roof hole ham antenna mount option questions

[troyboy162]

ive got a few questions for the group.

pl-259 mounts seem to be what the larger antennas are using rather then NMO. are pl-259 mounts suitable to just drill a hole in the roof like a NMO? they dont seem to be made with roof mounts in mind judging from the design.

given a PL-259 mount on a roof, will that be strong enough for a 50-60 inch antenna without ripping the sheet metal when the antenna is whiping around in the rocks?

how much will my roof rack mess up the signal? i plan to install the mount right in the middle of the roof. the rack isnt on often but when its on id likly be needing plenty of tx/rx range like in death valley. attached is pic to show how high up the roof rack will be on the roof mounted antenna

[4x4mike]

I'll have to respond tomorrow when I have more time. But really quick PL 259 is the name of the connector that goes into the radio, has nothing to do with the other end of the coax. Next you don't need an antenna that long. The roof rack won't mess up anything but just be in the way, this is why I went with a mag mount in front of my rack and behind my sunroof.

[CJM]

I really dont think thats a good idea to mount it there. I know mounting it to the roof itself is preferable but a 60in whip might stress the roof metal to much (toy metal is thin and flexy ya know) and I would be willing to bet the roof rack interferes with the signal quite a bit since the waves will bounce all over it.

[troyboy162]

yeah ive learned though searching that its a SO-239( female PL-259) this is the best looking one so far. another forum had a good idea to reinforce it with a thin plate to distribute the load better.
http://www.gigaparts.com/store.php?a...e&sku=ZCM-3D4M

[4x4mike]

Why do you want such a large antenna? I would suggest you find out what people are using in DV and see if they have the same needs as you. Second I would search for a radio that will output the amount of power you will need. Keep in mind you can push as much as 200 watts through an antenna depending on your radio settings, antenna and modulation.

If you want to use simplex with others wheeling you can get away with a 1/4 wave that is about 10 inches tall and a hand held with low wattage.

For me locally I can contact and transmit 250 miles with the 1/4 wave on repeaters in mountainous terrain. Depending on your area the repeaters can have selective use and aren't necessarily for your group for the entire weekend. Up here they are used for chatting but not for extended time. Groups and clubs that maintain the repeaters have scheduled usage and if you're "hamming it up" all weekend on it they'll have you move. From there you need to know where to go, pl codes and offsets.

I have a 5/8 wave antenna that is twice as tall than my 1/4 and it works the same 98% of the time. The 5/8 wave antenna has more gain than the 1/4 wave but has a larger radiation pattern so in some situations it can reach farther than the 1/4 wave.

HAM is a hobby and has some very complicated aspects to it. If you want you can find a cheap radio and antenna, memorize the answers and take the test. What is best is to learn about the hobby as well as how it all works and go from there.

If you want to drill a hole I'd get an NMO for thick surfaces. This will allow you to install a base plate that will help your grounding and make the mount a little more stable. With any large antenna you run the risk of it bending at the base and shortening it's life. Find a mount that will allow you to run different antennas for your needs. If I were you I'd get a $10, 1/4 wave and play with it for a while. From there you will know it's limitations, it'll give you a chance to learn your radio and you can practice making contact.

Your rack won't interfere with the antenna. I've got a Yakima rack, roof basket and cb antenna on my roof and it's all fine. Hell I can have 2 bikes on the roof as well and it makes no difference. I know it's HF and a little different but the local cop cars here have no less than 10 antennas on them. GPS, HF, UHF, VHF all kind of play nice from what I can tell.

I can bore you with a lot more on antennas if you'd like. It's because I've done a lot of research recently and didn't want to waste much time or money. FWIW I do not have my license but am on my third HAM book. I have a mobile 2m setup installed and in use but I mostly listen. My only transmitting has been for newbies with local (and some non local-sat in on a club meeting that was being held in Austin, Texas with my 1/4 wave) clubs on their round tables. I have a local club that has tests every month but I'll take it when I'm good and ready.

[troyboy162]

for dual band antennas with 5/8 on both bands they are in the 50-60 inch range. my cb antenna is 36 inches so it dosnt seem too long. im going to be working with 50 watts and the desert has some very long LOS range. i do plan on getting a 1/4 wave rubber antenna for woods runs. here is the best pic ive seen to describe antenna performance at a set power. im only interested in the antennas with fold over hinges at this point



what have you found in terms on the durability of the ham antennas? i have a firestick on a spring for my CB right now and that thing goes bezerk when im bouncing through the rocks. i am definatly concerned the high end ham antennas will not hold up.
right now im interested in these...
http://www.cometantenna.com/products...ID=4&childID=4

the SBB-1 looks like a good bang around antenna and the SBB-5 looks durable as well. the SBB-7 has the gain id like to have and a few jeepers have them

oh and you might as well just go take your test. i realize its not any kind of measure of ham knowledge but its so darn easy and then you can legally key up.

[4x4mike]

I have never heard anything bad about Larson antennas so thats what I went with. The mag mount I have has an NMO interface so I can attach many different antennas. When I started looking at antennas I was looking for a mount that would attach to my hood and have a fold down feature. All of them were quite expensive and not nearly as durable as I wanted. The owners manual for my radio also suggested roof top mount due to the amout of power that can be transmitted. It even said to transmit on the lowest power level when in parking lots and when there were occupants in the vehicle. Roof top it was.

After digging up some paperwork it looks as if my 5/8 wave is actually a 1/2 wave, sorry. I'm not sure why I thought it was a 5/8. My 1/2 wave (model W2/70B) is a dual band antenna and is attached to a Larson NMO2/70B CO. Both are shown in this link: http://www.larsen-antennas.com/docfi...bandVHFUHF.pdf
No need for a fold down feature as you can reach up there and unscrew it by hand.

I'm not a fan of fiberglass antennas, they are pretty heavy and I've shattered 2. A whip is the way to go. You can get a mount from Larson that looks just like the NMO2/70B CO and have a 3' whip in there and you won't even know it's there. The whip is stiff and quiet.

[mysticzt4r]

I use the comet sbb-1 daily and my sbb-5 for longer distance needs both are mounted on a diamond k400c mount.

[troyboy162]

what do you think about the SBB-1? i like it alot but its still pricey for what it is. im wondering if i could get away with a 2m 1/4 cheapo for both 2m and 70cm

oh and an update. one of the jeepers guys says hes taken the SBB-7 on all the rock runs and its still working well. ill find out soon but im thinking its probably very light weight for its length. maybe it wont sling around as bad as im thinking

[4x4mike]

The stainless whips don't whip around as much as a fiberglass antenna. I'd say the whip on my cb (Wilson lil wil) and my 1/2 ham don't deflect more than 8" and that's a stretch.