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Battery issues - FT-857 mobile with ATAS-120

 

I believe that the ATAS-120 and the FT-857 both need to be grounded to the same potential.? ?There is a 3rd, brown wire for the power connector on the FT-857 which, if I recall, serves the purpose to provide control to the ATAS-120.


73

KA0KAF
 

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The brown wire when connected to ground reduces output of the 857D to 20 watts automatically.

KA2HPG


On 5/22/2018 9:35 PM, Jeff Maxwell ka0kaf@... [FT-857] wrote:

I believe that the ATAS-120 and the FT-857 both need to be grounded to the same potential.? ?There is a 3rd, brown wire for the power connector on the FT-857 which, if I recall, serves the purpose to provide control to the ATAS-120.


73

KA0KAF

Virus-free.

marty duplissey
 

Actually the brown wire is a battery sense. It changes the power out to conserve battery when it is energized. The atas120 is controlled by a dc voltage imposed on the coax line. Less than approximately 9v go down more than 9v go up.?
N5KBP?
 

Yes, thank you.? Douglas Wyman was kind enough to remind me.? That is what I get for attempting to go straight from memory instead of visiting the manual before posting.

I do vividly recall that for the ATAS-120 to work well, though, that both the radio and antenna need to be at the same, lowest ground potential.

In some rare cases, if the radio is mounted in the cab of a truck and the antenna on the bed, and these are not at the same ground potential, they may not work well.??

I had mine, on my previous truck, mounted directly to the cab roof and the radio to the sheet metal inside the cab against the back.??

Unlike other radios, the FT-857 does not have a ground lug, and you may correct me if I am wrong here, and I am sure someone will, but the grounding comes from the mobile mount.??

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