Need Input on SWR Readings

[l3loodred]

Any ideas on why your swr readings on BOTH 40 and 1 drop or increase together? It was my understanding that as you tune your antenna, your readings should converge, not drop or rise together..?

5' FS2 Firestik Antenna / Firestik Dome mount / Front-driver location, on the 4" protruding lip of an ARB bumper (ground verified via multimeter)

[javaman34]

Check your swr on channel 20, then channel 40, then channel 1. If channel 40 is higher than 1. Your antenna is too long, channel 1 higher than 40 antenna is too short. Any reading 3 or over is to high. You want to get as close to 1 as you can.

[l3loodred]

Right. My initial pull was around 2 on channel one (first read), and almost 1.3ish for channel 40, so I lengthened the top of the FS2 slightly. I expected to see my second set of measurements bring channel one's ratio-read down, and channel 40's read up, instead BOTH went down. My channel 40 read is screaming, solid 1 np. Channel 1 also falls just under 1.5. Granted, both reads can be seen as done; they both fall consistently under 1.5. But they both fall and rise together, the only eluding aspect here is getting both readings "as close as possible" as shown in Right Channel's video. Is there a hit taken to performance or quality in this scenario... where numbers simply drop, but are not close?

I'm curious about involving 20... do you think i'm missing something by tuning via spectrum ends only? Thanks for the 411 btw :cheers:

[javaman34]

20 gives you a base to go off of. If it falls well below 3, you should be fine. On mine 20 is at 1.25, 1at 1, and 40 is at 1.5

[Bob]

Both went down because the antenna was also slightly too short on channel 40. Now you get a perfect 1:1 on 40, so the antenna is now the correct length there. It is still slightly too short for channel 1 with SWR of 1.5:1.

If you lengthen the antenna a bit more, ch 1 will get better and ch 40 will probably get a little worse. As you said, below 1.5:1 it isn't very important anyway.

The easiest thing to do generally is tune for minimum SWR on ch 20. That is mid band. Then just check that SWR is less than 1.5:1 on ch 1 and 40. If it isn't, then something is wrong, or you have a very short antenna (with a good loading coil) which is going to have a narrow bandwidth.