SWR Indication Varies

WA2SQQ

Just noticed something on my 6500, and I’m wondering if its something others have seen.  If I place the radio in TUNE mode (~10W) and look at the SWR, sometimes I can see it jump around, very slightly. Like from 1.2:1 to perhaps 1.3:1 However, neither the SWR meter on my ACOM 1000 nor an external SWR meter show any change.

I’m thinking that perhaps during one of the past updates (v2.x) the display resolution of the on-screen indication may have been changed – such that I’m right on a transition point and the display bounces back and forth. I also thought that it might be a problem with the relay that switches between the two antenna inputs.

Stan VA7NF

The lower the transmit power the more sensitive the reverse power is to other sources.  Are there any large local signals?

Bill -VA3WTB

I see it too, was just looking at it. Looks not to be a problem. What it looks like to me is it is very sensitive.

WX7Y

on my 6700 running 3.28 using the AT-Auto antenna tuner I see NO SWR jumping here on the Radio SWR meter, or on the WaveNode Power meter reading before and after the AMP/Tuner which I monitor here Remotely, It may be different with a SWR of 1.2 - 1.3 but for 1.1 which I have here there is no changes. 
WX7Y

Warren Gaspar

I have a similar problem during xmit. The SWR is 1 to 1 then climbs to 2.5 during an FT8 xmsn on 80 and 160 meters. Lower power seems to negate the problem. It

WA2SQQ

I would expect to see a slightly different SWR when you're measuring it at different points along the cable. Last winter I had a problem while running ft8 similar to the one mentioned here. That turned out to be a bad relay in the remote antenna switch. If you running more than a hundred Watts and you may have a high SWR I suspect that's why the relay contacts may have failed. my observation is just that this isn't causing me a problem but I was curious.

Logan KE7AZ

I had a similar issue when running high power. I found that a tree branch had come in contact with the antenna. At 100 watts, no problem. However, at high power things were fine until the branch started to smolder! Then the SWR started to climb. A little tree trimming and things were fine, again. Logan, KE7AZ

Stan VA7NF

Warren,
What you are describing is typically a ferrite core (balun or current choke) heating up, often when the swr is fairly high

WA2SQQ

No, because I'm seeing it on several bands (different antennas), even running only10W.