SWR higher on SSB

[Backwoods40]

So I got the new QT-80 and had a 3ft firestik on the rear passenger side of the truck cab, and everything was great.
Decided I need to upgrade the antenna, and put a Sirio P5K on a mag mount centered over the cab.

AM is fine, but now when I go to LSB, if I turn the power up to 13 or 14 on the dial, the swr reads 1.0 - If I go to 15 or higher, I get a high swr warning from the radio.
On the QT-80, Tx power settings go from 1-45. If I start speaking before the warning, SWR shows 1.7 and stays there as long as I'm speaking. Not sure if the radio automatically dials back power to protect itself, or why it drops.

On the firestik, it never gave me any warnings. Not sure what the difference is or what if anything I'm doing wrong.

Like I said, I can turn it all the way up on AM no problem. Any ideas?

 

[prcguy]

SWR is not dependent on or affected by power, unless you start arching something at higher power.

 

[wjm1129]

Sounds like you had a better ground on the fire stick and it was making a better connection.

 

[merlin]

SWR is independent of any modes. SSB typically has higher peak power than some other modes, so any reflected power will increase accordingly.

 

[prcguy]

Was the radio SWR meter calibrated like transmit in AM, turn knob until it reaches set then switch to SWR? Or does it just read SWR without calibrating?

 

[Backwoods40]

Was the radio SWR meter calibrated like transmit in AM, turn knob until it reaches set then switch to SWR? Or does it just read SWR without calibrating?

I calibrated using a separate meter which matches very closely to the meter on the CB.
Calibrated on AM of course.

 

[prcguy]

I calibrated using a separate meter which matches very closely to the meter on the CB.
Calibrated on AM of course.

For SSB you would need to recalibrate using a constant tone or whistle, then read SWR using the same tone or whistle. In AM mode you calibrated with about 4w carrier on a stock radio and that cal is only good with the same 4w carrier during the SWR measurement. When you go to SSB you are putting out upwards of 12w on a stock radio and that will make the SWR reading show much higher because the cal was done at 4w. Not to mention erratic SWR readings unless you put a constant tone into the mic.

 

[WSAC829]

According to another forum, the anytone 6666 pro (and rebranded QT80, etc) has a "bug" that causes this. The fix is simple, but it disables the internal SWR meter. Download and install the programming software, then disable the "swr protect" option. That should allow full power on SSB without any issue. It worked for others. Hopefully it'll work for you as well.

 

[Backwoods40]

Moved the radio to the sedan, same issue.
High swr if I try increasing power on ssb.
Rx is much better than the 3 ft stick, just need to figure out whats going on with this antenna. Oh well - back to it, I guess.

 

[WSAC829]

High swr if I try increasing power on ssb.

Try the "fix" I mentioned above.

 

[Backwoods40]

According to another forum, the anytone 6666 pro (and rebranded QT80, etc) has a "bug" that causes this. The fix is simple, but it disables the internal SWR meter. Download and install the programming software, then disable the "swr protect" option. That should allow full power on SSB without any issue. It worked for others. Hopefully it'll work for you as well.

Why would I want to disable built-in protection when there was no issue with the firestik?
Sounds like an issue with the antenna to me.

Perhaps you could point me to this other forum discussion you mention?

 

[Davidbt]

Why would I want to disable built-in protection when there was no issue with the firestik?
Sounds like an issue with the antenna to me.

Perhaps you could point me to this other forum discussion you mention?

I'm a couple of weeks away from installing mine with the Tram 3500. I'm going to be watching how your setup pans out.

 

[Backwoods40]

I'm a couple of weeks away from installing mine with the Tram 3500. I'm going to be watching how your setup pans out.

Definitely keep me updated with yours as well.

I'm just trying to figure out why it's triggering a warning to start with. SWR can be at 1.1, then I turn it up just a single notch, and it shows the high swr warning on the radio.

The thing is, on lsb, there's no carrier, so it shouldn't show anything if there's no sound going into the mic. It should only trigger the warning if swr is high while speaking.

BUT, if I figure anything out, I'll definitely update & let you know.

 

[Davidbt]

Definitely keep me updated with yours as well.

I'm just trying to figure out why it's triggering a warning to start with. SWR can be at 1.1, then I turn it up just a single notch, and it shows the high swr warning on the radio.

The thing is, on lsb, there's no carrier, so it shouldn't show anything if there's no sound going into the mic. It should only trigger the warning if swr is high while speaking.

BUT, if I figure anything out, I'll definitely update & let you know.

I did a Google search of the qt80 and 6666 pro and didn't come up with anything. I'm pretty technically illiterate, so take that with a grain of salt 🥴

 

[prcguy]

I don't think it would be accurate or even practical to test SWR in SSB mode without a very smart and somewhat expensive computer driven meter that can measure forward and reflected power simultaneously and calculate SWR at any power level or varying levels as in SSB. I have one but it costs a good part of what your whole radio costs. So it's probably best to use AM or FM mode and forget about measuring SWR in SSB.

 

[Davidbt]

I don't think it would be accurate or even practical to test SWR in SSB mode without a very smart and somewhat expensive computer driven meter that can measure forward and reflected power simultaneously and calculate SWR at any power level or varying levels as in SSB. I have one but it costs a good part of what your whole radio costs. So it's probably best to use AM or FM mode and forget about measuring SWR in SSB.

Thanks for the information @prcguy

 

[WSAC829]

Why would I want to disable built-in protection

Because it seems to be a bug in the firmware of the radio. Not an antenna issue. If you use an external swr meter i bet it doesn't spike.

Here is the link

 

[prcguy]

Because it seems to be a bug in the firmware of the radio. Not an antenna issue. If you use an external swr meter i bet it doesn't spike.

Here is the link

SWR will spike and be erratic on all but a few expensive meters in SSB mode, that’s just the way it works.

 

[WSAC829]

SWR will spike and be erratic on all but a few expensive meters in SSB mode, that’s just the way it works.

Not the built in meters on the AnyTones/Strykers/etc. On SSB my radio's show 1.0 and "jump" to 1.1/1.2 when i talk. I wouldn't call that erratic. These radios would be the Retevis HS4 (AT5555 clone), and QT40 (Ares II clone). I guess i never tried an external meter on SSB. Just AM when setting up my antennas.

 

[prcguy]

Not the built in meters on the AnyTones/Strykers/etc. On SSB my radio's show 1.0 and "jump" to 1.1/1.2 when i talk. I wouldn't call that erratic. These radios would be the Retevis HS4 (AT5555 clone), and QT40 (Ares II clone). I guess i never tried an external meter on SSB. Just AM when setting up my antennas.

If you put a T adapter on the radio then connect two 50 ohm loads to make a 25 ohm load, the radio SWR meter or external should read a 2.0:1 SWR. Try that in AM and SSB mode and let us know what happens. I would be surprised if it reads a constant 2.0:1 SWR on SSB.