Enough!

[The Tech]

Alright, enough of this. I tried adjusting the SWR on my little wil tonight...

I tuned to channel 1 and set the calibration on my meter to match up with the calibration point. I'm using a roadpro swr meter picked up from the local truck stop...

I key up the mic (with my Stryker 440 at full tx power) and the SWR is like 1.2 to 1.3. Then up on channel 40 the same SWR reads about 2.3. So I figure I need to cut some off...

I ended up cutting off a half-inch before giving up, and here's all I could end up with. Now I have even 2.0 swr on channels 1 and 40 (give or take) but in the middle channels around 19 and 20 I get lower SWR about 1.5 to 1.75. I don't know what I've done now, and now I'm really confused. Once you turn to channel 1 and set the calibration...should I ever adjust the calibration knob again (like when moving to channel 40, for example)?

Anyway...now I think my tx and rx is worse than it was before I made the attempt? I suppose now I need to buy a new antenna? lol

[BobOstro61]

Maybe not a whole new antenna. what about just replacing the whip and trying again?

[The Tech]

Yeah I sent a PM to RA already to see if he could get a replacement whip...

My next thoughts are going ahead and upgrading to a Wilson 5000. But I was thinking I don't know if I want to drill any holes in the car, so I was wondering something maybe someone can answer....

Does a "trunk lip mount" still require any drilling to the car? I was under the impression that a cable would snake up over the trunk lip into the antenna, but from what I'm seeing online...I can't tell if that's the case or not. I was thinking of putting a Wilson 5k trunk mount, but if I have to drill a hole...maybe I'll just try another little wil whip for now.

[BobOstro61]

I have a Wilson 5000 mag mount. It works great. SWR's are flat. I had to trim off about an inch or so of the whip to get it set.

[BigBopper]

Line


1. Choose a clear location to adjust the SWR.
Antennas are very sensitive to objects close to them. Go to an open area to tune your antenna, such as a parking lot. This can be done at home, providing you are not close to the house. Do not try to tune inside a building, under trees, near or under power lines, nor with someone standing next to the antenna. This distorts the signal and causes a reflection back into the antenna giving false readings. Also, close all doors, the hood and trunk lid.

2. Setting the SWR.

1. Test with the radio only. If you have an amplifier, either turn it "Off" or preferably remove from installation.
2. Insert the antenna whip 1" into chrome antenna adjustment mast at the top of the coil.
3. Using either the meter built into the radio or a good external SWR meter, calibrate on channel 20. Switch back to SWR and record the readings on three channels; 1, 20, & 40.
4. If the lowest SWR reading occurs on channel 1, the antenna whip is to long and must be shortened. Loosen the mast set screws and lower the whip 1/4" into the mast. Tighten mast set screw and again read SWR. Repeat until lowest SWR is obtained.


If the whip is fully lowered into mast and the SWR is still high, remove the whip from mast. Using a hacksaw, grinder, or bolt cutters, cut 1/4" from the bottom part of the whip. Re-insert the whip into the mast and test again for SWR. Repeat the above procedure until the SWR is below 1.5 of all channels.
If the lowest SWR reading occurs on channel 40, the antenna whip is to short and must be raised. Loosen the mast set screws and raise the whip 1/4", re-tighten set screws and test SWR again. Repeat the above procedure until the SWR is below 1.5 of all channels.

3. The whip is raised to the top, but the SWR is still lower on CH 40.
This generally occurs on vehicles with very small ground plains, such as the compact cars, cars with hatch-backs, etc. It indicates the need for a longer whip than the standard one supplied. Wilson Antenna has a longer whip (66") available for these situations.

4. The SWR on a trunk lid mount is 3.0:1 on all channels.
When a reading of 3.0:1 is present on all channels, this indicates a lack of ground for the antenna. For example, some of the vehicles today use a fiberglass trunk lid or insulate their trunk lid from the actual chassis or frame, ground of the body. This is done by inserting plastic washers on the trunk hinges, and/or sandwiching a layer of styrofoam type material between the two piece trunk lid. To eliminate this situation, a jumper wire must be installed from the actual bottom lip of the trunk lid to metal on the body of the auto. To accomplish this, loosen one of the hinge bolts on the trunk-lid side and install a braided strap. Re-tighten the bolt. Loosen the bolt on the other side of the hinge (trunk-body side). Install the other end of the braided strap to this bolt and re-tighten. Be sure to leave a long enough loop to prevent pulling apart when the trunk lid is fully open. As added ground insurance, you may wish to add a jumper from the set screw on the trunk lip mount to the hinge bolt on the trunk-lid.

5. My needle pegs the side.
When the SWR meter needle slams the side on all channels this is generally an indication that you have a short in the system. This will probably be from the coax or mount. Disconnect the coax from the radio and the mount. Using an ohm meter or continuity tester, check the mount first (it may have been installed improperly). There should be no signal between the center pin of the coax connector and the ground side of the mount. If there is, you may have forgotten to install the nylon washer or put it in the wrong position. If the mount checks good, proceed to the coax. If you have replaced the connectors on the end, there may be a short from the multi-strands of the shied. Again, using an ohm meter or continuity tester, touch one lead of meter or tester to the center pin of the PL-259 connector on one end of the coax. Touch the other lead to the shield (or outer connector ring) of the same connector. If this shows a shorted condition (or reads continuity), the coax has a short and must be repaired or replaced. NOTE: The coax may have an unseen break in it. To test for breaks, use the following method: touch one lead of meter or tester to the center pin of the PL-259 connectors on one end of the coax. Touch the other lead of meter or tester to the center pin of the PL-259 connector on the other end of the coax. If this shows a shorted condition (or reads continuity), the center portion of the coax is in proper working order, no reading will indicate a break. Now repeat the process for the shield side of the coax, using the outer ring of the connectors.

6. If the SWR is good until power is applied:
The antenna is not the problem. In this case, it is the amplifier. You have already established that the antenna is properly tuned and in good working order with low SWR, except when power is applied. Assume a ham operator is on 10 meters using a solid state amplifier. With the radio only, the SWR is 1.1:1; when the amplifier is turned on, the SWR jumps to 2.0:1. The amplifier is not only transmitting at 28 MHz, but is also transmitting on a second frequency of 56MHz. This is known as a "second harmonic" (2X the fundamental frequency of 28 MHz). Thus the SWR meter is reading both the reflected signal of the normal frequency and the rejected second harmonic signal. The antenna will not accept energy transmitted at 56 MHz, and returns it all back to the radio, which shows up on the meter as high SWR because the meter can not tell the difference between 28 MHz and 56 MHz. In fact, as much as 30% of the power is at 56 MHz. The primary cause is an amplifier that is not adequately filtered. Adding a Low-pass filter at the amplifier output is the easiest solution. For best results, connect the low pass filter directly to the amplifier using a barrel connector or very short coax cable.

7. How low can the SWR be brought down to?
Ideally it is nice to get the SWR to 1.1:1, but practically a 1.5:1 works just as well. Some installations will not even allow you to achieve a 1.1:1 SWR because of the grounding of the vehicle, the amount of metal available as a ground plane, and other circumstances. However, the loss with a 1.5:1 (using 18' of coax) is actually less than 1/2 of 1% of your output power, which on a normal 4 watt radio means a loss of .025 watts of power. This means that instead of transmitting 4 watts, you are actually transmitting 3.88 watts. This is not even noticeable at a receiving station. Therefore, spending the extra time to get below 1.5:1 is purely a matter of choice, especially if you have a high performance antenna.
But, what happens if your SWR is 2.0:1 instead of 1.5:1 or less? Most CB radios today have protection circuits that starts to shut down (by lowering the output power) when the SWR reaches above 3.0:1. This reduces the output power of the final transistor amplifiers. So generally, anything between 1.5:1 and 2.0:1 is acceptable and useable for good, solid, reliable communications. Readings of 3.0:1 or higher indicates a problem may exist in the system, and we do not recommend continued use or permanent damage can occur. Check for complete grounding of the system (see #3 above ).

8. Why do I get different SWR readings when I move my SWR meter to a different part of the coax?
This generally happens only under two conditions.

1.
If the antenna is not matched to the coax (at the antenna feed point), there will be RF voltage on the outer conductor of the coax and can disrupt the accuracy of the readings. A matched SWR should show the same reading any where the meter is installed along the coax.
2.
When two SWR meters are used in one coax line, and the SWR does not read the same on both meters (assuming that the antenna is matched correctly), one or both of the meters are not balanced to 50 ohms. Due to poor design or a component failure, one or both may be actually be matched to 60 or 40 ohms.

[Rex_foxhound]

I would check and see if it is grounded good. Where is it mounted?

[The Tech]

It's a magmount stuck right on the center of my roof...

Should I do any more grounding? Sorry...

[BigBopper]

if it's a mag, no more grounding needed

[The Tech]

Alright, I didn't think so. So let's say I've got SWR around 2 on both channels 1 and 40...

From that point...if the SWR is equal on channels 1 and 40....how would I go about getting it LOWER on both channels? I guess that's what I don't understand at all....

[231]

I don't know what "full power" means. How many watts are we talking about here? The Lil-Wil won't handle much. It's fairly narrow banded as well. Most who run any wattage at all will step up to at least a Wilson 1k/2k magnet mount. Many will just go right to the Wilson 5k. I'd leave it if it were me. Half inch isn't all that much off a stinger whip IMO. Heck, even my little ol' 3' base load Valors took more than that.

I'd simply slide the stinger up a tad if you can. And you can go to a lip mount if you want, and simply run additional ground strap(s) off of the mount if need be. I personally am not a fan of magnet mounts to begin with...but that's just me.

[The Tech]

The Stryker 440 has an output power knob. I think after Mike's swp on it, it should be doing no more than 60 watts when turned all the way up. I guess my biggest question is whether or not a trunk-mount Wilson 1k or 2k will outperform a roofmounted little wil. I'm not running a lot of power through it.

[BigBopper]

a Wilson 1000 will really out perform the lil Wil, I have both,,,and the Wilson 1000 woke up my radio,,,,lil wil isn't much of an antenna, its OK for a small cobra radio,,,but you have a big radio now,,trunk mount will work good for you or a mag mount setting on the trunk deck will also work

[The Tech]

See I can't use a mag mount on my trunk...I think it's fiberglass. The little wil won't stick to it. Which brings up another concern. What should I use as a "grounding strap" for a trunk mount 1k to a chassis ground?

[The Tech]

For that matter. Will a Wilson 1k or 2k being trunk-mounted on a fiberglass trunk cause performance issues? I know I would need to run a grounding strap somewhere. But doesn't the antenna need a good metal ground-plane?

[231]

First off there are many ways and types of grounding straps. Braided is the key. If it were me, I'd probably try using simple stranded wire (like 10 or 12 gauge) that I already have laying around the house someplace. If I couldn't get the SWR's down, that's an indication of a bad ground. Given that, I'd probably just use good ground strap that is sold. I don't have any links to show you...but it's out there.

As far as mounting it on a fiberglass trunk, keep in mind the rest of your car is probably steel. Even if it's a unibody design, there will still be steel in it for a ground plane. What about using a Wilson 1k magnet mount? Better yet, a 5k? Either one should work fine with the under 100 watts PEP you are running.

And I'm with Bopper. The 1k, 2k, and 5k should out perform the Lil-Wil quite a bit. Even if the mounting location is less than perfect. Just my opinion anyway.

Hope that helps a little bit.

[The Tech]

Well I would prefer the antenna on the roof. Common sense tells me it's going to perform better up there. However, I bought the little wil because I'm in and out of low parking garages a lot and I didn't want to go much taller than the 36 inches of the little wil. So that's why I was thinking if I got a 1k or something along those lines in a trunk mount, the antenna would be taller...and would probably outperform the little wil, however by lowering it a couple feet to begin with (moving the base to the trunk lip rather than the roof) I would gain the extra height clearance needed for the longer (62 inch) whip of the 1k for example. Does this make sense? I also found on double-u dot walcott all kinds of trunk-mount kits as well as the firestick "no ground antennas." How well would those work? Anybody know? Or should I just go with a Wilson 1k trunk mount and grounding strap? I swear, I wish there was someone nearby that could help me tune my SWR down. lol

[The Tech]

Alright, now my antenna is really janked up. lol

I can still transmit decently. But now, I can't even hear the guys that I would normally talk to like they were next door. I think I must have really screwed up in my attempt at adjusting my antenna. First off...now I realize I should have calibrated on channel 20 before doing anything. Then...I think should have turned the Mic gain down? I had the mic gain cranked full-blast. Could that have had a big effect? Shew...well I placed my order for a new whip...guess I'll try again next week. Meantime...I guess I got an ear infection, cause I can't hear a darn thing.

Anybody in the Kentucky area willing to help a fellow cber out? I'll pay for services.

haha

Shew...I need another beer.......

[BigBopper]

yea you are right, turn the mic down

[The Tech]

I think I'm just going to start grinding on it tomorrow and see if it gets any better. If not...my new whip should be here sometime next week.

Hey another question, does it matter if you cut off from the top...or from the bottom. My stinger has a rubber tip that comes off. But when you remove it, it doesn't look like it would matter. It looks the same on both ends. For that matter...would it even matter if I got the stinger upside down? As long as the rubber tip gets put on top...

[BigBopper]

On a Lil Wil, it doesn't matter

[The Tech]

Good...one less thing I can screw up. lol