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Old 17-10-2016, 08:44   #61
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Re: Too much RX noise on HAM setup

Quote:
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, 08:52   #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, 14:33   #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, 15:01   #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, 15:19   #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, 16:37   #66
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Re: Too much RX noise on HAM setup

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Originally Posted by El Pinguino View Post
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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Old 25-12-2016, 12:55   #67
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Re: Too much RX noise on HAM setup

Hi all,
I'm starting to get all equipment together, and preparing the installation with the help of the Manual from TL Sparks: ICOM M-802 Starting from Scratch.
I put some questions in another thread, about DSC Antennas.
Here may be you give give m,e some advise about the ferrites. There are special ferrites: mangan- zinc (Mn-Sn ferrites) and Nickel-Zinc ferrites. Everywhere I read only ferrites. But which ones are functioning the best? Or is there no difference. TL Sparks also is indicating the ferrites whre to put and how many?. I think the snap-on ferrites are the best i.s.o. the ring ferrites, which are too big in dia and cannot be mounted when the connectores are fitted !

regards,
Theo
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Old 25-12-2016, 15:43   #68
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Re: Too much RX noise on HAM setup

I bought mine from fair-rite.com type 31 part number 04-31-164-281 for the 1/4" hole size and 04-31-164-181 for the 1/2" size. I always loop the wire thru the ferrite basically doing a 360 so the ferrite captures the wire twice.

Look up the article by Jim Coreman called Solving RF interference Problems. Unlike the self help book it's free

Good luck

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Old 26-12-2016, 08:49   #69
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Re: Too much RX noise on HAM setup

Theo,
The short answer is:
Use Mix 31....

And, BTW, all of the pertinent RFI info is in the links in the "sticky", right at the top of the "Marine Electronics" page...
Marine SSB Stuff (how-to better use / proeprly-install SSB, & troubleshoot RFI, etc.)


The long answer is:

1) First off, please understand that entire books are written about RFI...with many technical papers published fairly regularly...
So, the details of this topic are well beyond the scope of this thread...
But...
But, I can lead you thru to some useful info...


2) Next, understand that there are two types of RFI we are attempting to control on-board....transmit RFI (where your transmit signal is causing interference to other devices/systems) and receive RFI (where other devices and systems are causing interference to your receiver)....
And, it is the latter (receive RFI) that causes most of the problems.....with the former (transmit RFI) typically only effecting laptops connected to the radio, etc. and/or an occasional boat having an autopilot error when transmitting...

3) Much of the transmit RFI issue is handled by:
a) having an adequate Antenna ground / RF ground....(such as a direct, low-impedance, sea water RF Ground)
b) use of a quality "line isolator" on the coax (at the remote tuner end)...
c) ferrites on the other device's / other system's cables, just as these cables exit their respective cases/enclosures...

4) Much of the receive RFI is handled by:
a) removing RFI generating devices from your boat...(or better yet, designing your boat's on-board electrical / electronics systems to be as RFI free as possible)
b) turning off the RFI generating devices/systems when using the HF radio...
c) using as short of inter-connecting cables as possible, between various electronics systems on-board, and keeping these cable's routing as far away from your HF antenna (and remote tuner) as possible...
d) using ferrites on these other device's / other system's cables, just as these cables exit their respective cases/enclosures...


5) The good news is that you don't need to worry about nickel vs. manganese....
It's all about the "mix" number....and which mix to choose is primarily based on the frequency of interference / frequency of operation...

And, for our purposes (HF radio RFI), that means Mix 31, Mix 77 (used to be named Mix 73), or Mix 75....
{note, for VHF RFI, Mix 43 is best....but Mix 31 does still work...}

In the US, you will find most "split-beads" and "clamp-on" ferrites for sale, for RFI suppression to be Mix 31 or Mix 77 (or labeled Mix 73)....and as far as I know, this is also the common retail sales practice in Europe, but I'm not sure about in Asia???
Quote:
Originally Posted by Sea Angel1 View Post
Hi all,
I'm starting to get all equipment together, and preparing the installation with the help of the Manual from TL Sparks: ICOM M-802 Starting from Scratch.
I put some questions in another thread, about DSC Antennas.
Here may be you give give m,e some advise about the ferrites. There are special ferrites: mangan- zinc (Mn-Sn ferrites) and Nickel-Zinc ferrites. Everywhere I read only ferrites. But which ones are functioning the best? Or is there no difference. TL Sparks also is indicating the ferrites whre to put and how many?. I think the snap-on ferrites are the best i.s.o. the ring ferrites, which are too big in dia and cannot be mounted when the connectores are fitted !

regards,
Theo
6) As I wrote above, there are whole books written on this subject....so, here is the quick and dirty info...

a) Buy a Line Isolator...
DX Engineering or Radio Works...
https://www.dxengineering.com/parts/dxe-fcc050-h05-b

T-4


b) Buy Mix 31 (or Mix 77) Ferrites...
Ferrite Mix Selection - Palomar Engineers®

Snap On Split Beads - Palomar Engineers®

https://www.dxengineering.com/search...-ferrite-beads

Round Cable Snap-Its Archives - Fair Rite



I think the above should be all you need to know...
But, if you want to read more....have a look here...
http://audiosystemsgroup.com/SAC0305Ferrites.pdf
Common-mode chokes
http://www.yccc.org/Articles/W1HIS/C...S2006Apr06.pdf


Fair winds..

John
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Old 26-12-2016, 09:05   #70
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Re: Too much RX noise on HAM setup

Theo,
In addition to Chuck's advice here (Jim Corenman co-wrote the Sailmail Primer), please have a look at the "sticky"...
Marine SSB Stuff (how-to better use / proeprly-install SSB, & troubleshoot RFI, etc.)
It too, is free...

Here is Jim Corenman's article...
RF Interference

And, here's the Sailmail Primer....also free!!
https://sailmail.com/wp-content/uplo...2/smprimer.htm

Quote:
Originally Posted by chouliha View Post
Look up the article by Jim Coreman called Solving RF interference Problems. Unlike the self help book it's free
And, when you really want to know about the M-802, how-to use, etc...and about HF-DSC communications...and about Maritime HF comms, etc....
Please have a look at these free videos as well...

Icom M-802 Instruction Vidoes
https://www.youtube.com/playlist?lis...rC-8QKVyMb4tVr


HF-DSC Comms
https://www.youtube.com/playlist?lis...ga2zYuPozhUXZX


Offshore Weather
https://www.youtube.com/playlist?lis...zdjTJjHlChruyY


Offshore Sailing
https://www.youtube.com/playlist?lis...KgTCj15iyl6qoY


Maritime HF Comms
https://www.youtube.com/playlist?lis...ZDo_Jk3NB_Bt1y



Hope this helps...

John
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