I have purchased a GPSmap 188c and been unable to use it. It
causes tremendouse interference with my VHF radio. I've tried
all the obvious electrical fixes to no avail.

Does anyone have any experience with this?

Dwight

Dwight wrote:

I have purchased a GPSmap 188c and been unable to use it. It
causes tremendouse interference with my VHF radio. I've tried
all the obvious electrical fixes to no avail.

Does anyone have any experience with this?

No, Mine is OK. Did you install the ferrite isolators on the cables?

In article ,
(Dwight) writes:

I have purchased a GPSmap 188c and been unable to use it. It
causes tremendouse interference with my VHF radio

Interesting question. I just had the same problem. It occurred after I
temporarily removed for service another instrument (an Apelco combo
fishfinder/GPS) that takes NMEA output from my very old Garmin. The VHF began
locking in on Ch 70 and would not scan. Reception is otherwise clean on all
channels, however.

I suspect the fact that the Garmin temporarily is unterminated while the Apelco
is out for service. A ferrite gizmo on the Garmin didn't help. I also suspect
that I may be getting compressor or other electronic noise from my new AC/DC
fridge.

While I don't have a suggestion to help you I am glad to see the post and can,
perhaps, learn from the ideas offered you. This is 101 stuff: check the
antenna connections to make certain they aren't corroded or loose. A piece of
metal screening between the two units has been known to assist. Finally,
perhaps, there is a problem with the Garmin known to their tech support folks.
Joel Albert
Potomac, MD
))

I'm having the same problem. But over the weekend, I experimented by moving
the unit farther from the VHF radio antenna. That fixed the problem. If you
can't move it, you may experiment by wrapping a short length of metal
screening--perhaps 12"-- over the a portion of the VHF antenna near the Garmin.


That should not crimp VHF reception significantly.
Joel Albert
Potomac, MD
))

Jralbert wrote:

I'm having the same problem. But over the weekend, I experimented by moving
the unit farther from the VHF radio antenna. That fixed the problem. If you
can't move it, you may experiment by wrapping a short length of metal
screening--perhaps 12"-- over the a portion of the VHF antenna near the Garmin.


That should not crimp VHF reception significantly.

OTOH it might badly degrade it. I'd try a couple ferrite beads on the
VHF coax, one near the xcvr and the other near the antenna, plus more on
both the GPS coax and on its power/data lines. If that don't work put a
low-pass filter in the VHF coax to block harmonics.

73, K3DWW

In article , Vito writes:

That should not crimp VHF reception significantly.

OTOH it might badly degrade it. I'd try a couple ferrite beads on the
VHF coax, one near the xcvr and the other near the antenna, plus more on
both the GPS coax and on its power/data lines. If that don't work put a
low-pass filter in the VHF coax to block harmonics.

I did try the ferrite gizmos without luck. however, your idea to try a bunch of
'em sounds worth pursuing -- after Isabel goes on by.
Joel Albert
Potomac, MD
))