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5teve
15th February 2008, 09:11 AM
Hi Guys

i have Navman ma7270 27mhz marine radio plus a 2.4m navman antenna and the radio has been working and picking signals up from k's away... until the last 2 trips.. last but one trip volume kept going real low but signal of the reception was still showing strong. people could hear us transmitting. last trip nobody could hear us and we were not getting much in the way of signals coming in.. unusual for the area at that time of day (ocean reef pm)

i cant put my finger on whether its the antenna or the radio... both are 2 months old and like i say have been working great!

have you guys got any ideas?

thanks in advance as usual

Steve

waynep
15th February 2008, 02:54 PM
A simple check you can do yourself is the volts to the radio - if you can measure volts across the power plug into the radio with the radio plugged in ( you might need to take the cover off the plug so you can get at the pins )- it should be 12V or above on both recieve and transmit
After that I'd suggest you need to get someone to do a VSWR check of the antenna, as a first port of call ( excuse the pun ).
If its neither of those then sounds like a warranty job on the "brick" itself.

pk.hoarder
17th February 2008, 07:11 PM
Steve

a few things to try, you my have checked some of them already:

- check if the antenna is loose where it mounts onto the base. Should be clean and dry underneath when you unscrew the antenna element from the base.

- check the coax from the antenna base back to the radio. Coax dosn't like sharp bends or stretching. It can be difficult to give the coax a nice curved path, especially from the bottom of the bracket. If the antenna took a hit on one of the trips it may have pulled the bracket and damaged the coax.

- if you can, plug a different antenna in and see how that goes

- don't transmit without any antenna connected, 27M sets (older ones, maybe yours is better than this) used to destroy their output stage if they were operated without a load (i.e. antenna or dummy load).

- if none of those then I'm with Wayne, back to the shop...

Good Luck