ALS-1306 & LPF 10/12m setting

[WM4CH]

I don't know if there is a hardware issue with my radio or if it is a particular issue with the ALS-1306 but just letting everyone know how I either fixed or compensated for a 10 meter transmit issue with the 700DLE MKII and the ALS-1306

The amp has a function that if it sees too much 11 meter signal it ceases amp operation automatically.

This was happening to me on a regular basis trying to use 10m. I thought I had an amp problem, and maybe I do, I don't know.

I was able to stop this problem by changing the LPF filter for 10m to the bottom of the 10m band at 28.000 instead of the default of 24.000. I guess that filters out the 11 meter signal that for some reason the radio is producing when in 10 meters.

Has anybody else seen this issue?

Could I have a hardware issue with the radio....again?
Could it be an amp issue with seeing 10 meters as 11 meters?

Why would there be 11m signal from the radio when on the 10m band?

Any ideas are appreciated.

[w9ac]

would there be 11m signal from the radio when on the 10m band?

Doubtful but you can verify the presence of a <28 MHz RF component with a general coverage receiver or a TinySA handheld spectrum analyzer.

https://www2.randl.com/index.php?main_page=product_info&cPath=16_16990&products_id=75961

If nothing is detected, it's probably time to contact MFJ/Ameritron for troubleshooting ideas.

Paul, W9AC

[w-u-2-o]

I was able to stop this problem by changing the LPF filter for 10m to the bottom of the 10m band at 28.000 instead of the default of 24.000. I guess that filters out the 11 meter signal that for some reason the radio is producing when in 10 meters.

The settings in BPF1/LPF (and BPF2) do not change the filter skirt points. All filters are third order LC filters and are not adjustable in any way.

What those settings do is to cause the firmware to select that (non-adjustable) filter when the TX VFO frequency is between the two frequency setpoints. By changing the low end setpoint from 24 to 28 MHz you have made no difference in the hardware's behavior when operating within 10M band limits.

Therefore something else has to have changed if the problem has gone away.

[WM4CH]

I was able to stop this problem by changing the LPF filter for 10m to the bottom of the 10m band at 28.000 instead of the default of 24.000. I guess that filters out the 11 meter signal that for some reason the radio is producing when in 10 meters.

The settings in BPF1/LPF (and BPF2) do not change the filter skirt points. All filters are third order LC filters and are not adjustable in any way.

What those settings do is to cause the firmware to select that (non-adjustable) filter when the TX VFO frequency is between the two frequency setpoints. By changing the low end setpoint from 24 to 28 MHz you have made no difference in the hardware's behavior when operating within 10M band limits.

Therefore something else has to have changed if the problem has gone away.

damn

I thought that fixed it but it did not and based on what you said, could not.

So I did some more trouble shooting.

On a dummy load everything is fine except the radio shows an SWR of 1.2 when it is in fact 1.0

On my 10 meter dipole ( which is a little long and needs a tuner ) , the amp trips off in SSB not in tune mode, sometimes, seems to be dependent on how close the tuner tunes to 1.0, if I fine tune the MFJ-998 it doesn't do it. If I have as 1.3 SWR or so, the amp trips off saying illegal 11 meter operation.

The radio shows a 1.2 SWR into the amp ( IC-7300 shows 1.0 ) when keyed which I know is usually very inaccurately low from testing I have done, but now seems to be 1.2 when in fact it is really 1.0. There seems to be a hardware issue with the SWR sensing. The forward power reading looks correct, the reflected power reading is usually way low, so something must have failed, like a reflected power op amp maybe, looking at the schematic. I have another thread about this issue.

maybe this radio reflected power issue is influencing the amp in some way I can't figure out or there are 2 problems with the radio. With the IC-7300 connected to the amp I can SSB a full 1200 watts on 10m on the antenna with the same tuner with no issues. So this entire thing must be something wrong with the 7000 DLE MKII and although I am not sure, it looks like a hardware issue once again when I thought it was a software / settings issue. I apologize for this being in the wrong section.

This used radio has been nothing but problems and I guess I need to send it back to Doug, again.

[WM4CH]

It now looks like it may be an RFI issue with the ANAN. I had a bunch of chokes on the antenna coax coming into the shack.

I took them off and put them on the coax on the radio and the issue appears to be gone.

It was worse on the low part of 10 meters intermittent on the mid section of 10 meters and almost non-existent on the upper portion of the Voice DX section.

I knew it didn't happen on the dummy load. I knew it didnt happen with the IC-7300

So someone had mentioned someplace to check for RFI and I get a lot of RFI in the shack on 10 meters with my cheap field strength meter.

So I put all the chokes on the coax coming out of the radio and poof. The issue appears to be gone.

Time will tell.

Thank you for the help and suggestions.

[WM4CH]

Just an update on what the problem was and how it was corrected.

It was an RFI problem, 10 meters was coming back into the shack via the 600 ohm ladder line from the 160 meter doublet.

When I disconnected the ladder line outside the house instead of just using the double knife switch inside the shack, the problem completely went away and no chokes needed anywhere.

[w-u-2-o]

Subtle! Well done, not an easy thing to find!

[WM4CH]

Subtle! Well done, not an easy thing to find!

The weird part is that I checked the ladder line several times with a field strength meter and did not get a higher reading. The highest reading was up against the ground strap coming into the shack ( also have a knife switch on the ground so I can isolate the shack from the world ) . Disconnecting the ladder line outside solved the issue, but the ladder line did not seem to be radiating according to the field strength meter, but it obviously was. Maybe it has something to do with ladder line length, I don't know.

So I am a bit confused, but happy I no longer have the issue.