Category Archives: Radio Modifications

Bill discovers a number of Tecsun S-8800 Hidden Features

Many thanks to SWLing Post contributor, Bill (WD9EQD), who writes:

I’ve owned a Tecsun S-8800 for about eight months and have come to enjoy it more all the time. It, along with my PL-880, have become my main work horses for shortwave listening.

The S-8800 is perfect on the desk connected to a wire antenna and the PL-880 is perfect for carrying around.

Since I knew of the hidden features of the PL-880, it got me thinking on whether the S-8800 had any hidden features.

A quick Google search turned up the following Web Page:

http://swli-05940-mi.blogspot.com/2017/03/tecsun-s-8800-hidden-features.html

I used Google Translate to get a rough translation and then spent some time testing the features out and also just pressing and holding buttons to see if anything else showed up.

Following is what I have come up with:

(Note: some of these are in the manual)

With the radio off

Toggle Longwave on/off: With the Radio OFF, Press & Hold 2

Toggle backlight permanently on/off: With the Radio OFF, Press & Hold 3 – Note that this means the light will be on even when radio is off. While the light does go out when radio is turned off, any operation of a control will turn the backlight on and it will then stay on. Too bad they just didn’t install a slide on/off switch. Plus I know of no way to turn the backlight on permanently without the remote.

Toggle Seconds display on/off: With the Radio OFF, Press & Hold 8

Displays “0888”: Maybe this is version?: With the Radio OFF, Press & Hold “Back”

Displays all segments of display: With the Radio OFF, Press & Hold “AM NORM” – Displays all segments of display. Press & Hold again to display “H802”

With the radio on in FM mode

Displays “75US”: With the radio ON, Press & Hold 5

Squelch Setting: With the radio ON, Press & Hold 9 – Range 0-5. Use Tuning Knob to set. Press 9 again to set.

With the radio on in SW/AM mode

Toggles Extended functions on/off: With the radio ON, Press & Hold 4

With extended functions on:

Press & Hold 6 – Toggles DNR (Dynamic Noise Reduction) on/off.

Press & Hold 9 – Squelch Setting. Use Tunng Know to Set. Press 9 again to set.

Squelch ranges:

MW: 0-40

MW with USB/LSB: 0-30

SW: 0-25

SW with USB/LSB: 0-30

So far that’s all I’ve been able to find. Has anyone else found any others?

Post readers: please comment if you’ve discovered other hidden features on the Tecsun S-8800! I’ll compile a complete list and post it separately.

Guest Post: A DSP Hi-Fi “Stupid Radio Trick”

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Many thanks to SWLing Post contributor, TomL, who shares the following guest post:

Stupid Radio Trick – DSP “Hi-Fi”

by TomL

If you can remember the 1960’s, there was an audiophile rage going on called Hi-Fi. The base unit consisted of a ponderous piece of furniture consisting of a rectangular cabinet and equally large mellow sounding speaker of fairly smooth frequency response, say in the range of around 40 – 15000 Hz. They would have a built-in radio (using vacuum tubes) with large analog scale. Most would also have a “record player” embedded on the top to spin some vinyl discs (78 or 33 rpm).

For pedestrian consumers, it became a decision of how to keep up with the Joneses, so-to-speak. And that meant a trip to Sears to look at the latest offerings. When the decision finally came to purchase, of course no one could buy it outright. So, to add to the suspense, one had to put money down on “Lay-A-Way” plan that did not allow you to take possession of your prized choice until the last monthly payment! One had to visit or mail in a check every month.

So where am I going with all this? Well, as you can see from the photo [above], I have purchased three portable radios for three very different purposes. All three were painstakingly studied and reviewed and weighed against all other possible choices. All are highly rated by the usual reviewers like RadioJayallen, SWLing Blog readers and other internet personalities. The Sangean is for home use and listening to baseball games when I did not want to fire up the stereo hooked up to the Grundig Satellit 800. The small Sony ICF-19 is a phenomenal knock around radio for the car and listening while out to lunch or a walk in the park. The large Tecsun S-8800 is a possible replacement for my ailing 20+ year old Sony ICF-2010 for shortwave use.

Well, I was tired of listening to any one of them in terms of sound quality. The Sangean has too much upper bass/lower mid range, the small Sony is very carefully maximized for total speech clarity, and the Tecsun seems to lack a little in the mid range frequencies (compared to highs and lows). Staring at them, I thought to self, “What if I turn on the Sangean and Sony together???” What ensued was a revelatory sonic experience (it sounded pretty good)! One seemed to fill in the other in certain ways. But it was not perfect.

Duh, I had the new Tecsun in a carry case while trying to decide if I send it back for a tuning quirk and dug it out and plopped it on top. Turning it on, I heard more lows and highs, just like a Field Radio should have but with the mid range filled in! After very careful volume adjustment, I now have something that could rightly be called DSP Hi-Fi. At least, that is what I am calling it for now. ?

Violin and piano pop-out of an orchestra but not too harsh sounding. Rock & Roll sounds loud and punchy without that boombox effect. Bass lows are there (could be better, now all I need is a small subwoofer connected to the Tecsun line-out ???). Highs are there too but well controlled. Mid range voice clarity is stunning, as if someone is in the room with me but not sounding too forward! It is not room-filling but acts more like a near-field monitor. I like that I can line-up the speakers over each other.

The really fortunate thing is that all three radios have complete DSP for FM and receive my favorite over-the-horizon station with very similar reception quality. Also, they process DSP with a similar delay before output to its respective speaker. The sound is fairly coherent and even though it is still mono output, the full range of musical fidelity can be appreciated better. It is not audiophile quality but it is very satisfying and I can actually hear more details in the music than with any one of the radios by themselves. Just goes to show you that you CAN teach a new Radio dog old Tricks (LOL)!

Happy Listening,

TomL

I love it, Tom! Thanks for pointing out that sometimes it takes a “stupid radio trick” to really produce some amazing audio fidelity! This reminds me that in the early 90s, I used to have a Zenith Transoceanic and RadioShack DX-440 on my radio table in my room. If I recall correctly, the Zenith was on my left and the DX-440 on the right. I used to tune to shortwave, MW and FM stations and produce a makeshift “stereo” effect by playing both at the same time. Sometimes, on shortwave, it actually helped me discern voices in weak signal work!

Thanks again, Tom!

Kenwood R-2000: Luke’s simple fix for a frozen encoder

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Many thanks to SWLing Post contributor, Luke Perry, who writes:

Hi Thomas, I thought I would share with the people on the SWLing Post my new radio purchase.

I needed a receiver with a noise blanker as you might (or might not) recall my issue that I was having with electrical noise at my listening location. So I saw this on the local Craigslist for $50 and called right away and I was lucky to be the first one to respond.

The seller was the original owner and he had bought it back in the 80’s after coming back from Saudi Arabia so he could listen to the BBC. It was fully working but when I got home I noticed that tuning dial was not working and this set does not have direct frequency input for some reason.

I went online and scoured the internet for a possible fix and found a old posting that said to adjust the pots on the encoder board behind the main tuning knob. I found a service manual online and located the position of the board and thankfully that was the fix. But for some reason the position that they both were in was not the correct position so I don’t know if someone had been in there before but I doubt it.

Anyway, I am very happy with the purchase and the noise blanker seems to really work as I could not listen to any frequencies above 5 MHz on my old radio due to RFI. Also, the R-2000 seems to be very sensitive just from the small wire antenna that I have been using so I plan to get a better antenna and I am hoping to get some good DX catches.

Anyway, I thought I would share the news of my new purchase and hopefully the fix for the tuning knob might be of some use to others down the road.

I’m so glad you found the fix for the encoder function, Luke. Thank you for sharing because, no doubt, others will be searching for this solution. Sounds like it was a simple enough fix and certainly did the trick. If you ever need to re-cap the R-2000, you can find kits like this one to make the process easier. If you don’t want to do the work yourself, my friend Vlado recaps radios for a very reasonable price.

I’m sure you know you really snagged a deal grabbing that R-2000 for $50! Wow!

Gary pulls apart and examines the XHDATA D-808

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Many thanks to SWLing Post contributor, Gary DeBock, who shares the following report of the XHDATA D-808:

XHDATA D-808 AM-LW-FM-SW-AIR Portable- Tech Report

by Gary DeBock

The XHDATA D-808 portable is an AM-LW-FM-SW-SSB-AIR band model which has already been the subject of many excellent reviews. Until recently the model was not marketed to North American purchasers, but recently a couple of Chinese sellers have started soliciting North American buyers via eBay listings.

My own interest in the model was in comparing its AM Band performance to that of the best performing Ultralight radios– specifically the CC Skywave and Skywave SSB models. Although the D-808 is slightly larger than the 20 cubic inch limit for Ultralight radios, its size and weight make it very convenient to take along as a “travel portable,” specifically as an SSB-enhanced model capable of checking transoceanic station carrier strength on exotic ocean beaches. The Skywave SSB model can also do that– but at a $169.99 list price, compared to the $112.86 (plus $10 shipping) cost of the D-808. In addition, none of the published D-808 reviews seemed to have any information about internal components like the loopstick, or Si4735 DSP chip.

My first test was to compare the stock Skywave SSB model with the D-808 in fringe AM station reception. The Skywave SSB model has a reputation of being one of the most sensitive Ultralight radios, but the D-808 clearly outperformed it on both low band fringe station (550-KARI) and high band fringe station (1700-City of Auburn TIS) reception. The D-808 couldn’t quite hang with a 7.5″ loopstick Skywave model, but that only made me curious about how the same modification could enhance the D-808. So… it was time to disassemble the D-808, and find out why its loopstick was such a superior performer.

The D-808’s 3 7/8″ (98mm) loopstick is shown adjacent to the 2 3/4″ (70mm) loopstick of the CC Skywave models. The D-808 is much easier to disassemble than the CC Skywave models, though, so enhanced loopstick transplants should prove to be quite popular in the D-808.

The D-808 loopstick is 3.7/8″ (98mm) long, while that of the CC Skywave SSB model is only 2 3/4″ (70mm) long. Other reviewers have noted the excellent performance of the D-808 on the AM band, and this is probably one of the main reasons. The SSB mode operates very similar to that of the Skywave SSB in providing a quick check of carrier strength on weak AM band targets– the LSB mode can be set to +55, and the radio tuned to different frequencies to check fringe station carrier strength. This can provide a real-time check of propagation changes during time-limited propagation openings for live ocean beach DXing with Ultralight radios or other portables (or with the D-808 itself, if desired).

The D-808’s Si4735 DSP chip was initially used in the Eton Traveler III Ultralight radio model, which was fully reviewed in the 2015 Ultralight Radio Shootout (where it won top honors for MW sensitivity). The D-808 augments that capability with a significantly longer loopstick, plus multiple DSP filtering selections. As such, the D-808 in stock form should be a very superb performer.

The Si4735 DSP chip has markings of “3560, DCUL, .738” and provides a wide range of AM bandwidth choices for the Medium Wave DXer (6K, 4K, 3K, 2.5K, 2K, 1.8K and 1K). These perform very well, and as with the other DSP-enhanced portables, the narrowest bandwidth (1K) provides the most sensitive AM band reception.

In construction very similar to that of the CC Skywave, the D-808 separates into two main circuit boards, connected together by a plug-in ribbon cable. One strange quirk is that the Si4735 DSP chip is located on the RF board (close to the center right edge). The Si4735 DSP chip is also used in the Eton Traveler III Ultralight radio, and although that model lacks the multiple DSP filter selections of the D-808, is has been the subject of highly successful 7.5″ loopstick transplant modifications– proving that such enhanced Medium Wave and Longwave loopsticks will perform very well in the new, Si4735 chip- powered D-808.

Disassembly of the D-808 model is fairly straightforward in comparison to the CC Skywave models, and the technician doesn’t need to memorize a detailed reassembly protocol in order to perform a routine loopstick transplant operation. Neither C.Crane nor XHDATA are likely to show any sympathy to someone botching up an antenna transplant, so you need to be confident that that your skills are superior to those of the company technicians before taking the plunge. In the CC Skywave and CC Skywave SSB models various parts fit together like a puzzle, but the D-808 isn’t like that. It should prove to be a fairly popular model for enhanced MW and LW loopsticks.

Those considering a purchase of the D-808 should be advised that its type 18650 Li-ion 3.7v battery is not commonly available at most stores, and that Postal regulations supposedly forbid shipping these batteries through the mail. One of the eBay sellers (harelan ecommerce) did manage to ship me two of the standard XHDATA type 18650 batteries through the mail (along with two new D-808 models) but if your seller won’t do this, you can still purchase the batteries on eBay. Some of the 18650 batteries sold on eBay have a flat positive terminal which won’t contact the D-808 cabinet’s positive battery connector terminal, but in such a case you can simply insert a #8 lockwasher in between the two, and the arrangement will be very secure. From that point on you can simply recharge the battery with a USB terminal connector.

Thank you for sharing this technical overview of the XHDATA D-808, Gary! I’m looking forward to the antenna mods you’ll no doubt make to this compact DX machine!

Click here to read other posts about the XHDATA D-808 and here to read posts by Gary DeBock.

The AirSpy HF+ R3 bypass modification

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After SWling Post contributor, Guy Atkins, posted the survey results of his excellent Elad FDM-S2 vs AirSpy HF+ weak signal comparison, I received a few questions about the AirSpy HF+ “R3 Bypass” modification Guy mentioned in his post.

Guy has not yet performed the modification on his HF+–neither have I–but he points out that others have noted it: “significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues.”

I reached out to AirSpy president, Youssef Touil, for a little more insight about this modification. Youssef replied:

During the early phases of the design R3 was a place holder for a 0 ohms resistor that allows experimenters to customize the input impedance. For example:

A 300 pF capacitor will naturally filter the LW/MW bands for better performance in the HAM bands

A 10µH inductor would allow the use of electrically short antennas (E-Field probes) for MW and LW

A short (or high value capacitor) would get you the nominal 50 ohms impedance over the entire band, but then it’s the responsibility of the user to make sure his antenna has the right gain at the right band

A custom filter can also be inserted between the SMA and the tuner block if so desired.

Click to enlarge. (Photo source: RTL-S1DR.com)

R3 and the nearby resistors have been intentionally left outside of the RF shield, and their size was picked to be big enough to allow anyone to play with them. You will notice the size difference with the rest of the components.

In general, unless one knows what he’s doing, it’s not recommended to alter a working system. “If it’s working, don’t fix it”. But, we are hobbyists, and not doing so leaves an uncomfortable feeling of something unachieved. Most brands addressing the hobby market leave some tweaks and even label them in the PCB.

The main purpose of the HF+ is the best possible performance on HF at an affordable price. This is to incite HAMs to get started with this wonderful technology while using an SDR that isn’t worse than their existing analog rig.

The MW/LW/VLF crowd may have slightly different requirements, but that can be addressed by shorting a resistor.

Regards,

Youssef Touil

Thank you, Youssef, for replying to my inquiry so quickly and thoroughly.

No doubt, I too will eventually modify R3–it’s very difficult not to experiment, especially when a product was designed with the experimenter in mind.

I really feel like AirSpy has knocked it out of the ballpark with the HF+. For those of us primarily concerned with HF performance, this SDR is very hard to beat–especially at its $199 price point!

Video: How to calibrate the Tecsun PL-660 frequency offset

34 Replies

Many thanks to SWLing Post contributor, Mike Mander, who writes:

I’ve recently really been enjoying swling.com. Thanks for having such a great resource online with shortwave radio and hardware reviews, tips and more! I started listening to shortwave on an old Philips portable receiver back in the late 70’s as a teenager. Recently, after decades of not listening to shortwave, I decided to buy an Eton ‘Grundig Edition’ Satellit radio and in no time at all, I had also acquired a C.Crane Skywave SSB and now, within the last week, a Tecsun PL-660.

[…]I thought I’d record a video showing how one can calibrate AM, FM, SW wide-bandwidth as well as SW narrow-bandwidth independently, and how to reset those calibrations back to factory default. I have not heard it mentioned anywhere that one can calibrate both wide and narrow bandwidth SW modes independently.

Online, I have read about many people being disappointed in their PL-660’s wide-bandwidth frequency calibration, where often being on-station results in the frequency being up to 5 kHz too low, and it seems many simply return their radios as defective, not realizing how easy it is to recalibrate. This is the first “instructional” video of this sort that I’ve ever posted online, so you’ll have to pardon if I am perhaps not explaining things clearly enough:

Click here to view on YouTube.

Excellent video, Mike! You’ve done a fine job making the explanation clear and easy to follow. Thank you for sharing!

A $25 upgrade for the Elecraft KX2

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Many of you know I’m quite a fan of the Elecraft KX2. I take this little transceiver along almost any time I travel. Not only is it a full-featured ham radio transceiver, but it’s also an exceptional shortwave broadcast receiver.

The KX2 is a quality US-built rig (like all of Elecraft’s gear) but I’ve never been a fan of its plastic encoder knob. It lacks a finger dimple and feels cheap compared to the rest of the radio. Don’t get me wrong: the stock encoder knob gets the job done, but it’s not nearly as nice as the one on the slightly larger Elecraft KX3.

Comparing the Elecraft KX3 (top) and KX2 (bottom) at Elecraft’s Dayton Hamvention booth.

Two weeks ago, I ran into another Elecraft KX2 owner and happened to notice that his KX2 had a solid aluminium encoder knob with a finger dimple. Turns out, he purchased the knob from a ham radio operator (W1JH) in Maine who manufactures and sells this knob on eBay.

The price was $24.95 US shipped. I didn’t hesitate to place an order.

You might think $24.95 is a lot to pay for such a small item, but third party Elecraft vendors tend to charge much more for comparable items. I’ve also considered adding a heatsink to my KX3, for example, but those can total upwards of $100!

My new encoder knob arrived in only a couple of days via the USPS–installing it was a breeze.

It took me all of thirty seconds to pull the plastic knob off of the KX2 and replace it with the new aluminium one. The seller even includes an Allen wrench to secure the new knob.

The new knob is slightly larger in outer diameter, but fits the KX2 like a glove. The slightly larger size makes the finger dimple a practical addition for smooth band-scanning.