7.5 inch (19cm) AM Loopstick Qodosen SR-286 Ultralight Radio
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- Опубліковано 3 лют 2024
- Demonstration of the AM-DXing reception of a stock Qodosen SR-286 model, followed by the far stronger reception of the 7.5 inch loopstick model while receiving fringe station 1520-KXA in Snohomish, WA. The enhanced model uses a transplanted loopstick with a 638 uH main coil and a 4 uH tickler coil (93 turns of 175/46 Litz wire, and 2 turns of SAE 22 solid wire). These duplicate the inductances of the internal stock loopstick.
- Наука та технологія
Those antenna mods are always extremely interesting, Gary! Oh no, technical prowess needed...already outside of my capabilities ;-) I guess I keep my new stock SR-286!
Thanks, Walt! As limited free time allows, when I become more skillful in this modification I do plan to make up a few of these models for TP-DXer friends, assuming that the supply and company quality control hold up.
Thanks very much, Gary! While doing the antenna mod is way beyond my technical skills, I am anxiously awaiting the arrival of this radio. It will be coming with me on my upcoming Australia/NZ/south Pacific trip in March/April.
Thanks Stephanie, I'm sure you will like your SR-286 when it arrives. Have a great South Pacific trip!
Dear Gary, seems to be that the Qodosen-Rx is a unique and wonderful receiver. Thank you for the video from Germany !
Dear Klausputh, thank you very much for your comment. Best of DX to you, my friend! 73, Gary
WOW, IT can be a new DXpedition champion with this qodosen
Thanks FRLAZone2018, your comment is appreciated!
Hey Gary, the PL-330 also allows to switch between the internal ferrite rod and the telescopic antenna by long pressing 3. What I found is, in front of the sea, at noon local time, the telescopic antenna also brings way better results! My theory is the internal circuit (perhaps the DC-DC booster) causes too much QRM in very low noise locations like the beach.
But, neither the PL-330 nor the SR286 in their telescopic antennas, at the same beach location, could beat the Belka DX 0.1-30MHz version! I highly recommend the Belka for MW DX too.
Interesting that the circuit is different. I'd love to see a schematic of the front end. I always wondered why so many radios have more than two wires going to the loopstick. (not counting LW windings, or regenerative receivers)
Very nice ! 👍
Hello Gabrymir-radio, thank you for your comment!
Thanks for sharing.
Thanks for your comment!
This is great thanks for explaining that you made a 7.5" version of the onboard loop stick. Of course we want to see what it can do a nighttime and compared to your other radios with the 7.5 add on modification. I just bought the xhdata d-109, an The AM is great , i have eton traveller3 radios but they make loud clicks and pops in the ear phones when settings are changed, also there is the hiss sound with the volume down. The D-109 doesn't do any of this an the AM is comparable and the filters are easy to locate.
Hello Doug, this enhanced SR-286 model is the winner over all my other 7.5" loopstick models in MW sensitivity, primarily because of its low-noise TEF-6686 chip, which the others don't have. It provides lower noise in the S/N ratio for extremely weak stations. Unfortunately the SR-286 has limited selectivity options, so it gets beat out by the other models in limiting splatter from pest stations. The 3 kHz filter of the SR-286 just won't compete when chasing split-frequency transoceanic DX on MW.
That's what I am saying, I might have to order this radio soon to replace my Tecsun receivers such as the PL-606 and PL-398BT, PL-880 since Tecsun cannot make decent radios like I thought they did. I hope that they will be available, but still I want order me a TEF86 receiver, because I think the TEF86 has the same chipset inside.
So the internal ferrite stick is even worse that usng the telescopic antenna for MW ?
Digitalmediafan, actually the internal ferrite stick performs very well for the radio's tiny size-- it's just that the whip antenna performs better for MW reception. The SR-286's whip antenna will beat out all of the compact portables in MW reception.
@@DXerGary OK hmm a bit strange. If I get one I was hoping it would work with my wellbrook loop for MW tbh
The ferrite still provides better reception on most common reception locations, that is, inside your house or outside in urban areas, where you're still around sources of noise.
Once you go to a low/very low noise location - this is my theory - the internal receiver noise is captured by the ferrite rod as it's only a few centimeters of the microprocessor, display drivers and switched regulators. This is when the telescopic antenna gives outstanding results.
I've tested three receivers - SR286, PL-330 and Belka DX - and had excellent results at the beach during noon time with their telescopic antennas. When I switched the SR286 and PL330 to the ferrite rod antenna, SNR decreased by 6-10db.
However, as soon as I got to the Airbnb apartment we rented, reception on the balcony was way better with ferrite antenna; the telescopic antenna was flooded with electric QRM from LED bulbs, LCD TV sets and switched power supplies.
I get more stations with even just the built-in whip, but a TON more RFI. I had no idea that the streets of my suburb were THAT full of electrical buzz. You don't hear it (or only faintly) on the loopstick. Even through the buzz, though, I can find more stations. I just would never want to try to actually listen to them with the buzz.
The 10 and 50 foot wires out my back window work just fine, though. I'm not sure why they aren't full of noise.
Super interesting. Tnx Gary. 73 Greg
Thanks VA7BC, your comment is appreciated! 73, Gary (N7EKX)
...hopefully this radio will be the clarion call for ALL radio manufacturers to churn out these radios, and if these chips (TE6686) are so specific to one chip maker, then something can be made that is close enough to these, without copyright infringements. It shouldn't be that difficult to find someone to make these radio chips if they can make a profit
Yeah the SR-286 radio not available on US Amazon yet.
Gary, please compare Radiwow R-108 and Qodosen SR-286 on medium waves. Thank you. I have Radiwow R-108. I wonder if Qodosen SR-286 will be better than Radiwow R-108?
Hello Orionstar640, the new Qodosen SR-286 is more sensitive on medium wave than either the Radiowow R-108 or the XHDATA D-808, when using the SR-286 whip antenna. When using the internal loopstick, the XHDATA D-808 is slightly more sensitive, but the SR-286 can still beat out the R-108. The SR-286 uses a different DSP chip (the TEF-6686), providing less noise in the S/N ratio. In selectivity, however, the SR-286 cannot compete with the other two, because its narrowest filter is a 3 kHz selection, compared to the 1 kHz filter of the D-808 and R-108.
@@DXerGaryThanks for the answer.
@@DXerGary ... and one more question. Where is the better sound on the radiwow r-108 or qodosen SR-286? Which one do you like the sound of? I would be grateful if you show these two radios in the video.
@@orionstar640 I have completely disassembled both the R-108 and SR-286, and know that they both use the same kind of bass-oriented, powerful speaker. This compact, powerful speaker is also used in the D-109, D-109WB and D-608WB models. As such, the audio from all these models sounds about the same. The R-108's audio amp is wimpier than the other models on MW, though, so it bails early on very weak stations. The R-108 was fully reviewed in the 2021 Ultralight Radio Shootout (along with the XHDATA D-808, Tecsun PL-330, Tecsun PL-380 and C. Crane Skywave), posted at
dreamcrafts.box.com/s/8y6855bnfmy45rnk46mzr7hb4pwjz8u8
@@DXerGaryThank you for the information. With respect to you.
Hi Gary - love your videos (how can I not enjoy someone playing with radios in their backyard, I've been doing it since I was 5!) If you could post something about how to take this radio apart. Mine has an interior vibration that I can't fix from the outside. Not sure what it might be, but something needs to be tightened down. I removed all the case screws, but there seems to be a hang-up on the side where the tuning knob and volume are located. I really don't want to crack the case. Thank you in advance and much appreciated!!
Hi Jkratoville, the tricky thing about cabinet disassembly on the SR-286 is the rubber "feet" on the bottom of the cabinet. After you have removed the six screws, you must also pry half of each rubber foot off of the cabinet base before you can separate the front and back sections. Then, gently pry the two sections apart with a rocking motion. There is a snap connector on the side where the tuning and volume controls are located, and this is usually the final hangup before complete separation. Also, be careful of the wires from the battery connectors-- they break off very easily.
I really, really hope someone from Sangean, Tecsun or C. Crane is watching this!!!
We consumers are tired of the silicon labs medicare DSP-IC tuner chips, when NXP has been tirelessly working on there latest DSP chip and co processor.
It is WAY past the time these NXP DSP tuner chips to start making there way into portable radios. I'd be willing to pay a premium for such a IC-tuner chip (on there top model), but that option has not been given to use consumers.
From what I'm hearing, the NXP TEF386* is quite the IC chip, and essentially making the silicon labs chips look like cheap toys.
I'm a DXer like you Gary, and have over 14 portable radios, and all of them are very close, because they all use the same darn Si-labs chip.
I have ordered the SR-286, and can't wait for it to get here. I'm in the bay area, so I'm hoping that I will finally be able to hear all the radio stations from Fresno, Sacramento, and Monterey on open FM frequency's.
@petegallaguer8978, I agree with all your comments. The TEF-6686 chip from NXP provides a whole new league of AM and FM-DXing performance compared to the Silicon Labs' Si473x series chips. Hopefully the radio manufacturers will upgrade their models with NXP chips as soon as possible!
I can see how it seems the TEF is a much newer chip, but the data sheet copyright is 2005, not much later than the SiLabs chips. It's not a new chip, it's just new to portable radios. WHY it took 20 years to be "discovered" I haven't heard a good answer to. NXP wouldn't sell it to anyone not a major mfg? I don't buy that, not for that long a time period.
The power consumption does make it kind of an 18650 only sort of chip. 150mA or so just to power on.
Also, I'm enjoying my new radio, but not finding it to be more than a tiny bit better than any of the competition. I think you have to be in a VERY low RFI area to hear a difference.
I think I will stick to my Belka DX Max and its whip!
can you please tell me how the older (1990) version of the Sangean ats-803/Realistic DX-440 performed compared to radios of today. I had a new Realistic DX-440 in high school, then sold it, and now I have some reservations and regrets that I did, but I didn't use it for more than 1 month...
Sorry Dadwire1483, I've never owned a Sangean ATS-803 or Realistic DX-440, so I can't really answer your question. This Qodosen SR-286 in stock form is the most sensitive AM-DXing Ultralight-sized radio I have ever tested, though (when the whip antenna is used).
..thanks for your reply..@@DXerGary
3:17 i just bought this radio and I'm so impressed. Does anyone offer the mod in purchased radios for a price? Thanks for this awesome review.m
@user-fo2ud9kq4k, congratulations on your purchase of this exciting radio! As for the upgrade loopstick modification, unfortunately nobody is currently offering to do it for a price, although I will provide technical details to anyone who is interested. Best of DX, Gary
have you use the extenal antenna socket ?
Hello Dobrindorin1420, no, I haven't used the external antenna socket yet. Most of the external antennas here are inductively coupled (FSL's and tuned air core loops), so there is no need to use the antenna socket on the MW band.
Question for anyone: On MW, how might this modified model perform compared to an unmodified one connected to a passive tunable loop such as the TERK AM ADVANTAGE plugged into the external antenna jack or inductively via the radio’s own stock loop-stick?
Gary, can you show OEM Qodosen with FSL antenna? Thanks!
Yes Alexey, you can watch the stock Qodosen SR-286's performance with a 5 inch FSL antenna in the following video (from 3:30 until the end of the video)
ua-cam.com/video/ZCmP6Po7CWU/v-deo.html
Also, I plan to make more videos showing the stock SR-286 with an FSL antenna. Good DX to you!
Hi Gary, looking at the loopstick photo I don't understand the connections.
Could you please explain technically. It seems to me that the 2 turns loop should be connected to the antenna and the 93 turns loop should be connected to the variable capacitor of the receiver. It's correct ? Thanks a lot Gary, nice mod.
@tiqueky, Thanks for your comment! In developing this modification I simply duplicated the connections of the stock loopstick, which are shown in the photo at the following link (with the connections labeled in yellow lettering). Qodosen does not give out a schematic diagram of the SR-286 model, so that is the only way to connect an improved loopstick
dreamcrafts.box.com/s/ajrv2do0x45jc0ep8spqxxguye0s8lu1
Gary's modified Qodosen SR-286 7.5 inch loopstick version is ideal for MW DXers attempting to DX away from home in mobile situations where being more discreet among non-DXers is sometimes desired. But for DXing at home, my Sangean PR-D3 portable radio with 5 inch diameter speaker + inductively coupled tunable 2 ft diameter circular PVC loop will somewhat excel the SR-286 7.5 inch loopstick version. It is also somewhat disappointing that the TEF6686 chip does not feature high MW adjacent selectivity like it does on 65 to 108 MHz FM. The TEF6686 tuner variants are undoubtable the most sensitive, selective, and IMD resistant pocket size 65 to 108 MHz radios available anywhere.
Hello FrozenDoberman, I agree with all your comments. A 7.5" loopstick in the SR-286 will provide far more MW sensitivity than the stock loopstick, but inductively coupled air core loops or FSL's will always win out over a loopstick in ultimate sensitivity. This enhanced model was designed for travel situations, where inductively coupled loops are not convenient to set up. In that mission, it's a real thriller.
Did you have both radios positioned for max signal?
@n1kkri, yes, both 1520-KXXA and 1520-KMPG (the Spanish co-channel) are on north-south bearings from my location, the same way that the radios are set up for best reception. Here on the west coast most major stations are located along the coast.
Hi Gary, I have modified the Tecsun PL-380 with a 16cm external ferrite bar according to your plans, and I must say that the receiver has been reborn. I recently purchased the Qodosen and am using it with a self-built FSL with very good results. Even with its external antenna it works very well, from the balcony of my house (I reside in Italy, central Tuscany area) where there is less noise, I was able to listen to two stations from Iran: Radio Qoran on 900khz and Radio Ardabil on 1512.
Regarding your interesting project on the Qodosen, for now I do not dare to get my hands on it, we will see in the future. Instead, I would like to modify the Tecsun PL-380 again with the FSL wired as per your design.
I ask you one last thing: is there a file of the orange stand to make it with a 3D printer?
Thank you and congratulations on your excellent work.
Hello DoctorWu03, Congratulations on your successful modification of the Tecsun PL-380! The project to hard wire a small FSL into the PL-380 (in place of the loopstick) works well, but it's a challenge to find the lightweight 100mm x 20mm x 3mm ferrite bars in some countries. I'm sorry that I don't have a file to make the orange antenna frame with a 3D printer-- I usually just cut these on a miter power saw. Best of DX to you! 73, Gary
What would happen if you got a longer ferrite, instead of the loop stick? And would a longer ferrite work on other radios that use a conventional ferrite for MW, like XHData and Tecsun?
Hi Steverolfeca, a longer ferrite (like the Amidon 12 inch long Type 61 rod) would provide a slight increase in sensitivity over the 7.5 inch rod, but generally not worth the $95 cost and decreased portability. It would also require a new coil design, if used with the SR-286. For the XHDATA D-808, CC Skywave and other Silicon Labs 473x DSP chip models (PL-380, PL-330 etc,), these 12 inch long ferrite rods also provide a slight sensitivity boost over the 7.5 inch rods, but at very high ($95) cost and decreased portability. It's much better to get a sensitivity boost from an inductively coupled FSL antenna, if more sensitivity is desired.
@@DXerGary thank you for your advice. I grew up around tube and solid-state audio equipment, but RF is a whole new world for me.
Hello....can you show me the connection outside and inside ?.....a sketch....jpg ?
Here is a photo of the upgrade loopstick connections (labeled in small yellow letters)
dreamcrafts.box.com/s/ajrv2do0x45jc0ep8spqxxguye0s8lu1
Here are the stock loopstick connections
dreamcrafts.box.com/s/urylz3scpcl7iv7ln5789020udj4tx2r
Here is the upgrade loopstick design
dreamcrafts.box.com/s/79ygesyaqh3er2u6zebqxvvik3ym5ldm
Where can one buy the loop
Sorry. it is a homebrew project not for sale, but the design diagram is available at this link
dreamcrafts.box.com/s/79ygesyaqh3er2u6zebqxvvik3ym5ldm
Try this for A3Z 1017 khz Tonga and see for yourself
Thanks, I will certainly do that!
Electric cicut.
Next video sir .
I am whating.
..plz,, details.
.
Mor
Upgrade loopstick design diagram
dreamcrafts.box.com/s/79ygesyaqh3er2u6zebqxvvik3ym5ldm
Stock loopstick connections
dreamcrafts.box.com/s/urylz3scpcl7iv7ln5789020udj4tx2r
Upgrade loopstick connections (with yellow letter labeling)
dreamcrafts.box.com/s/ajrv2do0x45jc0ep8spqxxguye0s8lu1
..it would be a good idea if you can find a (machine?) shop that will manufacture this AM antenna, as it would be cheaper than attempting to fabricate one by ourselves.....
5:03
Loop antenna 📡 📡📻📡📡
ua-cam.com/users/shorts2GAou8pMg6w?si=TkoaIN7S33bnpQNB
My loop antnna.
..sir I am student
@@vintagetransistorRadio.Radio.h Thanks for sharing. Good luck in your studies!
Wow im not impressed. Oits not very stable. Whats with all the pulsing about
AM-DXing is like that, Ronald. It is pushing your luck to receive weak and unstable stations far away from your location.