Wilson 1000 Hi SWRs. . . across the band.

[rowemesp]

My foray into HF is getting off to a rocky start! I got the Q5NII installed, and the (new) Wilson 1000 (mag mount) put on the center of my truck's roof. I realized there'd be some trimming of the whip involved, but after about 2 hours of carefully removing 1/4"-1/2" pieces off the length and rechecking SWR, I still have a HI SWR indication from 28.300-29.300. When I first started this process, I couldn't hear anything on USB, but as the antenna length was shortened I began to receive stations in Mexico, South America and California, so I believe I'm heading in the right direction. I stopped cutting the whip at about 53" length and I don't really dare to go any further until I get more info. I'm relying on the radio SWR indications to guide me in my cutting--so far, the only improvement I've noted is in the receiver--I can now hear distant stations really well. The radio won't let me key up longer than about .25 seconds (nor do I want to burn the finals up) due to the hi SWR.

I know there's a formula for predicting the appropriate length of antennas, but as the Wilson 1000 is base loaded, I assume that the formulas don't apply, correct? I also have an inexpensive Astatic SWR meter for CB that I also connected to the radio and it seems to mimic the hi SWR indications as the radio although due to the short transmits being allowed by the radio, the SWR meter is pretty useless.

So, barring any better suggestions from you guys, my plan is to keep trimming the whip length until the HI SWR indications disappear or have a local radio shop put an analyzer on it. What say you? Does anyone have 10m experience with the Wilson in a similar installation? Should the whip length be much shorter than 53"? I expect the base loading would reduce the length of the whip, no? Also, the antenna is placed in the middle of the roof, no other antennas or anything else up there--just a flat steel surface. My previous Little Wil CB antenna worked well there. . . thanks in advance for your comments! --Rob

 

[fourstringburn]

Welcome to the forum!

To help you better you need to tell us what your actual SWR is at on those frequencies. The warning light just tells us that it's high.

That antenna should have enough adjustment on the whip without cutting to tune 10 meters but to get a full MHz of bandwidth at a low SWR, that shouldn't be expected.

At best, you should tune the lowest SWR at the center of the band (28.800 MHz) and let the antennas bandwidth cover each end. This antenna should have at least +/- 600 kHz at an SWR below 1.9 which is plenty acceptable.

It may have even more bandwidth but that also means it has high losses in the loading coil but those are compromises we deal with.

An analyzer is best and easiest for tuning antennas but your Astatic meter should do fine.

There is really no set formula for antenna whip length on a mobile install because there are too many variables from grounds, mounting locations, to loading coil variances.

Here's how I would tune your setup…

Start over with the antenna whip all the way down but leave the set screws on the whip snug but enough to move the whip and select a clear frequency around 28.300 on your radio.

Raise the whip and listen for the static to come up and peak. This means your are close to the tune point.

Now key your radio and check with your SWR meter. If your SWR is still high or not good enough, keep raising the antenna and make a note to see if the SWR is rising or going down as you extend the whip. This will tell you to keep raising or lower it some.

Remember as you go up in frequency, the antenna gets shorter but gets longer as you go lower.

Hopefully you didn't cut the whip too short where you can't tune it. Flying J and Pilot truckstops sell Wilson replacement whips or you can find them online.

No guarantees you'll get a flat match but do try to find the lowest SWR at the center of the band you want to operate.

Good luck!

 

[W4KVW]

Welcome to the forum!

To help you better you need to tell us what your actual SWR is at on those frequencies. The warning light just tells us that it's high.

That antenna should have enough adjustment on the whip without cutting to tune 10 meters but to get a full MHz of bandwidth at a low SWR, that shouldn't be expected.

At best, you should tune the lowest SWR at the center of the band (28.800 MHz) and let the antennas bandwidth cover each end. This antenna should have at least +/- 600 kHz at an SWR below 1.9 which is plenty acceptable.

It may have even more bandwidth but that also means it has high losses in the loading coil but those are compromises we deal with.

An analyzer is best and easiest for tuning antennas but your Astatic meter should do fine.

There is really no set formula for antenna whip length on a mobile install because there are too many variables from grounds, mounting locations, to loading coil variances.

Here's how I would tune your setup…

Start over with the antenna whip all the way down but leave the set screws on the whip snug but enough to move the whip and select a clear frequency around 28.300 on your radio.

Raise the whip and listen for the static to come up and peak. This means your are close to the tune point.

Now key your radio and check with your SWR meter. If your SWR is still high or not good enough, keep raising the antenna and make a note to see if the SWR is rising or going down as you extend the whip. This will tell you to keep raising or lower it some.

Remember as you go up in frequency, the antenna gets shorter but gets longer as you go lower.

Hopefully you didn't cut the whip too short where you can't tune it. Flying J and Pilot truckstops sell Wilson replacement whips or you can find them online.

No guarantees you'll get a flat match but do try to find the lowest SWR at the center of the band you want to operate.

Good luck!

If you cut the whip length to short you may also replace it with a Stainless steel welding rod that you can buy at some auto parts & hardware stores for pretty cheap.It will not have a small ball on top but they work very well.No shipping costs either. {:>)

 

[sp5it]

What's swr on ch1 and ch40?

 

[rowemesp]

Welcome to the forum!

To help you better you need to tell us what your actual SWR is at on those frequencies. The warning light just tells us that it's high.

That antenna should have enough adjustment on the whip without cutting to tune 10 meters but to get a full MHz of bandwidth at a low SWR, that shouldn't be expected.

At best, you should tune the lowest SWR at the center of the band (28.800 MHz) and let the antennas bandwidth cover each end. This antenna should have at least +/- 600 kHz at an SWR below 1.9 which is plenty acceptable.

It may have even more bandwidth but that also means it has high losses in the loading coil but those are compromises we deal with.

An analyzer is best and easiest for tuning antennas but your Astatic meter should do fine.

There is really no set formula for antenna whip length on a mobile install because there are too many variables from grounds, mounting locations, to loading coil variances.

Here's how I would tune your setup…

Start over with the antenna whip all the way down but leave the set screws on the whip snug but enough to move the whip and select a clear frequency around 28.300 on your radio.

Raise the whip and listen for the static to come up and peak. This means your are close to the tune point.

Now key your radio and check with your SWR meter. If your SWR is still high or not good enough, keep raising the antenna and make a note to see if the SWR is rising or going down as you extend the whip. This will tell you to keep raising or lower it some.

Remember as you go up in frequency, the antenna gets shorter but gets longer as you go lower.

Hopefully you didn't cut the whip too short where you can't tune it. Flying J and Pilot truckstops sell Wilson replacement whips or you can find them online.

No guarantees you'll get a flat match but do try to find the lowest SWR at the center of the band you want to operate.

Good luck!

That's the info I was looking for--makes perfect sense! Thanks for the help! --Rob

 

[fourstringburn]

That's the info I was looking for--makes perfect sense! Thanks for the help! --Rob

Glad to help!

I meant to say tune your radio to check for the lowest SWR at 28.800 for the center of the band you mentioned between 28.300-29.300 MHz.

To truly operate at a low SWR across a full MHz you'll need a tuner or matching device and adjust it as you make big changes in frequency.

The MFJ-910 or 909 match boxes will work by adding capacitance for matching which is usually all that's needed for 10 meters.

There are small travel tuners that give more tuning variations which is better but either one will work.

There were CB match boxes made by Paradynamics and others but no longer available. These were cheaper and do work between 26-30 MHz. Might be available used on Ebay or elsewhere.

 

[rowemesp]

UPDATE: I have some experience dialing in the SWR on CBs. . .what I was seeing didn't make sense. After sleeping on it, I decided to go to the radio shop and have a tech use an antenna analyzer on it--he determined that the NEW Wilson 1000 he'd sold me yesterday was BAD out of the box. He said it's rare, but it does happen. He took a another new one off the shelf and had me up and running in about 10 minutes (that's why I like doing business locally). Kudos to DTB Radio in Carlisle, PA for their great service! My SWR at 28.300 is about 2.0 and at 29.300 is about 1.5. At 28.800 it's about 1.0.

10m wasn't really very active today, but this afternoon while waiting for my wife at the mall, I heard an operator talking to several people on 28.4930 USB. I threw my callsign out and he immediately replied. . . my first contact on HF was with NP2ZZ in St. Croix, USVI, some 1700+ miles from my location in Harrisburg, PA! . . . . 60 watts on a Wilson 1000 mag mount antenna--I couldn't be happier.

Thanks to all of you guys who replied--I'm a relatively new ham, but have some CB experience that came in handy while I was trying to sleuth this antenna thing out. You guys were able to help me fill in the missing information to help me decide how to proceed.

What I learned: 1. New antennas can be bad out of the box. 2. Antenna analyzers trump cheap SWR meters. 3. HF is awesome! --Rob

 

[sp5it]

My SWR at 28.300 is about 2.0 and at 29.300 is about 1.5. At 28.800 it's about 1.0.

Antenna is too short.

 

[rowemesp]

Antenna is too short.

Yup. . . it is. The result of me cutting it, trying to reduce an SWR on a broken antenna. I bought a spare whip while I was at the radio shop that I intend to use after I get the 11m band working. I don't know if this antenna will cover both 10m and 11m (without a tuner), but the SWR's I've seen so far look promising.

 

[H1driver]

I had a pickup that I could never tune with the Wilson 1000 and 62” whip. Finally bought the 66” whip and was able to dial it right in. This was mounted on the roof but closer to the back. The ribs in the roof prevented placing it in the center. But that is the only time I ever needed the longer whip using the Wilson 1000.