SW Reception Problems...NEED HELP!!

[mfn002]

Ever since I started listening with my Grundig Satellit 750, I've had problem receiving certain frequency ranges, such as:

2000-3180 kHz
3190-4835 kHz
4845-5020 kHz
5030-5740 kHz
5760-5870 kHz
6300-6870 kHz
6900-7200 kHz
7580-9260 kHz
9270-9300 kHz
9985-11500 kHz
12165-13565 kHz
15000-15115 kHz
15175-15195 kHz
17000-17550 kHz
17870-21495 kHz

These "dead zones" are just that--dead. It's all static, and I have never picked anything up in this range. Also, I have terrible problems with electrical interference, despite have nothing on when I'm listening besides my computer and a lamp. Even the stations that I can pick up are usually almost entirely static, making it almost impossible to decipher what's being said, even with high-quality headphones on.
I'm using the radio's telescoping antenna next to a window. I can't install an outdoor antenna. Anyone have any idea how I can fix this problem and fill in these "dead zones"?

 

[wizardb]

Could be interference from the computer or oven the lamp. If your using it on electrical power try a different outlet. What's in the wall? I have a wall full of water pipes in one side of the room and I can't get anyrhing on my radio when it was near that wall. I'm no expert, just suggesting things you could try, if you haven't already

 

[mfn002]

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There's nothing in my wall, except for wires running to two outlets, and those come from outside and go in near the floor. I do have a power pole with a transformer on it in my backyard. I'll add a pic later.
It still does't explain why I can't receive anything in those dead zones. There is nothing there, just static.

 

[k9rzz]

Read about Ridge's TV noise discovery.

Either your radio is kaput (which I doubt) or your noise floor is covering anything to be heard in those bands. Those are not shortwave broadcast frequencies, so anything to be heard there will not be loud, especially with the radio's built in whip. Find your source of noise, and you'll find the answer to your 'dead band' problem as well.

 

[mfn002]

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I got it new in November, so it's definitely not broken. I'll try some other things and see what happens.

 

[ridgescan]

Get a 25' run of speakerwire, run it out preferably east west in your room and out into the next room-hook an end to your whip at the top and dial around. If there are stations showing up, you need more antenna than that whip. If that is the case, we'll tell you here how to rig an indoor one.

 

[mikepdx]

Have your receiver on battery power.
Turn off the MAIN breaker in your electrical panel.

Check for interference (or not).

That will rule-out or confirm that the problems coming
from your own home.

 

[mass-man]

Pick up the radio and go outside...down the street, to a local park, and determine if you stilll have the dead zones. As stated above, there are myriad types of interference, and you need to track them down and eliminate the nasty buggers! Maybe even a piece of wire attached to the whip will allow you to hear those weak signals...I would unplug anything in the house that could create interference, TV, lights, whatever. Just turning it off often won't work. But odds are very good you need more antenna.

 

[Jimepage]

Give 3330 a try after the dun goes down and try to receive the time station in canada if you do then you know the zone is now dead . I own a 750 and it works really well but is sensitive to qrm from electical sources. it can even be a neighbors plasma tv your picking up.

 

[mfn002]

You might be right about that. I actually do pick up alot of stations, but there is seemingly always this annoying electrical interference, and it gets worse as the morning progresses. By about 1600 UTC or so, I lose pretty much everything below about 9000 kHz . By 1800, it's everything below about 12000 kHz. Before I got the 750, I had a Grundig G6 Aviator that was on a slightly lower nightstand, and I had alot better reception there. Unfortunately, my 750 wouldn't fit there, so I had to put it on top of another, taller nightstand. When I put my 750 on the taller one, I got tons of electrical interference, something that wasn't a problem with where my G6 was.

 

[majoco]

Has that table lamp got a dimmer in it? If so, unplug it from the wall, especially if it has one of those CFL bulbs.

 

[jackj]

Anything today that has a clock or a remote control isn't off when you turn it off, Michael. The power supplies are still running in order to furnish power to the IR receiver for the remote and/or the clock. In fact most all electronics today isn't really turned off when you push the off button even if it doesn't have a clock or remote control. Heck, they have even put remote controls in ceiling and floor fans. Virtually 100% of these power supplies are switching supplies and some of them generate tons of noise. Light dimmers and touch control lamps are really bad news. My wife had a touch-control lamp that would even blank out the AM band and noise up local 5 Kw stations. Doggone lamp quit working one day. hehehehe Finding and eliminating RF noise generators today is almost impossible if you live in an urban area.

Good luck!

 

[mfn002]

The light does not have a dimmer or a CFL bulb. Since my G6 is closer to the lamp, logically, if it were the problem, I would get more noise. I didn't. I'm going to try one of those roll-up SW antennas that I have hanging on my wall and see if that works tomorrow morning. Also, I have terrible problems on the 2000-8000 kHz range with reflections and bleedover from some local AM broadcast stations. At one point, I mistook one of these for a shortwave station (it somehow appeared on 3840 kHz). It is really the worst in the 7200-7300 kHz range. I noticed that when I do use that shortwave antenna, I get horrible interference from the local NOAA station on 17500 kHz.

 

[ka3jjz]

It's unlikely that there would be a NOAA station on 17500, which is the outer edge of 16 meters. I smell an overload situation here.

Mikepdx has the right idea, just not quite detailed enough. Turn off every appliance in your home. Take your G6 and fully collapse the whip antenna. Tune to an AM frequency that is unoccupied (best during the day), and note the noise level. Turn on the appliance. If the noise level rises, you've found your culprit. And it wouldn't surprise me to hear there was more than one here.

Do you have a MW (AM) or FM station tower nearby? This can also be a source of broadbanded crap - and some broadcasters are limited in the power during either day or nite ops, or are required to change their broadcast pattern, so that may account for some of the issues you are seeing...best regards..Mike

 

[mfn002]

It's unlikely that there would be a NOAA station on 17500, which is the outer edge of 16 meters. I smell an overload situation here.

Mikepdx has the right idea, just not quite detailed enough. Turn off every appliance in your home. Take your G6 and fully collapse the whip antenna. Tune to an AM frequency that is unoccupied (best during the day), and note the noise level. Turn on the appliance. If the noise level rises, you've found your culprit. And it wouldn't surprise me to hear there was more than one here.

Do you have a MW (AM) or FM station tower nearby? This can also be a source of broadbanded crap - and some broadcasters are limited in the power during either day or nite ops, or are required to change their broadcast pattern, so that may account for some of the issues you are seeing...best regards..Mike

What I meant to say was that I was getting bad interference from the NOAA station. There are at least three or four towers within my immediate vicinity. I'm not too entirely sure, but I think one is for a local TV station, another for the local SO's VHF channel, and I'm not really sure about the other, but I think it's for one of the local FM stations. The SO tower has a very, very powerful xmitter on it (they thought, "hey, there's reception problems out there, so let's make the signal stronger"). I used to get heavy bleedover and reflections from that thing all the way down to the VHF airband before they toned it down after switching to 800. Anyway, I doubt that appliances are really the problem. The kitchen's on one side of the house, and my room is all the way on the opposite side and separated by a living room. I do have some AC adapters plugged in, but I've tried those with little success.

I had the same overload situation with my scanners. I had to attenuate the heck out of my PSR600 until I replaced it with a 996XT which has less sensitivity issues. For some odd reason, my room seems to be some sort of RF magnet.

 

[jim202]

You have been given a number of suggestions on how to limit or locate the interference problem. You haven't come back yet saying you have tried much.

1. Run the radio off of batteries and then pull the main power breaker to your house. Did the noise change?

2. If the noise changed with the breaker off, do you have a large screen TV? Pull the plug and see if the noise goes down. Plasma TV sets have a known issue with causing all sorts of HF noise like yours. Don't forget to pull the plug on the cable TV box if you have one.

You can't just shut off the devices your trying to eliminate. You have to pull the plug out of the wall to tell if they are a source or not. Many devices still have power to some of the electronics. This includes any computers and network hubs you might have going.

Does the noise change with the weather? Like does it get worse or better when it is raining outside?

Does the noise change or get worse when the wind picks up and the power wires start dancing around?

Let us know the steps you took and what the results are.

 

[kb2vxa]

Hey guys, what's with all the "suggestions" when we haven't got a clue? He's there, we're not so let's start at the starting point.

1) The uneducated call any kind of unwanted signal, electrical interference in particular "static". Narrow it down, what does it sound like? A detailed description is the first order of the day keeping in mind there may be more than one kind of interference present, mixed signals.

2) I saved the best for last, when he went to a higher shelf it got worse. Stop an d think, that's closer to the source(s). He's using a portable receiver but not using it to locate the source which keeping in mind the source is the incidental radiator (an antenna of sorts) and not necessarily what's generating the signal(s) which in some baffling cases have been traced to miles away usually down the power line.

Bottom line here is forget the AM broadcast band which usually comes to mind, that's not a starting point but may be useful in some cases since the receiver may have a built in loop antenna which is directional. First of all keep the telescoping whip short, the less signal input the better. The starting point is the frequency of least interference, if it's loud and broad you'll never find it, if it's barely audible you'll easily hear the varying signal level as you move the receiver around. If it gets loud and broad at some point, tune for a frequency that sounds weak like where you started. If and when you get lucky the only place you'll hear it is right next to the noise generator(s)... BINGO!

Just a technical note, rarely does such a receiver have an RF gain control you can use to lower the signal so you're stuck with the automatic gain control (AGC) circuit in the receiver. It gets worse, I haven't seen a receiver where you can switch the AGC off and manually control gain since the days of boat anchors and they were anything but portable. Before I get too far off the beam, the whole idea behind keeping the "static" down to a barely audible level is keeping it below the point where the AGC kicks in and levels the volume so you can't hear it rise and fall.

As a footnote; since the AM broadcast band and loop antenna were mentioned, sometimes it's a useful approach in some cases but "how to" is a horse of a different color and a topic of another discussion entirely. That being the case let's hold it in reserve as not to confuse the issue.

 

[ilgrant]

It's been a while since I listened to Shortwave but a couple of thoughts...

1. If there is a ground terminal I would definitely ground the receiver. You'd be amazed how much the noise level goes down when you run a wire from the ground terminal of the receiver to the a cold water pipe or ground terminal of an outlet.

2. Generally, lower frequencies will be received better at night and terrible in the day. During the daytime the higher frequencies are received better and awful at night.

 

[nanZor]

I see the wall-wart is plugged in. My 750 picks up so much garbage from the ac line, so I only run from batteries. Good battery life at least.

Unrelated tip: if the band-edge beeper is driving you nuts, just press and hold the ZERO key and it will toggle the band edge beeper on and off.

Are those shades vinyl or metal? If metal, perhaps roll them up during listening sessions...

 

[mfn002]

I see the wall-wart is plugged in. My 750 picks up so much garbage from the ac line, so I only run from batteries. Good battery life at least.

Unrelated tip: if the band-edge beeper is driving you nuts, just press and hold the ZERO key and it will toggle the band edge beeper on and off.

Are those shades vinyl or metal? If metal, perhaps roll them up during listening sessions...

The shades are vinyl. I'll try the batteries. I got one of those roll up wire antennas and it seems to have fixed some of the problems. I noticed that some of the stations I was having trouble receiving are coming in alot clearer now than they were before. It also seems to attenuate some of the stronger signals (9980 WWRB comes to mind--if i'm not careful with the volume, i'll get blasted by that thing; it pegs the RF meter at the max). It still needs some tweeking, but I suspect I might have rectified some of the problems because I put that wire antenna up near where the wall joins the ceiling, and thus away from most of the interference-causing wall warts (the outlets are about 6 inches above the floor). Also, I mentioned earlier about the NOAA weather radio thing...after some testing, that wasn't a problem anymore.