Need some help

[MSGED2007]

Ok, so first off let me say that this is my first post here and it is nice to have a place to come to get help/advice from more knowledgeable people, so thank you in advance.

Now, my issue. I recently mounted a cb in my work truck. The radio is a Midland 1001lwx and the truck is a 2011 f150 extended cab (2 half size rear doors) with a ladder rack. I have replaced the stock Mic with an rf limited 2018 turbo powermic and have turned the modulation pot up in the radio. I took it to a respectable local cb shop and had it tested and they said it was dead keying 4 watts and swinging to 16 with 100% modulation. I am running 18' of mini 8 coax to a homemade mount on the ladder rack just behing the third brake light. The mount is made out of 1/4" 3"x3" angle. I have a workman swr3 swr/power/ field strength meter and an 18" mini 8 jumper. This is my equipment.

I have tried 3 different antennas to date: a 5' Wilson silverload, a 4' firestick ll, and a 3' everhardt sott. The Wilson and the firestik both tuned really well. Swr was 1.2 on the ends of the band and flat in the middle. But something funky happened with the everhardt. When I tuned it to lowest swr (1.2 on the ends of the band and flat in the middle) the radio would not output full power. Now I know that modern radios cut back their power if there is not a good antenna match, so I marked the whip for lowest swr position and started lengthening the antenna (the radio wouldn't output full power below channel 30) I was effectively using the radio's signal strength meter as a gauge to see where the radio liked the antenna better. After extending the whip approximately 1.25", full power was achieved on all 40 channels. I marked the whip again for full power output position. In this position swr meter read 2:1 on channel 1 and about 2.3:1 on channel 40.

The next day, while talking to a friend approx. 3 miles away, I tried both positions to see which one output the strongest signal, and it was the position that the radio liked better, but that showed a higher swr. Now, after having thought about what happened, is it possible that the everhardt, being a 1 1/2 wave antenna, was screwing with my swr meter, giving me a false reading? I know from experience that this little Midland radio is picky about it's antennas, as it starts cutting back power on its signal strength meter at anything above 1.3 vswr. I did get it tuned using unconventional methods, but thought I would put this out there to see if anyone else has encountered this before. And btw, in another unexpected twist, I tried all three antennas in a comparison with another friend receiving on his base approximately 4 miles away, and the 4' firestik ll beat out the 5' Wilson silverload and the 3' everhardt, but not by much. He had an 8 on his signal strength meter for the firestik ll and a 7-7.5 for the other two. Right now my truck is wearing the everhardt because it is the shortest of the three and for all practical purposes performs the same. The farthest local contact so far is 15 miles as a crow flies to another base station.

 

[nosepc]

An SWR meter is not the best to adjust antennas.
You can even measure 1:1 with very different impedances to 50ohms.With a load of 25ohmios it will indicate a ROE 2:1, BUT ALSO WITH A LOAD OF 100 OHMS WILL ALSO INDICATE 2:1 ..

A noise generator is much more accurate and efficient at the same price.
If you can get even borrow an antenna analyzer, you will also get one more truthful adjustment.

 

[MSGED2007]

I was figuring that the meter was the problem. It is a cheap meter. Was one of those buys you get before you really know enough to not get it. But what I could not understand is the wilson and the firestik ll are both 5/8 wave antennas, and the everhardt sott is a 1 1/2 wave, so none of the 3 are actually 1/4 wave antennas. I know that it is said that even though the electrical length is not 1/4 wave, that all of the shortened fiberglass antennas act like 1/4 wave antennas, but then why would the meter have issues with one antenna and not the other 2, all else being equal (same radio, coax, mount, mounting location, etc...)? I guess I am more trying to understand what is going on here rather than figuring out how to fix it, as I already have the antenna tuned and working great. Oh and btw, the first antenna i tried was a wilson little wil mag mount, and it also tuned good on the roof of the truck, but the ladder rack was screwing with it too much, blocking out the signal. I would be hearing and talking great for about a mile, but then all of a sudden.....nothing. That's when I figured out that I was going to have to go with a top loaded antenna, to get the coil out of and above the ladder rack.

 

[M0GVZ]

I have replaced the stock Mic with an rf limited 2018 turbo powermic and have turned the modulation pot up in the radio.

So it distorts like a bitch now because its over modulating. No point having a good swing if people can't understand what the hell you're saying.

 

[Lil'Yeshua]

.

 

[MSGED2007]

MOGVZ, why in the world would you lead with a comment like that? No, it does not distort, it actually sounds awesome for being a compact radio. I even listened to a friend on it with his cb in his truck sitting 30' from mine to check for distortion and it sounded great.

You should not assume that you know more or even really know what is going on before you ask questions to get the info you are talking about. Had you done that you wouldn't have made yourself look like an ass, but as it stands you are wrong and now everybody knows it. Good job : )

 

[MSGED2007]

What is even worse, MOGVZ, than jumping in halfway through a conversation and making a stupid comment because you assumed that I didn't know what I was doing, is not reading the comments before it prior to doing it. Lmao.

I said I even took it to a local cb shop and had them check it out on their test equipment in my first post. Are you illiterate too? Read before you speak man, you are making yourself look foolish!

 

[Robb]

Ok, so first off let me say that this is my first post here and it is nice to have a place to come to get help/advice from more knowledgeable people, so thank you in advance.

Now, my issue. I recently mounted a cb in my work truck. The radio is a Midland 1001lwx and the truck is a 2011 f150 extended cab (2 half size rear doors) with a ladder rack. I have replaced the stock Mic with an rf limited 2018 turbo powermic and have turned the modulation pot up in the radio. I took it to a respectable local cb shop and had it tested and they said it was dead keying 4 watts and swinging to 16 with 100% modulation. I am running 18' of mini 8 coax to a homemade mount on the ladder rack just behing the third brake light. The mount is made out of 1/4" 3"x3" angle. I have a workman swr3 swr/power/ field strength meter and an 18" mini 8 jumper. This is my equipment.

I have tried 3 different antennas to date: a 5' Wilson silverload, a 4' firestick ll, and a 3' everhardt sott. The Wilson and the firestik both tuned really well. Swr was 1.2 on the ends of the band and flat in the middle. But something funky happened with the everhardt. When I tuned it to lowest swr (1.2 on the ends of the band and flat in the middle) the radio would not output full power. Now I know that modern radios cut back their power if there is not a good antenna match, so I marked the whip for lowest swr position and started lengthening the antenna (the radio wouldn't output full power below channel 30) I was effectively using the radio's signal strength meter as a gauge to see where the radio liked the antenna better. After extending the whip approximately 1.25", full power was achieved on all 40 channels. I marked the whip again for full power output position. In this position swr meter read 2:1 on channel 1 and about 2.3:1 on channel 40.

The next day, while talking to a friend approx. 3 miles away, I tried both positions to see which one output the strongest signal, and it was the position that the radio liked better, but that showed a higher swr. Now, after having thought about what happened, is it possible that the everhardt, being a 1 1/2 wave antenna, was screwing with my swr meter, giving me a false reading? I know from experience that this little Midland radio is picky about it's antennas, as it starts cutting back power on its signal strength meter at anything above 1.3 vswr. I did get it tuned using unconventional methods, but thought I would put this out there to see if anyone else has encountered this before. And btw, in another unexpected twist, I tried all three antennas in a comparison with another friend receiving on his base approximately 4 miles away, and the 4' firestik ll beat out the 5' Wilson silverload and the 3' everhardt, but not by much. He had an 8 on his signal strength meter for the firestik ll and a 7-7.5 for the other two. Right now my truck is wearing the everhardt because it is the shortest of the three and for all practical purposes performs the same. The farthest local contact so far is 15 miles as a crow flies to another base station.

The Silver Load is really what you might want to stick with anyway. Those 3' antennas have a really narrow usable freq range by design. Same goes for the ~3' K-30 antenna, the SWR will be very poor at both ends of the channel spectrum and only reasonably low in the middle. They all pretty much do that. So IMO don't bother yourself with the 3' and enjoy the Silver load. You will both hear and transmit better anyway. Just about any antenna is better than the 3' or even 4' antennas.

 

[Mudfoot]

Hard day at work?

 

[MSGED2007]

Thanks Robb for the good advice. I plan on doing some receive tests too, to see which antenna can hear the best. I can't go any higher though, it is a company truck and they have rules about stuff like this.

If you are talking about me M42Duster, no, it wasn't a bad day, thanks for asking though. I just don't like mean spirited people who try to make themselves look good by making others look bad. In more times than not, and as in this case, they end up making themselves look stupid instead. I don't even know MOGVZ, but had he just asked me I would have gladly shared what I had done. I have a feeling though that he wasn't really interested, he just wanted to make a smartass comment to make himself look good. Too bad he didn't read my first post before he did it though, it might have helped him keep his foot out of his mouth. : ) Have a nice day.

 

[MSGED2007]

And Robb, I was pleasantly surprised by how good these short antennas tuned. I mean, as far as I know, an 18' run of good coax at 27Mhz is almost like plugging the antenna into the back of the radio (1 wavelength through copper) but I could be wrong. And with the ladder rack, I didn't know if it had a good RF ground or not, but all three covered the entire cb band below a 1.3:1 vswr. My prior experience with a 3' antenna (wilson lil wil) on my personal vehicle wasn't as good, with a 1.6:1 on channels 1 and 40 and flat in the middle of the band, but not so this time.

Also, the people who I have talked to on the other end have given me good comments and on a couple of occasions have even asked how I got that compact radio to sound that good. It's no high end unit, but it is doing really good for what it is.

 

[M0GVZ]

I said I even took it to a local cb shop

Most of them don't know their ass from their elbow and they're not going to tell you that the mod where it took longer to take the lid off than do which they've just charged you $30 for is going to cause a problem are they? Did you get to see them put it on an oscilloscope and check for flat-topping on the waveform?

Also, the people who I have talked to on the other end have given me good comments and on a couple of occasions have even asked how I got that compact radio to sound that good.

Given the crappy audio a CB typically reproduces and the fact that CBers seem to typically favour overdriven booming crud that's not really saying a lot.

As for not knowing what you're doing, yes I think exactly that. You've ramped up the internal audio gain with no proper equipment to monitor the output and then you've shoved a power mike on it which overdrives the mic pre-amp input making a bad situation even worse. So yes, I do think you don't know what you're doing.

 

[GnG8d]

WTH? Why are people so negative about something of which they have no knowledge or interest?

 

[Robb]

Most of them don't know their ass from their elbow and they're not going to tell you that the mod where it took longer to take the lid off than do which they've just charged you $30 for is going to cause a problem are they? Did you get to see them put it on an oscilloscope and check for flat-topping on the waveform?


Given the crappy audio a CB typically reproduces and the fact that CBers seem to typically favour overdriven booming crud that's not really saying a lot.

As for not knowing what you're doing, yes I think exactly that. You've ramped up the internal audio gain with no proper equipment to monitor the output and then you've shoved a power mike on it which overdrives the mic pre-amp input making a bad situation even worse. So yes, I do think you don't know what you're doing.

Just a little bit over the top then; eh mate?

100% modulation for an unmodified radio would imply a symmetrical sinusoidal signal that is neither flat-topping the positive peak nor flatlining the negative peak. Otherwise, it would not be 100% modulation.

So, you're assuming that the tech cannot read a scope?!?
Right; you know what they say about 'assuming' then.

 

[AudioShockwav]

M0, take it easy man, you are in the CB section.
Retract the claws a little bit.


73
Jeff