Monthly Archives: October 2019

More advice on avoiding scams

In response to Paolo’s recent post regarding Internet scams, SWLing Post contributor, 13dka replies:

Sellers should be aware too: the same scammers have various schemes to scam sellers as well, and these fake ads play a role in those too, IIRC one popular variant is that the scammers try to buy your item, and offer the same thing on another platform in a different country, then they give their buyer your bank data to let them pay for your item, which gives them the advantage that they don’t even need a bank account to scam you. At the end the scammers have your item, the other buyer reverses the payment because he didn’t get anything.

Anyway, of course the same type of scams can be found with any article on the various “classifieds” platforms, also including eBay and Amazon’s “Marketplace” – RVs, cars, cellphones, computers, anything rare, collectible and/or vintage, pricey and sometimes even more common and cheaper things.

I noticed a serious wave of fake ads for guitars and other music gear on the German “eBay Kleinanzeigen” platform this year. One day I noticed several offers for vintage Gibson guitars usually sold in the $6,000-$10,000 range, each offered around 2,000, of course with pictures and article descriptions stolen from ended eBay auctions and US shops. It wasn’t only the price that wasn’t right, the descriptions being obviously translated from English was quite a dead giveaway. A few days later I found new offers like this and this went on and on, making me curious how many of those might be published every day.

To understand this properly, you need to consider that these “classifieds” are usually searched for local offers people can pick up personally, particularly with musical instruments that people often want to see, touch and try before buying. If I found that many fake offers just in my state, how many of those might show up in the entire country? In short, the amount of fake ads I found on a random sample basis (its impossible to survey the entire thing) was devastating. Even worse, I found that this extended to much less obvious, relatively low-priced current production instruments, also offered at prices that were only “attractive” or “very fair” and not obviously alarming.

A common denominator with all of these scams is indeed the stolen pictures from ended auctions and shops, and original article descriptions translated. You need a bit of “Google-Fu” to retrieve the origins of those and it takes a bit of common sense to distinguish fake offers and offers where the seller was just too lazy to take pics,. However, digging as deep as I could I found out that this musical instrument scamming goes on for at least 12 years now and there are so obvious similarities in the communication between sellers and buyers and shipping addresses that I think it’s the same scammers doing this successfully for that long time. The authorities are apparently over challenged and powerless due to the international character of the scam. Mind you, I checked only this one area of expertise I have and the result was alarming. The dark figure of scam attempts and actually scammed people might be incredibly high if I extrapolate this to all kinds of items.

If you want to stay on the safe side, just don’t try to buy stuff you can’t pick up yourself (or where the seller tries to avoid this by claiming he’s currently in some other country), don’t fall for surprisingly low prices offered by Amazon Marketplace dealers outside of your own country (like the brand new Icom 7300s offered for 599€ a while ago), on everything eBay/Kijiji/Gumtree/whatever try to check the seller’s reputation thoroughly so you don’t fall for 100% reputation scores gained from selling used baby clothing before the account was hacked and used to sell pricy things. If you have the faintest feeling of doubt, just let the deal pass. If you haven’t thoroughly read up on eBay scams et al, keep buying your stuff at local stores.

Thank you for sharing! All very sound advice. As for performing a little “Google-Fu” to find the source of an image, check out this tutorial on Google reverse image searches. Read the entire article as it describes doing this from tablets, phones and PCs. In addition to asking the seller to photograph something specific and unique on the item (like asking them to tune it to a specific frequency or to write their callsign on a card and include it with the item) I also perform a reverse image search anytime I’m purchasing from someone I don’t know.


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A liquid-based VHF/UHF steerable antenna

Many thanks to SWLing Post contributor, Marty, who shares this fascinating article from the IEEE Spectrum:

A new antenna that uses saltwater and plastic instead of metal to shape radio signals could make it easier to build networks that use VHF and UHF signals.

Being able to focus the energy of a radio signal towards a given receiver means you can increase the range and efficiency of transmissions. If you know the location of the receiver, and are sure that it’s going to stay put, you can simply use an antenna that is shaped to emit energy mostly in one direction and point it. But if the receiver’s location is uncertain, or if it’s moving, or if you’d like to switch to a different receiver, then things get tricky. In this case, engineers often fall back on a technique called beam-steering or beamforming, and doing it at at a large scale is one of the key underlying mechanisms behind the rollout of 5G networks.

Beam-steering lets you adjust the focus of antenna without having to move it around to point in different directions. It involves adjusting the relative phases of a set of radio waves at the antenna: these waves interfere constructively and destructively, cancelling out in unwanted directions and reinforcing the signal in the direction you want to send it. Different beam patterns, or states, are also possible—for example, you might want a broader beam if you are sending the same signal to multiple receivers in a given direction, or a tighter beam if you are talking to just one.[…]

Click here to read the full article.

 

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Iconic Berlin TV Tower turns 50

Photo by ?? Claudio Schwarz | @purzlbaum on Unsplash

(Source: Deutsche Welle via David Iurescia)

It served as a symbol of communist power and remains a remarkable landmark of the now reunited city: the Fernsehturm on Alexanderplatz was inaugurated on October 3, 1969.

With its iconic glittering sphere, the TV Tower looks over the once divided city that has been reunited since 1990. The 365-meter-high (1,198-foot-high) Fernsehturm on Alexander Platz in East Berlin was almost 220 meters taller than West Berlin’s broadcasting tower, the Funkturm at the Berlin Exhibition Center.

When the Fernsehturm was completed in October 1969, it was the second-highest television tower in the world, right after the Ostankino in Moscow (537 meters). TV towers built afterwards, such as in Tokyo, Guangzhou, Toronto, Shanghai, Tehran or Kuala Lumpur, have since broken the records of the time.

The head of the East German state, Walter Ulbricht, inaugurated the building to mark the 20th anniversary of the foundation of the GDR, on October 3, 1969. The structure served as a demonstration of the power of the communist state. The tower was indeed a masterpiece of engineering — even West German experts were ready to admit that.[…]

Click here to read the full story.

Note: Corrected title from Radio to TV Tower. 🙂

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Encore – Classical Music on Radio Tumbril on Sunday and Friday

Encore – Classical Music on Shortwave – Broadcast on Sunday afternoon in Europe and USA with a repeat on Friday

Encore – Classical Music this weekend is being broadcast as usual by Channel 292 (Europe) on 6070 kHz at 15:00 UTC Sunday 6th of October.
And by WBCQ on 7490 kHz at 00:00 – 01:00 UTC Monday 7th of October
There is a repeat on 6070 kHz on Friday 11th October at 19:00 UTC.
This week’s programme starts with the overture from Mozart’s Magic Flute, then we have the three Gymnopédies by Erik Satie. After that a short excerpt from Stimmung by Stockhausen – a piece for voices – it’s followed some 12th Century monastic monophonic chanting by way of compare and contrast… Some Bach partita and Ravel’s Pavane after that and then Debussy’s sonata for flute, viola and harp to finish.
Another interesting mix I think. I hope you can pick up the broadcast.
Both Channel 292 and WBCQ do live streams if the reception is poor in your location. Easy to find their sites with a google search.
Thank you for spreading the word about Encore – Classical Music on Shortwave. And thank you to everyone for letting us know how well the signal is received where you live.
Brice Avery – Encore – Radio Tumbril.
Regular Broadcast times are:
15:00 – 16:00 UTC Sunday, and repeated 19:00 – 20:00 UTC Friday on 6070 kHz (Channel 292 Germany).
00:00 – 01:00 UTC Monday on 7490 kHz 9WBCQ – Maine).
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Mike’s tips for decoding SW Radiogram broadcasts

Many thanks to SWLing Post contributor, Mike (KA3JJZ), who writes:

Have you ever heard of the SW Radiogram digital broadcasts? These are produced by Dr. Kim Andrew Elliott and started way back when as the VoA Radiogram. They are now carried on 2 other stations (WRMI and WINB) on a schedule (check every week for a summary of images) that you can find on the SW Radiogram website;

https://swradiogram.net/

These tests consist of both text and images. Currently MFSK32 and 64 have been used, and an occasional ‘secret’ mode has been slipped in at the end of the transmission. The last time this was done, the mode was PSK125R.

You might ask how you can receive these broadcasts, and what you need to decode them. We have 2 wiki articles that go into great detail – one for PCs, and one for Android devices – here;

https://wiki.radioreference.com/index.php/Decoding_the_SW_Radiogram_Broadcasts

https://wiki.radioreference.com/index.php/Decoding_the_SW_Radiogram_Broadcasts_with_TIVAR

Yes, you can copy these broadcasts using an Android powered phone or tablet using an application called TIVAR. John VK2ETA has written a quick start guide which is available on the SourceForge website as well as the RadioReference wiki (the links are provided in the article)

These articles are written for folks who are just getting their feet wet, so the above articles touch on radios (no, you don’t need to use an expensive radio, though many do), antennas, propagation and more. The most popular software is FLDigi, but if you happen to have MultiPSK or DM780 (part of Ham Radio Deluxe), they can be used as well. Links are given for the software and any available support.

Along with Tumblr, SW Radiogram has both a Facebook and Twitter page (where members often post decoded images) here…

https://www.facebook.com/groups/567099476753304/

https://twitter.com/swradiogram

Thank you, Mike! Yes, I’m a big fan of the SW Radiogram–the community that has formed around this particular shortwave program is quite amazing. Thanks for all of the tips!

Click here to view the SW Radiogram website.

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“G8JNJ Reverse Engineers and Reviews the MLA-30”

Many thanks to SWLing Post contributor, Paul, who shares the following story from the RTL-SDR.com blog:

Last month we posted a collection of reviews about the MLA-30 which is a budget magnetic loop antenna designed for receiving HF signals. The overall consensus from the reviews was that it worked decently for the price, but of course could never live up to the high end loops that cost hundreds of dollars.

Recently Martin (G8JNJ) reverse engineered the active circuit used on the loop from photos taken by M0LMK and has made some observations on it’s performance, noting that it’s design isn’t very good. First he notes that the amplifier chip is a Texas TL592B two stage video amplifier which isn’t that great for this application. His measurements show an OIP3 of 20dBm, a P1 saturation of -3dBm and a noise figure of 12dB.

Of interest, he explains that the creator of this loop has designed it poorly as the impedance match of the loop to low pass filter is very wrong, resulting in a very poor amplitude/frequency response. He shows how the response can be improved with a few termination resistors, but is still not great.[…]

Click here to read the full article at RTL-SDR.com.

 

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