Category Archives: SWLers

Guest Post: More Anti-Noise Ideas

In a previous guest post, SWLing Post contributor TomL, shared his “Evolving, Morphing, SW Listening Station” where he detailed the many ways he’s trying to fight heavy radio interference at his listening post. The following post is TomL’s update:


More Anti-Noise Ideas

(Continuing the hunt for better reception in a foul RFI environment)

by TomL

toml-radios

I have made the following changes:

  • Created a prototype mini-loop based on a crossed-parallel idea from VE1ZAC (Jeff).
  • Added a balun from LNR Precision (Parfitt’s EF-SWL) in an experimental configuration.
  • Added to the balun, an outdoor amplifier – Wellbrook ALA-100M.
  • Added a noise canceling unit (MFJ-1026).
  • Added 2 preselectors, an old Grove TUN-3 connected to the main loop feed and an MFJ-1046 connected to the ground connection of the balun. Both feeds go into the MFJ-1026.
  • Added BHI Compact In-Line DSP filter and two switch boxes to cut it in/out as needed.
  • Added a medium wave noise canceling unit that I have not figured out how to use yet. (Quantum Phaser). The MFJ unit does not work on medium wave without modification.
  • Purchased from eBay a used Grundig Satellit 800, a somewhat more robust fixed-station receiver to replace my aging Sony ICF-2010.
  • Other non-related (not shown): Whistler digital scanner + UHF over-the-air TV + FM broadcasts + an AM/FM HD digital radio + high pass filters from MiniCircuits.com – (audio from all these sources is passed to an existing high fidelity stereo power amp and NHT Super One speakers on the computer desk for near-field monitoring). Associated antennas are also hidden on the outside deck (shhhhh!).
  • Large charge card balance!!

So, here are some pics for the crossed-parallel loop. VE1ZAC web site has all the references if you want to explore further or google him. Mine is purely a prototype and not finished. And should eventually be placed on a rotor (but how to keep my Nazi-like condo association from finding out?!?!?!?).

loops

It is three 14 inch quilters hoops from Joann Stores plus some 1-inch copper strips cut from a small 2 meter roll of thin copper from eBay. Then, it is wired in parallel with silver-plated aviation wire on each side with a feed in the middle. Not an optimal placement of the feed, (should go straight down along the pipe). Will fix things up whenever I get some more time.

loops-closeup

loops-closeup2
Seems to be an efficient way to prototype small loops. It is now mounted on a short ¾” inside diameter PVC pipe into a cheap plastic sand-filled deck-umbrella stand. Loops are light and somewhat flimsy, so I mounted the three loops on a plastic triangle ruler and dowel sticks glued to the sides for some extra strength. Good enough for now.

The EF-SWL balun is also in an experimental configuration. Since I read somewhere that loop antennas have a very low impedance at the feed point (like, 10 ohms or lower), I thought I might try a balun that is meant to lower the impedance and mount it backwards. I don’t have a picture of it but the SO-239 output is facing the loop and the screw terminals are facing the direction of the radio. My feeble brain thinks since it is a passive device of coils on ferrite, it should work bidirectionally for receive only applications like this. It seems to work but I have the excuse that I really don’t know what I am doing! 🙂

bhi

BHI unit in action.

The BHI DSP filter is useful in some circumstances but I find it fatiguing to listen to. The audio from the Sattelit 800 is so nice, I mostly like it without the DSP. The DSP narrows the bandwidth significantly, somewhere around 4 kHz or less from my hearing. I like that the Grundig has two tone controls. And it also has a stable SSB and on very strong signals with clear audio, I like to listen with SSB lower or upper sideband. But the DSP is useful at times for hash-like noisy signals; it is not quite as good on buzzing noise and I wish the Satellit 800 had a noise blanker, but that would have been a more costly purchase, like a Drake R8A.

So, in a nutshell, I have a discovery about noise here: it is all around me and ubiquitous, like the air I breathe!

I find it hard to null and also worry about peaking a station signal at the same time. However, I do have a lower noise floor with the experimental loop sitting outdoors, especially on medium wave (the Wellbrook amp + loop works great on the lower frequencies – am able to get eight different medium wave stations carrying Major League Baseball games at night – it would be nine to get WFAN for the New York Mets but the local Chicago Cubs station covers the adjacent frequency with horrible digital hash! ***Bleeping*** digital junk!).

Also, the signal level is noticeably lower using the loop. Then, add in the effect of the MFJ Noise Canceling unit, the usable signal gets even weaker.

The bottom line is, I can now finally enjoy listening to many SW broadcasts, BUT only the strongest signals. Anything else is still hopelessly lost in the noise. So, gains are limited.

On the other hand, and something else I learned by doing is that, any 1 or 2 dB signal/noise ratio improvement will help with the final audio output in the end product. Using low-noise amps, loops, noise canceler, preselectors, grounded connections, ground isolators at the input of every receiver, high quality stereo amplifier and speakers, tone controls, SSB vs. AM Sync, weird antenna configurations, etc, etc. It all helps in the end to some degree.

Tinkering is an art that involves a lot of thinking/doing iterations! And high quality parts must be used all along the chain or it could degrade the signal.

Below are some audio samples, not very well recorded, but can give some idea of the incremental improvement with each enhancement (turn up the volume). NOTE: other people may get better or worse results depending upon individual situations, type of antennas used, etc, etc.

Recording 1: R. Marti. First 10 seconds an indoor antenna with no noise reduction, second 10 seconds the outdoor loop without the MFJ-1026, the third 10 seconds with the MFJ-1026, then switched off and on to hear the difference.

Recording 2: R. Marti. MFJ -1026 is ON. Last 15 seconds is SSB, very thin sounding. Really only good for strongest signals. I liked the AM Sync better (Satellit 800 is really a Drake SW8 in disguise with a quality AM Sync). But, SSB can sound excellent with very clear voices with a steady and strong signal (The Satellit 800 does NOT have IF-shift or a BFO to fine tune an SSB reception, so the station must be exactly transmitting on the kHz mark, which most are nowadays).

Recording 3: R. Marti. MFJ-1026 is ON. Last 20 seconds you hear me switch in the two audio switches and the BHI DSP is on its lowest setting. Narrower and clearer with some reduction of background noise. I find I only like going up to about 4 on the DSP dial, after that the audio fidelity starts getting more choppy with digital artifacts that sound like dripping water. I tend to like higher fidelity. One nice thing about the BHI DSP is a faux-stereo that helps a little with voice intelligibility by helping the brain naturally filter the noise. Faux-stereo is ON even when the noise reduction circuit is manually turned off (power must be on and bandwidth still sounds narrowed).

Recording 4: R. Nacional Brazilia. First without MFJ-1026, then ON, then OFF, then ON, then with the BHI kicked for the last 20 seconds.

Recording 5: Greece. Switching the MFJ-1026 on and off every 5 seconds. In this particular case, the signal was weak and fading a lot. The MFJ OFF was also weaker than with it turned ON. That is interesting behavior, usually it is opposite. It pays to play with the settings a little. At other times, and less frequently, the MFJ unit turned OFF sometimes sounds better than with it ON and tuned for less noise. Go figure!

After all the tweaking is done, and I cannot get any more performance out of this, I will probably have to move to a nice, quiet neighborhood and setup a nice antenna farm!!

In the meantime, I do enjoy listening to the stronger stations from North America, Cuba, Brazil, Europe, and Australia with less noise than before.

73’s

TomL from NOIZEY Illinoiz


Once again, Tom, thanks for sharing your RFI elimination journey!

I love how you take on this noisy problem by experimenting and seeing it more as a challenge than an obstacle to enjoying your hobby.  Great job! 

SWLing Post Reader Contest: remembering your “dream radio”

The Sony ICF-2010 was my dream portable in the 1980s.

The Sony ICF-2010 was my dream portable in the 1980s.

Fred Osterman, President of Universal Radio, recently expressed his interest in supporting another SWLing Post Reader Contest. Of course, I eagerly agreed, and we quickly came up with a theme:

Think back to your first days in radio…What was your “dream” receiver?  And why?

Or–if you’re new to shortwave radio–what is your “dream” receiver currently, and why?

Many of us had a radio they dreamed of in their youth, or when they first began to hanker after the radio experience. What was yours?  For newer hobbyists, what is yours? And just what made–or makes–this radio so special? Did you ever obtain one?  And if so, did it live up to your expectations?  Share your experiences with the Post!

ShortwaveReceiversPastAndPresentThe winners of this contest will be chosen at random, using a randomizer application; an independent non-entrant will make these selections.

Thanks to Universal’s generosity, there will be two winners–a US winner and an international winner.

The US prize will be a copy of Shortwave Receivers Past and Present by none other than Fred Osterman. I reviewed this book a couple years ago: it is an invaluable reference tool and also a fun “dream” book.  With sincere apologies to my international friends, this prize must be limited to the US simply because shipping this weighty volume internationally would cost more than the book itself.

The international winner may select between the following (less weighty!) books, also very good references: Joe Carr’s Loop Antenna Book or Buying A Used Shortwave Receiver: A Market Guide To Modern Shortwave Radios.

Entering the contest is easy. Simply go to our entry form (below or click here) and fill in the required fields.  Be descriptive! This will make the contest fun. Let us know in detail why that radio was (or is) so significant to you.

Your entry will be recorded, and the winners chosen at random on Sunday October 16, 2016. We’ll publish the responses once the contest concludes, sharing only the name you provide.

Datawake: Steven’s new “floating lab”

stephen-roberts-datawake

Photo: Steven K. Roberts

Many thanks to SWLing Post contributor, Steven Roberts, who shares the following update:

Hi, Thomas!! Thought I’d send an update… I did in fact find a buyer for Nomadness, and have since gone to the Dark Side… for 8 months, I have been living aboard my Delta 50 named Datawake. The sale of Nomadness was via the geek grapevine… last Spring I built a power cart named Shacktopus, and West Mountain Radio used my story about it as their quarterly newsletter. A fellow on the East Coast read that, followed the links, recognized my bike, saw the Amazon 44, and bought it… and he is now preparing to head down the Pacific Coast.

Photo: Steven K. Roberts

Photo: Steven K. Roberts

Here’s the new ship, and the console now includes four HF rigs, D-Star, a few SDR devices, crosspoint audio routing with web interface, electronics lab, and networking goodies. Nice to be back on the air after a year without a proper skyhook!

http://microship.com/meet-datawake/

Amazing, Steven! You have a super power in your ability to turn boats, bikes and pretty much anything into mobile techno-wonders! What craftsmanship!

I love Datawake and appreciate the tour with photos and details you’ve posted. I noticed the Icom IC-7300–perhaps we can have a QSO someday on the air? I’ll look forward to any report you may have about the IC-7300 as a maritime mobile station.

We look forward to future updates!

South American shortwave catches, rarely heard in Europe

RCRI

r9djHi there, I thought I would share some DX catches, all of which are rarely reported in Europe and yet I was fortunate enough to catch in Oxford UK, using a couple of different set-ups. The first is Radio Chaski Red Integridad from Urubamba Cusco, Peru, heard using an Elad FDM DUO and Wellbrook ALA1530 active loop antenna (indoors). The two subsequent receptions originate from Brazil; Radio 9 de Julho, Sao Paulo and Radio Transmundial,Santa-maria rtmCamobi, both of which were caught using the venerable Sony ICF-2001D portable receiver and my 200 metre longwire antenna. In all three cases, persistence was necessary whilst optimum conditions of propagation aligned with my listening schedule at home and my less frequent, but regular DX’peditions.

I am soon to deploy a 200 metre Beverage with adjustable termination resistance for nulling ‘rearward’ signals and matching transformers suitable for 75 and 50 Ohm receiver antenna inputs. I hope this will further improve my reception capability on both the MW and SW bands.  Another post specific to that project is in the pipeline, but in the meantime, thanks for reading/ watching and I wish you all very good DX.

 


 

Direct link to Oxford Shortwave Log for Radio Chaski Red Integridad reception video

 

Direct link to Oxford Shortwave Log for Radio 9 de Julho reception video

 

Direct link to Oxford Shortwave Log for Radio Transmundial reception video


Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

Tropical Band DXing at home with Elad FDM DUO and Wellbrook ALA1530 active loop

2-jungleRecently I have spent a little more time listening out for Tropical Band stations from my shack in Oxford UK, attempting to emulate some of the very nice signals I have previously recorded out on DX’peditions. The obvious problems with this (and they are numerous) include the relatively weak signal strength of many tropical band stations, the ubiquitous blanket of QRM, resulting in generally poor SNR, lack of space for a large antenna……need I go on?! Fortunately, the Elad FDM DUO has proven to be a very senstive and selective receiver, capable of, at times, incredible SNR, coupled with almost limitless signal conditioning options and SSB, SYNC, ECSS etc. Throw the Wellbrook ALA1530 active loop into the mix (not literally!) and you have a very powerful Tropical Band receive set-up. The Wellbrook is able to null most (although not all) QRM in my shack and that really can make the difference between simply observing a carrier and actually hearing audio. Clearly one cannot expect to hear DX at home under heavy QRM as well as you might outdoors, however, the following stations were logged in the past month or so, with respectable signals, with the ALA1530 indoors:

Video links also follow below, thanks for reading/ watching.

Direct link to Oxford Shortwave Log video; Radio Logos 4810 kHz, Peru

Direct link to Oxford Shortwave Log video; Radio Cultura Ondas Manaus 4845 kHz, Brazil

Direct link to Oxford Shortwave Log video; AIR Bhopal 4810 kHz, India

Direct link to Oxford Shortwave Log video; Rádio Educação Rural 4925.2 kHz, Tefé, Brazil

Direct link to Oxford Shortwave Log video; Radio Mosoj Chaski 3310 kHz, Bolivia

 

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.