antenna help

[Joseph3402]

Hi all ! Been out the hobby 40+ years. This setup I'm doing is for hurricane // storms extra communications in short distance At my home , no car install. For now is an old cobra handheld , yes I know sad. But for a storm all I have to do is get out 2.7 miles to a troop laydown yard always setup in my area. Rubber duck works but only 1 mile the most. I setup in yard on a metal trellis 6' high a 4' firestick. Antenna tuned to 1.1 between 1 and 40 and gets out about 3-5 miles. For a handheld not bad. Grounded well : lighting and for rf grounding . Does well for what I need. But we / me always want more... Tried to setup mast 15' up. All grounds test good. Problem swr's now upper 3's . What happened to my 1.1 swr reading at 6'. Any ideas please. Not trying to keep up with the big guy's, just an extra means to get help after storms if needed.

[Windwalker]

Hi Joseph3402
Im sure you will get help with antenna issues but here are my thoughts.
First go with a radio other than a handheld. You dont have to go big but the chance of lightning even though you are grounded is greater.
Now That Firestick antenna doesnt have the best reputation plain and simple. They are hard to tune and have less than optimal receive.
If you just want to stick with the set up you are trying to put together then I suggest that the coax length might be a part of the problem. Possible connection problems like corrosion or not being screwed tight can cause major SWR problems. Moisture in the air can sometimes also cause a problem.
That said if it were me I would get another radio even if it was just a cheap mobile and maybe a 1/4 wave whip. That wont cost much but might make a world of difference.
Im sure others will have added good quality advice too !
Welcome to CBRT !

Windwalker

[Joseph3402]

MY question is // why my swr's increasing with antenna height ?

[Windwalker]

My guess without seeing it is the length of the coax.
Check for bends and kinks in the coax and tight connections.
If you have a Mulitmeter check the coax for OHMS.
Check to make sure the 2 conductors of the coax are not touching even the smallest amount.

[Bozo]

Hey @Joseph3402,

When you increase the height of your antenna, several factors can cause a change in SWR (Standing Wave Ratio):

1. Antenna Length and Height: The change in height can affect the impedance of the antenna. At a different height, the antenna might not be resonating as well as it did at a lower height.

2. Ground Plane Effects: When the antenna is close to the ground or mounted on a metal structure like a trellis, the ground plane effect can significantly impact the SWR. Moving the antenna higher up changes the ground plane effect, which can alter the impedance and hence the SWR.

3. Nearby Objects and Structures: At a higher elevation, the antenna may be influenced by nearby objects like buildings, trees, or other structures. These objects can reflect or absorb radio waves, affecting the SWR.

4. Cable Length and Type: The length and type of coaxial cable used can affect the SWR. Longer cable runs can introduce more loss and potential impedance mismatches.

5. Antenna Mounting and Connections: Ensure that all connections are secure and free of corrosion. Higher installations might expose the setup to more wind and weather, potentially loosening connections.

Steps to Diagnose and Fix the Issue

1. Recheck Connections: Ensure all connections are tight and corrosion-free.

2. Test with a Different Ground Plane: Try using a different ground plane at the higher height, or add a temporary ground plane to see if it affects the SWR.

3. Check Nearby Objects: Make sure there are no large metal objects or structures near the antenna that could affect its performance.

4. Measure Impedance: Use an antenna analyzer to measure the impedance at the feed point. This can help identify if there is an impedance mismatch at the new height.

5. Adjust Antenna Length: Sometimes, a slight adjustment in the antenna length can bring the SWR back down. This is because the antenna's resonant frequency might have shifted due to the change in height.

6. Check Coaxial Cable: Ensure the coaxial cable is in good condition and not introducing losses or impedance mismatches.

Additional Considerations

- Balun or Unun: Consider using a balun (balanced-to-unbalanced transformer) to help match the impedance and reduce SWR.
- Antenna Tuner: If the antenna is used primarily for emergencies, an antenna tuner might help achieve an acceptable SWR across the frequencies you need.

By methodically checking each of these factors, you should be able to identify the cause of the increased SWR and take steps to correct it.

Good luck and 73,
Bozo

[Joseph3402]

Thanks for the good detailed info.
Will go over all again. I used multimeter to check continuity on grounds but forgot after all these years to check coax for problems with the multimeter. Coax is very old and may not be able to work with the firestick. I just ordered some new coax and decent crimpers and fittings.
Also being a tinker , looking at making a dipole being a temporary setup. Don't have enough wire for ground radials. Only have 400 feet 10 gauge wire I don't really want to cut it up. Most what I read says 6 gauge.
Lots of rain the next few days but will give all a once over next week , time for new coax to come in.
See I wont be able to keep it simple and use my decades old equipment , in for an inch go for a mile...'s.
Thanks again.
Will have some results next week.
Could settle for 6' high antenna with my 3-5 mile range since it will reach the compound . But now I want more range.
I see were this is going... like my 70's setup.

[MDYoungblood]

A ground radial system will work if it is a ground mounted antenna but being 15ft up you will need to fashion a ground plane. Make 3 or 4 wires about 8.5 to 9ft long spread out equally from the base of the radiating antenna (where the antenna and mast meet). These wires can be at a 45deg angle or more to the ground, add some rope to be long enough to be used to support the mast ie: guide wires/rope. Check the SWR and move them in or out to get the best reading.

3's

Greg

[Joseph3402]

Here's were I'm at as of today. Firestick gave it to a neighbor...
Using what I had (wire...) and $24 for a couple parts made a horizontal dipole. Once cut to size placed it in thin wall pvc. From all I read this was the way for me. Typically no ground plane needed. Started with 110" in both directions of 12 gauge copper wire // to get swr's down to 1.2 cut down to 106 1/2". I called my fishing partner told him get on his cb. He lives 7 miles away. Modulation on both ends is very good , it a clear nice day here today. Works great for what I need. Remember only for storms if needed. It's a backup to a backup. Military always sets up a compound 2 miles away from me and I know they monitor cb channel 9 too. After several storms the commander and I talk a lot.
Simple and does what I need and want for a few dollars.
Thanks to those who tried to help.

[De_Wildfire]

Bozo gave some great information along with the other responses on here. I know I am straying away a little here but for emergencies, try shooting for a ham Technician license and use VHF/UHF with a handheld. Around here, when there are storms, I hear a lot of activity on repeaters which have backup power. The range can go to 25 milers or more and when they are linked up, it could be coast to coast to coast. (Another subject later.) Now the range of a VHF will go farther line of site, hand held to hand held and even greater if someone has a base antenna. There are only 35 questions on the Technician test and when you pass, you will have the best of both worlds using 11 meters (no license) and VHF/UHF licensed frequencies. I see people all the time passing the tests with a perfect score or missing only one question. The test is easy. Remember the the old REACT from 40 years ago? Well on VHF and UHF, there are emergency services like ARES and RACES that relay emergency communications and many radio clubs do it. I didn't mean to deviate from the post here but just wanted to throw it out there.

Now, as for the coax. From the past I had an issue like you are having and the coax went bad from old age. I replaced it and my SWR's on 11 meters went back to 1.1.

[Joseph3402]

As I stated I’m been out the cb world for several decades. Yes technology has changed “a lot” . Retired old man now with a low budget. I posted ,what I made does work well and gets me the short distance I need / want.
Problem ! I’m hooked and want more range maybe 25 miles local only , would never be able to afford Dxing on my budget. Looking at the A-99 with ground plane kit but on a short mast due to HOA issue… Mast 15’ antenna about 18’ and trying to hide it… Remember I’m going barefoot for now. This will be in my back yard away for my house but 20’ away from all property lines. Could this type antenna get me out more and clear with only a 4 watt radio. I understand most here are the big guy setups with lots of power but we all had to start somewhere.

[MDYoungblood]

I'll try to give you my honest opinion.

First the Antron A99 is a good antenna, basically a half wave vertical dipole, it is a wire antenna inside a fiberglass tube, this tends to cause some static build up noise. As for performance, in that location it might do as well as a good mobile antenna system. Forget the ground plane kit, they might work if the antenna is high in the air but at ground level to me it is just a waste of money. You are using about 15ft of mast, that antenna will do a lot better than the above mentioned mobile. Get good coax, the large stuff will get more of your wattage to your antenna and make a choke, (5 wraps at 4'' in diameter for 27mhz), just below the antenna feedpoint.

Location sounds good, anytime a antenna is in the clear it performs better than surrounded by obstructions.

I hate HOA rules on antennas, there are paints out that I have read others used to camouflage the antenna, be careful here, if it contains metal they will effect the SWR. Don't paint the connections. Hunters have a tape that you might look into.

3's

Greg

[Joseph3402]

Thanks ! I was looking at this one (a-99) because fiberglass, maybe safer for lighting ... even with good grounding. Got any ideas in same price range ? Also my newest very old radio is a cobra29 (am) old ! I'm not even going to try my old 23 channel radios. Will need a good shop to check it out. Thinking since FCC approved FM with cobras help how about there duel mode 29 . Even in old days ( cobra 29) had great filters. Would an FM radio with great filters like the 29 help reduce that static buildup noise?
Can tell my budget is going out the front back and side door.

[De_Wildfire]

I have an iMAX 2000 vertical similar to the A-99 and I painted it green and hid it inside the tree sticking out a little at the top. It sits on a five four foot military pole sections. It blends in with the tree line. We have HOA's here too. A-99 is a decent price but you have to shop around, The poles, I got a couple bags of military poles at the flea market so as the trees grows, I keep adding a four foot section. Hamfests and flea markets are the best ways to get stuff at a low price. More and more the older radio ops are selling off their stuff because they are moving to assisted living places so you can get deals on used equipment and antennas. Also estate sales are good.