Icom 802 Reception Issues

[Sailabel]

A quick update- it's kinda nice being out at anchor, because we're far enough out to not get noise from buildings, marinas, docks, or neighboring boats. Following the advise given, we disconnected the house loads, with no noticable effect in RF noise on the radio.

Yesterday, we were temporarily installing led lights of varying types, and I was checking to hear if any of them contributed to RF interference. Nope, not an issue. However, I inadvertantly disconnected power from our charger/inverter. The 'noise' reduced significantly.

This has be a bit confused, in that we always turn off the charger/inverter when using the radio. Because we're at anchor, there is no AC going into the unit, just the 12vdc... and the inverter function is turned off. But as was mentioned, there is a difference between being 'turned off' and 'disconnected'.

We're going to continue tracing down any further sources of noise; and we did order the 'clear speech' DSP speaker- which should arrive via another cruiser in a few weeks. I'll give a report on that once we have a bit of experience with it.

Thanks again for all the input. The 'issue' is at least 80% solved at this point.

Steve

[goboatingnow]

Damm those MOSFETs

[matauwhi]

G'day, Steve. Not a reception issue, but a transmission issue, has your 802 had the "clipping issue" addressed. Just had a boat this morning on the Rag of the Air in the South Pacific on passage with an 802 that was clipping very badly and barely readable. If you haven't had this taken care of, I would highly suggest you do before heading to far offshore. Cheers.

[ka4wja]

Originally Posted by Sailabel

But as was mentioned, there is a difference between being 'turned off' and 'disconnected'.

Steve,
1) I'm glad that we could be of help!!!!

2) You haven't mentioned what your noise levels actually are????
But, be assured that if they are much higher (on the M-802's "S" meter) than I indictated in my earlier post, you most probably still DO have internal RFI issues.....
If you're trying to figure this all out, as has been mentioned already the easiest thing to do is DISCONNECT everything electric / electrical from every battery on board, except for the M-802......
This may sound like a real project, but if you do take this seemingly strange advice, you WILL be able to find any RFI issues quickly and easily!!! And it won't cost you a dime!!!

{These things can be a real pain to trck down sometimes......one of my friends found a battery-powered digital kitchen timer to be interfering with his HF receive......no fooling, I true story!!!!}


3) You have also not mentioned what settings you have on the M-802, so there is little more that we can do for you at this point.....save for recommending that you closely follow the advice already given!!!

Originally Posted by Sailabel

and we did order the 'clear speech' DSP speaker- which should arrive via another cruiser in a few weeks. I'll give a report on that once we have a bit of experience with it.

There's nothing wrong with the "Clear Speech" DSP speaker, but it will NOT rid your boat of RFI, and (in my opinion) is a waste of $$$ (so
please be sure you can return it), and isn't much better of a speaker than the Icom SP24 which is supplied with the M-802....
If you find the Icom speaker to not be to your liking, then an inexpensive (~ $ 30) pair of headphones would be a very workable solution......

If you find the AF DSP (the Icom M-802 has DSP noise reduction / "noise blanker" already) functions of the Clear Speech to improve your reception versus the Icom speaker, then there is a high liklihood (>90%) that you still have internal RFI issues on board and/or have an internal M-802 issue....
But, since we don't know what you noise levels are (on the M-802's "S" meter at differemt frequencies and times), we cannot give you a 100% assured answer......



Good luck....

John
s/v Annie Laurie

[Sailabel]

Thanks John and matauwhi- we had the 'clipping issue' addressed by Icom last time I was in Bellevue. It was nice to be able to drop by get things taken care of. The 'inverter issue' seemed to have taken care of the major issues... not to say that we won't continue to track down any other sources of RF on the radio. The 'disconnecting' everything at the battery didn't have a noticable effect... other than the inverter and the other 'normal' stuff that we always shut off: refer, wind generator, etc.

We'll advise if we find any other great revelations.

Steve

[SaltyMonkey]

Noise suppression locally:

Ferrite Chokes
DSP filter on radio
Noise cancellation speakers and headphones
Power conditioner
External DSP products
Balun

Some of the nose can be coming from poor ground or the Transceiver itself...

A spectrum analyzer should be able to tell you where in the spectrum your noise falls and may help isolate if it is related to equipment.

But some of your noise at this point can be coming from the actual signal you are receiving (atmospheric, thermal etc), and in that case you'll need to use filtering techniques or multiple antennas in phase etc.