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Old 17-10-2016, 09:44   #61
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Re: Too much RX noise on HAM setup

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Originally Posted by autumnbreeze27 View Post
[...]

I appreciate the help, but trying to say "Well, since you won't jeopardize your safety to check to see if it's coming from something you have no control over doing anything about, tough luck."
The reason you should temporarily disconnect your battery / solar / whatever, is so you can find the source of your interference. Once you find it you can stop looking. If these aren't causing the interference then you continue your search. If, say, it turns out your battery management system is the interference source then you may not be able to eliminate it, but you may be able to reduce it with ferrites. Perhaps you can't do anything. But until you find the source, you can't even try.
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Old 17-10-2016, 09:52   #62
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Re: Too much RX noise on HAM setup

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The reason you should temporarily disconnect your battery / solar / whatever, is so you can find the source of your interference. Once you find it you can stop looking. If these aren't causing the interference then you continue your search. If, say, it turns out your battery management system is the interference source then you may not be able to eliminate it, but you may be able to reduce it with ferrites. Perhaps you can't do anything. But until you find the source, you can't even try.
The power cable for the radio has ferrites on both ends. I can connect it to an 8D battery that has nothing else connected to it, or I can connect it to the Lithium battery. The problem persists. So I guess what e
verybody is saying is it's radiated RFI, but from what, I cannot fathom.

If you look at Michael Jefferson's SSB reference on the SSS
Resources | Singlehanded Sailing Society
http://sfbaysss.org/resource/doc/Mar...ns_MJ_2016.pdf
Page 15, I've followed that doc... ferrites in all those locations, and the t4 isolator as well.

Maybe I need a witch doctor.
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Old 17-10-2016, 15:33   #63
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Re: Too much RX noise on HAM setup

Regardless of whatever steps have already been taken to reduce the interference, the absolute best way to diagnose the problem is to find the source. The easiest way to do that is to disconnect the power from each / all devices and see it the noise goes away. Once you have the source (or sources) located, then you can more effectively come up with a solution. There may be no practical solution, but at least you won't be chasing your tail on a fruitless quest.

First locate the source. Then work on a fix.
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Old 17-10-2016, 16:01   #64
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Re: Too much RX noise on HAM setup

I will share my experience since it may help but also because I am open to advice.

I have an 802 with a whip antenna. I hear what I think is excessive noise. I have been told that if the background noise is a constant 3 bars, as it is, at just over 10 Mhz, I have excessive noise. I am not sure that is true?

I have turned off everything, except the circuit driving the radio, and still have the same 3 bars. Even when I am away from shore, I pretty consistently have 3 bars.

I happen to own a second 802 (both were brand new, factory sealed when I purchased). I hooked it up temporarily, using a dedicated power supply (120v - 13.8v converter), but I still used the installed system's ground, AT140 and antenna. Perhaps it is relevant to note that I put the replacement 802 on the flybridge, about 4 feet from the AT140, while the original 802 is in my pilot house helm. The coax from the original 802 to the AT140 runs through a 3" diameter conduit that is stuffed with wires -- it is easy for me to imagine that my original 802 is picking up RFI interference there. It is also easy for me to imagine that the original 802 is picking up interference from all the wires that are connected to / run parallel to / the 12v supply. In any event, I get 1 or zero bars with my new temporary installation.

At this point, I need to decide whether to go with the new unit on the flybridge, or to continue to swap parts and locations in and out until I locate the problem. It could be that I have a bad 802 in the original location (right)? The biggest problem of moving everything upstairs is that although I can run my pactor modem (7800) from the pilot house with a blue tooth connection, I will not be able to look at its screen (which presumably is providing useful information).

BTW, unlike OP, I am able to make airmail / winlink connections at stations from 100 to 600 miles away (but not consistently).
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Old 17-10-2016, 16:19   #65
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Re: Too much RX noise on HAM setup

And some thoughts to OP:

1. I don't think the T-4 will help much with your problem.

2. You might try receiving some weather faxes to make sure you can receive those cleanly -- that should give you some comfort about noise on the receiving end.

3. Have you confirmed that you have a good SWR?

4. As an alternative to disconnecting your 12v system, perhaps try a dedicated power supply. That may have made all the difference on my system.
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Old 17-10-2016, 17:37   #66
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Re: Too much RX noise on HAM setup

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I've only skimmed this thread.... has anyone suggested using a small sony/tecsun/grundig/whatever receiver as an RFI sniffer?
Sure seems that tuning this is to a known offending frequency and moving the portal unit close and then far away to the BMS system should answer if that is a significant cause of the RFI.
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