Tram 1094

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seth21w

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Hi everyone I have a question, I just bought a tram 1094 and put on the roof of my house and I am using it on my bcd536hp. The antenna comes with 2 sections, I was wondering if I should undo the top section to tune more for 800mhz I am trying to improve 800mhz reception. It also comes with 17 foot rg58u coax is this as good as rg6?
 

mmckenna

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No, removing the top section won't likely improve 800MHz coverage.

What will improve coverage is getting the antenna as high up as you can safely get it and feeding it with the best coax you can afford.

RG-58 coax is pretty low grade stuff. It's OK for mobile use where the cable run is pretty short. If you are going to need more than the 17 feet, then use a higher grade cable. Good RG-6 will outperform the RG-58.

Also, since this is a mobile antenna, it's designed to sit on top of a ground plane, like a vehicle roof. Make sure you install the antenna on a suitable ground plane for best results. That may be a steel sheet, baking pan, pizza sheet, piece of sheet metal, metal garbage can lid, etc.
 

mmckenna

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Using RG-58 at 800 MHz over a 17 foot run is losing almost half your signal. 2.45dB to be exact. If you were using this for transmitting (I know, you aren't, but just for example) if you put 100 watts in at one end, you'd get about 54 watts out of the other end at 860MHz. The other 46 watts are lost in the cable, converted to heat and never make it to the other end.

On the other hand, if you use RG-6:
1.5dB of loss at 800MHz, or if you put 100 watts in, you'd get about 70 watts out the other end.

RG-58 is used in mobile installations because it's small, flexible and cheap. In a base installation, you'd really want to use something better if you can, especially if you need more than the few feet of cable you have.
While you were at it, I'd say get a real base antenna, it'll likely last longer and work a bit better. But, budgets are budgets, and we do the best with what we can afford.
 

mmckenna

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Well, what's your budget, and what frequencies are you most interested in?

Discones can be a good option in some cases. They'll cover a lot of the spectrum that most scanner listeners are interested in. They don't have any gain, but that's OK. If you coaxial cable run is pretty short, then you don't necessarily need to spend a lot of money there.

Your trailer roof is acting as an excellent ground plane, so that's something you've got working for you.

There's a lot of different options for antennas, and it really depends on exactly what you are trying to do:

Vertical omnidirectionals are good for coverage all around you.
Directional antennas are a good option if the signal you are trying to get is on one band and is in one general direction. Drawback is they work best in one direction.
Discones are a good all around option, but they are not stellar performers. Where they work well is covering a lot of spectrum, but they do that at the cost of gain.

For the average scanner listener, a discone is a good choice, but you'll pay a bit more for it.

If the system you are wanting to listen to is far off then a band specific antenna with some gain might be a better choice, or even the directional.
 

mmckenna

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35 miles on 800MHz shouldn't be an issue if you have a clear line of sight at the system. If there is mountains/hills in the way, then it's going to be difficult.

An easy test is to take your scanner up on the roof with it's antenna attached on the back.
See if you can hear what you want to. If you can, then your location is good. If you can't, it's going to take some antenna work to make it happen.

If 800MHz is all you want to listen to, then a dedicated 800MHz omnidirectional antenna would be a better choice.

If you want more than 800MHz, then probably the discone would be a better option. If you shop around, you may be able to find a good one for less than $100 bucks. Used, if in good shape, can be a good option. Deals are out there, you just have to know where to look. Scored my discone for free, but that's a long story.

Put a discone up has high as you can safely get it. Feed it with some RG-6 coax with the proper connectors, and you'll probably do pretty well.

If you are hearing what you want with the current antenna on the roof, but it's scratchy, more height and better coax will probably improve things on it's own.
 

captainmax1

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I have been using discone antenna's for decades with great results for scanning. I have a discone antenna on a 25' mast and use 50' of LMR 400 cable which can receive signals from up to 60 miles away. Guess I have about $300 invested but well worth the extra bucks for long term enjoyment of your scanners. The discone is also great with UHF/VHF Ham radio TX and DX.
Diamond D130J Discone Antenna
 

mmckenna

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A long, long time ago I had a centerfire base antenna that I was using as a GMRS base. It was built OK, but never could quite get it tuned correctly. Sort of turned me off on the brand. I know others have had good luck with them.

The Diamond that Captain Max linked to is a known good antenna. That's the one I scored for free a few years back. Not a high end commercial unit, but perfectly suitable for hobby use. Can be a bit fragile, so be careful when installing it.
The antenna comes in two models. One has the UHF/SO239 type female connector. The other has the N type connector. If you are buying new or have a choice of used ones, go for the N connector. Slightly better performance on the higher frequencies and a better connector design. Prices should be the same.

LMR-400 is a good choice, but if your cable run is really short, the slight improvement that you would get would be hard to recognize without some good test gear. If you can work it into your budget, do it. If not, don't sweat it. Use a less expensive cable and upgrade when you decide you need to. If you are doing OK with a magnetic mount with 17 feet of cable and it reaches your radio, then the difference between 17 feet of RG-58 and LMR-400 becomes pretty small. If you do put the antenna up higher, then additional cable will be needed and it's probably a good idea to step up to the LMR400 if you can swing it.

Get the correct ends on the cable to match your radio and antenna. Adapters cause headaches.
 

mmckenna

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There are so many brands of rg6 coax that i dont know which is quality thats why i need a link to known good rg6 or lmr400
RG-6 = Belden, BerkTek, CommScope
LMR-400 = Only maker of "true" LMR-400 is Times-Microwave. Everything else is a knock off. Beware of any company advertising "LMR-400 like" or "LMR-400 Equivalent". There are other compatible brands, but make sure it's from a US manufacturer. There are some cheap Chinese knock offs.
 
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