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N8YQX
09-20-2010, 05:36 PM
I bought a used FT-890 recently, and to my surprise, it came with the automatic tuner option (ATU-2 tuner, making this radio FT-890AT). The tuner seems to work for lower frequencies, but not for the higher frequencies.

Here's what I know so far.

With the tuner ON, the radio showed very high SWR, even on frequencies with very low SWR. Meaning, on these frequencies, tuner ON = high SWR, tuner OFF = low SWR. To investigate further, I hooked up a 50-ohm dummy load. Here's what I found out. (For all bands, the SWR is 1:1 with the tuner OFF).

160m, 80m tunes OK, 1:1 SWR
40m tunes OK, but 1.5:1 SWR
30m tunes OK, but 3:1 SWR
20m and above, won't tune, shows high SWR

Based on this trend, I suspect some of the inductance (coil) are not engaging. My first thought is the relay for engaging the coil is bad, but I have not confirmed yet.

Has anyone ran into similar problems with this tuner?Thanks!

-Yohei (N8YQX)

NW2K
09-24-2010, 11:00 AM
Welcome!

I have not experienced what you are seeing with that tuner.

1. The tuner requires a minimum rf level. What output power level are you using for these tests?
2. Have you also measured SWR with an external meter? As I write this, not sure what good it will do....
3. Have you opened the rig and verified that the tuner was installed correctly (there are two coax cables running from the tuner to the main board, IIRC) and that the connections are good?

I'm sorry that I cannot be of more help....

KL7AJ
09-24-2010, 03:22 PM
I bought a used FT-890 recently, and to my surprise, it came with the automatic tuner option (ATU-2 tuner, making this radio FT-890AT). The tuner seems to work for lower frequencies, but not for the higher frequencies.

Here's what I know so far.

With the tuner ON, the radio showed very high SWR, even on frequencies with very low SWR. Meaning, on these frequencies, tuner ON = high SWR, tuner OFF = low SWR. To investigate further, I hooked up a 50-ohm dummy load. Here's what I found out. (For all bands, the SWR is 1:1 with the tuner OFF).

160m, 80m tunes OK, 1:1 SWR
40m tunes OK, but 1.5:1 SWR
30m tunes OK, but 3:1 SWR
20m and above, won't tune, shows high SWR

Based on this trend, I suspect some of the inductance (coil) are not engaging. My first thought is the relay for engaging the coil is bad, but I have not confirmed yet.

Has anyone ran into similar problems with this tuner?Thanks!

-Yohei (N8YQX)

Try it out on a dummy load and see if you get the same results

N8YQX
09-24-2010, 05:13 PM
Welcome!

I have not experienced what you are seeing with that tuner.

1. The tuner requires a minimum rf level. What output power level are you using for these tests?
2. Have you also measured SWR with an external meter? As I write this, not sure what good it will do....
3. Have you opened the rig and verified that the tuner was installed correctly (there are two coax cables running from the tuner to the main board, IIRC) and that the connections are good?

I'm sorry that I cannot be of more help....

NW2K,

Thanks for the feedback. I did try low and high power settings, but the result is the same. As for the connection, it looked OK, but the radio is quite old, so maybe the connection needs cleaning.

-Yohei (N8YQX)

N8YQX
09-24-2010, 05:15 PM
Try it out on a dummy load and see if you get the same results

The values (SWR reading) is into a 50-ohm dummy load. With the tuner turned OFF, it shows perfect 1:1 SWR.

-Yohei (N8YQX)

KE5MC
09-24-2010, 07:30 PM
Yohei,

Silly question and I donít know the operation particulars for an 890. Have you imitated a tuning sequence and hear the relays clattering to find the combination of L and C for lowest SWR? The information I found about the tuner (FC-800) is limited but looks like one that is mounted at the antenna, much like my SG-237. It will tune with RF applied and high SWR. An Icom AH4 I believe you have to send a tune control signal to the turner.

Mike

NW2K
09-25-2010, 01:02 AM
I think that the tuner has its own 31 channel memory and I am not sure how the data is stored/used when the band selector is changed. I think that there are a few paragraphs on the tuner in the operating manual. Please PM me if you do not have it already.

N8YQX
09-26-2010, 05:08 PM
Thanks for all the help.

With this particular tuner, there is the option to start tuning regardless of the SWR by hitting the START button. So, even if there are previous memory setting, I can over-write them with the START button (I think).

As for the actual tuner, I can hear the motor for the capacitors turning. I will have to operate it with the tuner open to see if both are turning. I don't remember if the relays are chattering or not.

Since I have the tuner out, I'll check the RF connection for any corrosion first.

-Yohei (N8YQX)

KD8NJ
10-11-2010, 06:44 PM
Yohei I have a 890at and I habe the same problem,sounds just like your problem. I got mine new about 95-96 great rig most the time I have good match so leave tuner off ,but in rain or snow I'm out of luck. If you solved the problem I would love to hear from you . Thanks 73 Tom KD8NJ

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