question about longwire

[dnlbrrg]

I have a Satellit 750 and have about 100ft or so of wire strung outside and grounded. It used to work great, but now I can't get any reception with it, it's like it stopped working suddenly. The whip antenna now does better, for some reason, and I get aboslutely nothing with the long wire. Don't really know what happened here.

Any thoughts?

It's been happening for a while now.

 

[ridgescan]

Hi-
how is it grounded, are you running coax as feedline, did you get MORE noise across the bands generally along with the signal loss or is your noise level the same?

 

[dnlbrrg]

The Grundig 750 has a socket on the site where you can put in a piece of the stripped wire, I think they call it a high impedance socket (not sure). Right next to it is another socket just like it but for the ground wire. I ran the ground wire outside and clipped it to a water pipe.

It worked well for a long time, but suddenly stopped.

 

[ridgescan]

What changed in your environment since it worked fine before? Are you getting more noise? ok so I assume you have that 100' wire going directly to the antenna terminal with no feedline like coax or twinlead.
This may be attracting too much noise.
Speaking only from my own experience, you should run a coax feedline from your 750's 50 ohm antenna terminal, and hook that 100-footer to the coax center lead, then ground the coax braid to that pipe.
It's tough to tell from here but if it was fine before either ther is a new break in the 100' wire or it's shorted somewhere near the house, or someone's running something nearby that's generating big noise.

 

[w2xq]

Wirelessly posted (Moto Droid Bionic: Mozilla/5.0 (Linux; U; Android 2.3.4; en-us; DROID BIONIC Build/5.5.1_84_DBN-74) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1)

Nearby lightning storm? Front-end components could have taken a surge. Just a guess... HTH.

 

[Boombox]

One possibility is static from a lightning strike may have zapped an RF transistor... but it's also possible your problem could be the antenna connector itself. I'd start by substituting another wire antenna in place of the longwire, and see if there's any improvement.

You could also try to connect the end of your longwire into the 50 ohm BNC socket and see if you at least get signals. This could help you troubleshoot whether the problem is with the antenna itself, or something inside the radio.

Hopefully, it's just something with the antenna. Good luck.

 

[WA1ATA]

Corrosion causing a bad connection is the most likely reason an antenna stops performing as well as it used to. Or as ridgescan noted above, perhaps a short in the system.

Since the whip antenna gives you decent coverage it is not likely that the problem is lightning damage to the radio.

My recommendation is to first do a careful visual inspection of the antenna and coax/feedline. Then go in and mechanical stress things (fancy words for pull, twist, and yank a bit) and see if anything changes. Sometimes this will show you where a short and open circuit is located.

After that, then I would start doing things like using an ohmmeter to check the feedline for a short. Then disconnect the antenna and short the feedline and check for continuity.

If you haven't found the problem by that point, then the next step is to replace either the feedline or antenna.

My experience is that bad connections inside connectors is the most common problem.

 

[dnlbrrg]

Well, I took down the wire and inspected the connections, no corrosion. For good measure, I re-soldered and mounted it again. I soldered the end of the wire to a BNC connector and hooked it up to the radio. It works better, but not like before. This makes me think there is no internal damage to the radio.

Could mother nature be causing the problem?

 

[Boombox]

I don't know much about your radio (never have had a Grundig) but I notice from reading about it that it has an internal / external antenna switch. Have you exercised it to make sure it hasn't oxidized? I know on my Realistic DX-440 sometimes the int./ext. antenna switch can oxidize if set in one position for a long time, and switching it back and forth a couple times can bring the external antenna back to life.

I read a review of this radio on eHam.net and a guy said the switch on the 750 can sometimes be 'intermittent'.

Just an idea.

Good luck.

 

[KC4RAF]

+1 with Boombox.

I also have the DX-440; a couple of years back it became deaf. After checking the antenna, connection, etc., I flipped the int./ext. switch up and down a few times and it started hearing again. It is just a very small amount of voltage from the antenna coming in, and it doesn't take much corrosion to stop it.

 

[nanZor]

I flipped the int./ext. switch up and down a few times and it started hearing again. It is just a very small amount of voltage from the antenna coming in, and it doesn't take much corrosion to stop it.

You beat me to it. I have a 750, and once in awhile, the INT / EXT switch will not function electrically, and get stuck on one port, despite repeatedly switching it. Seems like a mechanical problem, but seems to be static related.

So dnlbrrg, try removing the antenna, and all power, INCLUDING internal batteries as well for awhile. In one instance, it took over two hours for the static charge to decay, and allow the int / external switch to function.

You can see if this is the case since it will show up in the display, and won't change state as you move the switch. And just because it might say EXT, when in fact it is using the whip means that you may have been hit by this static bug.