SWR higher on SSB

[robertwbob]

i got a q6666 and no matter what mobile or base high swr. disabled swr used my reliable meter antennas are right. but go back to internal vswr and reads high and stops transmitting. its worked 8 months in my esclade just fine with vswr meter shut off. wish they left internal vswr meters out of radios

 

[paulears]

Come on guys - join the dots here. Meters are designed to work on AM or FM. Any form of disjointed or not continuous RF does very strange things (as do power meters) Set you radio to digital, and the pulsed RF stream makes the meter misread. So does SSB, because the carrier has been suppressed and the other sideband. Meters can be designed to read accurately, but few people have them. The reading you get on FM is the correct VSWR. The higher (or lower) reading on SSB is RF at the same frequency, measured less accurately. That's it. The continuous nature rather than peak audio power is the vital bit for measuring the match. Chopping the signal up does not have any way to change the VSWR. It's like old VU meters on tape decks back in time - they read very poorly when certain things (like drums) were involved. Metering systems need designing for what they are measuring.Few analogue meters read SSB or data signals well.

 

[Backwoods40]

Update - Found that if I key up with the external swr meter connected, the radio doesn't throw an error.
Thought I would throw that out there as an FYI if anyone else is troubleshooting the same issue.

 

[paulears]

Then something is wrong. Adding a meter should have no impact on the radio, unless the meter and short cable are changing something. Id put a dummy load on the transmitter and check that also produces a no fault condition. Sounds like an antenna fault to me.

 

[robertwbob]

Then something is wrong. Adding a meter should have no impact on the radio, unless the meter and short cable are changing something. Id put a dummy load on the transmitter and check that also produces a no fault condition. Sounds like an antenna fault to me.

was thinkin same but usually when i post i get shot down

 

[niceguy71]

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.

as far as I knew you adjust the SWR / antenna... always using AM and when it's good that's it..... after it's set, use the radio on AM FM or SSB and it should be all set?... I know you said you would need an expensive meter to test sideband ( I'm amazed you have one PRCGUY )

but am I mistaken? once the antenna swr is set, it's done????

I understand the original poster Backwoods40 is having a SWR warning problem on the 6666 PRO radio that radio puts out over a 100 watts on SSB so I'm sure the radio meter is going to spike and do all kinds of crazy things... so as WSAC829 said.....just disable the warning feature it seems to be a bug in these radios..... crazy to put a warning feature on a radio with that kind of power......
most of the 5555 N II radios seem to be set from the factory at a SWR warning of something VERY high like 5:1 and you need the computer and cable to change it... ...I never understood why they did that... but now that I think of all that power on SSB I'm sure that would give the warning feature fits!
Backwoods40 I may be wrong.... but if you have a separate SWR meter I would make sure it's as good as you can get it .... under 1.9 .....and disable the warning feature and enjoy the radio

 

[prcguy]

as far as I knew you adjust the SWR / antenna... always using AM and when it's good that's it..... after it's set, use the radio on AM FM or SSB and it should be all set?... I know you said you would need an expensive meter to test sideband ( I'm amazed you have one PRCGUY )

but am I mistaken? once the antenna swr is set, it's done????

I understand the original poster Backwoods40 is having a SWR warning problem on the 6666 PRO radio that radio puts out over a 100 watts on SSB so I'm sure the radio meter is going to spike and do all kinds of crazy things... so as WSAC829 said.....just disable the warning feature it seems to be a bug in these radios..... crazy to put a warning feature on a radio with that kind of power......
most of the 5555 N II radios seem to be set from the factory at a SWR warning of something VERY high like 5:1 and you need the computer and cable to change it... ...I never understood why they did that... but now that I think of all that power on SSB I'm sure that would give the warning feature fits!
Backwoods40 I may be wrong.... but if you have a separate SWR meter I would make sure it's as good as you can get it .... under 1.9 .....and disable the warning feature and enjoy the radio

A typical SWR meter is simply an RF power meter using two directional couplers with diode detectors to rectify the RF. The SET/SWR switch in SET mode selects the directional coupler that reads forward power to the antenna and the set knob allows you to calibrate that power level to some predetermined point on the meter. After doing a cal in SET mode, when you switch to SWR it selects the reverse directional coupler measuring any power from the antenna going back to the radio. Instead of the meter reading watts its scales are figured out for SWR.

So when you do the SET cal you are calibrating the meter for whatever power the radio is putting out on that channel at that moment so the meter will accurately read SWR at that power level and on that channel. If you vary power level after the cal then the cal is out the window and SWR readings are bogus, they will read higher SWR with higher power and lower SWR at lower power even thought the SWR is actually the same.

SSB has no carrier and relies on the amount of audio put into the microphone which will produce different levels of RF power. The only way (and its not really a good way) would be to feed a fixed tone into the microphone circuit to force the radio to put out a constant RF level on transmit and you might be able to make a somewhat accurate SWR reading if you cal and read SWR with that fixed tone into the microphone.

There are power/SWR meters that read power and SWR directly without needing any cal, but they have an internal PIC processor or some kind of computer that figures out the needed levels in real time. These meters can cost several hundred $$ and more than mosts CB radios, so you probably won't have that feature built into your CB radio.

 

[paulears]

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

No - the R in VSWR is ratio - so the reflected power at 4W is exactly the same ratio as the reflected power at 40W - it does not change. The amount of reflected power goes up, but so does the output - so the VSWR stays exactly the same. If the meter readings change the meter is faulty or just poorly designed. If you look at the Bird meters, the ones many aspire to but cannot afford, they use a little insert that you rotate through 180 degrees to measure forward and reverse - the point being that one component is used in forward and reverse, so there are no errors. Other designs with switches have two devices that need to be electrically identical, and most are not. They try to measure VSWR over a wide power range and fail to be linear - which gives rises to changes in the VSWR reading that are not actually there in real life.

 

[prcguy]

No - the R in VSWR is ratio - so the reflected power at 4W is exactly the same ratio as the reflected power at 40W - it does not change. The amount of reflected power goes up, but so does the output - so the VSWR stays exactly the same. If the meter readings change the meter is faulty or just poorly designed. If you look at the Bird meters, the ones many aspire to but cannot afford, they use a little insert that you rotate through 180 degrees to measure forward and reverse - the point being that one component is used in forward and reverse, so there are no errors. Other designs with switches have two devices that need to be electrically identical, and most are not. They try to measure VSWR over a wide power range and fail to be linear - which gives rises to changes in the VSWR reading that are not actually there in real life.

No, I'm talking cheap SWR meters that have a cal knob and CAL/SWR switch. They are only accurate at the power level you did the cal, raise or lower the power after the cal and the displayed SWR will change all over the place. Yes the ratio of forward and reflected power are always the same at different power levels but cheap SWR meters do not measure or display the ratio, they display forward and reflected power in a custom scale calibrated in SWR and only accurate after a cal.

 

[Backwoods40]

Update - Found that if I key up with the external swr meter connected, the radio doesn't throw an error.
Thought I would throw that out there as an FYI if anyone else is troubleshooting the same issue.

Scratch that. It worked for a day, then started throwing the same error.
I'm done troubleshooting this.

On standard AM, I'm consistently talking to base stations 30 to 50 miles out. Good group of guys that are on just about every night.
On side band, I've talked to Wales, Ireland, Mexico, Italy, and the opposite side of the country (Arizona/California/Washington).

It may be an incorrect reading from the internal swr, it may not, but regardless - I'm hearing and being heard, so I'll keep doing what I'm doing.

 

[niceguy71]

Scratch that. It worked for a day, then started throwing the same error.
I'm done troubleshooting this.

On standard AM, I'm consistently talking to base stations 30 to 50 miles out. Good group of guys that are on just about every night.
On side band, I've talked to Wales, Ireland, Mexico, Italy, and the opposite side of the country (Arizona/California/Washington).

It may be an incorrect reading from the internal swr, it may not, but regardless - I'm hearing and being heard, so I'll keep doing what I'm doing.

So is the Sirius 5000 any better than the fire stick or not as good??????

 

[robertwbob]

So is the Sirius 5000 any better than the fire stick or not as good??????

Id say its not grounding properly

 

[Backwoods40]

So is the Sirius 5000 any better than the fire stick or not as good??????

For local, it does do a bit better, but I don't think it's worth the upgrade if local is all you're interested in. (keep in mind, the firestik is hard mounted and better grounded - a firestik on a mag mount would be far inferior).
For dx, it is definitely much better and is worth the upgrade if you want to talk skip.

It also has a MUCH wider frequency range than the firestik. My swr on the firestik was 1.2 to 1.4 on D band (standard CB) and I could use it on the top half of C band and bottom half of E band if needed. (roughly 26.75 to 27.65mhz) So the firestik would have to be re-tuned for each band if you want to use C or E.

The Sirio doesn't need retuning. It can be used on 24 to 30mhz once tuned to CB band.
Of course, on different bands, you could tune it a little better, but it really isn't necessary.
If you don't have your ham license, the other bands don't matter anyway.
Unless of course you want to use the rest of the 11 meter freeband channels (24.265 to 27.995)

The firestik being hardmounted makes a huge difference as well. Although the Sirio performs exceptionally well, it's on a mag mount and the slightest movement affects signal.
If I move it a few centimeters in any direction, swr can swing as much as .5 so once you tune it, it would be best to leave it where it is rather than removing it or moving it around. The Sirio 145 mag mount is secure and doesn't move on its own.

Those that have said it's best to hard mount center mass are correct, but mag mounts serve their purpose.

 

[niceguy71]

For local, it does do a bit better, but I don't think it's worth the upgrade if local is all you're interested in. (keep in mind, the firestik is hard mounted and better grounded - a firestik on a mag mount would be far inferior).
For dx, it is definitely much better and is worth the upgrade if you want to talk skip.

sorry to hear that.. guess you should stick with that great FireStick. our resident expert on the Sirio 5000 Performer is SlowMover and he could give you some great advice if he wasn't in RadioReference temporary jail right now.

I don't know how the magnetic mount would be a lesser ground plane than the FireStick .... you said for local the Sirio is a bit better and you said Sirio is better for DX. so the Sirio seems to have a good working ground plane.

but if it's only marginally better than the FireStick why bother with that huge Sirio and the magnet..... perhaps SlowMover will get a FireStick now too.

 

[Backwoods40]

but if it's only marginally better than the FireStick why bother with that huge Sirio and the magnet..... perhaps SlowMover will get a FireStick now too.

Not sure where you got the idea that it's "marginally better".
I did say it's slightly better with local contact, but again, the firestick is hard mounted and well grounded.

The Sirio is FAR superior as far as dx contact and a much wider range of frequencies.
I am able to use the full 11 meter band and get excellent rx on both 10 & 12 meter without having to re-tune the antenna.

I already know what SlowMover would say. lol - Throw the magnet in the trash and drill a hole in the truck.

But yes, if the only thing you're interested in is talking to guys around town, the firestik works great.
I enjoy all the extra contacts I'm able to make from countries around the world, so I'll stick with the Sirio.

 

[robertwbob]

Not sure where you got the idea that it's "marginally better".
I did say it's slightly better with local contact, but again, the firestick is hard mounted and well grounded.

The Sirio is FAR superior as far as dx contact and a much wider range of frequencies.
I am able to use the full 11 meter band and get excellent rx on both 10 & 12 meter without having to re-tune the antenna.

I already know what SlowMover would say. lol - Throw the magnet in the trash and drill a hole in the truck.

But yes, if the only thing you're interested in is talking to guys around town, the firestik works great.
I enjoy all the extra contacts I'm able to make from countries around the world, so I'll stick with the Sirio.

every sirio ive encountered is superior to most.
my 2008 base antenna blows my a99 out of the water.its survived extremely hard winds 2 years running