Firestik Firefly

[Mr Mac]

I have a 4' Firefly on the back of my Jeep Wrangler that does a good job for me. I was able to get the SWR (as read on the radio itself) down 1:1 on 1 and 1.65:1 on channel 40. The issue was that initially I had about 1.25:1 on 40 with the little rubber cap off the tip. When I put the tip back on the SWR slid up to 1.65 and then back down with it off again. I did make sure the adjusting ring was locked down so I know it wasn't that that moved. Why would it change with a piece of rubber on the end? I can't run without it as I tend to smack the occasional tree branch when roaming in the woods.

[Radar-DLDN]

Any object near or touching the antenna will affect it. Firestik does specify in their instructions that you need to have the cap on when testing the SWR and this is why.

Since you probably won't get a perfect match across the entire band try to get a 1:1 match on the frequency you will use most (probably 19) and as long as it is lower than 2:1 across the band you will be fine. If you can get it under 1.5:1 all the better.

Sent from my HTC Thunderbolt.

[Mr Mac]

When out on the trails we use Ch 24 more than anything else and she sits at about 1.4:1 so I'm very happy with the results I've gotten.

[ltdoc]

I have no idea why that little cap would make such a difference but it does. As you have the thing SWR set now it isn't bad so I'd also recommend just leaving it alone.
I wonder what that cap is made of. Plain plastic shouldn't really affect things much, some sure, but it seems like they'd select another cap that doesn't affect things. Oh well...
- 'Doc

[Mr Mac]

I would think that the cap itself would be the same plastic/rubber material used for the entire antenna and be pretty much invisible to the RF but... As I stated before, it all works well with it on so no need to fix what ain't broken. I was just hoping someone could explain why.

[MDYoungblood]

I have seen it happen and for the life of me I don't know why. One reason I am not a big fan of FireStik Antennas. I am guessing it squeezes the windings at the top tighter together. I have had some luck in warming up the cap before putting it back on, it seems to help.

3's

Greg

[Lonestar]

Any capacitance at the end of the antenna [even a plastic/vinyl end cap] will affect its tuning. 1.65:1 SWR is, in itself, not bad. Run it as-is; periodically check the SWR and if it changes, investigate.

[fourbyfour]

the cap isn't required. I read that somewhere before.

I test my SWR with the cap on.

[Mr Mac]

the cap isn't required. I read that somewhere before.

I test my SWR with the cap on.

When you're out in the woods and there are low hanging branches, the cap is certainly required to keep things from moving around!

[fourbyfour]

the cap isn't required. I read that somewhere before.

I test my SWR with the cap on.

When you're out in the woods and there are low hanging branches, the cap is certainly required to keep things from moving around!

In that case yes, it would be. For the antenna to function, no it's not required. As already stated, the tip should be on when testing SWR. Here's the doc from firestik's site [Please login or register to view this link]

[Mr Mac]

Thanks for the link! I actually found all that out (including a video) after I first posted this thread. The goon news is, I also determined the ground I had between the coax shield and the Jeep body was non-existent and once I [Please login or register to view this link] it I got my SWR down to 1:1 across the board!

Mac

[fourbyfour]

How did you run the ground? What cable/stud/mount are you using?

[Mr Mac]

I apparently posted the wrong link...my bad! [Please login or register to view this link] is the correct link for the fix.

Mac

[795]

The cap is rubber material which slides over the top. The SWR adjustment is like a screw/flat top which turns out to adjust the swr. I have a 5 foot model which I was going to use in a experiment but haven't experimented yet. One of those dipole adaptors where you can screw one stick in each end and use as a rotatable dipole
795/DOCTOR