Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: Jeep Wrangler 2M Range Issues  (Read 8036 times)
KD9FGI
Member

Posts: 8




Ignore
« on: April 03, 2016, 08:38:39 AM »

Hello all,

New to HAM, just received my license in January. Since then I have setup a Kenwood 710g in my 2005 Wrangler but appear to be having issues with getting decent range for 2m. My setup is:
- Kenwood 710g, direct wired to aux battery
- Larson Dual band 2m/70m antenna, NMO mount
- Terraflex taillight mount, drilled out for NMO. Removed powder coating and have verified continuity of zero between mount and body

I have tested SWR, all bands are ok, not perfect but below 2. I have used the 70M band to hit repeaters fine in the Chicago area and appear to have decent enough range. The 2M is the problem, I can't hit digipeters for APRS unless I am right near them, less than 2 miles.

Wondering if the groundplane for the terraflex mount is not large enough to really get range out of this antenna. There is also potential the coax from the antenna is  not great so I could replace that. Struggling right now with the right path forward.

If anyone is in Chicago area and has an antenna analyzer I would really appreciate that, could really help.

Other thoughts?

Thanks much
Kevin
KD9FGI
Logged
W8JX
Member

Posts: 12052




Ignore
« Reply #1 on: April 03, 2016, 11:49:58 AM »

If you are serious about performance on 2m you need to scrap tail light mount. Even a simple 1/4 wave on roof would out perform it. If roof is not metal you could put a metal plate or counterpoise in head liner beneath it. If you go topless you could mount it on top of roll bar. It is important to get antenna at least 1/4 wave from metal objects in radiation plane. Companies that dream up tail light mounts for easy installation do not even consider how it will work in certain applications. For HF the car body does not have much impact because of its size relative to signals wave length. On VHF and UHF it is a different matter. I want to also add that I used a Hustler 5/8 over 1/4 wave collinear on a bumper mount on a Suburban for many years with good results. I think it did so well because the 5/8 wave part of antenna was fully above roof line. It performed MUCH better than a simple 5/8 on same mount.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
KD5BVX
Member

Posts: 106




Ignore
« Reply #2 on: April 03, 2016, 01:07:39 PM »

If you are serious about performance on 2m you need to scrap tail light mount. Even a simple 1/4 wave on roof would out perform it. If roof is not metal you could put a metal plate or counterpoise in head liner beneath it. If you go topless you could mount it on top of roll bar. It is important to get antenna at least 1/4 wave from metal objects in radiation plane. Companies that dream up tail light mounts for easy installation do not even consider how it will work in certain applications. For HF the car body does not have much impact because of its size relative to signals wave length. On VHF and UHF it is a different matter. I want to also add that I used a Hustler 5/8 over 1/4 wave collinear on a bumper mount on a Suburban for many years with good results. I think it did so well because the 5/8 wave part of antenna was fully above roof line. It performed MUCH better than a simple 5/8 on same mount.

When I read his post earlier I assumed he has a soft top on the Wrangler.  If that assumption is correct, a roof mount is not possible.  You also mentioned if he drives with the top off then mount it on the roll bar and I'm not saying that wouldn't work but he would have to remove it and replace it every time he put the top on and took it off.  Not everyone can roof mount an antenna; while that may be the best option, many times hams have to seek other methods for their install (I did on my previous vehicle).  

To the OP, I would suggest mounting the antenna up front on one of the fenders via some type of mount and see if that helps.  It won't be perfect but it will be better than the tire mount, I'm sure.  Also, you suggested the coax may be a fault so when redoing the mount you could get new/better coax, too.  
« Last Edit: April 03, 2016, 01:10:11 PM by KD5BVX » Logged

Mark
KD9FGI
Member

Posts: 8




Ignore
« Reply #3 on: April 03, 2016, 02:28:17 PM »

Thanks, few clarifying things:
- Yes it is a fiberglass hardtop and it will be removed in 3 weeks for a soft top
- I do take the soft top off during summer so I can't do a roll bar mount
- The current antenna is quite a ways above anything metal currently, it extends about 2" above the fiberglass top
- It is not actually a tire mount, it mounts to the taillight. This is an example:
 http://noliberty.com/antenna1.jpg

That is not my jeep but very similar. I have the uhf/vhf on the left side and a CB on the right side.

I can look at a front mount, was trying to avoid it but would be willing to give it a go.

QQ, What is best way to test coax for loss? Any other ways to test antenna without using an analyzer? I have a SWR and power reader.

Thanks
Logged
KD5BVX
Member

Posts: 106




Ignore
« Reply #4 on: April 03, 2016, 02:39:46 PM »

Sorry for the misspeak about the tire mount; was envisioning third brake light mount (as I've seen some done) and said tire some some reason.  Turns out I was wrong anyway; the picture helps get it through my thick skull.  Not sure why you are having trouble with the antenna setup but the coax could be the culprit. 

I would be curious to know if moving it to a mount on the front made a difference; one of the fenders or whatever.  I keep thinking K0BG will pop in here with an idea. 
Logged

Mark
W8JX
Member

Posts: 12052




Ignore
« Reply #5 on: April 03, 2016, 03:35:37 PM »

If it was coax 70 cm would not work well either but OP said no problem. It is either antenna location or antenna itself. Also due to crash/roll over standards I am pretty sure it has a frame inside fiberglass top so I would not call it RF neutral by default.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
K5LXP
Member

Posts: 5226


WWW

Ignore
« Reply #6 on: April 03, 2016, 04:14:11 PM »

I can't hit digipeters for APRS unless I am right near them, less than 2 miles.

What about 2M repeaters and active simplex channels?  I get that maybe APRS is your primary goal but maybe the problem isn't your antenna but the i-gates or whatever APRS stations you're accessing.

I find it hard to believe range would be so severely limited on 2M and not 440.  I would more exhaustively test the setup to determine where the problem is.

Mark K5LXP
Albuquerque, NM

Logged
KD9FGI
Member

Posts: 8




Ignore
« Reply #7 on: April 03, 2016, 05:30:35 PM »

Interesting. I don't actually know although can work to see. I have found that two separate i-gates required me to be very close to register.

How else would you test the setup? I think I need to connect with some folks in the Chicago area as this is my first radio and I am still learning a lot. Needless to say there is also a question about my skill (or lack thereof) and the setup.

Logged
KF5QIU
Member

Posts: 12




Ignore
« Reply #8 on: April 03, 2016, 05:44:55 PM »

I did a larsen 2/70 NMO mount hood mount.  I have no problems hitting a repeater 20 miles away.  I may provide a better ground plane than a rear mount.
Logged
N8EKT
Member

Posts: 574




Ignore
« Reply #9 on: April 03, 2016, 05:53:07 PM »

The Larsen NMO 270 is a center loaded half wave on 2 meters so it really doesn't care about a groundplane I've used NOTHING but the open coil version for the past 20 years without any issues

You may need to move it away from the body and front Cowl mounted may be the fix
Logged
K5LXP
Member

Posts: 5226


WWW

Ignore
« Reply #10 on: April 03, 2016, 06:54:12 PM »

I have found that two separate i-gates required me to be very close to register.

Point being, i-gates are often a station at someone's house.  The antenna could be just a vertical on a rooftop.  At such a low height, simplex range to a mobile is limited to single-digit miles.

In the flatlands you can expect 20-30 miles of range from a repeater in a good location.  If you can get that, then your setup is working as well as can be expected.  Maybe not optimum, but it would take a serious defect (not just antenna proximity to the vehicle) to cause the severity of range reduction you observe.  The fact 440 seems to work tells me it's not the antenna. 


Quote
there is also a question about my skill (or lack thereof) and the setup.

That gets my vote.  Not to beat you up but it appears you don't have enough data to make a conclusion.  The advice you're being offered here is sound based on the premise of installation optimization but the improvement of 3, 6 or even 10dB isn't going to change much in terms of your range or communications effectiveness for most purposes.  The first thing I would try would be to go through a list of repeaters in your area and see which ones you can access at varying power levels.   Some repeaters are better than others or may have voting receivers located about the area but in general you will find out right away if you're having to use high power all the time to hit close repeaters, or there are a number a fair distance away you can hit even on low power.  Simplex contacts can be telling too but that's harder, because the other station location, antenna and geography can be quite varied.  Another experiment to try is a temporary antenna located on the hood, cowl or windshield frame and swap between the antennas to see if that makes any difference.  Bottom line, try something besides the one mode and one antenna, and see how far you get.  My gut feel is you will find your antenna is working OK.


Mark K5LXP
Albuquerque, NM

Logged
KD5BVX
Member

Posts: 106




Ignore
« Reply #11 on: April 03, 2016, 07:29:01 PM »

If it was coax 70 cm would not work well either but OP said no problem. It is either antenna location or antenna itself. Also due to crash/roll over standards I am pretty sure it has a frame inside fiberglass top so I would not call it RF neutral by default.

Good point. 

OP - try hitting some repeaters around the area and see if you can make some contacts on those.  Find out where the repeaters are located so you can judge how far away from them you are and ask the other station you are talking to for a signal report (full quieting, noisy, static, how staticky, etc.).  This will give you a better idea.  As mention, i-gates aren't the best test; there is one here that doesn't have good range from my mobile (sometimes <2 miles depending on where I am) but I can hit standard (good quality) repeaters 30 miles away easily.  So you might want to do this test first, before making any changes to your setup. 

Be sure to keep us posted.
Logged

Mark
KD9FGI
Member

Posts: 8




Ignore
« Reply #12 on: April 04, 2016, 08:39:53 AM »

Quote
Good point. 

OP - try hitting some repeaters around the area and see if you can make some contacts on those.  Find out where the repeaters are located so you can judge how far away from them you are and ask the other station you are talking to for a signal report (full quieting, noisy, static, how staticky, etc.).  This will give you a better idea.  As mention, i-gates aren't the best test; there is one here that doesn't have good range from my mobile (sometimes <2 miles depending on where I am) but I can hit standard (good quality) repeaters 30 miles away easily.  So you might want to do this test first, before making any changes to your setup. 

Be sure to keep us posted.

Thanks! I will try that. I have been hitting two repeaters (both 440) pretty regularly but will get more specific and try the 144 repeaters.

Quote
Point being, i-gates are often a station at someone's house.  The antenna could be just a vertical on a rooftop.  At such a low height, simplex range to a mobile is limited to single-digit miles.

In the flatlands you can expect 20-30 miles of range from a repeater in a good location.  If you can get that, then your setup is working as well as can be expected.  Maybe not optimum, but it would take a serious defect (not just antenna proximity to the vehicle) to cause the severity of range reduction you observe.  The fact 440 seems to work tells me it's not the antenn

Fair enough, will check it out and understand your point on i-Gates.

Quote
That gets my vote.  Not to beat you up but it appears you don't have enough data to make a conclusion.  The advice you're being offered here is sound based on the premise of installation optimization but the improvement of 3, 6 or even 10dB isn't going to change much in terms of your range or communications effectiveness for most purposes.  The first thing I would try would be to go through a list of repeaters in your area and see which ones you can access at varying power levels.   Some repeaters are better than others or may have voting receivers located about the area but in general you will find out right away if you're having to use high power all the time to hit close repeaters, or there are a number a fair distance away you can hit even on low power.  Simplex contacts can be telling too but that's harder, because the other station location, antenna and geography can be quite varied.  Another experiment to try is a temporary antenna located on the hood, cowl or windshield frame and swap between the antennas to see if that makes any difference.  Bottom line, try something besides the one mode and one antenna, and see how far you get.  My gut feel is you will find your antenna is working OK.

Not beat up taken here, I am new and one of my goals is to learn so this is a good learning opportunity. I will start to try a few things and get back at it. Unfortunately work causes me to be a little challenged to test during the week so I may not be able to get on it again until weekend. Will let you all know what i find out.

Logged
KT4NR
Member

Posts: 548




Ignore
« Reply #13 on: April 04, 2016, 08:44:57 AM »

If you have a bull bar try mounting on that.

Also, the repeater test should be a good idea of how well things work. Do it static in your driveway and then driving around.

 Do you know the APRS iGate OP? If the iGate is at his house, call him see if you can try a voice simplex contact. Go from there.
Logged
KD9FGI
Member

Posts: 8




Ignore
« Reply #14 on: April 04, 2016, 08:54:21 AM »

Unfortunately I do not know them.
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!