Need help trying to make the best within my constraints

[w9cll]

With a good antenna mounted on the roof you should do 15 miles with 100 watts. Just remember 11 meters is not line of sight and you may talk better skip than local. Tried talking "local" on 10 meters and with 100 watts into a good antenna I was barely making it 20 miles but had three stations out west come back and say I was 59 there. It's all about propagation.

 

[Nick23]

He wants a short antenna, sometimes we have hight issues. A little wil wilson will preform better than his current setup. Rx and Tx 15+ miles

 

[W5LZ]

I'm not a fan of shorty antennas and won't recommend one. All of them are at a disadvantage to start with no matter where they are mounted.
I do agree that mounting an antenna -beside- metal isn't the best idea in the world, but sometimes it's necessary. Any 'extra' height from the side of a vehicle to that vehicle's roof is pretty well a waste of time. It isn't that the thing is any higher, it's that it isn't 'shielded' or obstructed by metal, that's the biggy. Metal under an antenna has the least obstructive affect on that antenna's behavior. But, sometimes that's just not possible.
So, while the antenna's present location may not be optimal, it's better than nothing by a long shot. Not getting the 'performance' you want? Sorry 'bout that. And trying to use "range" as a measure of how well an antenna is performing on HF is ridiculous. Not too sorry 'bout that...
- 'Doc

 

[w9cll]

He wants a short antenna, sometimes we have hight issues. A little wil wilson will preform better than his current setup. Rx and Tx 15+ miles

Maybe, maybe not. A mobile setup is a compromise at best and nothing more. Can't have a long antenna then you have to work with that you got. As has been said range is not necessarily a factor for antenna performance on HF.

 

[M0GVZ]

Well the fact he's running a 100W amp suggests it might be.

 

[Nick23]

Let us know what you decide on...

 

[Chubaca]

Who tuned the radio? Sounds like they didn't work on the receive and the radio is essentially deaf.

Its an off the shelf radio. Only modification was to lower the DK for the amp.

All of the above are symptoms caused by your antenna installation from not being able to be heard to not being able to hear people to the randomly not transmitting. The latter is caused by common mode current on the coax, which is basically RF on the outside of the coax where you don't want it, getting back to the amp plus the fact the antenna is so close to metal.

I can do more than 15 miles with 4 watts and be heard as clear as day. How yours is working is exactly how I'd expect it to work with the antenna being installed where it is.

So you think the random "not transmitting" issue is common mode current? Im hoping its something related to the antenna and not an issue with the radio or amp.



I notice while tuning swr that when I "cal" the meter the needle will come up a little (after keying down) and then a second later it swings further to the right. It looks like the radio's SWR protection circuit is messing with things. Im getting under 1.5swr so I dont know why it would be doing this but I read another guy with the same radio that said his would go into "protection mode" over about 1.3SWR. Any way to disable this feature/circuit?



It looks like roof mount is pretty much my only option then. I think I can compromise by leaving the tail-light mount and coax so that I can run the 4ft fiberglass on the trails but then add a roof mount and just switch between the two depending on where im driving.

Would a 4ft whip of some sort work well on the roof? What would be a good one to get? What good options do wilson or sirio have for 4ft whips?

 

[M0GVZ]

but I read another guy with the same radio that said his would go into "protection mode" over about 1.3SWR. Any way to disable this feature/circuit?

You don't want to. There's a reason its there and that is to save frying the finals.

Would a 4ft whip of some sort work well on the roof? What would be a good one to get? What good options do wilson or sirio have for 4ft whips?

Sirio 3000 is about 4ft or thereabouts. But its a very flexible whip. Not quite sure why you'd have to swap the antennas on the trails. You can bend the Sirio whips over double and they'll spring right back. Mine has been hitting a tree at the end of my road at least twice a day plus going under all the low height barriers at drive thrus and car parks for nearly 4 years.

 

[222DBFL]

If you are going to do the 4ft whip thing, might as well get a sirio pl5000 performer and 145 mag mount. You won't be disappointed. It's worth the cost and the antenna folds down as well. Check out DNJ radio, there is some videos on there showing the antenna. This is JMO. But you are talking a couple more ft of antenna, it's not that much. And the increase should be noticeable with a roof mount, even a mag mount in this case, stay away from the k40 mag mount, they are junk IMO, and the Wilson's are hit or miss these days as well. The sirio line seems to be well constructed and of good quality. I know I keep preaching this, but I promise if you get a decent antenna up on the roof of that 4 runner, it will talk a lot further than it does now.

 

[Rick330man]

I've got an F150 and a late 1970s Archer/Radio Shack magnetic mount. This humble antenna has performed well for over three decades. My whip is only 32" long. I cut and tuned it so that my SWR is flat on channel 19. With a stock radio, this humble set up gets me 15 to 18 miles mobile to base, and that's talking to an unimpressive Archer/Radio Shack 1/2 wave Crossbow fiberglass base antenna (really a Shakespeare Big Stick sold by Radio Shack).

Were I to get a better mobile antenna and mount it at the same point, I can easily see a few extra miles range. Were you to stick a good antenna like a Wilson 5000 or a Sirio Turbo 5000, I suspect you'd likewise see much better results.

 

[222DBFL]

Yes on a ford f150, mount the antenna on the roof about as close to center as possible, some have better luck with antenna a bit more towards the rear of center. And yes the taller the antenna the better. The sirio 5000 is 6.5ft tall, is about as close to a 108" whip as you will get and have a great antenna. I am able to talk locally 50-70 miles consistently with my sirio turbo 5000 with the pl145 mag mount and using lmr240 coax. Double shielded coax helps with the mobile install as it keeps the rf in and the signal going to where it needs to, the antenna. I know numbers don't show that rg8x and lmr240 are much different, but it's the makeup of the coax and the shielding that's important. Good shielded coax will help keep stray rf away. I know it helped my install, that and keeping the coax from bouncing off my roof I use sticky backs and tie wraps and also 11 ferrite chokes that make over a foot of Coax chokes. All of these things have helped in the end and like I said I can talk up 70 miles locally from Orlando airport to Daytona beach area I have talked to me friend that has a good base and is able to talk back to me as well. It's cool to be able to talk this far, but I would venture to say a more realistic number would be 40-50 miles with a sirio 5000 setup right.

 

[hammer0630]

On my Tacoma I finally found an antenna that has a 20 inch base so the coil is above the roof and the antenna is 6 foot 4 inches long. It is also using a spring which helped bring my swr down to 1.3 because my swr was high and I needed to lengthen the antenna so the spring helped me out with that. ( This pic is was shot b-4 the spring was added ) I am also running a ground from the antenna mount to the frame of the truck. It does get out better in certain directions because of where it is mounted but I won't have anything on the roof even a magnet but I run a modded Galaxy 959DX and a KL203 amp and it receives and gets out great.