Antenna connection question

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#1
Got a question about mobile antenna connections. I have a Larsen mobile radio thru the glass antenna but it has a PL259 connection on the end of it. I used a Pl259 to BNC adapter to connect it to my 996XT.Would I get any better reception if I changed out the end and put a new BNC on the cable instead of going thru the adapter?

Thanks
Rich
 

Craigmoe

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#3
If it is a good quality adapter and all connections are solid, I doubt your ear could notice (hear) a difference on that short a run. I suppose, however, an adapter less connection would be preferable.
 
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#5
While there will be loss when using an adapter, you probably won't see it unless you have a very marginal signal to begin with (and the adapter won't be the real solution to that problem).

Think of it this way, you have a bathtub filled with water. This represents what signal you're now getting. You get a glass and fill it up with water and dump it into the bathtub. This represents what signal you'll get after the effort of cutting off the existing connector and replacing it with one that doesn't require the adapter. In both cases, you'll have more (water or signal) without the adapter, but will most likely never notice the difference.
 
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#7
Glad to see we have all the experts on here giving advice on connectors. I don't see one of them providing any technical spec sheets to substantiate a thing they have said except one. The bathtub example is about the best one given so far.

The comments on the glass mounts have not provided any proof one way or the other about just how good or how bad these type of antenna mounts function. I will say that at the VHF band they are not the best. As you go higher in frequency, they do become more effective. The down side is that the glass that many of the auto companies use today has metal particles in the glass for tinting that effects how well these type of mounts work. Trying to get an answer about this out of the dealerships is nearly impossible. Plus many of the mounting location on the rear windows will have the heating wires and again this causes a problem.

In my years of doing mobile radio installs, using the radios myself on both a roof mount and a glass mount, I have seen little difference between a roof mounted 1/4 wave antenna and a glass mount antenna. I say this by doing some testing in a noisy signal area. Swapping the coax cable between the roof mount and the glass mount while not moving, I saw little difference on the noisy signal. I was using a good glass mount unit and not one of the low cost brands for the frequency range being tested. In this case both UHF and 800 MHz (not the same glass mount for both bands).

I will also point out that the glass mounts are designed for one frequency range only. The coil design that couples the RF energy from one side of the glass to the other is frequency dependent. There is no one model works for the range of VHF through 800.

ps: I don't like this site twisting anyone' comments into "add income". I didn't place the link to the "auto companies" glass add into my comments. That was done by this web site. Interesting, now that I have pointed this out, it is gone.
 
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#8
Glad to see we have all the experts on here giving advice on connectors. I don't see one of them providing any technical spec sheets to substantiate a thing they have said except one. ...
Nor do I se any in your post. :)
 
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#9
Here's another factor that might be relevant to this thread. There are two levels of quality in coaxial connectors and adapters. One is for the imported units and the other (much better) one is for connectors and adapters made by name-brand American companies. BNC connectors are particularly subject to this difference; the "good" units fit tightly, but the imported ones slop around on the connection like you wouldn't believe unless you've actually experienced the difference. I was involved with large CCTV installation sales at one time and our factory engineers flat-out refused to allow the imported connectors and adapters in our installations.
 
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#11
I've posted on the subject of through-glass antennas several times but the inaccurate and misleading information about them persists. Briefly stated, the glass is a capacitor, the RF signal is an alternating current (AC), and the basics of electronics teaches that AC passes through a capacitor but the capacitor blocks DC. The fact is that there is nothing wrong with a through-glass antenna if it's installed and tuned properly, and the blanket statement that such installations are "really bad to begin with" is simply not true. Now, if one insists on installing such an antenna on dark-tinted glass, or directly over defroster wires in the glass, the antenna will not operate properly, but if you install it correctly it should work as well, or almost as well, as an antenna with a regular ground plane mounted on a trunk lid.
 
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K9DUO

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#12
I have used glass mount scanner antennas for years and they work great. I routinely pick up Missouri Highway patrol in the east coast of Virginia. FDNY right often too. I have no complaints.
 
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