step in this adventure was. I flipped the included belt clip for the radio upside-down, so it pointed above the radio. Then I extended the loopstick's wiring with a different 3.5mm audio jack and a couple more inches of wire so it would reach the radio's antenna input. The 200mm loopstick was then tie-wrapped to the inverted belt clip after drilling four small holes into the clip. That combo resulted in a sturdy, but removable support for the larger antenna.

I'd upload a photo, but I no longer own this radio... I think my description of the mounting method is clear enough though.

73,

Guy Atkins
Puyallup, WA


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

Hello All,
 
While checking the latest eBay listings I came across this 200mm plug-in upgrade loopstick for the Tecsun PL-360 model, sold for $35.00 (+ $9 shipping) from a company in Greece: 
 
A demonstration video of the 200mm plug-in loopstick's MW performance is posted at
 
Since this type of antenna is very similar to the 7.5" upgrade MW and LW loopsticks that I designed for the PL-360 model four years ago (the article posted at http://www.mediafire.com/view/2cqwsqj0bvajf6k/7.5_inch-LS.doc ) 
I thought that I would offer a couple of comments. The $35.00 price seems very reasonable, although no details are given of the loopstick's coil design or inductance. The design lacks any type of locking system like the rubber hose clamp on the 7.5" plug-in loopsticks, which means that the antenna will rotate around freely in the plug-in socket (similar to a ham radio antenna on a tower, with no brake). Finally, whoever shot the video apparently wasn't aware that whenever you change plug-in loopsticks on a PL-360 you must shift the frequency off slightly and then back on, in order for the Si4734 DSP chip to readjust to the different loopstick inductance, and provide maximum sensitivity. In any case, it will be interesting to see how many sales this company will end up with, and the ultimate performance of their 200mm loopstick design.
 
73, Gary DeBock (in Puyallup, WA, USA)


RobertR
 

Tony brought his PL-360 yesterday and I had a chance to both see and use it.   It works well and in his case, the nulling capabilities are impressive.  The antenna was able to change azimuth's quite easily so perhaps a brake mechanism would be a worthy addition.

I have a spare 7.5" Amidon ferrite bar.  Guy, are you shooting in the way of coil impedance?   Perhaps the same as on the PL-380 project?.... was it 552 mh?

My next project is going to add a 1/8" female, stereo jack to the C. Crane Skywave to input a crate loop.  When the loop's tuning capacitor is fully unmeshed, I connect the modified PL-310 to the Loop VIA the now modified for MW, antenna input on the radio VIA a 12" piece of separated, very flexible, speaker wire.  An 18"/ side Crate Loop outperforms the signal catching ability of a PL-380 w/ 7.5" ferrite combo consistently by 10db.   The Skywave is, IMHO a much more "listenable" radio with its 3rd (or 4th?) generation DSP chip.

Good day to all!

Chuck Rippel


RobertR
 

Oh, did anyone notice the radio in the YouTube was a PL-365 v/s a PL-360 ?  They are most likely identical models but am not sure about that.

Chuck


Clyde Smith <hkryclyde@...>
 

are there any worries about introducing static discharges-not noise- into the skywave innards.   where do you hook the new plug into the radio??

what about doing similar thing  for an external sw antenna???

thanks    clyde



On Sunday, October 18, 2015 6:31 PM, "lantareamon@... [ultralightdx]" wrote:


 
Oh, did anyone notice the radio in the YouTube was a PL-365 v/s a PL-360 ?  They are most likely identical models but am not sure about that.

Chuck



bsaylor
 

I came to this party late, having seen the video posted on the SWLing.com blog last week. I looked at the large ferrite antenna on ebay but decided to try to build one. The small PL-360 replacement antenna arrived quickly from Anon-Co, and I used a surplus Russian 10x120mm ferrite rod that I bought several years ago on ebay. I re-used the Litz wire from the original antenna and found that it took about 25 fewer turns to reach the same inductance with the larger rod as the original antenna measured (about 330 uH). I used Guy's trick of turning the belt clip around and tie-wrapped the antenna to that to make it secure. The increase in signal strength from this larger antenna is indeed remarkable. In all it took about an hour to construct - a nice Friday evening project that went smoothly. Thanks for the information!

Brett Saylor
W3SWL
State College, PA