Hustler IC-100SB magnet mount w/spring SWR issues

[FPR1981]

Okay, I wanna check my work against some of the brilliant minds we have on here.

Last night I installed a white Hustler IC-100SB magnet mount 11-meter antenna with the spring on my wife's nice Honda Pilot. I could not go with a Wilson or Stryker because she did not want a HUGE antenna. I was going to use the Tram 300, which is every bit the antenna of a Little Wil, but got a good deal on the Hustler. Plus, it's white and has white coax, and looks good on her vehicle. This is Hustler's K30, or Little Wil.

I installed it center of roof and began adjusting SWR. I got a 1.2 to 1 on channel 1, and the best I can get on channel 40 is 1.6 to 1, despite raising the whip as far as I can raise it without it not being able to be tightened by the Allen.

Could I start adding stainless steel washers around the antenna base, where it threads, as a means of lengthening and trying to get it down more at the top of the band?

 

[K4EET]

<snip> I installed it center of roof and began adjusting SWR. I got a 1.2 to 1 on channel 1, and the best I can get on channel 40 is 1.6 to 1 <snip>

If 1.6:1 is your worst reading, there is nothing wrong with that relatively speaking. It would help to have a list or plot of SWR readings from Channel 1 to Channel 40 by taking a reading every third channel, including Channel 40. Do not adjust the antenna during the test. Leave everything alone except for the channel selector, including on where you are sitting. Don't have anybody around the vehicle either.

With the "sweep" from Channel 1 to Channel 40 and the resulting list or plot, we can better see how the antenna is tuned.

Cheers! Dave

 

[FPR1981]

If 1.6:1 is your worst reading, there is nothing wrong with that relatively speaking. It would help to have a list or plot of SWR readings from Channel 1 to Channel 40 by taking a reading every third channel, including Channel 40. Do not adjust the antenna during the test. Leave everything alone except for the channel selector, including on where you are sitting. Don't have anybody around the vehicle either.

With the "sweep" from Channel 1 to Channel 40 and the resulting list or plot, we can better see how the antenna is tuned.

Cheers! Dave

Excellent idea! I will get on that tonight.

With the mast sunk all the way down in the spring, it was giving me almost a 2 on channel 1 and over 3 on 40. I started working the mast upward and it was dropping rapidly on 1, and less so on 40, but I did finish with a 1.6 on 40.

 

[K4EET]

Here is a list of the Channel Numbers versus actual Frequency. This listing came from:

CB Radio Frequencies and Channels

The CB Radio spectrum is broken up into 40 channels with frequencies ranging from 26.965 to 27.405 MHz. Learn more about CB Radio channels, common uses, and what happens if you break the rules. More CB Radio Advice & How-To Articles at Right Channel Radios!

www.rightchannelradios.com

CB Channel	CB Frequency (MHz)	Common Usage
1	26.965	Open to everyone
2	26.975	Open to everyone
3	26.985	Open to everyone
4	27.005	Open to everyone - Often used for 4x4s/off-roading
5	27.015	Open to everyone
6	27.025	Open to everyone
7	27.035	Open to everyone
8	27.055	Open to everyone
9	27.065	Emergency communications
10	27.075	Open to everyone - Often used by truckers for regional roads
11	27.085	Open to everyone
12	27.105	Open to everyone
13	27.115	Open to everyone - often used by marine/RVers
14	27.125	Open to everyone - often used by walkie-talkies
15	27.135	Open to everyone
16	27.155	Open to everyone (and SSB)
17	27.165	Open to everyone - often used by truckers re: north/south traffic
18	27.175	Open to everyone
19	27.185	Truckers re: East/West Highway Traffic
20	27.205	Open to everyone
21	27.215	Open to everyone - Often used by truckers for regional roads
22	27.225	Open to everyone
23	27.255	Open to everyone
24	27.235	Open to everyone
25	27.245	Open to everyone
26	27.265	Open to everyone
27	27.275	Open to everyone
28	27.285	Open to everyone
29	27.295	Open to everyone
30	27.305	Open to everyone
31	27.315	Open to everyone
32	27.325	Open to everyone
33	27.335	Open to everyone
34	27.345	Open to everyone
35	27.355	Open to everyone
36	27.365	Open to everyone (and SSB)
37	27.375	Open to everyone (and SSB)
38	27.385	Open to everyone (and SSB, LSB)
39	27.395	Open to everyone (and SSB)
40	27.405	Open to everyone (and SSB)

 

[DaveJacobsen]

I wouldn't worry at all about that... Anything 1.5 or under is "good" and 1.6 is close enough.
Did you test in an OPEN field? or in a driveway? You want to be away from anything and everything when you test. Your SWR will swing wildly while driving down the freeway or in a city -- don't stress it too much.

 

[FPR1981]

I wouldn't worry at all about that... Anything 1.5 or under is "good" and 1.6 is close enough.
Did you test in an OPEN field? or in a driveway? You want to be away from anything and everything when you test. Your SWR will swing wildly while driving down the freeway or in a city -- don't stress it too much.

That should work pretty good. More Height is more performance and range. Possible improvement is use a 1 to 1 current Balun between the coax and antenna, the Balun prevents RF Currents from radiating from the coax shield. A simple install. Good going!

Jay in the Great Mojave Desert.

Environmental factors certainly may have been in play. I'm gonna go out tonight in a very large open parking lot at a park and check it.

 

[KEWB-N1EXA]

Okay, I wanna check my work against some of the brilliant minds we have on here.

Last night I installed a white Hustler IC-100SB magnet mount 11-meter antenna with the spring on my wife's nice Honda Pilot. I could not go with a Wilson or Stryker because she did not want a HUGE antenna. I was going to use the Tram 300, which is every bit the antenna of a Little Wil, but got a good deal on the Hustler. Plus, it's white and has white coax, and looks good on her vehicle. This is Hustler's K30, or Little Wil.

I installed it center of roof and began adjusting SWR. I got a 1.2 to 1 on channel 1, and the best I can get on channel 40 is 1.6 to 1, despite raising the whip as far as I can raise it without it not being able to be tightened by the Allen.

Could I start adding stainless steel washers around the antenna base, where it threads, as a means of lengthening and trying to get it down more at the top of the band?

If you go up in frequency the antenna gets shorter 234 / freq x12= X inches

Experiment with a piece of #12 electric wire ( romex ) or a welding rod before you start chopping the antenna 1.6/1 is not bad for ch40
with Magmount Antenna !

Where is she going to talk 38LSB or 19 AM ?

Peter N1EXA

 

[FPR1981]

I apologize, everyone. I realized that I recited the situation backwards.

The 1.2 is on Channel 40. The 1.6 is on channel 1. I realized this morning that I wrote it backwards. I will correct the post.

 

[FPR1981]

Normally I am building dipoles and battling the opposite, where I need to trim. This is the first time in ages where I've needed to lengthen. Brain fart. I apologize.

 

[FPR1981]

It's worse than I thought today

Here is the SWR figure up the band:

Channel 1: 1.9
Channel 3: 1.9
Channel 6: 1.85
Channel 9: 1.75
Channel 12: 1.65
Channel 15: 1.6
Channel 18: 1.55
Channel 21: 1.4
Channel 24: 1.35
Channel 27: 1.25
Channel 30: 1.2
Channel 33: 1.2
Channel 36: 1.15
Channel 39: 1.125

What can I do to get this more consistent?

 

[cmdrwill]

Your antenna is a little short, Higher SWR on lower frequencies.

 

[K4EET]

@FPR1981, what channel(s) do you foresee talking on the most?

 

[FPR1981]

Your antenna is a little short, Higher SWR on lower frequencies.

I know. I've adjusted the mast all the way up. Cannot go any higher.

 

[FPR1981]

@FPR1981, what channel(s) do you foresee talking on the most?

15, 19 and 22.

I'm just miffed at the variance. My Tram 300 is about the same size and it's a 1.3 on 1 and a 1.2 on 40. I tuned it very easily. Surprised this one is being such a fickle specimen.

 

[K4EET]

@FPR1981, on your wife's Honda Pilot, is there a sunroof? If there is, just for giggles move the antenna to the other side of the sun roof and do those SWR readings again. If there is no sun roof and wherever you have the antenna now, make SWR readings over the front seats, in the middle of the roof and over the rear cargo area. You probably have the antenna in the center of the roof now. Finally and again just for giggles, put the antenna in the center of the hood and make the same SWR readings. I suspect that the readings will be different.

Finally, what you really want to see is a dip of near 1:1 at Channels 18 and 19 based on your planned operations. What I would do is contact the manufacturer with the data that you collected in this thread to prove that your whip is too short. Make sure that you tell them you have not cut the whip and tell them what the overall length is. They might be willing to send you a longer whip to get that SWR dip at Channels 18 and 19. The Channels 1 and 40 would not be so bad. Also, based on what you find by moving the antenna around, you can find the best spot for your antenna to make it "SWR Happy" based on the ground plane under it. Believe it or not, I have seen antennas mounted on the hood for that very reason.

 

[merlin]

Here is a list of the Channel Numbers versus actual Frequency. This listing came from:

CB Radio Frequencies and Channels

The CB Radio spectrum is broken up into 40 channels with frequencies ranging from 26.965 to 27.405 MHz. Learn more about CB Radio channels, common uses, and what happens if you break the rules. More CB Radio Advice & How-To Articles at Right Channel Radios!

www.rightchannelradios.com

CB Channel	CB Frequency (MHz)	Common Usage
1	26.965	Open to everyone
2	26.975	Open to everyone
3	26.985	Open to everyone
4	27.005	Open to everyone - Often used for 4x4s/off-roading
5	27.015	Open to everyone
6	27.025	Open to everyone
7	27.035	Open to everyone
8	27.055	Open to everyone
9	27.065	Emergency communications
10	27.075	Open to everyone - Often used by truckers for regional roads
11	27.085	Open to everyone
12	27.105	Open to everyone
13	27.115	Open to everyone - often used by marine/RVers
14	27.125	Open to everyone - often used by walkie-talkies
15	27.135	Open to everyone
16	27.155	Open to everyone (and SSB)
17	27.165	Open to everyone - often used by truckers re: north/south traffic
18	27.175	Open to everyone
19	27.185	Truckers re: East/West Highway Traffic
20	27.205	Open to everyone
21	27.215	Open to everyone - Often used by truckers for regional roads
22	27.225	Open to everyone
23	27.255	Open to everyone
24	27.235	Open to everyone
25	27.245	Open to everyone
26	27.265	Open to everyone
27	27.275	Open to everyone
28	27.285	Open to everyone
29	27.295	Open to everyone
30	27.305	Open to everyone
31	27.315	Open to everyone
32	27.325	Open to everyone
33	27.335	Open to everyone
34	27.345	Open to everyone
35	27.355	Open to everyone
36	27.365	Open to everyone (and SSB)
37	27.375	Open to everyone (and SSB)
38	27.385	Open to everyone (and SSB, LSB)
39	27.395	Open to everyone (and SSB)
40	27.405	Open to everyone (and SSB)

I sort of made up my own frequency list going back to early 80s.

 

[merlin]

Back to the OPs problem.
Your indicated SWR is only part of an antenna system. 1.6/1 is generally acceptable.
It would be nice to use an antenna analyzer or at least a dip meter to find your resonant point. the length of the rod determines that. Then there is coupling to the feed line (coax) and helps if you can tune out any reactance that leads to reflected power (SWR) This is the job of the loading coil. Adding a small variable capacitor like 22 uuf you can adjust for minimum SWR. Antennas like 'Lil Wil' and K40 have no tuning to ground, Just the series loading coil.
Good antennas but noisy compared to Wilson 1000M or Antenna Specialist M125 with direct DC ground.
They all provide some little gain, more than enough to offset your match.
Steps I use tuning antennas is 1> make the radiating element resonant. 2> Match the antenna to the feed line. there are numerous methods for that.(Gamma, series section etc.). The idea is to provide a pure 50 ohm, non reactive resistance at the radio, and if needed, proper coupling there.

 

[FPR1981]

@FPR1981, on your wife's Honda Pilot, is there a sunroof? If there is, just for giggles move the antenna to the other side of the sun roof and do those SWR readings again. If there is no sun roof and wherever you have the antenna now, make SWR readings over the front seats, in the middle of the roof and over the rear cargo area. You probably have the antenna in the center of the roof now. Finally and again just for giggles, put the antenna in the center of the hood and make the same SWR readings. I suspect that the readings will be different.

Finally, what you really want to see is a dip of near 1:1 at Channels 18 and 19 based on your planned operations. What I would do is contact the manufacturer with the data that you collected in this thread to prove that your whip is too short. Make sure that you tell them you have not cut the whip and tell them what the overall length is. They might be willing to send you a longer whip to get that SWR dip at Channels 18 and 19. The Channels 1 and 40 would not be so bad. Also, based on what you find by moving the antenna around, you can find the best spot for your antenna to make it "SWR Happy" based on the ground plane under it. Believe it or not, I have seen antennas mounted on the hood for that very reason.

Wonderful dialog. Thank you for the informative and well thought responses.

Her Pilot has a sunroof and it's at the very front. I have the antenna in the center. As noted in my corrected post, for those just seeing this, my SWR is significantly higher on channel 1 than on 40 and I have raised the mast as high as it will go.

K4eet, I will try moving it back over the cargo area and note the change. I also ordered a Workman ground plane kit for it to see if that helps my issue any. For $19 shipped, it's worth a try.

Also, I have an antenna analyzer that's new in the box and never used. It came in a box of CB stuff I bought. It requires a 12V power adapter, which I don't have, at least not matching. I notice that it has a frequency counter and SWR meter, but only one SO239 connector.

Long story short, I have no idea how to use it.

 

[K4EET]

@FPR1981, I will be interested to know if moving the antenna over the cargo area and/or using the "Workman ground plane kit" has any significant impact on your SWR readings. As for your "antenna analyzer" that came in a box of CB stuff you bought, does it have a make and model number on it? Also a picture of it would be helpful too. An antenna analyzer that most of us would think of runs several hundred dollars. If you actually had one of those, great! That is what @merlin was talking about. Anxiously waiting to know what you bought!

 

[FPR1981]

Here's what it is