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Author Topic: Receiving LWBC in North America  (Read 1131 times)

Offline circuitmike

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Receiving LWBC in North America
« on: February 26, 2022, 1900 UTC »
I'm wondering what it takes to receive any of the longwave stations from Europe / Africa in the US, specifically at my location in Massachusetts. With my existing setup I can occasionally get the faintest of signals - I can see a carrier but not hear audio, and one time I even got faint, unintelligible audio from BBC 4 at 198 kHz (I could tell it was the shipping forecast, confirmed by checking the internet stream). I'd love to hear more, though. For those of you who've done it, what kinds of antennas worked well for you? Times of day / year? Locations (I've read that being on the coast helps a lot)? Any pointers would be appreciated.

Thanks!
QTH: Western Massachusetts (FN32rp)
Receiver: KiwiSDR (on-site)
Antenna: Wellbrook ALA-1530LN loop

Offline NJQA

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Re: Receiving LWBC in North America
« Reply #1 on: February 27, 2022, 1501 UTC »
I have received them in Virginia on a KiwiSDR and a Wellbrook loop before, but not every day.  Conditions need to be good.  Winter is better because thunderstorm QRN is much reduced.  Many believe the best months for LW propagation are Sep-Oct, but there will still be audible thunderstorm QRN.  A large Loop-On-the-Ground (LOG) antenna worked well too, better I think than the Wellbrook.

If you hear electrical noise when you tune through the LW band, you probably need to work to reduce that first.

You need to put effort into reducing any local noise sources and eliminating common mode noise.  Common mode filters on your feedline, at both the antenna and at the receiver, that use the correct ferrite mix for LF (e.g. Type 75 or 77) are important. I also use a LPF that cuts out the AM BCB.

Offline circuitmike

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Re: Receiving LWBC in North America
« Reply #2 on: February 27, 2022, 2000 UTC »
Thanks! I've already put a bunch of effort into reducing electrical noise and while things are far from perfect, I don't have any huge amounts of crap in the LWBC band. I've been meaning to experiment with a loop-on-ground antenna for a while now, too, and I have the parts to build one; I just haven't gotten around to it (plus there's still a bunch of snow on the ground at my QTH for now). I have other radios I can try, too, so I'm not limited to just the KiwiSDR. I should probably invest in a few more ferrite toroids and the like. There's still so much noise coming out of my house! And I do have an AM BCB filter around here somewhere, so I'll experiment with putting that in line.
QTH: Western Massachusetts (FN32rp)
Receiver: KiwiSDR (on-site)
Antenna: Wellbrook ALA-1530LN loop

Offline NQC

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Re: Receiving LWBC in North America
« Reply #3 on: February 28, 2022, 0132 UTC »
Hey All ,   

2030 EST 2/27/22  VERY  GOOD Morocco  in full wide AM  on 171 Kc

Fair BBC 198 Kc in USB Narrow, beat up a bit by DIW / Dixon NC beacon

HF U SDR NE Bev

K
Station main receiver : Bed springs to  blue razor blade detector to 2000 ohm cans to steam  radiator. Grid FN 42

Offline circuitmike

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Re: Receiving LWBC in North America
« Reply #4 on: February 28, 2022, 0154 UTC »
I'm not hearing anything at my QTH right now, so maybe I missed it. I sure wish DIW would get decommissioned, though! Speaking of, I do see the characteristic "bumpy" carrier at 198 kHz that tends to imply there are actually two carriers there, probably BBC4 and DIW.
QTH: Western Massachusetts (FN32rp)
Receiver: KiwiSDR (on-site)
Antenna: Wellbrook ALA-1530LN loop

Offline NJQA

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Re: Receiving LWBC in North America
« Reply #5 on: February 28, 2022, 1439 UTC »
I should probably invest in a few more ferrite toroids and the like. There's still so much noise coming out of my house! And I do have an AM BCB filter around here somewhere, so I'll experiment with putting that in line.

Be sure to use ferrites with the right mix!  Mix type 75 or 77 is what you should be using.  You can get them at DXEngineering.

I also have all of the connections to my KiwiSDR going through Type 77 ferrite cores - antenna, GPS, ethernet, and power.  Each has two cores glued together, and then wrapped in fiberglass cloth tape (the tape helps protect the ferrites from chipping).

The purpose of the LPF is to ensure that strong out of band signals on the BCB or SW don’t drive the receiver into compression.

The KiwiSDR is a very capable LW receiver.




Offline ~SIGINT~

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Re: Receiving LWBC in North America
« Reply #6 on: February 28, 2022, 1502 UTC »
Here is my "cheat sheet" on ferrite materiels.

Materiel Types
There are two basic ferrite material groups:

 (1) Those having a permeability range from 20 to 850 µ are of the Nickel Zinc (NiZn) class (mix 43, 52, 61); and

 (2) Those having initial permeabilities above 850 µ are usually of the Manganese Zinc (MnZn) class (Mix 31, 73, 75)

The Nickel-zinc (NiZn) ferrite cores (mix 43, 52, 61) have low permeability and exhibit high volume resistivity. Nickel-zinc ferrites have a higher resistivity and are used at frequencies from 2 MHz to several hundred megahertz.

The Manganese-zinc (MnZn) ferrite cores (Mix 31, 73, 75) have high permeabilities above 800 µ, have fairly low volume resistivity and moderate saturation flux density. They offer high 'Q' factors for the 1 KHz to 1 MHz
frequency range.

These cores are also very useful for the attenuation of unwanted RF noise signals in the frequency range of
2 MHz to 250 MHz.

MIX 31 -> 1 MHz - 300 MHz, good for HF
MIX 75/J -> 150 KHz - 10 MHz

Offline circuitmike

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Re: Receiving LWBC in North America
« Reply #7 on: March 01, 2022, 0419 UTC »
Thanks for the ferrite primer! I've been meaning to build some ferrite rod antennas, and maybe a ferrite sleeve loop at some point. I have some 200 mm rods, including some that are 30 mm thick or so which are MnZn of an unknown mix. I'm curious how well those will perform on longwave. I might stick them end-to-end inside a piece of ABS pipe and see if I can make a giganto-ferrite rod!
QTH: Western Massachusetts (FN32rp)
Receiver: KiwiSDR (on-site)
Antenna: Wellbrook ALA-1530LN loop

Offline ~SIGINT~

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Re: Receiving LWBC in North America
« Reply #8 on: March 01, 2022, 1412 UTC »
Here are some interesting build your own articles for you.

Giuseppe’s homebrew rotating ferrite antenna
https://swling.com/blog/2021/01/giuseppes-homebrew-rotating-ferrite-antenna/

Giuseppe discovers his homebrew rotating ferrite antenna works amazingly indoors and nulls RFI
https://swling.com/blog/2021/01/giuseppe-discovers-his-homebrew-rotating-ferrite-antenna-works-amazingly-indoors-and-nulls-rfi/

Giuseppe’s Homebrew “TFerrite 2” Mediumwave & Shortwave Antenna
https://swling.com/blog/2021/09/giuseppes-homebrew-tferrite-2-mediumwave-shortwave-antenna/

Guest Post: Pavel’s Homebrew “Monster” Drain Pipe FSL Antenna
https://swling.com/blog/2021/12/guest-post-pavels-homebrew-monster-drain-pipe-fsl-antenna/

Offline RobRich

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Re: Receiving LWBC in North America
« Reply #9 on: March 23, 2022, 1037 UTC »
I have not bothered much with LW BCB in quite awhile, but I used to often hear Medi 1 (1.6MW!) out of Morocco at night using my Kenwood R-2000 and 148' LoG antenna. The other usual LW BCBs were occasionally noted, but admittedly they were largely hit or miss in comparison.

My old LoG uses a "shielded" coaxial design, so differential currents should be relatively balanced and common mode currents somewhat mitigated, thus I do not bother with a balun or impedance matching transformer at the feedpoint. There are few snap-on chokes of whatever mix I had in the parts box at the time, so even those are highly suspect at such low frequencies.

I do have KD9SV common mode chokes near the input of some of my receivers, and I suspect the design is mix 7x due to being optimized for lower HF.
« Last Edit: March 23, 2022, 1045 UTC by RobRich »
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | Kenwood R-600 + R-2000 | 2x RTL-SDR V3 + NE602 | Si-Tex 200 | Soft66LC4 | Yaesu FRG-7
148' "Shielded" Loop-on-Ground | 2x 18' End-Fed Verticals | 31' Vertical | 2x PA0NHC MiniWhips

Offline pinto vortando

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Re: Receiving LWBC in North America
« Reply #10 on: March 30, 2022, 2016 UTC »
Have never had much luck with LWBC here in the upper Midwest... can sometimes hear something on frequency
but cannot seem to "pull it in".  My antenna is obviously not up to the task. 
Das Radiobunker somewhere in Michigan

Offline MojaveBeaconeer

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Re: Receiving LWBC in North America
« Reply #11 on: April 25, 2022, 1316 UTC »
171 Medi-1 seems to now be inaudible "out west" here in CA compared to the early 2000s to about 2010 - I think this is because they went to a directional pattern that nulls North America - . Once quite easy in Inyo Co. CA to hear after evening dusk in the winter when the K-index was ZERO (and I caught them loudly in western AZ April 2009 with just a random wire atop some Saguaros). This before they went to the NA-semi-null.

The best antenna for LWBC and LW in-general is a good directional BEVERAGE antenna (look that one up).  You will get a lot more help with LWBC reception at the LWCA site and IRCA/NRC (the principle North American DX clubs). "Beverage on ground" wires (i.e. - simply spool out 300m/1000 feet on the ground or atop shrubs/etc. in-lieu of those 3m tall (plus) poles will offer amazingly directional reception - these are called "BOGs" and DXers employ them with amazing results!  "Terminate" the far-end of the wire to a ground rod 1m meter deep if possible (alternatively attaching the far end to another spool of wire and just putting the spool onto a ground rod or even wrapping it in a plastic bag and burying it just under the soil surface works to reject signal reflection from the far-end thusly reducing the undesired "back-lobe" ( most BOGs do not really need that 200-400 ohm resistor in-series to the earthing-rod - I find - as earth grounding is rarely low enough resistance with a single earthing rod). As such, this all makes the wire quite unidirectional toward the axis of direction of the wire. 

BOGs have a cool phenomenon pertaining to a "velocity-lag" of the signal in the wire vs. light-speed, and this further pulls the reception pattern into the reception-lobe along the axis of the wire.

For amazing receptions of LWBC stations via Bevs, listen to samples here:

https://archive.org/details/TheBestOfHawaiiMediumwaveamBroadcast-bandDx-86To91

AND:

https://archive.org/details/KeelerFenceBeverage1

For the time being - "forget about it" now, as storm static noise (QRN) and now a rising solar-max and huge attenuation of LW signal DX now (including NDBs) has now ensued - it is now like a -20 dB suck-down of LF signal strengths has ensued - just since the January 2022...

Solar-Minimum periods (such as between 2016 to as recent as October 2021) were the BEST epoch for long-haul LWBC DX, but it's all going away and the LWBC signals are rapidly leaving the air, too (alas!). 

Brave New World... 73MB
« Last Edit: April 25, 2022, 1328 UTC by MojaveBeaconeer »

Offline circuitmike

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Re: Receiving LWBC in North America
« Reply #12 on: April 26, 2022, 2237 UTC »
Thanks for the good info! I'm familiar with beverage antennas and I'd love to set one up, but I just don't have the real estate for that on my quarter-acre lot. I hadn't heard of beverage-on-ground antennas, though - that's interesting. Maybe one day I'll live somewhere with the room to set up something like that.

I don't know as much about propagation as I'd like to, so I had no idea that the solar minimums were actually good for LW propagation. I wonder how many LWBC stations will even be left when the next one rolls around. I do some casual NDB listening and I've logged a bunch of them from Quebec and Ontario but never anything I'd really call awesome DX. But I've done all that with my Wellbrook loop, which is great, but I realize it's no beverage.

The rising QRN is really frustrating, as is locally-generated noise.
QTH: Western Massachusetts (FN32rp)
Receiver: KiwiSDR (on-site)
Antenna: Wellbrook ALA-1530LN loop

Offline Helen

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Re: Receiving LWBC in North America
« Reply #13 on: May 15, 2022, 1515 UTC »
Dear circuit Mike

You were asking about  a suitable ant for low frequency.   Firstly  a simple loop antenna  a few turns of insulated wire on a simple frame made of wood.
is simple and very cheap. It is also practical.  and will out perform any of the long wire Antennas previously described since the Antennas suggested are ment to be several wave lengths long. The beverage is a great receiving antenna if you have half a mile or more of space and can pay for the copper.

If you look at old books from the 1930s you can see radios advertised with a 10 inch loop in the back. They were the standard for long and medium wave radios. with the desired move to smaller radios loops were modified to use a ferrite core making the antenna smaller with out loosing to much performance.
The length for a halfwave dipole  is  the speed of light devide by the frequency that gives you the wave length. The half wave length is the wave length
devided by two.  300,000.000 / 180  = 1666   div 2   =833 meters  multiply that by ten for the long wire antennas and that is a lot of real-estate.

Look around the technical web page that engineers and radio hams use. they have some really good ideas. And experiment.   Making good antennas for low frequency has almost become a forgotten art.
Kind regards
Helen
.
Loops work very well. you can make one for two 200khz  by using 30 40 turns and a tuning capacitor. 
Or you can make a bigger loop maybe 4 ft square you need less turns.   
Look up ham radio web sites or even Wikipedia  will give you more information.  The big advantage the loop is directional so by pointing it carfully you can make the signal you want stronger and reduce interference.  In the country be for FM became popular a lot of people used loops. If you are interested in Radio join a local Ham radio club.  Checkout Wiki maybe by the ARRL hand book or similar.  Where I live they are closing a lot of the beacons.  The Marine Band has been closed for years now.  But there nis still a lot of stuff around.  Good luck.