Category Archives: Radio Modifications

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

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

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.

If you own an Elecraft KX2 (or the Elecraft KX1) I highly recommend this simple encoder/VFO knob upgrade!

Click here to order on eBay.

Doctor Vlado repairs the Panasonic RF-2200 (Part 1)

Panasonic RF-2200 at Hamvention

Last year, at Hamvention, I picked up a Panasonic RF-2200 for $70. It came with the original box, manual and was in superb cosmetic condition.

The seller told me that over the years he exclusively used the radio to listen to a local FM station.

At that price, I didn’t hesitate to make the purchase even if this would have simply been a non-functioning parts radio for my other RF-2200.

After I brought the radio home, I unpacked it and gave it a quick test.

FM worked brilliantly. Mediumwave and shortwave, however, were essentially deaf. I made the assumption that the ‘2200’s switches and pots likely needed cleaning with DeoxIT. The next day, I was leaving for a two month trip to Canada though, so I packed the RF-2200 back into its box and set it to the side of my shack table.

Fast-forward to yesterday…

While digging around my shack, I re-discovered the boxed RF-2200. Since I was planning to visit my buddy Vlado (the best radio repair guy in the world) yesterday evening, I thought I’d take the RF-2200 and do a proper contact cleaning. Several of the RF-2200’s switches and pots cannot be easily cleaned without removing the chassis.

(Click photos to enlarge.)

Vlado is familiar with the RF-2200 and since it’s not the easiest radio to work on, I asked for his expert hands on the job. Within seconds of handing him the radio, he plugged it in, tested the switches and pots, then removed the back cover (disconnecting the battery compartment leads) and then the front cover (disconnecting the speaker leads).

The magic behind the RF-2200’s classic analog dial:
Vlado offered a word of caution to anyone operating on their RF-2200: as you can see in the photo below, the dial string snakes around the front of the radio and is very close to some key components. You must exercise caution when having a soldering iron tip near the string, or using lubricants nearby.I didn’t realize this, but by the time Vlado started taking apart the RF-2200, he had already determined that even though the contacts needed cleaning, this wasn’t the source of the audio problem for the MW and SW bands.Vlado expertly pulled out the pot for the FM/AM/SW selection–not an easy task–began cleaning it, testing it and re-soldering contacts.

Vlado determined the pot was actually in good shape, thus started testing the rest of the circuit.

After a few minutes of performing tests and getting intermittent performance, he determined that at least one, if not more, of the RF-2200’s caps need to be replaced. Of course, neither one of us was terribly surprised. At this point though, it was getting late and I had an early wake up time in the morning, so I left my RF-2200 with Vlado.

Am I worried about this prognosis?  No, not in the slightest…

Doctor Vlado is on the job!

Vlado will have the RF-2200 back on the air in no time, working as well as it did when it was new. He’s actually performed a similar RF-2200 repair for an SWLing Post reader and I’m willing to bet this repair job is relatively simple compared to most he encounters (including the Icom IC-7200 he recently repaired after it was hit by lightening!).

I’ll try to post a “Part 2” update with photos of the RF-2200 repair.  Follow the tag: Panasonic RF-2200 Repair

Rolf’s Sony ICF-SW35 mod removes the beep sound

Many thanks to SWLing Post contributor, Rolf Snijder, who shares the following modification for the Sony ICF-SW35. The mod is very simple: remove one capacitor.

Rolf shows the capacitor location on the following images:

Click to enlarge.

Click to enlarge.

Thanks, once again, for sharing your modifications, Rolf!

Pacific Island Results from Gary DeBock’s Hawaii Ultralight DXpedition

Clearing the southern coastline of Maui en route to the Big Island. (Photo by Gary DeBock)

Many thanks to SWLing Post contributor and intrepid Ultralight DXer, Gary DeBock, who shares this DXpedition summary with recordings:


Kona, Hawaii DXpedition– Pacific Island Results

by Gary DeBock

From December 17-20 a Mini-DXpedition was conducted in Kona, Hawaii with a 5 inch (13cm) “Frequent Flyer” FSL antenna and a 7.5 inch (19cm) loopstick C.Crane Skywave Ultralight radio.

The FSL antenna was a new type designed to easily pass through TSA security checkpoints at airports, and provide inductive coupling gain roughly similar to that of a 4 foot air core box loop. South Pacific island reception was generally good from 0630-0800 UTC daily, but usually became problematic after that when powerful Asian stations tended to drown out the exotic Pacific island stations as sunset progressed over Japan, Korea and China. By 0900 daily only the most powerful Pacific island stations on 621, 846, 1098 and 1440 had much of a chance of surviving the Asian signal onslaught, and even some of those were drowned out. During a similar visit to Kona, Hawaii with identical gear in April (DXing at the same motel) the Pacific island stations were generally stronger, and had no co-channel competition from the Asians from 0800-1030 UTC. As such the South Pacific results during this trip were slightly down from April, although there were still plenty of strong signals to record.

The new 846-Kiribati on Christmas Island was a star performer as the strongest island DU station, with local-like signals shortly after the Hawaiian sunset each evening. Despite this it had an intermittent transmitter cutout issue, with the signal failing to transmit at odd intervals (including one stretch with six signal dropouts within one minute, as documented in an MP3 linked below). In addition 846-Christmas Island’s programming had a variable time delay with that of distant 1440-Kiribati in Tarawa, with both a 19-second and 35 second time delay noted. This may be related to the transmitter cutout issue, with the time delay changing after a major dropout. DXers looking for a parallel with 1440 should keep this programming quirk in mind. Although both 846 and 1440-Kiribati signed off at the usual 0936 UTC time on the first couple days of the trip, they had both switched to a 1009 UTC sign off on the last couple of days. Whether this is a permanent programming change is unknown, but the loud 1000 Hz audio tone is still being broadcast before power is cut, resulting in a very easy way to distinguish the stations at sign off time (even in heavy domestic QRM).

846 and 1440 weren’t the only exotic DU’s with transmitter issues. 621-Tuvalu came down with distorted audio on December 18th, a problem which got worse and worse on the remaining two days. By the last day it was sounding very garbled, making a bizarre combination with 621-Voice of Korea’s buzzing Japanese service transmitter. Whether 621-Tuvalu has repaired its garbled audio is also unknown.

540-2AP was somewhat weaker than it was in April, while 558-Radio Fiji One was MIA during the entire trip (probably because of Asian QRM). Efforts were made to track down 630-Cook Islands but only a weak UnID was recorded. 801-Guam was possibly received during a Pyongyang BS/ Jammer fade, but 990-Fiji Gold was given a golden knockout by 990-Honolulu. 1017-Tonga showed up for a couple of good recordings, but got slammed by Asian co-channels after 0830. Efforts to track down 1035-Solomons ran into heavy 1040-Honolulu splatter, while 1098-Marshalls became the only Pacific island station to have stronger signals than in April. Its overwhelming signals after 0700 daily were one of the bright spots in Pacific island reception. Finally the new 1611-DWNX in Mindanao, Philippines was received at a strong level at 0855 on December 19th, apparently with a major boost from sunset skip propagation.

540 2AP Apia, Samoa, 5 kW Christian worship music at a good level through the T-storms at 0751 on 12-17, but not nearly as strong as in April:

Click here to download audio.

621 R. Tuvalu Funafuti, Tuvalu, 5 kW This station had very strong signals until around 0800 on most evenings, when it usually began to be pestered by Asian QRM (China, N. Korea and NHK1). It also came down with a garbled audio issue on December 18th, which continued to get progressively worse until I left Hawaii. Sign off time is still around 1006, but by that time it ran the gauntlet of powerful Asian co-channels during the December propagation.
Local employment offers read by the usual lady announcer at an S9 level at 0750 on 12-18. This was the last undistorted audio signal recorded from the station during this trip; after this the audio went “south”:

Click here to download audio.

Guest speaker in Japanese-accented English, followed by local island-type music at 0835 on 12-18– the first sign of audio distortion:

Click here to download audio.

Full Radio Tuvalu sign off routine at 1003 on 12-18, but with China QRM initially. Tuvalu’s signal prevails during the national anthem, but the audio distortion is quite noticeable. The carrier apparently stays on for over a minute after the audio stops:

Click here to download audio.

630 UnID While trying for the Cook islands (Rarotonga) I came across this weak Christmas music with English speech at 0742 on 12-17, although this could just as easily be a west coast domestic station playing the “exotic” to fool a hopeful DXer. Walt says this station is a notorious underperformer:

Click here to download audio.

801 UnID (Guam?) Apparent Christian female vocal music received during Pyongyang BS/ Jammer fade at 0931 on 12-18, but no definite ID clues:

Click here to download audio.

846 R. Kiribati Christmas Island, 10 kW This newly rejuvenated station had awesome signals, and was overall the strongest Pacific island station received. Of all the Pacific island DU’s it faded in at the earliest time after sunset, and maintained its strength even during strong Asian propagation — as long as it managed to transmit without its signal dropping out. Unfortunately this seemed to be a pretty common occurrence while I was in Kona. Island-type music at typical S9 strength at 0735 on 12-18:

Click here to download audio.

This segment at 0620 UTC on December 17th features 6 signal dropouts within one minute:

Click here to download audio.

This segment at 0944 UTC on December 18th is even worse– 9 dropouts in 90 seconds:

Click here to download audio.

After a prolonged 846 transmitter dropout it seemed like the programming time delay between the distant 1440-Kiribati on Tarawa Island and the new 846-Kiribati on Christmas Island would change. On December 17th I recorded two different time delays– 19 seconds, as in the following recording (the MP3 starts out on 846 at 0635, switches to 1440 at the 1:02 point, then switches back to 846 at the 1:34 point, with a 19-second time delay evident between the 1440 and 846 programming (846 lags behind):

Click here to download audio.

Later on the same evening there was a 36 second time delay between 1440 and 846, with this MP3 starting off on 1440 at 0645, and switching to 846 at the 11 second point:

Click here to download audio.

1017 A3Z Nuku’alofa, Tonga, 10 kW Female native language speech at a very good level at 0858 on 12-19:

Click here to download audio.

Somewhat weaker through the T-storms on 12-17 at 0734:

Click here to download audio.

1098 R. Marshalls (V7AB) Majuro, Marshall Islands, 25 kW This station was very strong in Kona with its island music every night, and rarely had any Asian co-channels.
S9 Island music and native language speech (and possible ID) across the 0700 TOH on 12-17:

Click here to download audio.

Equally strong island music and native speech at 0813 on 12-18:

Click here to download audio.

1440 R. Kiribati Bairiki, Tarawa, 10 KW Somewhat weaker than its rejuvenated 846-Christmas Island parallel (which has variable programming delay times, as explained above), this home transmitter could hold down the frequency until around 0800 every night, after which it was usually hammered by JOWF in Sapporo. Despite this it often put up a good fight until its new sign off time of 1009, and it continues to use the loud 1000 Hz tone right before the power is cut (an awesome aid for DXers hoping to ID the station through heavy QRM).

Typical island language speech and strength level at 0830 on 12-18, just as it is starting to get jumbled by JOWF (a Japanese female “Sapporo desu” ID is at 25 seconds):

Click here to download audio.

Full sign off routine at 1005 on 12-19, including the National Anthem and the 1000 Hz tone before the power is cut. The tone gets through the JOWF QRM like a DXer’s dream:

Click here to download audio.

1611 DWNX Naga City, Mindanao, Philippines, 10 kW (Thanks to Hiroyuki Okamura, Satoshi Miyauchi and Mauno Ritola for ID help) Received at 0855 on 12-19, this station was a mystery until the Japanese friends matched the advertising format with that of a new, unlisted station which just came on the air in the Philippines. The propagation apparently got a major boost during sunset at the transmitter:

Click here to download audio.

73 and Good DX,
Gary DeBock (DXing at the Royal Kona Motel with a 7.5″ loopstick C.Crane Skywave Ultralight+
5 inch (127mm) “Frequent Flyer” FSL antenna.

Demo video of the “Frequent Flyer” FSL antenna:

Click here to view demo on YouTube.


Thank you for sharing your Hawaiian DXpedition with us, Gary! Your mediumwave DX catches with modest equipment reminds us all that when HF propagation is poor, there is still so much signal hunting below 2 MHz!

Interested in Ultralight DX? Check out archived posts in our Ultralight DX category.

XHDATA D-808 modification to allow an external mediumwave antenna

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

I have added an external antenna capability for mediumwave on the XHData D-808.

Simply add a 27 pF capacitor on the backside of the PCB on C10 to the the ferrite antenna.

The mod causes no loss on FM or shortwave!

I also replaced the Ferrite antenna with a bigger one so I now have more performance on MW!

Longwave is not good in my radio, even with an external antenna, it is not performing well.

Thanks once again, Rolf! I must assume that the Digitech AR-1780 could be modified in the same way as the radios appear to be near identical. Perhaps someone can verify this at some point!

Rolf’s LED backlight mod for Sony ICF-SW35

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

This is a simple LED backlight modification for the Sony ICF-SW35.

Simply add a 120K resistor and a bright LED:

Overview of resistor placement. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of resistor. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of LED placement–replacement of capacitor is not necessary. (Click to enlarge)

When you push the backlight switch, the light stays on.

When radio is turned off, the light goes off–then push light switch and backlight will stay on for 15 seconds or so.

Thanks for sharing this simple mod, Rolf!