VHF interference from my Garmin 188

I spoke with Garmin Tech support today. They agree that the unit has a problem
and are willing to look at the unit. Since it is well out of warrantee, this won't
be free, but the cost is considerably less than any sort of replacement. So, off
it goes and we'll see what happens.

Mike
 
Yep me too. My C80 Raymarine setup has a nice bridy signal
on 22 American and Coast Guard broadcasts well don't sound so
nice. I think I am stuck with it as all the systems are tied together
in one box. Too much stuff in too a little of space. Bob Heselberg
Eatonville Wa
 
I was joking with Garmin and suggested that they convince boat makers
that instead of installing electronics shelves, they create electronics cubbies all
over the boat. That should solve the problem. Radio is the port stern, GPS
stbd, radar midships-stbd, etc.

Mike
 
Well, that was a waste of $105. The tech said the unit functioned as
designed. They then included a thoughtful note telling me to keep
the antenna 2' from the VHF antenna. Apparently they didn't bother
to actually test anything or read the description of the problem
or they would have discovered that the problem has nothing to do with antenna. You can mount the GPS antenna 30' from the VHF antenna
nd the GPS will still make a racket near the unit itself.

Best advice is to test wire anything new and return whatever doesn't
work before you get stuck with it.

Anyone know if the FCC regulations that the device is supposed to adhere
to can actually be enforced? Anyway...this is all probably a waste of
time. Best to just get a small handheld since I'm not going to spend
what it costs to get something that actually works.

Hmmm...Garmin is in Kansas. I think I'll contest the Mastercard charge.

Mike
 
Hi Mike,
I had a 188 Gray Screen and now a 398c (Color) and the radio is a cheapo mounted on the electronics shelf with the 398c mounted on the dash in front of the helm. I have no problems to report. Can I suggest you stop by West Marine or other supplier and bring the boat on trailer...and test drive one of their new Garmin's in the parking lot. Cables should match up ok and you can get some real time comparsions. I agree it is most likely the units screen producing the problem but at least you will know for sure if it's all or just the one...you bought.
 
mikeporterinmd":2nk3evb6 said:
Well, that was a waste of $105.
Best advice is to test wire anything new and return whatever doesn't
work before you get stuck with it.

Hmmm...Garmin is in Kansas. I think I'll contest the Mastercard charge.

Mike
Click to expand...
How can this thing be out of warranty? Wasn't it just installed in the boat? I'd send it back to Garmin, along with a blistering letter, attention Garmin's head office, attention their CEO.

If that does not work, then do the Mastercard bailout.
 
I just bought the boat. I replaced the radio with one that scans and
ran into the problem. I have verified that it is not the radio because
I can hear the same noise on a hand held. I can verify it is not
the boat's wiring or anything related to the boat because I can
demonstrate the problem with the GPS in the house running off a Nicad
battery pack.

I'll try and get my money back and then auction the unit on Ebay. It
seems to only make noise on 21 and 22 which are Coast Guard
channels. I will disclose this and hopefully sell to someone that
does not have Coast Guard broadcasts. Then we'll probably buy
that small Lowrance that was being talked about recently. Or
just run the old Garmin 188 I have.

I have no reason to believe all Garmin 188C units make this
noise. I'm sure they don't as the FCC or Coast Guard would have
forced a recall.

Anyhow - just check this stuff out before your time to return a
unit to the store expires. Eventually the manufacturers will
learn that it is costing more in returns than it would cost to
make the units correctly in the first place and so they will make
them correctly. Notes from others in this thread indicate the
problem isn't limited to Garmin, either, so this thread shouldn't
be interpretted as a Garmin bashing.

Mike
 
Yes, I've tried ferrite. Spoke to Garmin this morning. They now admit the 188C
broadcasts on a number of frequencies and this is an overall design flaw in
the unit. According to Garmin, the only option is to keep 4' between the 188C and a VHF.
He listed a number of frequences which are presumably related in some fashion, but
I did not write down the numbers. GPSMAP-182 units are also effected.

I spent some time reading FCC Part-B, but I don't see anything that would
force Garmin to do anything other than not sell the 188C or 182 (which they
don't).

The customer service rep is working on trying to get a refund on the "repair" price.
Their phone support people have been quite decent so far. I don't fault
the original person for not knowing the 188C is flawed in this manner.

4' is sorta relative as the RF leak occurs down the power supply wires too. So,
you need 4' from the head unit and the wires supplying the unit. I guess
if I designate Bonnie as the navigator and install the unit on the port side,
we could use it.

Mike
 
Here's another possible (simple) cause for interference to check out. The problem may originate at the battery/batteries (e.g., two wires both connected to the same battery).

I encountered a temporary interference problem with my VHF radio this summer when, while underway, I connected my 3-way charger to one of the batteries, the one to which the VHF line was connected (it causes no problem when connected to the other battery).
 
Well, I tried a Lowrance LMS-337C DF. It is pretty darn quiet. There were some
minor tones on the VHF, but the units were close and the tones weren't that
objectionable. Perhaps some ferrite on the VHF power feed would help.

Except on VHF weather channel 3. The LMS-337C DF totally wipes out the
signal with a barrage of noise.

Since I bought this unit two weeks ago from West Marine, I can return it
and possibly try a different unit.

Spoke to Lowrance. The lady actually told me:

a) The unit was in compliance with FCC part B. Since part B mostly says
manufacturer should "try" to not emanate stray RF, I suppose she is
correct. I can't see anywhere where the manufacturer actually has to
succeed or face any sort of penalty. Indeed, the only penalty I can
find is if the interference is high enough and causes other people problems,
I'm not allowed to use the device. Did I miss anything?
Also, I think GPS class devices can be "self-certified", which I guess
means the FCC never saw or tested the unit.

b) She also said it was not possible to design around these limitations.
Strange statement. But, I'm guessing she is not an EE. Neither am
I, so I dropped that statement.

The problem is interesting. It only happens in chart mode, and only when
a chart chip is in the unit. I'm guessing some other processor is getting used
when the chip is installed and making the racket. Works fine using
the builtin in charts. As you change settings, and cause charts to appear
and disappear, the noise tracks. I will put a different chip in tonight and see
what happens. However, I don't have any more chips with charts on them, so
I suspect I won't hear anything. Presumably I can't copy the contents of
a NauticPath chip to another chip.

Oh, and it was also apparently shipped with incompatible levels of firmware
between the LGC-2000 and the LMS-337C CF. At least I think that's what
the head unit is trying to tell me. I'll update the firmware and see if that
allows the GPS to work.

I checked all the usual stuff. The head unit was several feet from the VHF and
it's antenna. The GPS unit itself doesn't even work, and was not connected.
The head unit was powered off of a NiCad battery pack - no wires in common
with the VHF wiring, nor were any wires particularly close.

The sound on channel 3 was basically a "roar". Really, really loud. Much louder
than the Garmin 188C ever was. I made a "movie" of this. I'll post a link when
I get it converted to an MPEG.

Also: I spent nearly 3 hours on hold with Lowrance today. Could be the
season, but "that's not so good".

If the local West Marine has some time, perhaps we'll be able to test out the unit(s)
in the store.

Mike
 
Software! I updated the LGC-2000 (the GPS), and it started to
work. Then I updated the LMS-337C DF, and 99% of the noise
disappeared. To be sure, there is some, but it's not that bad. Certainly
acceptable, and most likely if I work on wire placement, I'll be able
to solve some of it. There is some RF leaking from the sounder
cable where it connects to the speed log, but perhaps I can wrap
it or move it.

I'm guessing the original software left the device that reads from the
card turned on, and the updated code turns it off when not needed.
Or perhaps there was a busy loop and the CPU was running 100% all
the time. Right now, you can hear a bit of noise during major chart
updates, but it doesn't seem too bad. Won't know for sure
until the boat is moving, I guess. Maybe we'll tow it down the street
and see what happens!

Mike
 
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