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Yesterday, Tony (K3DY), shared a video (via Twitter) demonstrating his new home brew loop antenna and amplifier.
This is actually a great demonstration of how even a relatively simple, inexpensive loop antenna can improve reception in locations with heavy radio interference. Tony includes the following notes with his video:
“Testing a new receiving loop antenna that I built today. It uses a pre amplifier based on deferential setup of two 2N5109 transistors. Loop is made out of coaxial cable, only the shield is connected to the circuit.
Quick demo on 31 meters, lots of stations at sunset time. No time for further testing but I observed a pronounced directivity below 7 MHz. 75 meters is so quiet that it makes me forget I live in a townhouse. As a comparison, my noise level on 75 meters is at S8 on an end fed [antenna].
https://www.youtube.com/watch?v=bq_gKNQSVeA
I will use this loop primarily for SWLing purposes but I may use it as a separate receiving antenna with my amateur radio equipment.
A lot of fun, loops are fascinating and efficient!
Indeed, Tony! And perhaps the icing on the cake is that loop antennas are so portable, low-profile and easy to deploy. They’re ideal for those living in restricted areas and with picky home owners’ associations.
Inspired by my buddy Vlado (N3CZ), I’ve actually been collecting the pieces to build my own mag loop antenna this winter. I doubt the parts for my loop will exceed ten dollars as I plan to use the shield of some heavy coax for the primary loop and a little PVC for support (much like Tony’s loop).
Tony’s video is inspiring me to go a step further and also build a simple amplifier. Any suggestions or schematics for doing so are most welcome!
Two weeks ago, I received a mystery package in the mail: a copy of the October 2015 issue of CQ Ham Radio magazine, sent directly from the publisher in Tokyo, Japan.
Supplement magazine shipped with the October issue.
Since I can’t speak or read Japanese, I was very confused why I would receive a copy.
Out of curiosity, last week, I opened the magazine to see what sort of articles it contained.
In short: I was very impressed. While I couldn’t read the content, of course, I was able to get an idea of the scope of this magazine–it contained numerous articles, news items, reviews and photos.
I was pleased to note a section that focused on good etiquette for amateur radio exchanges in English. After all, if you are a Japanese DXer, you will need to know enough English to log DX stations around the world as English is the staple DX language. Japanese hams are well known for their excellent on-air etiquette–ask anyone who has been on a DXpedition.
The magazine is thick, too; most of the pages are black and white news print, but there are several color/glossy sections as well. This particular issue was even mailed with a separate supplement magazine containing a history of ham radio ads throughout the years. I thoroughly enjoyed the trip down memory lane.
Once I landed on the page above, I quickly realized why I had been sent a courtesy copy of the magazine: my SDRplay RSP review had been translated and published. It was then I remembered granting permission to have the article translated into Japanese for a ham radio magazine. I had completely forgotten!
I’m honored my review was printed in CQ ham radio, but most of all, it has been fascinating to browse through what appears to be an excellent radio publication. I offer my gratitude to the translator who took the time to edit my article.
Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), for the following guest post:
International Radio Broadcasts via Satellite
by Mario Filippi
I find your SWLing Post blog a constant fountain of information on the world of shortwave listening. Having been a shortwave listener since the early 1960’s, I’ve depended mainly on shortwave radios to hear foreign broadcasts. I’ve owned more shortwave radios than shoes (hi hi)–! However, there is a not-so-well known way of receiving radio broadcasts from around the world, and this is by Free To Air Satellite (FTA).
Free To Air satellite reception requires using a minimum 30 inch Ku band satellite dish, an LNB (Low Noise Block) amplifier, a Free To Air satellite receiver, and skills to aim at a satellite carrying these broadcasts.
There are several Free To Air satellites in the Clarke Belt, and the reception is cost-free as these broadcasts are for expatriates living around the world who need to tune in to stations back home. One satellite in particular that carries many foreign radio broadcasts is Galaxy 19, located at a longitude of 97 degrees, and is readily accessible from the USA.
Now let’s start on what an FTA dish set-up looks like for this type of reception. Below is an installation of mine, consisting of a 30 inch WS International satellite dish and LNB. A 30 foot length of RG/6 coax is run into the shack and hooked to an AMIKO Mini HD SE FTA receiver. Typical cost for a dish, LNB, coax is under $200.
Below is my AMIKO Mini HD SE FTA receiver, also known as an STB (Set Top Box), which can be purchased from a number of FTA vendors. This allows one to receive international television and radio broadcasts. They run about $90.
As stated earlier, Galaxy 19 is one of the best satellites to use for international radio broadcasts–currently, it has about 90 radio channels available for listening. I did a scan today of what is available, and below are three screenshots of the stations available to the listener.
Duna World radio is from Hungary. IRIB stands for Islamic Republic of Iran Broadcasting. 3 ABN is Apostolic Bible Network. TGN is Thai Global Network.
Kuwait, Syria, and the Middle East are well represented by the radio stations above. Voice of Russia, and Congo radio are good ones.
Voice of Turkey, Polski Radio found above. Not too shabby!
[Y]ou’ll find a good how-to on FTA at the following link:
[T]his is just a little introduction to the world of international listening using satellite. I hope this is something you and SWLing Post readers might find interesting.
Indeed I do, Mario! Thanks so much for taking the time to show us how to tune in a variety of international broadcasters via satellite. Each year at the Winter SWL Fest, we have demonstrations showing what can be done via FTA satellite. Perhaps I should bite the bullet and invest in one!
Many thanks to SWLing Post contributor, London Shortwave, who is kindly sharing this guest post–a brilliant article he recently posted on his own website.
I’m very grateful: one of the most common questions I’m asked by readers is how to cope with the radio interference so many listeners and amateur radio operators experience in high-density, urban areas. If this is you, you’re in for a treat–just keep reading:
Dealing with Urban Radio Interference on Shortwave
Shortwave radio listening is an exciting hobby, but for many of us city dwellers who either got back into it recently or tried it out for the first time not long ago, the first experience was a disappointing one: we could barely hear anything! Station signals, even the supposedly stronger ones, were buried in many different types of static and humming sounds. Why does this happen? The levels of urban radio frequency interference, or RFI, have increased dramatically in the last two decades and the proliferation of poorly engineered electronic gadgets is largely to blame. Plasma televisions, WiFi routers, badly designed switching power adapters and Ethernet Over Powerlines (also known as powerline network technology, or PLT) all severely pollute the shortwave part of the radio spectrum.
Does this mean we should give up trying to enjoy this fascinating medium and revert to using the TuneIn app on our smartphones? Certainly not! There are many angles from which we can attack this problem, and I shall outline a few of them below.
Get a good radio
The old adage “you get what you pay for” certainly holds true even when it comes to such “vintage” technologies as shortwave radio. Believe it or not, a poorly designed receiver can itself be the biggest source of noise on the bands. That is because many modern radios use embedded microprocessors and microcontrollers, which, if poorly installed, can generate interference. If the receiver comes with a badly designed power supply, that too can generate a lot of noise.
So how does one go about choosing a good radio? SWLing.com and eHam.net have fantastic radio review sections, which will help you choose a robust receiver that has withstood the test of time. My personal favourites in the portable category are Tecsun PL310-ET and Tecsun PL680. If you want a desktop radio, investigate the type of power supply it needs and find out whether you can get one that generates a minimal amount of noise.
It is also worth noting that indoor shortwave reception is usually best near windows with at least a partial view of the sky.
Tecsun PL310-ET and Tecsun PL680, my two favourite portable shortwave radios.
Identify and switch off noisy appliances
Many indoor electrical appliances generate significant RFI on the shortwave bands. Examples include:
Plasma televisions
Laptop, and other switching-type power supplies
Mobile phone chargers
Dimmer switches
Washing machines / dishwashers
Amplified television antennas
Halogen lighting
LED lighting
Badly constructed electrical heaters
Mains extension leads with LED lights
Identify as many of these as you can and switch them all off. Then turn them back on one by one and monitor the noise situation with your shortwave radio. You will most likely find at least a few offending devices within your home.
Install an outdoor antenna
If you have searched your home for everything you can possibly turn off to make reception less noisy but aren’t satisfied with the results, you might want to look into installing and outdoor antenna. That will be particularly effective if you live in a detached or a semi-detached property and have a garden of some sort. Of course, you will need a radio that has an external antenna input, but as for the antenna itself, a simple copper wire of several metres will do. An important trick is making sure that the noise from inside your home doesn’t travel along your antenna, thus negating the advantage of having the latter installed outside. There are many ways of achieving this, but I will suggest a configuration that has worked well for me in the past.
Fig.1 Schematic for an outdoor dipole antenna.
I have used a three-terminal balun (positioned outdoors), and connected two 6 metre copper wires to its antenna terminals to create a dipole. I then connected the balun to the radio indoors through the feed line terminal using a 50? coaxial cable. In the most general terms, the current that is generated in the antenna wires by the radio waves flows from one end of the dipole into the other, and a portion of this current flows down the feed line into your radio. The balun I have used (Wellbrook UMB130) is engineered in a way that prevents the radio noise current from inside your house flowing into the receiving part of the antenna.
Wellbrook UMB130 balun with the feed line terminal disconnected
Antenna preselectors
There is a catch with using an outdoor antenna described above — the signals coming into your radio will be a lot stronger than what would be picked up by the radio’s built-in “whip” antenna. This can overload the receiver and you will then hear many signals from different parts of the shortwave spectrum “mixing in” with the station you are trying to listen to. An antenna preselector solves this problem by allowing signals from a small yet adjustable part of the spectrum to reach your radio, while blocking the others. You can think of it as an additional tuner that helps your radio reject unwanted frequencies.
Fig.2 Schematic of a preselector inserted between the outdoor antenna and the receiver
There are many antenna preselectors available on the market but I can particularly recommend Global AT-2000. Although no longer manufactured, many used units can be found on eBay.
Global AT-2000 antenna coupler and preselector
Risk of lightning
Any outdoor antenna presents the risk of a lightning strike reaching inside your home with devastating and potentially lethal consequences. Always disconnect the antenna from the receiver and leave the feed line cable outside when not listening to the radio or when there is a chance of a thunderstorm in your area.
Get a magnetic loop antenna
A broadband loop antenna (image courtesy of wellbrook.uk.com)
The outdoor long wire antenna worked well for me when I stayed at a suburban property with access to the garden, but when I moved into an apartment well above the ground floor and without a balcony, I realised that I needed a different solution. Having googled around I found several amateur radio websites talking about the indoor use of magnetic loop receive-only active antennas (in this case, “active” means that the antenna requires an input voltage to work). The claim was that such antennas respond “primarily to the magnetic field and reject locally radiated electric field noise”[*] resulting in lower noise reception than other compact antenna designs suitable for indoor use.
Interlude: signal to noise ratio
In radio reception, the important thing is not the signal strength by itself but the signal to noise ratio, or SNR. A larger antenna (such as a longer copper wire) will pick up more of the desired signal but, if close to RFI sources, will also pick up disproportionately more of the local noise. This will reduce the SNR and make the overall signal reading poorer, which is why it is not advisable to use large antennas indoors.
The other advantage of a loop antenna is that it is directional. By rotating the loop about its vertical axis one can maximise the reception strength of one particular signal over the others, once the antenna is aligned with the direction from which the signal is coming (this is termed “peaking” the signal). Similarly, it is possible to reduce the strength of a particular local noise source, since the loop is minimally sensitive to a given signal once it is perpendicular the latter’s direction (also known as “nulling” the signal).
It is further possible to lower the effect of local noise sources by moving the antenna around. Because of the antenna’s design, the effect of radio signals is mostly confined to the loop itself as opposed to its feed line. Most local noise sources have irregular radiation patterns indoors, meaning that it is possible find a spot inside your property where their effects are minimised.
Many compact shortwave loop antennas require an additional tuning unit to be attached to the loop base (much like the preselector described above) but broadband loops do not. Wellbrook ALA1530S+ is one such antenna that is only 1m in diameter, and it was the one I chose for my current apartment. I was rather impressed with its performance, although I found that I need to use a preselector with it as the loop occasionally overloads some of my receivers when used on its own. Below is a demo video comparing using my Tecsun PL680’s built-in antenna to using the radio with the Wellbrook loop.
As you can hear, there is a significant improvement in the signal’s readability when the loop is used.
Experiment with a phaser
Although the loop antenna dramatically reduces the levels of ambient RFI getting into the radio, I also have one particular local noise source which is way too strong for the loop’s nulling capability. Ethernet Over Powerlines (PLT) transmits data across domestic electrical circuits using wall socket adapters, as an alternative to wireless networking. It uses the same frequencies as shortwave, which turns the circuits into powerful transmitting antennas, causing massive interference. One of my neighbours has PLT adapters installed at his property, which intermittently become active and transmit data. When this happens, it is not merely noise that is generated, but a very intense data signal that spreads across the entire shortwave spectrum, obliterating everything but the strongest stations underneath. Fortunately, a mature piece of radio technology called antenna phasing is available to deal with this problem.
Fig.3 The principle of antenna phaser operation (adapted from an original illustration in Timewave ANC-4’s manual)
Signal cancellation using phase difference
A phaser unit has two separate antenna inputs and provides one output to be connected to the radio’s external antenna input. The theory of phase-based signal cancellation goes roughly as follows:
The same radio signal will arrive at two different, locally separated antennas at essentially the same time.
The phase of the signal received at the first antenna will be different to the phase of the same signal received at the second antenna.
This phase difference depends on the direction from which the signal is coming, relative to the two antennas.
The phaser unit can shift the phases of all signals received at one antenna by the same variable amount.
To get rid of a particular (noise) signal using the phaser unit:
the signal’s phase at the first antenna has to be shifted by 180° relative to the signal’s phase at the second antenna (thus producing a “mirror image” of the signal received at the second antenna)
its amplitude at the first antenna has to be adjusted so that it is the same as the signal’s amplitude at the second antenna
the currents from the two antennas are then combined by the unit, and the signal and its mirror image cancel each other out at the unit’s output, while the other signals are preserved.
Noise sampling antenna considerations
To prevent the possibility of the desired signal being cancelled out together with the noise signal — which can happen if they both come from the same direction relative to the antennas — one can use the set-up illustrated in Figure 3, where one antenna is dedicated to picking up the specific noise signal, while the other is geared towards receiving the desired broadcast. That way, even if the phases of both the noise and the desired signals are offset by the same amount, their relative amplitude differences will not be the same, and thus removing the noise signal will not completely cancel out the desired signal (though it will reduce the latter’s strength to some extent).
It is possible to use any antenna combination for phase-based noise signal cancellation. However, one has to be careful that, in the pursuit of removing a specific noise source, one does not introduce more ambient RFI into the radio system by using a poorly designed noise-sampling antenna. After all, the phaser can only cancel out one signal at a time and will pass through everything else picked up by both antennas. This is particularly relevant in urban settings.
For this reason, I chose my noise sampling antenna to also be a Wellbrook ALA1530S+. The additional advantages of this set-up are:
It is possible to move both loops around to minimise the amount of ambient RFI.
By utilising the loops’ directionality property, one can rotate the noise sampling loop to maximise the strength of the noise signal relative to the desired signal picked up by the main antenna loop.
Two Wellbrook ALA1530S+ antennas combined through a phaser
And now onto the phaser units themselves.
Phaser units
DX Engineering NCC-1 (image courtesy of dxengineering.com)
I have experimented at length with two phaser units: the MFJ 1026 (manual) and DX Engineering NCC-1 (manual). Both solve the problem of the PLT noise very well, but the NCC-1 offers amplitude and phase tuning controls that are much more precise, making it a lot easier to identify the right parameter settings. Unfortunately this comes at a price, as the NCC-1 is a lot more expensive than the MFJ unit. As before, a preselector is needed between the phaser and the radio to prevent overloading.
Below is a demo of DX Engineering NCC-1 at work on my neighbour’s PLT noise. I have chosen to use my SDR’s waterfall display to illustrate the nefarious effect of this type of radio interference and to show how well the NCC-1 copes with the challenge.
Cost considerations
Fig.4 Final urban noise mitigation schematic
It would be fair to say that my final urban noise mitigation set-up, shown in Figure 4, is quite expensive: the total cost of two Wellbrook antennas ($288.38 each), a DX Engineering phaser ($599.95) and a Global AT2000 preselector ($80) comes to $1257. That seems like an astronomical price to pay for enjoying shortwave radio in the inner city! However, at this point another old saying comes to mind, “your radio is only as good as your antenna”. There are many high-end shortwave receivers that cost at least this much (e.g. AOR AR7030), but on their own they won’t be of any use in such a noisy environment. Meanwhile, technological progress has brought about many much cheaper radios that rival the older benchmark rigs in terms of performance, with Software Defined Radios (SDRs) being a particularly good example. It seems fair, then, to invest these cost savings into what makes shortwave listening possible. You may also find that your RFI situation is not as dire as mine and you only need some of the above equipment to solve your noise problems.
Filter audio with DSP
If you have implemented the above noise reduction steps but would still like a less noisy listening experience, consider using a Digital Signal Processing (DSP) solution. There are a number of different approaches and products available on the market, and I shall be reviewing some of them in my next post. Meanwhile, below are two demo videos of using DSP while listening to shortwave. The first clip shows the BHI Compact In-Line Noise Elimination Module at work together with a vintage shortwave receiver (Lowe HF-150). The second video compares using a Tecsun PL-660 portable radio indoors on its own and using the entire RFI mitigation set-up shown in Figure 4 together with a DSP noise reduction feature available in the SDR# software package, while using it with a FunCube Dongle Pro+ SDR. As a side note, it is worth remembering that while DSP approaches can make your listening experience more pleasant, they can’t recover what has been lost due to interfering signals or inadequate antenna design.
Set up a wireless audio relay from your radio shack
The above RFI mitigation techniques can result in a rather clunky set-up that is not particularly portable, confining the listener to a specific location within their home. One way to get around this is by creating a wireless audio relay from your radio shack to the other parts of your house. I did this by combining the Nikkai AV sender/receiver pair and the TaoTronics BA01 portable Bluetooth transmitter:
Head for the outdoors!
So you have tried all of the above and none of it helps? As a last resort (for some, but personally I prefer it!), you can go outside to your nearest park with your portable radio. After all, if shortwave listening is causing you more frustration than joy it’s hardly worth it. On the other hand, you might be surprised by what you’ll be able to hear with a good receiver in a noise-free zone.
Acknowledgements
Many of the above tricks and techniques were taught to me by my Twitter contacts. I am particularly grateful to @marcabbiss, @SWLingDotCom, @K7al_L3afta and@sdrsharp for their advice and assistance over the years.
Thank you–!
What I love about my buddy, London Shortwave, is that he didn’t give up SWLing just because his home is inundated with radio interference–rather, he saw it as a challenge. As you can see, over the years, he has designed a system that effectively defeats radio interference.
I also love the fact that he uses an even more simple approach to defeating RFI: he takes his radio outdoors. A kindred spirit, indeed.
I encourage all SWLing Post readers to bookmark and search London Shortwave’s website. It’s a treasure trove for the urban SWL. We thank him for allow us to post this article in its entirety.
This morning, I noticed that we’ve crossed a small milestone here at the SWLing Post: as of this post, there are now 2,000 published posts in our archives.
It’s a bit incredible that it’s already been almost seven years since I started this blog. In the beginning, I had no aspirations for the SWLing Post to become a popular destination for shortwave and amateur radio enthusiasts; it was mainly a site where I could jot down things I found of interest to me and keep tabs on the radio and international broadcasting industry. I was simply making my bookmarks and thoughts public, perhaps a little in advance of the social media outlets that now exist for shortwave radio and related topics.
A couple of months after starting the SWLing Post, I began using Google Analytics to track readership. I was absolutely floored to discover that, after a year or two online, I had about 200 pageviews per day–meaning, our website guests were reading about 200 pages/posts of information per day! It seemed surreal.
Each year–indeed, each month–that number grew. Now, it’s hard for me to believe the site has about 5,500 daily pageviews. Per month? We’re up to 167,000. As of today, here’s what Google Analytics gives for our monthly figures:
The thing is, these numbers continue to grow.
Best of all, what does this say–loud and clear!–about these “dying” radio shortwaves, about this old and washed-up medium of communication–? It says to us: interest in this hobby is far from dead, but rather, is still alive and well…and perhaps even growing.
And the very best part about hosting the SWLing Post? The community it’s created. So:
Thanks to everyone who makes this possible–to all of those who create guest posts, to those who comment, and to those who help other readers; thanks to those who participate in and moderate the chat room. Thanks to the readers who follow, to the SWLers who listen, to all those who care about radio. Thanks to you all…for the camaraderie, the coffee, the chance to enjoy the growing company of so many readers and fellow-listeners from all around the globe…I am now, and will remain, most humbly grateful.
And to extend my thanks, I’m looking into hosting a forum here on the SWLing Post which should allow for even more interaction within the community. So, yet again, allow me to say: Stay tuned!
Many thanks to Joris van Scheindelen (PE1KTH)–an SWLing Post contributor from the Netherlands–for the following guest post:
High Tech AM-FM DSP Receiver From
The old mode AM is still an interesting mode for amateur radio communication, also in amplitude CW.
Building your receiver is not difficult and quite fun. The semiconductor industry makes interesting integrated receiver chips today that will be useful for an AM receiver. Not only for broadcast reception but also for amateur AM reception or as part of an AM transceiver.
Silicon Labs also makes Si4734/35 receivers; these need a CPU to control the receiver, but are of interest for amateur use because the frequency can be tuned in 1 KHz steps and the audio channel bandwidth in 7 steps. There is no need for the transmitter to be on the receiving channel…
Si4835 AM-FM receiver
Looking for a small SW broadcast receiver design, and pocket size, I came to the excellent range of modern DSP receivers in a single chip from Slicon Labs.
I made a test bed set up has been made for the Si4835 AM-FM receiver.
The target specification was:
minimal components,
no micro-controller,
low power,
backlash free mechanical tuning,
good sensitivity,
earphone,
robust housing,
a short and small antenna system for outdoor use,
and minimal controls.
The Si4835 makes miniature design possible on a PCB (see photo Figure 1).
The red Dip (band) switch was replaced by a rotary switch in the final receiver design (Figure 4).
The receiver power is minimal 2 x 1.2 = 2.4 volts or a one cell LI-ION accu.
5 volts is the maximum for the Si4835 chip; current consumption is 30 mA.
Fig 1. Testbed setup for the Si4835.
The receiver has an RF pre-amplifier transistor and the LF amplifier is the TDA7050T.
All receiver functions are in the chip; the schematic is very simple and can be built with minimal components (see schematic appnote AN555 Fig 2. below).
Only an LF amplifier has to be added to complete the receiver.
Fig 2. Receiver schematic Si4835 in the AN555 application note.
The Si4835 receiver has the following frequency bands–they are divided in sub bands 800 or 900 KHz wide (See Figure 3). The frequency step tuning is 10 kHz on AM, following the international broadcast raster standard.
Fig 3. Si4835 receiver sub bands.
This means there are 80 or 90 receive channels in the sub bands and make finding the BC stations on the scale more easy. The 10 KHz scale steps are linear. The frequency stability is locked to the 32 kHz X-tal via the synthesizer so there is no frequency drift. The AM LF audio channel is 5 kHz wide set by the DSP filter. Volume control can be done width 2 up-down push switches or by a LF potentiometer..
Fig 4. The experimental pocket aluminium receiver housing on PCB2.
Receiving results
I have been testing many hours and I am surprised about this little receiver.
The receiving results are excellent on FM and AM and signals of 2 -3 uV are well received.
Also the audio quality is good–especially on FM. As can be seen in the frequency table the 40 and 20 meter band are in the range. Clear AM phone amateur transmission has been received when the transmitter was tuned on the 10 kHz raster in 40 meter band on AM.
Also AM modulated CW signals can be received bud not un-modulated carrier CW–they sound “plop…plop”.
The 5 kHz wide LF channel is a bid too wide so many CW signals pass through the audio at the time, but if AM modulated that should not be a serious problem.
The broadcast stations in the SW bands (when the daytime conditions are good) up to 20 MHz are good and strong.
Conclusions
The Si4835 receiver can be a fine broadcast receiver for outdoor work and if an AM transmitter is tuned in the 10 kHz raster this receiver can also used for amateur phone reception.
Addendum: The Si4734/35 is a better amateur AM Receiver
The Si4734 and Si4735 are a better receiver choice for amateur AM purpose because the frequency tuning can be done in 1 kHz steps. Also the BW of the LF channel can be adjusted to 1 kHz wide.
In Fig 5. from the programming APP note you see the code 0X3102 AM CHANNEL_FILTER it is possible to adjust the audio width by sending this code to the Si4734/35.
Fig 5. From the programming APP note
The LF bandwidth can be set on 1, 1.8, 2.5, 2, 3, 4 and 6 kHz wide.
This is excellent for modulated CW and AM phone discrimination in the audio channel.
The disadvantage is the need of an CPU and LCD display, “away from a minimalistic design”.
See also the note 1 and 2 improved 100 Hz rejection. See data sheet of the Si4734/35.
It look like that this receiver is a good receiver for building a modern AM-(AM)CW receiver or in a transceiver application. Tuning can be done digitally.
Think about this receiver [and the Si4835 chipset] when you intent to build a high tech AM – T/RX.
73 ‘ Joris van Scheindelen PE1KTH
What a fantastic home-brew receiver, Joris! I love the simple design of your receiver and the fact that it’s quite portable. Thanks so much for sharing your notes and documentation.
In June, I made a small leap of faith and purchased a (dead) Sony ICF-SW100 from Universal Radio (see the listing on right).
You see, for many years, I’ve dreamed about owning this wee little receiver, now a classic among tiny radios, but used ones are typically too expensive for my modest budget.
This time, seeing the ad at Universal, I spoke with Universal Radio directly to obtain more details about their defunct unit; while they simply didn’t know what was wrong with the Sony, they were able to very accurately describe its cosmetic and functional condition…I took a deep breath, and decided to take a chance on it anyhow.
In full disclosure, I have a secret weapon in my camp: my talented friend, Vlado (N3CZ), who is not only the most adept electronics engineer/technician I’ve ever known, but one who trulywelcomes a challenge. The thought had occurred to me as I admired the wounded Sony, Wonder if Vlad would like to take this on–?
The answer, of course, was Yes! So I dropped the DOA Sony off at Vlad’s home last week. He disassembled the radio, only to discover that my ICF-SW100 was a victim of the (dreaded) damaged ribbon cable.
A short history of the Sony ICF-SW100 and SW100S
These radios are indeed brilliant, incredible performers for their miniscule size. Yet the first generation of ICF-SW100 radios–those produced before the fall of 1997–have a design weakness: the ribbon cables which connect the upper and lower portions of the radio’s clamshell design eventually fail. Multiple openings and closings bend and cut the cables, rendering the otherwise remarkable little radio useless.
SWLing Post contributor, Dan Robinson, recently shared his knowledge about the ICF-SW100 series. Dan notes:
SW-100 Seekers Beware
As shortwave veterans know, the classic SONY miniportables — SW-1, SW-100(S) and SW-07, represented some amazing technological achievements. SONY managed to shrink some fantastic technology into these receivers, including (with the last two in the line) — SYNC capability. The SW-07, which was the last of these receivers, still brings some high prices on Ebay.
But if you are searching for the ICF-SW-100S there are some things to consider and beware of. As everyone knows, the SW-100 suffered from the well-known ribbon-cable failure problem. SONY addressed this problem in later serial numbers, and changed the design of the radio case.
Modified SW-100s have a notch where the top cover meets the base.
There are some dishonest sellers out there who are trying to pass off older version SW-100s as modified ones. Usually, the tip-off is that the photograph in the Ebay auction will be dark or out of focus, so it’s hard to tell if the radio is the modified version or not.
It has become quite rare to find an original SONY modification kit, which includes a new top cabinet of the SW-100. And some sellers are trying to get as much as $300 for these, though they rarely sell at this level.
ICF-SW100 modification kit found on eBay at time of posting.
It’s also becoming rare to see SW-100S radios new-in-box. I had two of these, sold one and kept the other.
If you’re after one of these marvel radios, do what everyone should do when considering items on Ebay — ask many questions about [the] cosmetic condition, accessories, serial numbers, etc.
Universal Radio, a trustworthy seller I know, had fully disclosed the model number and problems with this radio, so I knew exactly what I was buying. Dan has a very good point, though: unless you know the seller to be honest, do your research and ask questions!
The ailing ICF-SW100
Vlado discovers the faulty ribbon cable (click to enlarge)
Back to my ailing unit: Vlado delivered the news about the ribbon cable via text message, and though I was well aware that the chances were high that was the ribbon cable, I was a little bummed, to say the least, to get the formal diagnosis.
Why? As Dan mentions above, you’ll find that the SW-100S upgrade kit Sony produced in the 1990s is no longer available new; sellers typically list these kits at prices in excess of $300 US. Out of my budget.
But Vlado, ever the intrepid engineer, had no idea I would be disappointed with this news; he was just giving me this FYI via text. Indeed, he seemed entirely unfazed, as in, hey, no serious internal damage here…
Another hour passed. Then came another message from Vlad; this one simply said: “Call me.”
Oh no, I thought. But I called, and Vlado answered cheerfully, “Hello? Tom, is that you? Sorry, I can’t hear you very well because your SW100 is playing too loudly. Hang on–let me turn the volume down!”
Vlad installs the replacement ribbon cable (click to enlarge)
“What!?!” I responded, in utter disbelief.
Yes, he’d got it working! It seems that Vlad had unearthed an old DVD player in his garage that he’d kept merely for parts. He opened it up, identified a ribbon cable with the right pitch, then cut and folded the cable to fit into the SW100. Ingenious!
That’s Vlado for you!
And should I be interested in replacing this used cable with a new one–or in repairing other Sonys–Vlad directed me to eBay listings for new cables which only total about $20, shipped. Truthfully, I’m in no hurry, as this one is functioning perfectly and changing out the ribbon cable seems to have no effect on stored memories, etc. With a single affordable eBay purchase of multiple cable sets, it occurred to me that Vlad would have enough replacement cables to repair the SW100 many times over…
So I bought the cables. (This one for the narrow cable and this one for the wider one.)
My “new” Sony ICF-SW100
Needless to say, I’m very pleased with my “new” (to me) SW100. It’s a little masterpiece of receiver engineering in such a tiny package. And since the ICF-SW100 is unquestionably the smallest portable I own–and is one of the few I own with a proper line-out jack–it may very well become my go-to radio for one bag travel.
It’s in the bag: listening to the ‘SW100 before I pack it for my next trip!
Stay tuned the review…
Vlado’s radio E.R.: the doctor is in
As I’ve said, Vlad is one of the most adept repair technicians I’ve ever known. At my prompting, he’s kindly agreed to let me promote his services here on the SWLing Post. Vlad acknowledges that he “likes a challenge,” adding that he enjoys nothing more than making repairs even when”parts are scarce” and radio”surgery” is required. Moreover, his bench fees will be quite reasonable, especially considering what you receive: new life for a failing radio. So, if you’ve got an ailing rig on your hands, and don’t mind waiting for Vlad to get to it, send it to his radio emergency room, where radios (like my Sony) have life breathed back into them once again.
Long live the Sony ICF-SW100! And long live Dr. Vlado, who makes this possible with his creative (and nearly miraculous) repairs.
To contact Vlad, simply contact me with a description of your radio and its problem and I’ll put you in touch with Vlado.
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You see, for many years, I’ve dreamed about owning this wee little receiver, now a classic among tiny radios, but used ones are typically too expensive for my modest budget.
