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 Post subject: Re: Antenna Systems 101
PostPosted: Sat May 09, 2015 10:40 am 
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TechnoWeenie wrote:
They're called *gasp* technical assemblers..

Shit, on the ODOT install, the STATE supervisor who was responsible for signing off on all the work, DEMANDED that we NOT cut the cable...and also demanded that we 'wrap it in a circle, as tight as reasonably possible'... :facepalm:

So, we had some rigs that would've had a 6' cable run, but had 11' of coiled wire sitting next to the XGM....

We had guys with EE's telling them WHY you don't wanna coil up the wire, and the guy just didn't care... 'we're paying for all the wire, so we're gonna use all of it'......

:nono:


So now your already costing me money... Jigs, extra people hanging around, This is why we make policies that don't seem to make sense sometimes.

If you have a customer that makes bad choices then it should be up to you to know why it's a bad choice and be able to explain it to them so that they become better informed.
Thus part of the reason for this thread in the first place. Your stepping over a dollar to reach a dime!

I pay my people to be smarter than my customers.

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 Post subject: Re: Antenna Systems 101
PostPosted: Sat May 09, 2015 1:31 pm 
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chpalmer wrote:
TechnoWeenie wrote:
They're called *gasp* technical assemblers..

Shit, on the ODOT install, the STATE supervisor who was responsible for signing off on all the work, DEMANDED that we NOT cut the cable...and also demanded that we 'wrap it in a circle, as tight as reasonably possible'... :facepalm:

So, we had some rigs that would've had a 6' cable run, but had 11' of coiled wire sitting next to the XGM....

We had guys with EE's telling them WHY you don't wanna coil up the wire, and the guy just didn't care... 'we're paying for all the wire, so we're gonna use all of it'......

:nono:


So now your already costing me money... Jigs, extra people hanging around, This is why we make policies that don't seem to make sense sometimes.

If you have a customer that makes bad choices then it should be up to you to know why it's a bad choice and be able to explain it to them so that they become better informed.
Thus part of the reason for this thread in the first place. Your stepping over a dollar to reach a dime!

I pay my people to be smarter than my customers.



Are you talking about me? or the state idiot?

If you're talking about me, I don't know where any of what you just said is coming from...

I'm not 'costing money', we didn't have people hanging around, etc.

There was no educating Mr. Inspector...what he said.. went... otherwise he wouldn't sign off, and the company wouldn't get paid....

It took hell and high water to get him to grant a variance, as he wanted us to install an antenna on the roof of a vactor, with the boom literally inches away, which articulated and swept the entire width of the roof... I guarantee an hour after it left, the antenna would've been snapped off by the boom...

Had to manufacture a groundplane, bolt it to the body, and run it that way, to clear the boom...


I've posted the pic before...

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 4:08 pm 
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TechnoWeenie wrote:

They're called *gasp* technical assemblers..

Are you talking about me? or the state idiot?
There was no educating Mr. Inspector...what he said.. went... otherwise he wouldn't sign off, and the company wouldn't get paid....


Im speaking of "any" body that would be there for the purpose you speak. I don't pay people to just do "technical assembly". I expect them to know why they do what I tell them to do. And if need be I do the educating. Ive walked away from a county over this. Not because I think Im right but because I don't want my name on it when it fails. And it did!

Anyway- Back on track.

Look up the Laird MBO16394 and let me know if you can even find that particular NMO mount to solder to any cable. That's already a likeness of your brand of LMR with that package. Ill post a picture after you try and look it up.

By now you should realize that my numbers I worked up do not agree with the data sheets of the coax they advertise. SO then- why not?

http://www.lairdtech.com/brandworld/lib ... 200709.pdf Hint- its not the one in the picture at the top left.

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 5:15 pm 
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195 is a 'high performance rg58'... IOTW, similar to RG8X...

Closest would be an FME NMO mount...If you don't wanna solder...


Again... You're talking about paying for a pre-made cable vs making a better one yourself, at a fraction of the cost of premade.

Cheaper, and better..

I'm not sure what your argument is?

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 6:06 pm 
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All I am going to say is, factory made is always better.

620 NMO/195/SMA assemblies installed. The ONLY ones to fail we're the ones that were terminated by the technicians. Granted itty bitty SMA connectors are harder than NMO mounts, but NO failures are more valuable than 1-2db


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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 6:21 pm 
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TechnoWeenie wrote:
195 is a 'high performance rg58'... IOTW, similar to RG8X...

Closest would be an FME NMO mount...If you don't wanna solder...


Again... You're talking about paying for a pre-made cable vs making a better one yourself, at a fraction of the cost of premade.

Cheaper, and better..

I'm not sure what your argument is?


See- I already knew you were going to say that. Ill do my test with that kit and also pctel mlfml 195 and post those results. My point is what your going to see and what you seem to believe are two very different things.

Thanks Badger! Ive found the same thing. Ive seen many installs where someone thought they could solder and it looked like crap. Ive also tested a couple that were installed and soldered and found them dead shorted. Reason I was there is the customer didn't trust the other shop any longer.

This thread is actually going better than Id hoped.

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 6:24 pm 
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Badger wrote:
All I am going to say is, factory made is always better.

620 NMO/195/SMA assemblies installed. The ONLY ones to fail we're the ones that were terminated by the technicians. Granted itty bitty SMA connectors are harder than NMO mounts, but NO failures are more valuable than 1-2db


I won't disagree with you there..

I hate SMA connectors..

I had to crimp an SMA connector on that LMR240.. Mother of god.

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 6:48 pm 
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chpalmer wrote:
TechnoWeenie wrote:
195 is a 'high performance rg58'... IOTW, similar to RG8X...

Closest would be an FME NMO mount...If you don't wanna solder...


Again... You're talking about paying for a pre-made cable vs making a better one yourself, at a fraction of the cost of premade.

Cheaper, and better..

I'm not sure what your argument is?


See- I already knew you were going to say that. Ill do my test with that kit and also pctel mlfml 195 and post those results. My point is what you're going to see and what you seem to believe are two very different things.

Thanks Badger! Ive found the same thing. Ive seen many installs where someone thought they could solder and it looked like crap. Ive also tested a couple that were installed and soldered and found them dead shorted. Reason I was there is the customer didn't trust the other shop any longer.

This thread is actually going better than Id hoped.


Nothing will get around shitty work or bad habits. Anyone who doesn't test their shit, isn't worth hiring...

To compare a shitty solder job done by some guy who clearly doesn't give a shit about his work, and obviously didn't test it, and using that as an example to 'always buy factory', is disingenuous at best.

In most situations, using a factory cable is the best route. It's easy, comes preassembled, and is the better all around option.

That's NOT to say it's the only option, or the best option, just usually the all around better choice in most scenarios.

You do what you do, I do what I do...

I choose to make my own cables for my personal installs.

For gov't installs, that's a bit different, as they usually specify a certain cable/mount, which is usually RG58... I do try to use RG8X cables/mounts where I can, but again, it depends on the system.

If they have a system with 96% portable coverage, then I'm not gonna worry about 2db loss on a 30W radio with a mounted antenna when a 3W radio with a dummy load for its antenna can still utilize the system.

If they're running simplex or semi-duplex non repeated base/mobile, then the difference between 85W and 75W COULD be the difference between being heard, and not.

Yes, only 1 or 2 db..



This has become a shitfest.. I'm not saying MY way is the only way, I'm just saying it's what I do...

Thank you for testing those cable assemblies, and I could probably submit one or 2 of the self soldered, and one of the FME base as well, if you don't already have something similar.

For the record, I do plan on picking up some FME base NMO mounts.. Should be easier to crimp an FME than solder those SOBs.. :D

I have my M1031 that has to be wired up, so it'll be fun..

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 Post subject: Re: Antenna Systems 101
PostPosted: Sun May 10, 2015 6:54 pm 
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Angus Cheeseburger
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Just did a NMO with FME today. Works like a champ and looks great!

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 Post subject: Re: Antenna Systems 101
PostPosted: Tue May 12, 2015 1:29 pm 
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Quote:
This has become a shitfest.. I'm not saying MY way is the only way, I'm just saying it's what I do...


Not at all! This is educational and no one is telling you what to do. Easy boy... How you walk away with this information is up to you. What I did say is I don't agree that you could do the job the manufacturer does. You would have to prove otherwise if you cared to convince me.

More than anything what Im trying to relate is that there is loss in installs and it all adds up rather quickly, and that fact seems to be ignored by most installers. Its also great for the manufacturers because it means more site infrastructure for them to sell.

Im trying some other test methods that will take some time such as an actual antenna install receiving from a standard source at multiple frequencies. I need to cut another hole in my roof for another radio so that just might be the ticket.

I would like to find some original Antenna Specialties ProFlex (Gray colored and similar to 8X) but PCtel doesn't seem to make it anymore. Proflex Plus is almost as lossy as rg58.

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 Post subject: Re: Antenna Systems 101
PostPosted: Tue May 12, 2015 2:33 pm 
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Quote:
What I did say is I don't agree that you could do the job the manufacturer does.


I would never make such a ridiculous statement. Sorry if I gave you the impression that my soldering and crimping job is better than a factory job. :-p


Quote:
I would like to find some original Antenna Specialties ProFlex (Gray colored and similar to 8X) but PCtel doesn't seem to make it anymore. Proflex Plus is almost as lossy as rg58.


I hear LMR240UF does pretty good.

:D


Quote:
More than anything what Im trying to relate is that there is loss in installs and it all adds up rather quickly, and that fact seems to be ignored by most installers.


I was just thinking about insertion loss on the FME connector on the NMO base, probably .01db...

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 Post subject: Re: Antenna Systems 101
PostPosted: Tue May 12, 2015 2:44 pm 
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Angus Cheeseburger
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"I was just thinking about insertion loss on the FME connector on the NMO base, probably .01db..."

Holy crap! There is a .01db loss on my NMO to FME install. Totally not horrifying!


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 Post subject: Re: Antenna Systems 101
PostPosted: Tue May 12, 2015 2:53 pm 
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Jim wrote:
"I was just thinking about insertion loss on the FME connector on the NMO base, probably .01db..."

Holy crap! There is a .01db loss on my NMO to FME install. Totally not horrifying!


Heh. I think it might be an acceptable loss.. Need more calculations.

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 Post subject: Re: Antenna Systems 101
PostPosted: Thu May 14, 2015 8:07 am 
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Interesting discussion. And good that it has people thinking and discussing.
Been at this awhile too.
Don't take this at all the wrong way, but I have run tests such as this over the years, and not found the loss to be as bad.
Of course, that varies a LOT more with manufacturers over the years than we would like.
The points made are well taken.
Would any folks be willing to elaborate on exactly how they did the measurements?
I have used both measuring the TX with Bird 43's AT the radio and AT the NMO mount, and using VNA thru the system.
With decent stuff, I get around half the loss as the OP found.
Still bad, but what ya' gonna do.
As people have said, the trusty "NMO" is good enuf up to maybe 500 mhz, but probably should have been replaced with something better 30 + years ago as things when higher.
I used to put RG-8 Foam cable on my OWN stuff above VHF.
But, I found it made to little difference to bother with.
I am just using an RG-58 foam, small button on 900... I guess I have gotten lazy. No doubt running something better would help even tho its only a 9 ft run.
I wish I had a pile of the different brand mounts to test.
But, today I am going to run TIA 603 characterizations on what I think may be dubious claims about a repeater.
We did run some interesting tests the other day on VHF low antennas "front cowl" mount, versus middle of the roof.
At least 8 dB difference. Meaning as you might drive roughly "towards" each other, versus roughly "away" from each other, you get a 16 to 20 dB difference. Some nulls were even worse.
I knew it would be bad, but I didn't think it would be THAT bad.
Keep up the discussion. I don't post that often, but I read.


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 Post subject: Re: Antenna Systems 101
PostPosted: Thu May 14, 2015 3:11 pm 
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petnrdx wrote:
Interesting discussion. And good that it has people thinking and discussing.
" mount, versus middle of the roof.
At least 8 dB difference. Meaning as you might drive roughly "towards" each other, versus roughly "away" from each other, you get a 16 to 20 dB difference. Some nulls were even worse.
I knew it would be bad, but I didn't think it would be THAT bad.
Keep up the discussion. I don't post that often, but I read.


VHF low? What antenna are you running? Ive got a system Im testing in the commercial band (48mc) and do not see that much difference from roof to front fender...

Transmit does show directional changes but as receive antenna I do not see a difference.

Im using these- https://www.tessco.com/products/display ... ventPage=1

They do not work very well without a similar ground plane such as the Laird models with a coil do.

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