April 19, 2009

FT897/857 Meter (G4LDS version)

Recently I upgraded my station to a FT897D, which like most rigs these days are fully menu controlled and can be operated via your PC.

To ensure that I can fully understand and operate the rig, I not only read the handbook (how many can say that!) as well as joined the yahoo FT897 group. Having read on the yahoo group about the FTmeter from LDG, I investigated further. The 897/857 has an output of 1mA to drive an external analogue meter. The LDG FTmeter is a 500µA meter in a box measuring 3.6W x 3.0D x 2.6H with a backlight that requires 10-14V @100mA. The meter comes with a 3.5mm mono plug on a one meter cable for connecting to the rig. (The meter is in series with a 10k trim pot). There is also an on-off switch and 2.5mm socket for the DC supply for the backlight. Cost of unit in UK = over £42! It can measure on Rx: S meter, discriminator, DC voltage or 1 mA calibration “signal”, on Tx: it can measure SWR, Power out, ALC or DC voltage: selectable via the rigs menu.

My version.

I decided to make a version without a backlight so I then purchased on e-Bay a 1mA meter for around £5-00 a nip to Maplin’s to buy a suitable case for around £3-50. I downloaded a suitable scale from the Yahoo group and glued over the original scale. Connecting the meter to the FT987, the menu allows you to generate a 1mA source to calibrate the meter (ie if using the 500µA meter, set to FSD using the pot). As you can see the attached picture my meter.

The meter I used has a black surround and the option of a backlight is not possible. However if you use a meter that can have backlighting (like the commercial version of this meter), then a 2.5mm DC panel mounting socket (Maplin JK10L)

plug 2.5 x 5.5mm long (L49ay)

a push on push off switch (N91ar)

backlight (PG77Jr) and a series resistor of around 270-500 ohms and cable is all that’s needed.



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