Longwave broadcasters

k9rzz · #1 (**permalink**) 10-20-2009, 08:23 PM

We're still on page 1 of this forum? Geeze.

I've been chasing the longwave broadcasters from Eu and northern Africa for the past 10 years and have only heard one, Iceland, with any kind of signal that I could listen to. I mean I've put up loops, and wires, and EWE's .... ZIP! Well, that all changed Saturday when I swapped out the germanium diode detector in my Icom R-71a to a Schottkey.

N2CBU's AM Diode Detector Improvement Modification

Over the last two nights I've heard over a half dozen stations down there between 153 and 252khz with good enough signals that I could tell you what language it's in, at least! WOW!!

Quick video: YouTube - DXing the longwave band

I've also heard some audio from Spain on 531khz medium wave.

It's going to be a great winter!!

lanbergld · #2 (**permalink**) 10-21-2009, 12:17 PM

Thanks for posting this. And you are in Milwaukee.

I'm on the East Coast, am a nightly VLF, LF & MF monitor, have a pretty nice set up for the low frequencies, I get WWVB really good, for example, as well as numerous beacons & Naval FSKs...I just cannot get European LW Broadcasters. No matter what I try. I only get weak heterodynes (at best) on those broadcast frequencies. And yes I've worked the gray line too.

So I've been curious as to how other East Coasters are getting the European LW broadcasters.

My core setup is as follows:

Yaesu FRG-8800 with all attenuation removed from the low end (4 resistors removed and/or jumped)

A slightly modified LF/VLF upconverter which takes me down to about 4 kHz (I removed a resistor from this)

A huge loop antenna containing 120 ft of 14 AWG wire

Larry Lanberg

Richmond VA

kb2vxa · #3 (**permalink**) 10-21-2009, 06:27 PM

Transatlantic propagation to the East Coast is weak at best so don't expect much. Setting up a resonant antenna is difficult not only because of the wavelengths involved but also that tuning is rather narrow and efficiency is very poor as well, ask any "lowfer". (Google it.)

lanbergld · #4 (**permalink**) 10-21-2009, 07:55 PM

Tell me about it. But naturally I get envious when I hear someone in the middle of continent getting those broadcasters clearly. I'm going to keep trying. I'm thinking that if I get just the right combination of capacitance & inductance then it will work with what I have (but again I rely on junk parts that I pull from old surplus electronics).

Sure, I've seen the large ferrite loopsticks that Stormwise sells for low frequency reception. I've thought about buying & trying one, yet something in me says to not put faith in ferrite loopsticks. Not for that type of long distance work anyway. I might be too cynical for my own good though.

Larry Lanberg

Richmond VA

k9rzz · #5 (**permalink**) 10-21-2009, 08:04 PM

Hey, wait a minute ... I get jealous of YOU guys being on the east coast and having it so much easier to hear that transatlantic propagation on MW and LW ! I know Neil Kazaross of the Chicago area has claimed some extraordinary DX from here in the midwest, but I'm always skeptical of it because no one else hears it, and because of the trouble I have hearing anything, yet he seems to 'hear it all' and can't seem to figure out how to record any of it on audio or video. I have tried all kinds of antennas short of full out beverages aimed at Europe and have just been so frustrated because I hear so little, but now suddenly with this modification to my receiver, it's like the light's have been turned on and now I'm hearing stuff.

I'm working on a comparison test of all the receivers I have which I will put on video. Stay tuned for that.

Edit: Oh, on my video listed above, each of those two coils resonate on the MW BC band with a 365pf variable capacitor, so for longwave I have those in series, and the capacitors in parallel to allow me to resonate the antenna down around 200khz. This does help quite a bit. I'll show more of this on the next video.

lanbergld · #6 (**permalink**) 10-21-2009, 09:38 PM

That's a beautiful set of coils there, k9rzz. I've been making my own inductance coils too, but not nearly as elaborate as your Litz honeycombs (mine also haven't worked very well, yet). I'm surprised you got down that low with a 365 v cap. My 365 'dies' below 600 kHz or so - that's with inductance coils rated up to 2500 uH.

Now yesterday I yanked a nice transformer coil from the cooling system of an old microwave oven. It looks like its got enough windings of thin magnet wire, length & diameter to give me a decent inductance value - and it is around an iron core - I just haven't incorporated it into a system yet. It just looks like its going to work.

Larry Lanberg

Richmond VA

k9rzz · #7 (**permalink**) 10-21-2009, 11:25 PM

I got those coils on eBay. Here's some similar (but much more pretty!): Diamond-weave COILS

I'm always experimenting with RLC phasing on the AM BC band and they also help reduce overload on my MFJ-1026 antenna phaser if I put one tuned circuit on each of the two antennas that I'm phasing. Otherwise that MFJ is sometime's plain useless due to the strong locals I have.

BTW, I had BBC Radio 4, 198khz, right on the verge of 'listenable' for a while earlier this evening. It faded in and out slowly, but I clearly heard the BBC ident.

k9rzz · #8 (**permalink**) 10-22-2009, 08:03 AM

Video from last night: YouTube - Longwave DXing - Kenwood R-1000

lanbergld · #9 (**permalink**) 10-22-2009, 04:47 PM

Those coils posted on Ebay have an inductance of 240 uH. I'm assuming for now that your coils have a similar value (?). Clearly something is going way over my head here -- You built a tuner that works on longwave with just a 365 pF v cap and 2 inductance coils of maybe 200-300 uH each? Or are you using the bypass when on longwave? Or maybe you have some fixed caps in there somewhere?

Larry Lanberg

Richmond VA

k9rzz · #10 (**permalink**) 10-22-2009, 11:59 PM

I've got all those coils in series and all those caps in parallel + I throw a 1,000mfd electrolytic cap in for good measure ( or two depending how low I need to go). As you can see, it's just all just tossed together for now and easily rearranged. Once this rain stops (a few more days) I'm going to try a larger multi turn loop antenna hung between a few trees to see how it compares to my rigid, rotatable 7 foot diameter loop I run now. I've got a small spool of 4 conductor cable that will make a nice multi-turn loop - perhaps 15 feet on a side and hung vertically. Will try to feed it with window line and tune it from the shack. That's worked real well for me on 40 meters in the past with a full wave loop and I've been just tickled pink with the results of the current loop antenna so why not go BIGGER!! LOL

lanbergld · #11 (**permalink**) 10-24-2009, 12:28 PM

Thanks. I figured there was something else in that engine. That's a good system you have there.

I almost got a station on 153 early this morning. I was able to zero beat it & was expecting at any second for the audio to come through. But it didn't. It was almost there...almost....My present system (which lacks a tuner at the moment) is actually strongest below 100 kHz. WWVB I can get really strong & clear. Really good reception between 6 - 110 kHz or so. It drops off to 'average' above that.

BTW about the loop antenna. The other night I reduced the size of my loop while keeping the same amount of wire in it (increased the windings of the same 120 ft wire to make a smaller area loop). The results were disastrous. Just thought I'd try it. In my situation the loop has to be really large. A huge difference.

Larry Lanberg

Richmond VA

kb2vxa · #12 (**permalink**) 10-24-2009, 06:14 PM

Hey guys, when you live in a skip zone you're schtupped, get use to it. No matter what you do short of moving, if the waves don't land there they're just not there. (;->)

Er, seems to me some of you are barking up a few wrong trees trying to resonate your tuned circuits. Right off the bat a 365pF "standard broadcast" variable just won't cut it, fully meshed the value is still WAY too small for LF work.
LC circuit - Wikipedia, the free encyclopedia
When it comes to winding inductors again there is so much you haven't considered, if you don't know the inductance value there's no way you can tune it to any known frequency.
Inductor - Wikipedia, the free encyclopedia
Scroll down to the bottom for the formulas.

gcgrotz · #13 (**permalink**) 10-26-2009, 09:19 AM

Sometimes you just get lucky too. After decades of tuning around down there it finally happened. Last Feb 1, I heard a number of EU stations on LF just using my 32ft vertical and R75. Turns out the auroral oval had shrunk up way up in Greenland so the LF sigs weren't absorbed. A benefit of no sunspots!

BTW, at the end of Sept I was at Va Beach, actually ON the beach. I took my R75 and battery, rolled out about 250ft of wire on the ground toward the water, and tuned up 1521 KHz usb around sunset. Sure enough fading up from the noise was BSKSA from Saudi Arabia with the distinct sound of Koran readings. Plain enough so My wife could hear it on the porch of the cottage. Of course, 2 megawatts on their end doesn't hurt. I suspect it would be pretty reliable there on the oceanfront. I didn't have any more time to just tune around...

kb2vxa · #14 (**permalink**) 10-26-2009, 07:45 PM

Now there's someone who knows about propagation! Hmmm, a Beverage antenna, sort of. Normally they're 4-6' above ground but on the ground will work obviously, not as well but it's better to trip people than hang them. (;->) The advantage here is a high signal to noise ratio, the signal may be reduced but the atmospherics reduced even more so it's a whole lot easier to dig the signal out of the noise that's not there.

You can always bury the antenna and work ground wave, then you don't need a skip filter.

gcgrotz · #15 (**permalink**) 10-30-2009, 10:10 AM

Yeah, I just ran it out on the beach. Most people were gone by sunset time but I marked it with some of those little contractor pink flags. I think the term is BOG for "beverege on ground".

I once had a 600' one that worked great. Used electric fence wire and insulators, grabbed a step ladder and a hammer and headed off through the woods. Later I added a ground rod at the end with a switchable terminating resistor fed with DC though the wire. Have a 75meter QSL from VK0GC on Heard Island to show for it. I really miss that antenna. If I tried that here I would have to cross a couple of streets and go under under a few power lines!

k9rzz · #16 (**permalink**) 10-30-2009, 08:59 PM

Playing with a new loop tonight - 12' per side of 4 conductor cable fed with window line (so it's a 4 turn loop, 12 feet per side strung between a tree and the house). No tuner just hooked up to RX.

Here's Morocco from a few minutes ago on 207khz.

207khz-1.wav

Antenna seems to loose it's advantage above 350khz but it's early in it's evaluation. It's also just barely above the ground on the bottom leg. Gotta fix that when I get some daylight. LOL

Edit - additional:

The Algerian party getting started on 252khz:

http://www.4shared.com/file/14501512...z_Algeria.html

k9rzz · #17 (**permalink**) 10-30-2009, 10:11 PM

One more clip before I do some chores:

252khz Algeria continues with it's Friday night dance party:

Algeria dance party

Not bad for someone in the midwest, eh? LOL

k9rzz · #18 (**permalink**) 10-31-2009, 01:49 AM

Can't keep my eyes open anymore, but one last one.

216khz Radio Monte Carlo in French at their sunrise:

4shared.com - music and mp3 sharing - download 216-MONTECARLO.wav

Recorded with the Icom R71a, AGC off, run through the laptop (like in the video) with SR5 (freeware) to knock down the beacon carriers then after recording, run though Cool Edit Pro to knock down the static crashes from thunderstorms. Turned out pretty well!

Gotta get the antenna up in the air more so I can drive my car under it. LOL

k9rzz · #19 (**permalink**) 11-03-2009, 08:15 PM

FYI - pretty decent condx on LW tonight. Was getting Algeria 252khz at S5 earlier and now RTE Radio 1 Ireland is dominating the freq. with some nice older rock music. Check it out.