High SWR When using a linear.

[Buick Mackane]

To top all the other crap iv'e had with this linear my anytone 5555 is now giving me a high SWR warning when i use it, Although only on high SSB voice peaks. My SWR is 1.2 (ish) My SWR stays constant at 100 watts on FM. It only happens on SSB like i said with high voice peaks, I had this problem with the anytone before using another antenna and without using a linear. Harmonics ?

[andymuza]

Doubt it will be harmonics but you may be getting some RFi into the cables. Try a few feritte clamps on the power cables, Patch Leads and Mic cable, in fact any cable that is connected the radio in any way.

[Buick Mackane]

Doubt it will be harmonics but you may be getting some RFi into the cables. Try a few feritte clamps on the power cables, Patch Leads and Mic cable, in fact any cable that is connected the radio in any way.

Its possible as i'm using a dipole in the attic and its right above my shack, Its been one of those days, Think i'll take up butterfly collecting

[listner132]

Best to check swr with an inline swr meter just to make sure your swr is ok and if it is then just turn off the high swr protection in your menu.

[163TM847]

This is a common fault with cheap Mosfet amps especially the KL203.

[Buick Mackane]

This is a common fault with cheap Mosfet amps especially the KL203.

Any way round it nick besides ramming it up their ass ?

[Buick Mackane]

And it is a KL203

[dt307]

Use a rig not from China with MOSFETs in it

Honestly the kl203s I have all hate China MOSFET rigs

Same supply same antenna same patch leads
Madison.grant.shogun.257.Benjamin.George. All good the 5555 .9900 keep giving high swr or holding the amp in tx u till magical smoke come from the rig

But swap out the kl203 for a b300p and will work with China or Italian or any thing else you feed it with

[Buick Mackane]

cheers for the info, i'll use my mark 1 lincoln see how that goes.

[jason]

I had this . Found my swr meter was patched in after the linear or before gave different reading .

[wa10]

That's normal,
with the meter after the amp your measuring vswr on the coax to the antenna, if the antenna is close to 50ohm with 50ohm coax and there is not much common mode on the coax braid you will have a good vswr,

with the meter before the amp you are measuring vswr on the coax from radio to amp, if the amplifier input matching is off you will have raised vswr,

the amps directivity also plays a role, the input & output are not totally isolated from each other,
high directivity gives decent isolation between input & output so input tune & output load don't mutually effect each other so much,

unstable operation can cause vswr issues on both ends of the amplifier, very few if any cb amps are unconditionally stable,

some are sensitive to what's connected to their input and will self oscillate with certain loads or patch lead length,
you unkey and your amp is stuck in TX, even with the rig off its still putting out power & vswr is in the red,

changing patch lead length on amps that are sensitive to what's feeding them can stop the oscillations.