Category Archives: Guest Posts

CQ Satellite: ARISS FM Repeater, Ham Sats, Tracking, Antennas, and Looking At The Future

Many thanks to SWLing Post contributor, Dan Van Hoy (VR2HF), who shares the following guest post:


ARISS FM Repeater May Be Back on Early December and a Short Ham Satellite Summary

by Dan Van Hoy (VR2HF)

I’ve recently had a lot of fun learning about the current batch of ham satellites and operating through some of them for the past several months with only a Diamond discone (and a short run of RG-213 double-shielded coax), Yaesu FT-817 (for SSB/CW) and TYT TH-9800 for FM satellites (more power, Scotty!). This simple set-up has yielded hours and hours of great fun. The last time I did satellite work was in the ’70s making contacts from my car through Oscar 6. If I had a car here in Hong Kong I might try it again!

Here’s my living room TV tray and sofa shortwave and satellite station (no XYL in house at the moment).

ARISS FM Repeater

One of the recent highlights for both newcomers to satellite operations and old-timers was working the International Space Station’s (ISS) new FM repeater which came on the air in early September. It is a specially modified Kenwood D710-GA VHF/UHF transceiver. Unfortunately, it was only operational for about a month. For the past several weeks it has been used mostly in APRS mode.

The ARISS FM repeater runs five watts and sounds just like a regular terrestrial repeater in many ways. You can work it with any dual-band VHF/UHF FM rig and the right antenna. Full-duplex is not required, but it helps. Lower power requires some kind of gain antenna, but receiving can be done with simple antennas.

The ARISS organization just updated the schedule for the ARISS operation with this announcement:

“Next mode change (cross band repeater) targeting early December.”

YEAH! What a nice Christmas present!

Here’s a link to the full ARISS information page:

https://www.ariss.org/current-status-of-iss-stations.html

ARISS QSO with E21EJC

Here’s a Youtube video of one of my ARISS contacts with E21EJC. It was right after he came back from his DXpedition hauling microwave gear and dishes out to the Thai countryside to work the QO-100 geosynchronous satellite. I tell him “welcome home and have a good rest.” Kob really is “Mr Satellite!” He has posted hundreds of Youtube videos of satellite contacts.

In addition, here is video of their HS0AJ/P special “portable” station antennas for QO-100. 10 GHz RX dish (downlink) and 2.4 GHz TX dish (the big one). I listened to Kob and his friend make several QSOs via the QO-100 WebSDR:

Amazing the things we hams do just to spray some RF in the right direction!

Beyond the ARISS: A Ham Satellite Summary

Presently, AO-91 is probably the most popular FM satellite, along with SO-50, AO-27 and PO-101. RS-44, a linear satellite for SSB and CW, is far and away the most popular for those modes. RS-44 is in a higher orbit providing less Doppler shift and longer contact times per pass. You can easily see from the Amsat status page which satellites are in operation and which are the most popular. Many of the ham satellites do not provide two-way communication capability, but still have beacons (CW and data) that can be heard (those are in YELLOW on the Amsat status page). Everyone with a ham callsign can contribute by by uploading a reception report of the satellites you hear or work.

Full-duplex on SSB/CW satellite work is very desirable but not mandatory. I have learned you can make contacts without it coupled with a little skill and some luck. Staying near the center of the satellite’s particular passband is helpful. Sadly, there are few full-duplex rigs available these days. One of the best may be the Yaesu FT-847 which can be found on the used market. Some satellite ops are using SDRs for RX and a ham rig for TX to achieve full-duplex. I’m going to try that soon using two Diamond discones and vertical separation.

For current status of all ham satellites and ARISS operation, go here:

https://www.amsat.org/status/index.php

Tracking

For tracking the ham sats and ISS, I like the Heavens-Above app (or Webpage: https://heavens-above.com/). The Pro version of Heavens Above is worth every penny. In the app, I put only the active satellites I am interested in in the search box. That way all the remaining unusable satellites will be ignored. Heavens-Above also lists the satellite operating frequencies for a quick reference.

 

One cool side note. With Heavens-Above, you can also see when ISS visible passes are available over your area (almost always near sunrise/sunset). Look for the passes with a magnitude greater than -3.0. If you have clear skies or a thin layer of clouds it’s quite a treat to see the ISS zoom overhead at 17, 000 miles per hour. When the ARISS repeater is operating, you can see and hear the ISS! The screen shot above is a visible pass at -3.9 magnitude, as bright as Venus.

Antennas

I have found my Diamond discone to work quite well for satellite operation. It’s probably the cheapest, simplest and most effective antenna you can use for this application If you really get interested in satellite work you can always spend the big bucks for AZ/EL rotators and beams as well as the software to run it all including tuning your rig to compensate for Doppler shift. Or you can buy quite expensive omni-directional antennas designed specifically for satellite use. So far, the KISS approach has worked well for me.

The Future Is Now

Finally, we can all get a taste of the future now by listening to the only ham radio geosynchronous satellite currently in operation, QO-100. It is centered on Europe and covers about 1/3 of the earth from Brazil to parts of Asia.

It was a thrill for me to listen (via the WebSDR listed below) to one of my new satellite colleagues, Mr Kob, E21EJC, who I call “Mr Satellite,” work Brazil and many other stations in the EU, the Middle-east and elsewhere through QO-100 during a special event operation from Thailand.

Anybody can listen to activity on QO-100 at the link below. When you get there just find the CLICK TO START SOUND! button. Then, click UNDER one of the signals in the waterfall and tune with the controls below. Weekends and holidays seem to be the best time to listen.

https://eshail.batc.org.uk/nb/

Because both the uplink and downlink frequencies are way up in the microwave bands, it’s not easy to get on QO-100, but, it appears to me, worth the effort. Maybe one day we will have two more QO-100-like birds linked together to cover the whole earth for 24/7 communication anywhere in the world. One can dream.

Full details about the QO-100 geosynchronous satellite can be found here:

https://amsat-uk.org/satellites/geo/eshail-2/

CQ Satellite!

When the propagation is bad, or actually anytime, ham satellites are a wonderful alternative to HF for having fun on the air.

Sorry, gotta go, RS-44 is just about here. CQ satellite, CQ satellite, de VR2HF…


Thank you so much for the satellite overview, Dan!

You’ve inspired me to get out of my comfort zone and try a little satellite work! The perfect project to do with my two daughters. I’m such a “below 30MHz” guy, I have to remind myself that there are actually some pretty amazing things you can do further up the band! When I purchase a discone antenna, I’m going to accuse you of being an enabler. Fair warning.

SWLing Post readers: Anyone else here tune to and track satellites? Please comment!

Spread the radio love

Paolo warns of persistent classifieds scams targeting radio collectors and advises how you can be scam savvy!

Many thanks to SWLing Post contributor, Paolo Viappiani (SWL I1-11437), who shares the following guest post:


A recent resurgence of Internet scams involving quality radios

by Paolo Viappiani (SWL I1-11437)

After my previous post on this subject, I found on the Internet other very dangerous fraud attempts concerning high-quality radios offered at very convenient prices. Below, you’ll find the details of a recent attempt concerning the highly-desirable SONY CRF-V21 receiver.

The methods are always the same, but the scammers greatly refine their fraudulent techniques, even going so far as to carry out real identity thefts, as in this case.

Of course, I knew from the beginning that it was a fraud (I don’t let myself be fooled anymore!), but I tried to continue corresponding with the scammer in order to get as much data on his real identity as possible. At the same time, however, I reported the fraudulent advertisement to the site webmaster in order to prevent other users from falling into the trap. The ad was promptly removed, but the scammer noticed it and immediately he slipped away…

Here is the story…

I have been trying to detect and report Internet scams from some time (since I was scammed!), and recently I found an advertisement for a SONY CRF-V21 radio, described as working and in good cosmetic conditions, on the Italian website “Clasf”, look at the picture below:

The radio was offered for Euro 2.600 from a seller who supposedly resided in Rome, Italy.

I sent him a message through the “Clasf” site and almost immediately I received a reply from someone who claimed to reside in Reichertshofen, Germany.

Déjà vu… Germany, Spain or Portugal always seems to be the same story…

But this time the very serious thing is the fact that the scammer identified himself as an “implantology dentist”–a fake identity–also providing a counterfeit website:

From my investigation it appears that both the picture and the website were stolen from a true professional from Hamburg, Dr. Bernhard Brinkmann, look at the websites (here and here).

Of course I tried to contact Dr. Brinkmann and I still make all the documents available to him, in case he wants to prosecute the thief.

About the pictures I received from the scammer (you’ll find some of them below):

All photos were stolen from a Canadian eBay advertiser instead:

So, buyer beware! The number of frauds in the radio market on the Internet is growing day after day, and it always advisable to keep your eyes wide open, even in the rush to purchase a much desired item at an affordable price.

Today scam techniques are increasingly refined, as shown in the example reported above.
Sincerely I don’t know if this user has something to do with the other European scammers (supposedly from Spain and Portugal) I quoted in my former post. The Italian Postal Police, after having examined the headers of the e-mails that I received along with other documents, believe that such scammers can reside anywhere in the world.

Most scammed

Anyway, the three “most scammed” radios are currently the Panasonic RF-8000, the Panasonic RF- 9000 and the Sony CRF-V21 (pictures below):

Please also notice that a number of advertisements on the most popular classifieds sites (Quoka.de and ebay-kleinanzeigen.de in Germany, Subito.it, Clasf and AAAnnunci.it in Italy, Le Bon Coin in France, ComoFicho in Spain, etc.) still are mirrors for larks only, and you have to pay a great attention in order not to be scammed.

A recent trip over all the mentioned sites revealed that only a few ads are really true…

Red Flags

I repeat some notes about scammers and their usual techniques:

A.) The scammer advertises a very rare radio in like-new conditions at an unbelievably low price. The buyer does not want to miss the bargain, so he contacts the seller and promptly transfers the money to him without further ado, but after that he waits in vain for the delivery of his item.

B.) If you contact the seller, the item is always abroad. The alleged seller then proposes to handle the purchase through a “trust company”. The radio should be paid in advance and the amount sent via cash transfer, but after that you never hear anything from the seller again.

C.) Alternatively, the buyer is requested to to deposit the money to the eBay company account to get the product. But the account is fake (eBay HAS NO “Company Account” and never handles private transactions!), so the buyer loses his money and receives nothing in return. Please also notice that often the fraudulent sellers offer a free period for evaluating the item, saying that if you do not like the device you can send it back. Please don’t fall into this trap, it is only one of the means the scammers use to entice you to purchase, but IT IS NOT TRUE AT ALL!

I repeat also some useful advices in order to make secure and safe purchases on the Internet:

1.) Always beware whenever the item is in a place (or a country) different from the one that was specified in the advertisement; also there is a valid reason for suspicion when the name or the address of the advertiser does not match the seller’s ones;

2.) Do not completely trust the pictures sent by the seller (they could be stolen from the Internet) and don’t forget to proceed to a “Google Reverse Image Search” in order to find the sources of similar ones;

3.) Always ask the seller for some specific pictures or videos (radio precisely tuned to various frequencies and/or modes) and do not accept any runarounds about it (“you can try the radio for some days”, etc.);

4.) Never pay the item in advance by rechargeable credit cards, Western Union or other non-secured/guaranteed ways of payment. Also Bank Transfer (Wire Transfer) is not a secure form of payment in order to avoid frauds;

5.) Always ask the seller for paying by PayPal “Goods and Services” (NOT “Send money to friends”); via “Goods and Services”, your purchase will be fully covered by the PayPal warranty.

In the case you are a victim of a scam anyway, please always report the incident to the Police or the Judiciary of your Country, and don’t forget to also warn the site where the announcement was found.

Best regards!
Paolo Viappiani – SWL I1-11437


Thank you so much for sharing this, Paolo! All very solid advice for avoiding scams. 

If you think about it, scammers want to optimize their scam profits per transaction–in other words, go for the “low-hanging fruit.” This is why quality, rare radios are their bait of choice. They know there are motivated collectors and buyers who need to act quickly in order to secure a deal. The stakes are very high if you’re purchasing a rare/vintage radio via online classifieds sites. 

Bookmark this article. Before making a radio purchase, re-read this post and follow Paolo’s advice. I promise: real vintage/rare radio sellers will happy take specific photos and videos in order to prove that the radio is indeed in their possession and that it functions as specified. If you receive an excuse–any excuse–from the seller, consider that a major read flag and do not proceed. 

Thank you again, Paolo! I hereby name you an honorary SWLing Post Investigative Reporter!


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

Matt’s Marathon MediumWave Matchup

Many thanks to SWLing Post contributor, Matt Blaze (WB2SRI), who shares the following guest post:


Matt’s Marathon MediumWave Matchup

by Matt Blaze

Here’s another simultaneous receiver comparison, this time of ten portable medium wave receivers plus the Icom IC-R9500 (as a “reference receiver”). Previously, I used the same antenna for all the comparisons, but since these are portable receivers, I wanted to compare their performance using their built-in antennas. I did two comparisons, both of moderate to weak signals, one in the evening of a DX signal and the other in the daytime of a regional station.

The receivers were the Potomac Instruments FIM-41 (a “field intensity meter”), the Panasonic RF-2200, the Nordmende GlobeTraveler Exec (a beautiful German SW portable from 1968), the Sony ICF-EX5MK2, the CCrane Radio 2E, the Sangean ATS-909X, the Sangean D4W, the new Tecsun PL-990X, the XHDATA D-808, and finally the CountyComm GP5-SSB, plus the Icom IC-R9500.

All the receivers were recorded simultaneously. The radios (except the Icom R9500) were on the roof of my building and oriented for best reception (signal/noise) and kept sufficiently away from each other and other metal objects to avoid interference, The R9500 was in the shack and used a Wellbrook loop on the roof, also oriented for best signal/noise. I took the audio from the Line Out if one was available and from the headphone jack (via a “direct box” level converter) if not. I tried to match the audio levels reasonably closely, but different ACG characteristics made it difficult to be completely consistent across all the receivers throughout the sessions.

As in previous comparisons, for each session I’ve got a narrated stereo mix with the R9500 on the left channel and each receiver, for a minute or so one after the other on the right channel. You definitely want to use headphones to listen to these so you easily tell the left from the right radio. I’ve also provided mono “solo” recordings of each receiver for the full 15 minute-ish sessions so you can hear a receiver you’re interested in in detail.

Sound Devices 688 Multitrack Recorder

The recordings were made with a Sound Devices 688 recorder/mixer (which can record 12 simultaneous channels of audio). The portable radios were hardwired to the recorder, and the 9500 (which was downstairs) was connected via a Lectrosonics digital radio link. (Everything except the R9500 was on battery power to avoid mutual interference and ground loops, etc). The narration used a Coles noise canceling ribbon mic. Everything was done in a single take per session – there was NO postproduction editing – so I apologize for a few glitches and awkward moments.

You can see a “class photo” of the setup below, although the position and orientation of the radios was different during the actual recordings.

KCJJ

The first recording was at night, where we tuned to 1630 KCJJ in Iowa City, IA. This is effectively a 1KW clear channel; other than a few TIS stations, there’s not much else there on the east coast, and the signal is reliably weak to moderate but readable here on the east coast.

Narrated L/R stereo comparison:

Individual solo tracks:

CCrane Radio 2E

Sangean D4W

XHDATA D-808

Sony ICF-EX5MK2

Potomac Instruments FIM-41

CountyComm GP5-SSB

Nordmende GlobeTraveler Exec

Tecsun PL-990X

Icom IC-R9500

Panasonic RF-2200

Sangean ATS-909X


WSVA

The next recording was made during the day, of WSVA, a regional station in Harrisonburg, VA running 5KW in the daytime. Their signal is also reliably weak-moderate but readable here.

Narrated L/R stereo comparison:

Individual solo tracks (receiver should be obvious from the file name):

CCrane Radio 2E

Sangean D4W

XHDATA D-808

Sony ICF-EX5MK2

Potomac Instruments FIM-41

CountyComm GP5-SSB

Nordmende GlobeTraveler Exec

Tecsun PL-990X

Icom IC-R9500

Panasonic RF-2200

Sangean ATS-909X

Hope your readers find it useful!

-matt


An absolutely amazing job again, Matt! Thank you so much for taking the time to put this comparison together and sharing it here on the SWLing Post.  

Click here to check out all of Matt’s receiver audio comparisons.

Spread the radio love

Steve builds a simple SWL antenna tuner that pairs brilliantly with the Belka-DX

Many thanks to SWLing Post contributor, Steve Allen (KZ4TN), who shares the following guest post:


A Simple Antenna Tuner for SWL Radios

by Steve Allen, KZ4TN

After reading 13DKA’s excellent review of the Belka-DSP on SWLing.com a few weeks ago I knew I had to have one! The size, features, and performance of the Belka-DX (latest version of the Belka-DSP) is phenomenal. I won’t go into reviewing the radio as I couldn’t come close to 13DKA extensive review. If you are considering this SWL receiver his review is a must read.

I love bedtime SWLing and have been putting off setting up an outside antenna specifically to feed into the bedroom for too long. Given that the resonant frequency of the antenna would not be broad enough for the tuning range of the Belka-DX I decided to build a small antenna tuner just for SWLing.

After a couple of hours searching the internet for a simple tuner I found just what I was looking for on http://www.hard-core-dx.com/nordicdx/antenna/lab/tuner.html. It’s a simple L match using a single variable capacitor and coil.

For the coil I wound ~100 turns of 26 Ga wire on a one inch diameter wooden dowel. The wire size can be whatever you have on hand. I twisted a tap every 10 turns. I drilled a hole in each end and glued in a machine screw to mount the coil to the bottom of the enclosure. I’ve had this enclosure in my junk box for a long time and have been waiting for just the right project. The variable capacitor I used was one I found on EBay a few years ago that had two sections, 330 pF and 120 pF. I tied them together for 450 pF. For the rotary switch I had to scratch around on eBay for a while until I found a 12 position single pole.

The plans for the tuner suggested adding a fixed value capacitor with a toggle switch to increase the lower end of the tuning range. I found a 510 pF silver mica and wired it into the circuit.

The antenna I put up is a sloper about 30 feet long.The high end is up about 40 feet and the low end is at about 12 feet. I put the antenna and tuner to the test last evening and the reception on the Belka-DX was superb. With the tuner the strength of the signal would peak about 2-3 units when I found the sweet spot.

The tuner also does double duty as an attenuator for very strong signals.

One mod I made to the Belka-DX was the addition of some grip tape to the tuning knob. It makes fine tuning much easier.

I believe we will continue to see a number of innovative receivers coming to market in the near term utilizing SDR technology. The ratio of performance to size of the Belka-DX is truly amazing in my opinion.


Thank you, Steve, for sharing this brilliant weekend project! As always, brilliant craftsmanship!

Click here to read Steve’s other posts and projects.

Spread the radio love

Guest Post: Why does radio reception improve on saltwater coasts?

Many thanks to SWLing Post contributor, 13dka, who shares the following guest post:


Gone fishing…for DX: Reception enhancement at the seaside

by 13dka

In each of my few reviews I referred to “the dike” or “my happy place”, which is a tiny stretch of the 380 miles of dike protecting Germany’s North Sea coast. This is the place where I like to go for maximum listening pleasure and of course for testing radios. Everyone knows that close proximity to an ocean is good for radio reception…but why is that? Is there a way to quantify “good”?

Of course there is, this has been documented before, there is probably lots of literature about it and old papers like this one (click here to download PDF). A complete answer to the question has at least two parts:

1. Less QRM

It may be obvious, but civilization and therefore QRM sources at such a place extend to one hemisphere only, because the other one is covered with ocean for 100s, if not 1000s of miles. There are few places on the planet that offer such a lack of civilization in such a big area, while still being accessible, habitable and in range for pizza delivery. Unless you’re in the midst of a noisy tourist trap town, QRM will be low. Still, you may have to find a good spot away from all tourist attractions and industry for absolutely minimal QRM.

My dike listening post is far enough from the next small tourist trap town (in which I live) and also sufficiently far away from the few houses of the next tiny village and it’s located in an area that doesn’t have HV power lines (important for MW and LW reception!) or industrial areas, other small villages are miles away and miles apart, the next town is 20 km/12 miles away from there. In other words, man-made noise is just not an issue there.

That alone would be making shortwave reception as good as it gets and it gives me an opportunity to check out radios on my own terms: The only way to assess a radio’s properties and qualities without or beyond test equipment is under ideal conditions, particularly for everything that has to do with sensitivity. It’s already difficult without QRM (because natural noise (QRN) can easily be higher than the receiver’s sensitivity threshold too, depending on a number of factors), and even small amounts of QRM on top make that assessment increasingly impossible. This is particularly true for portables, which often can’t be fully isolated from local noise sources for a couple of reasons.

Yes, most modern radios are all very sensitive and equal to the degree that it doesn’t make a difference in 98% of all regular reception scenarios but my experience at the dike is that there are still differences, and the difference between my least sensitive and my most sensitive portable is not at all negligible, even more because they are not only receivers but the entire receiving system including the antenna. You won’t notice that difference in the middle of a city, but you may notice it in the woods.

When the radio gets boring, I can still have fun with the swing and the slide!

2. More signal

I always had a feeling that signals actually increase at the dike and that made me curious enough to actually test this by having a receiver tuned to some station in the car, then driving away from the dike and back. Until recently it didn’t come to me to document or even quantify this difference though. When I was once again googling for simple answers to the question what the reason might be, I stumbled upon this video: Callum (M0MCX) demonstrating the true reason for this in MMANA (an antenna modeling software) on his “DX Commander” channel:

To summarize this, Callum explains how a pretty dramatic difference in ground conductivity near the sea (click here to download PDF) leads to an increase in antenna gain, or more precisely a decrease in ground return losses equaling more antenna gain. Of course I assumed that the salt water has something to do with but I had no idea how much: For example, average ground has a conductivity of 0.005 Siemens per meter, salt water is averaging at 5.0 S/m, that’s a factor of 1,000 (!) and that leads to roughly 10dB of gain. That’s right, whatever antenna you use at home in the backcountry would get a free 10dB gain increase by the sea, antennas with actual dBd or dBi gain have even more gain there.

That this has a nice impact on your transmitting signal should be obvious if you’re a ham, if not just imagine that you’d need a 10x more powerful amplifier or an array of wires or verticals or a full-size Yagi to get that kind of gain by directionality. But this is also great for reception: You may argue that 10dB is “only” little more than 1.5 S-units but 1.5 S-units at the bottom of the meter scale spans the entire range between “can’t hear a thing” and “fully copy”!

A practical test

It’s not that I don’t believe DX Commander’s assessment there but I just had to see it myself and find a way to share that with you. A difficulty was finding a station that has A) a stable signal but is B) not really local, C) on shortwave, D) always on air and E) propagation must be across water or at least along the shoreline.

The army (or navy) to the rescue! After several days of observing STANAG stations for their variation in signal on different times of the day, I picked one on 4083 kHz (thanks to whoever pays taxes to keep that thing blasting the band day and night!). I don’t know where exactly (my KiwiSDR-assisted guess is the English channel region) that station is, but it’s always in the same narrow range of levels around S9 here at home, there’s usually the same little QSB on the signal, and the signals are the same day or night.

On top of that, I had a look at geological maps of my part of the country to find out how far I should drive into the backcountry to find conditions that are really different from the coast. Where I live, former sea ground and marsh land is forming a pretty wide strip of moist, fertile soil with above average conductivity, but approximately 20km/12mi to the east the ground changes to a composition typical for the terminal moraine inland formed in the ice age. So I picked a quiet place 25km east of my QTH to measure the level of that STANAG station and also to record the BBC on 198 kHz. Some source stated that the coastal enhancement effect can be observed within 10 lambda distance to the shoreline, that would be 730m for the 4 MHz STANAG station and 15km for the BBC, so 25km should suffice to rule out any residue enhancement from the seaside.

My car stereo has no S-meter (or a proper antenna, so reception is needlessly bad but this is good in this case) so all you get is the difference in audio. The car had the same orientation (nose pointing to the east) at both places. For the 4 MHz signal though (coincidence or not), the meter shows ~10dBm (or dBµV/EMF) more signal at the dike.

3. Effect on SNR

Remember, more signal alone does not equal better reception, what we’re looking for is a better signal-to-noise ratio (SNR). Now that we’ve established that the man-made noise should be as low as possible at “my” dike, the remaining question is: Does this signal enhancement have an effect on SNR as well? Even if there is virtually no local QRM at my “happy place” – there is still natural noise (QRN) and that wouldn’t that likely gain 10dB too?

Here are some hypotheses that may be subject of debate and some calculations way over my head (physics/math fans, please comment and help someone out who always got an F in math!). Sorry for all the gross oversimplifications:

Extremely lossy antennas

We know that pure reception antennas are often a bit different in that the general reciprocity rule has comparatively little meaning, many antennas designed for optimizing reception in specific situations would be terrible transmitting antennas. One quite extreme example, not meant to optimize anything but portability is the telescopic whip on shortwaves >10m. At the dike, those gain more signal too. When the QRN drops after sunset on higher frequencies, the extremely lossy whip might be an exception because the signal coming out of it is so small that it’s much closer to the receiver noise, so this friendly signal boost could lift very faint signals above the receiver noise more than the QRN, which in turn could mean a little increase in SNR, and as we know even a little increase in SNR can go a long way.

The BBC Radio 4 longwave recording is likely another example for this – the unusually weak signal is coming from a small and badly matched rubber antenna with abysmal performance on all frequency ranges including LW. The SNR is obviously increasing at the dike because the signal gets lifted more above the base noise of the receiving system, while the atmospheric noise component is likely still far below that threshold. Many deliberately lossy antenna design, such as flag/tennant, passive small aperture loops (like e.g. the YouLoop) or loop-on-ground antennas may benefit most from losses decreasing by 10dB.

Not so lossy antennas, polarization and elevation patterns

However, there is still more than a signal strength difference between “big” antennas and the whips at the dike: Not only at the sea, directionality will have an impact on QRN levels, a bidirectional antenna may already decrease QRN and hence increase SNR further, an unidirectional antenna even more, that’s one reason why proper Beverage antennas for example work wonders particularly on noisy low frequencies at night (but this is actually a bad example because Beverage antennas are said to work best on lossy ground).

Also, directional or not, the “ideal” ground will likely change the radiation pattern, namely the elevation angles, putting the “focus” of the antenna from near to far – or vice versa: As far as my research went, antennas with horizontal polarization are not ideal in this regard as they benefit much less from the “mirror effect” and a relatively low antenna height may be more disadvantageous for DX (but maybe good for NVIS/local ragchewing) than usual. Well, that explains why I never got particularly good results with horizontal dipoles at the dike!

Using a loop-on-ground antenna at a place without QRM may sound ridiculously out of place at first, but they are bidirectional and vertically polarized antennas, so the high ground conductivity theoretically flattens the take-off angle of the lobes, on top of that they are ~10dB less lossy at the dike, making even a LoG act more like something you’d string up as high as possible elsewhere. They are incredibly convenient, particularly on beaches where natural antenna supports may be non-existent and I found them working extremely well at the dike, now I think I know why. In particular the preamplified version I tried proved to be good enough to receive 4 continents on 20m and a 5th one on 40m – over the course of 4 hours on an evening when conditions were at best slightly above average. Though the really important point is that it increased the SNR further, despite the QRN still showing up on the little Belka’s meter when I connected the whip for comparison (alas not shown in the video).

The 5th continent is missing in this video because the signals from South Africa were not great anymore that late in the evening, but a recording exists.

Here’s a video I shot last year, comparing the same LoG with the whip on my Tecsun S-8800 on 25m (Radio Marti 11930 kHz):

At the same time, I recorded the station with the next decent KiwiSDR in my area:

Of course, these directionality vs noise mechanisms are basically the same on any soil. But compensating ground losses and getting flat elevation patterns may require great efforts, like extensive radial systems, buried meshes etc. and it’s pretty hard to cover enough area around the antenna (minimum 1/2 wavelength, ideally more!) to get optimum results on disadvantaged soils, while still never reaching the beach conditions. You may have to invest a lot of labor and/or money to overcome such geological hardships, while the beach gives you all that for free.

But there may be yet another contributing factor: The gain pattern is likely not symmetrical – signals (and QRN) coming from the land side will likely not benefit the same way from the enhancement, which tapers off quickly (10 wavelengths) on the land side of the dike and regular “cross-country” conditions take place in that direction, while salt water stretching far beyond the horizon is enhancing reception to the other side.

So my preliminary answer to that question would be: “Yes, under circumstances the shoreline signal increase and ground properties can improve SNR further, that improvement can be harvested easily with vertically polarized antennas”.

Would it be worthwhile driving 1000 miles to the next ocean beach… for SWLing?

Maybe not every week–? Seriously, it depends.

Sure, an ocean shoreline will generally help turning up the very best your radios and antennas can deliver, I think the only way to top this would be adding a sensible amount of elevation, a.k.a. cliff coasts.

If you’re interested in extreme DX or just in the technical performance aspect, if you want to experience what your stuff is capable of or if you don’t want to put a lot of effort into setting up antennas, you should definitely find a quiet place at the ocean, particularly if your options to get maximum performance are rather limited (space constraints, QRM, HOA restrictions, you name it) at home.

If you’re a BCL/program listener and more interested in the “content” than the way it came to you, if you’re generally happy with reception of your favorite programs or if you simply have some very well working setup at home, there’s likely not much the beach could offer you in terms of radio. But the seaside has much more to offer than fatter shortwaves of course.

From left to right: Starry sky capture with cellphone cam, nocticlucent clouds behind the dike, car with hot coffee inside and a shortwave portable suction-cupped to the side window – nights at the dike are usually cold but sometimes just beautiful. (Click to enlarge.)

However, getting away from the QRM means everything for a better SNR and best reception. In other words, if the next ocean is really a hassle to reach, it may be a better idea to just find a very quiet place nearby and maybe putting up some more substantial antenna than driving 1000 miles. But if you happen to plan on some seaside vacation, make absolutely sure you bring two radios (because it may break your heart if your only radio fails)!

Spread the radio love

Matt compares the Tecsun PL-990 to the Icom IC-R9500 on an external antenna and the results are surprising

Many thanks to SWLing Post contributor, Matt Blaze, who shares the following comparison of the new Tecsun PL-990x and the benchmark Icom IC-R9500 communications receiver.

Matt’s excellent comparison  is in audio form. I highly recommend listening with headphones or, at least, an audio device with separate left/right channels as his comparison takes advantage of this.

I love not only how he set up this comparison with both radios sharing an identical antenna, but his evaluation also explores how well the PL-990 handles a proper external antenna via its external antenna jack.

Click below to listen to Matt’s piece, or right click here to download the audio:

Thanks for sharing this, Matt. You’ve inspired me to do similar narrated audio comparisons!

Spread the radio love

Steve builds a DC30B QRP Transceiver

DC30B QRP Transceiver ProjectMany thanks to SWLing Post contributor, Steve (KZ4TN), who shared the following guest post originally on QRPer.com, but I’ve posted it here as well because I’m sure it’ll resonate with those of us who love building kits!:


DC30B QRP Transceiver Project

by Steve Allen, KZ4TN

I wanted to build a lightweight backpackable transceiver I could take hiking and camping. I chose the 30 meter band as it is specific to CW and the digital modes. I am also in the process of building Dave Benson’s (K1SWL) Phaser Digital Mode QRP Transceiver kit for the 30 meter band. Also, a 30 meter antenna is a bit smaller than one for 40 meters and the band is open most anytime of the day.

I sourced the DC30B transceiver kit, designed by Steve Weber KD1JV, from Pacific Antennas, http://www.qrpkits.com. It appears that they are now (10-11-20) only offering the kit for the 40 meter band. The following information can be used for the assembly of most any kit that lacks an enclosure.

Lately I have been finding extruded aluminum enclosures on Amazon.com and eBay.com. They come in many sizes and configurations. I like to use the versions with the split case which allows you to access the internal enclosure with the front and rear panels attached to the lower half of the enclosure. Most of these enclosures have a slot cut into the sides that allow a PCB to slide into the slots keeping it above the bottom of the enclosure without having to use standoffs. The one requirement for assembly is that the PCB needs to be attached to either the front or rear panel to hold it in place.

DC30B QRP Transceiver Project

As the enclosure is anodized, I didn’t want to rely on the enclosure for common ground. I used a piece of copper clad board that I cut to fit the slot width of the enclosure and attached it to the back panel. I was then able to mount the transceiver PCB to the copper clad board with standoffs. This basic platform of the enclosure with the copper clad PCB provides a good foundation for any number of projects. All you have to do is mount the wired PCB on the board, install the components on the front and rear panel, then wire it up.

DC30B QRP Transceiver Project

I wanted to have the choice of a few frequencies to operate on so I searched eBay for 30 meter crystals and found a source for 4 different popular frequencies. I installed a rotary switch on the front panel and added a small auxiliary PCB with two, 4 pin machined IC sockets. This allowed me to plug the crystals into the sockets. I wired the bottom of the socket PCB first using wire pairs stripped from computer ribbon cable leaving extra length. I marked the wires with dots to indicate which sockets each wire pair went to so I could solder them onto the rotary switch in the correct order. It was tight but I always work with optical magnification so I can see exactly what I’m doing. I have used this crystal switching method in the past with good success.

DC30B QRP Transceiver Project

DC30B QRP Transceiver ProjectThe rest of the assembly was straight forward. I find that most kits are well designed and documented, and if you take your time and follow the directions carefully all should go well. The two most common speed bumps seem to be soldering in the wrong component or bad soldering technique. I double check all component values and placements prior to soldering, and I always use optical magnification while working. I inspect each solder joint and look for good flow through in the plated through holes, and make sure there are no solder bridges.

DC30B QRP Transceiver Project

DC30B QRP Transceiver ProjectThe finished product. I bought a Dymo label maker and it works very well for projects like this. I love using these enclosures and they are a leap forward from the old folded aluminum clam shells I used in the past. I could stand on this without causing any damage. Power out is 1-3 watts depending on the DC power in. The receiver is sensitive and the ability to choose from four frequencies is a real plus.

73 de KZ4TN

Steve Allen
Elizabethton, TN


Gorgeous work there, Steve! Thank you for sharing!

Spread the radio love