just for the record

Thank you for the reply. I for one, would like to hear about your success with these trucks. As you know there are many threads on the topic.

I understand where you are coming from. But if you care as you do, just put the information out there and let the information defend itself. We all want the same thing, to enjoy our hobbie. I just got my radio and love it! You say and others, that it's not a real HAM radio. That may be true. But because of knowledgeable people like yourself who share I'm able to continue to learn. So, I may pick up a good used real ham radio in the future.

If you would like to continue to help, you can pm those who ask for your method like myself. Or just put it out here for everyone to discuss. When you plant seeds, they all don't take root. Just focus on the ones that do grow.

Reconsider Ridgeline.

 

OK you will in a few minutes. I've been busy, between a sick kid and a wife who broke something in her back to the amount of work I've been doing in the last couple weeks, I haven't had time to write up details.

Yep there has been many threads and many people blame the truck when it really isn't the problem or looked that way when it was all said and done.

Defend?

I don't have a cat in this fight, my trucks won't ever be Cascadias - never ever ... so ...

Got it.

Here goes part one.

There are a few issues with the truck, mainly has to do with manufacturing, not the design. Contrary to what is thought, much of the issues stem from insulated panels within the cab and sleeper. This is due to the fact that adhesives are use in combination of steel, aluminum and composite materials. Western Stars are one such example of this combo, the sleepers are made out of a composite material where the roof is fiberglass and the cab is steel. Cascadia seems to have the same construction but without the problems because how the antennas are mounted.

The first issue at hand was to straighten up the ground plane, moving the antenna from the roof line, to the mirror mount helped with it but then it wasn't as effective as it should have been. We (the owner's son and I) had two types of mounts made for testing, one with the modifications I hinted at in other threads and one like the one being sold at T/S cb shops. The reason why was the former would offer a better ground due to the better design and the latter was more rigid for road use (there was others made which combined the two together but that's for another thread).

With the antenna at mount level at the base of the mirror (we tested with ten different antennas), the increase in signal strength on average for transmit was about 35% over our baseline (stock antenna position) while receive was lower. testing with antenna extensions that raised the antenna up above the driver's head (that was our standard level for testing), there was a slight improvement.

We tested the counter poise/dipole setup as many of you have and only saw an improvement of 45% over our baseline.

The next step was to add foil to the sides of the sleeper, to the doors and under the dash, which has another reason I will mention in part 2. This was used as a ground plane enhancer of sorts with a common grounding point and with an RF ground. It improved the system to the 55% over baseline but lacked a forward and rearward lobe we were trying to achieve. So after that, we added to the top of the sleeper/cab and there wasn't much improvement. I have to mention that we used aluminum foil, not copper because of a number of reasons, one is we got the same RF effect with either material but copper was harder to get. The other was cost.

Then we looked at the grounding again. most seem to think that a chassis ground is needed but we need an RF ground. So grounding straps were made and installed from the mounts back to the radio. This with the foil helped out a lot more than we thought, but still there was a nagging issue with the improvement for all antennas.

So I looked at a profile of the truck and realized that the hood was not involved but with metal hoods, there is some sort of effect with RF, so we foiled the hood and we ended up with a 65% improvement over the base line.

Next part two.

 

Part two -

With the ground plane coming into shape, I borrowed some more equipment from a freind to see if I can model the system. I puttered around with it for a day or two and returned it back to him. He made a comment about RF grounds that I won't mention but will explain in a moment. It got me thinking that maybe I missed something, especially with the counter poise/dipole setup which had me down in the getto at 3 am testing things out.

OK here is a little lesson on rf.

When you guys build a counter poised/dipole antenna with an earth ground, most of the time the tuning of the ground doesn't make much difference. However when you guys make a mobile with an artificial RF ground, you have to do something more to make it work right.

That is tune the ground.

AS stupid as this sounds, it seems that many people are grounding everything (including us) trying to produce a ground plane or to eliminate the secondary RF from the antenna system while ignoring the fact that the other half of the signal has to go somewhere and if it isn't in resonance, then it ends up back at the radio in one form or another.

SO here is what I did.

I took my handy VNA and tested the grounding system to find that it was way way off. It seemed I made it for a lower frequency than what it was supposed to be.

We deconstructed the entire truck at that point, taking out grounding foil, removing straps until we came up with a good resonance form the ground plane itself.

The improvement was immediately noticeable, we got 80% over our baseline with more or less a good solid pattern leaning towards an omnidirectional system.

We changed the single antenna into a dual antenna with phasing harness and got better gain out of them and closer toward that omnidirectional system.

One of the further things we did was to "tune" the ground, taking it to this level gave us latitude to actually improve it to the point we didn't need to worry about it. I built a simple antenna tuner out of old parts and used it between the radio and the antenna ground. Tuning it for the lowest reading on an RF amp meter.

So that's pretty much that.

A couple of other things.

Part of the problem was to maintain the ground for the mounts, which took more than just mounting the new mounts to the mirrors, His son had the idea of modifying the mirror mounts themselves to strengthen up so we had an internal low profile backing plate made for the mount and it would not move for any reason.

The other thing is we looked at the static issue, both my radio and his radio had static when the engine was running, this was part of my issue with the isolated grounds within the truck itself. I borrowed a ultrasonic receiver to test the interior of the truck when it had the interior out but the dash in. I traced some of the issue to this ground problem within the electrical system and solved it by using additional grounding points from the wiring harness to effectively channel the ultrasonics. The other issue was with harmonics of an ultrasonic signal being produced, I traced that to the power cut off/voltage boaster that is installed in some FL models, this actually was one source of noise on every radio that was put into the truck, and with the weak link (aka combiner) picking this up, it would attenuate the AM broadcast signal for the AM radio (which by the way was replaced with a new antenna and a new radio).

Part three next.

 

Part three.

A few other things, I am doing this from memory (my notes are not here but 750 miles away sitting in one of my trucks), so if there is a confusing thing here or there, well can't help that. The key is that there is a problem on a few fronts and these are suggestions how you 'techy' guys may find out how to fix them. IF you do, just give me credit for the idea. If you don't - don't blame me.

I learned that between two cascadias and a couple macks and a couple western stars, there is differences even between the same model same year. The two cascadias are built three weeks between each other and one used what I explained and the other needed half the work.

SO here is how we tested all of this --- equipment wise.

First off the his CB radio was a stock radio which had been tested to see if it was in spec, not even opened up. It was a cobra 29 something or other. Mine is a modified Radio Shack (don't laugh) which has had a highly modified front and AGC system. I used stock power limits and close to stock receive specs for a bunch of reasons, one is it is within a city so noise is a factor but the most important thing is I don't need a -135 or better front end to do this testing.

Second I setup on 10 acres (it is a 20 acre lot) twelve antennas for field strength tests with the vehicle in the middle. These antennas were hooked up to a device (I don't remember the name but I do remember the replacement cost for the insurance I had to get for it - $6370) that rotates the signal for those antennas electrically into four Rohde & Schwarz eb200 receivers which are connected to a laptop. The transmitter used for receive testing is an HP unit (also don't remember the model number but it is only $9500 to replace it) that covers 10kcs to 10 gcs - yes I'm old. It is hooked up to the same device that rotates the antenna and is also hooked up to the lap top.

We can and did plot both the antenna transmit and receive patterns from the trucks plus a weird ground plane pattern

Third the VNA device used is an HP unit (don't have the model number for that too but it is not cheap). There is an additional unit used for tuning the antennas made by ... me. I have since bought another VNA device and calibrated against the HP device so I won't have to pay the insurance on the HP device. The only issue I have is the pretty graphs the HP made won't happen any more.

Fourth, there is a long list of equipment used to test the grounds, the internal ultrasonics/RF and a number of a lot of other things - one wasn't a scope and another wasn't a spectrum analyzer.

NOW the caveat.

This worked for us, it has been done on two cascadias, two of my own and two from a customer of mine and will be on a few more. It isn't intended for a fix for all of you or to tell you guys how to do it in detail but to show you ONE possible path. There may be others, the people who lent me the equipment reminded me that RF is a funny creature.

HOWEVER ...

I DO NOT want to hear that you tried this or that from these posts and get mad at me if it didn't work.

I did this for a few reasons, one was to help out the guy and it did. I also did it because I wanted to know what in the hell was wrong. AND lastly I got tired of hearing my own drivers say that my trucks sucked even though they were not near the level of poor RF quality as Cascadias are.

I talked to Freightliner, to be exact some guy from Daimler was in on the conversation, they helped out with the electrical issues but in return asked for a copy of my notes. They said "we'll look into it" but that's BS so I don't expect it to go any further than these posts.

SO there. Hope this helps you all out somehow.

 

Really appreciate the time you took on the holiday weekend to share your results.

That was a lot of work. The gist I got from that was cophase with a dipole and ground straps are the best way to go without taking the truck apart. You didn't mention any particular type or size antenna. Did your test include different types of antenna, 5/8 vs 1/4, fiberglass vs metal, length and angle? Most people won't have the luxury of dismantling the truck.

If a noob like myself has options of driver mirror mount 7ft firestik, or spot mirror mount 5.6ft Browning center load or 4.5ft firestik. Which way would you go? If I understood correctly, 7ft drivers side mount with a dipole about 2ft with the mounts grounded to what the door? Then maybe line the inside of the hood with aluminum foil? Would these be steps in the right direction? Sorry if I didn't understand. Just really trying to learn this hobby and may be stuck with this 2016 Cascadia a few years.

 

Ridgline that was an extremely thorough test and write up. Thank you for the information. I drive a peterbilt 379 and am always looking to add knowledge and notes about antennas and tuning. Super job!!!!!!!!

 

You're welcomed. BUT I have to add this, what I posted is only part of them, there is a lot of other details and info that I have to go through and post when I get a chance.

Yep it was a lot of work, the focus was to find a fix for my couriosity more than anything else, all I've heard is the cascadia sucks and so on. I had some help for the testing, which is left out at their request but also had a ton of info coming from FL/Daimler and the company who makes the cab panels (they are part of one of my customer's clients groups).

The counter poise/dipole is only part of it, this should not be taken as a "dipole" in the physical sense but a dipole as in the RF sense. The important issue we found was a proper RF ground has to be there, it has to be tuned to be an equal to the radiator element but can be part of the truck or part of the antenna - think ground plane vertical like a star duster. This confirmed the need for more than a secondary element stuck onto the base of the antenna.

AND to counter Rabbi's recent comment, the ground has to be there, it has to. There is no counterpoise/dipole effect without it. You can reach an impasse with an RF feedback to the radio which will cause more issues on performance. The RF ground does not have to be one with a bunch of bradded copper things all over the place but to ensure that there is continuity from the radio to the antenna and then to the truck.

No I didn't mention them, they range from Siro to custom antennas. Looking at my antenna list, I think we actually tested 35 different antennas I own and there were at least 10 more that were bought for this test. AND I made (thanks to a company I service for the copper pipe and aluminium tubing) four antennas that worked really well. We made different mounts that were used, drilled a bunch of hold in the truck by the way and so on. It was the biggest PIA ever.

We also tested with some ham mobile antennas like my scorpion off my pickup just to see what happened. Not much.

Well there is a picture (from another thread on this site) of one of the best solutions we found that worked -



Now this is what worked the best with the combination of tuning the ground. You may notice that the antenna is elevated over the driver's head and the mount is ... well looks sturdy enough to stand up to all kinds of road crap.

>>>> added one thing after the posting of this - there is no real difference with antennas that are waving in the air like fiberglass whips or stuck in a near vertical position.

Why?

Because RF travels at the speed of light, the antenna does not. Those who put the antenna at ridiculous angles seem to claim that it is to improve their system but when we moved the antenna at different angles to see the effect, we could not detect any changes. What may be a problem is with the receive of the radio (a theory posted on another site) where the flutter is caused by the detector stage/agc of the radio not reacting to other interferences.

As I mentioned we used the driver's head as the point to get the radiating RF above, it eliminated as much of the deep lobes and made a more uniformed antenna pattern (see image below). All involved agreed that having a beam like effected (with two or three lobes) is rather useless in a mobile application so it is hard to get a perfect omnidirectional patter but it can happen to be a close one. I don't dispute other solutions, but elevating the antenna radiator element and adding the counter poised to the truck in either form of an antenna element or a proper RF ground is key. I may have been cryptic in my posts - sorry this week has been hell for me.

The following image was taken off the web and used under the fair use provision as an example.



This is an example of a two lobed pattern that we kept running across with dual antenna (the single antenna gave us a sharp null on the right or left side - opposite of the antenna), it was thought that because of the tuning of the counterpoise/dipole was giving the null effect. The tuning help eliminate this to a certain extent. This pattern was with both the antenna mounted on the mount and extending up past 14 feet and also with an extension.

This next example is shows a bit different pattern and is close (not exact) to what we achieved. (another fair use image - thanks google)



NOTE - the test equipment (actually the software on the laptop) gives both of these images but the one on the right never made much sense because we didn't change the elevation on the antennas.

This image (on the left) needs to be turned 90 degrees to give an accurate idea of what happened. The point is we made strides in how the pattern looked, the nulls were less than the first image I posted but still were there. They went shallower as we messed with the foil and grounds when tuning everything.

Again can't stress this enough, there seems to be a need to tune the RF ground.

I would start with getting the antenna system itself fixed where you have improvement and then focus on a ground (I know that makes no sense after all I posted but follow the path, get the antenna working so it is tuned, then the RF ground). No matter what the RF ground is needed and the truck has to be part of it, you can't get away without it. There is a lot, LOT more to this than what I posted, again doing it from memory is a PIA and I am giving key things only.

Don't want to go into the advising others how to do it because I am not there to point out little things I may have not mentioned, like the mounts and how they were put together.

Those store bought mounts have a couple flaws in them, outside of those flaws, they work. The ones we made work better but they are not for sale (yet??) nor am I going to say what changes are made to them because they are not easy to make.

I didn't talk about performance of the radio other than the percentage of gain from the baseline. The owner's son claims to talk all over the place when he had the stock CB in the truck, he didn't like mine but liked his dad's. He claimed (I wasn't around) that he talked to Germany and a bunch of Candian operators (that's suspect because we are 2.5 miles from Canada). So I had one of my ten meter rigs down at the site (it sits in my pickup), decided to put it in and try it out. This is a 5 watt rig, AM/SSB/CW with nothing other than being a plain jane radio. I talked all over the place, California was no problem, Russia, China and some other places were also contacted. It was odd so I didn't do much more than maybe an hour's worth of band work. The following week I brought my new fangled 10 meter rig there and used that for two hours. The band sucked for the first 2 hours and then opened up. I contacted a couple pacific islands and Japan, then I got SA and another African country. That radio is an SDR radio with 50 watts, it not a typical rig nor is it a super tech machine.

Hope this helps all of you.