distance?

[Aircargo]

whats the range on conventional monitoring versus trunked mode....is it the same.
seems like i cant pick up a certain trooper squad here in jersey..im on north end,can only monitor troop b....troop c is about 36 miles away...and i cant monitor it.
heading south w/freq. in scanner...i had to travel about 36 miles towards squad before i was able to receive...BUT!....IN CONVENTIONAL SCANNING...I WAS ABLE TO HEAR MY HOME TOWN POLICE DEPT FROM OVER 45-50 MILES...(.damn caps)
think ant. amp would help me when using my roof top w/bc250d. im running rg-8 100ft...ant is about 45ft above ground.

 

[K5MAR]

There are a lot of variables here. First, the frequency. It's probably safe to assume that the trunked system is 800 MHz., but what frequency is your local PD on? Relative tower heights and power output are two other factors that come into play. Finally, 100' of RG-8 is going to have a significant loss at 800 MHz. If you have to have that long a run of coax, you should consider a low loss alternative, such as LMR-400. An amp at the antenna would probably help also.

Mark S.

 

[Aircargo]

why...400 is thicker cable ? i understand the 100ft but i needed it...
going to try amp....have any sites with a decent amp and price? i figure 100 bucks.
i just would like to monitor next troop south of me....

ty for reply thou.....how much more would 400 cable cost(about 100-or 75ft)...i paid $45 for 100ft of rg-8 w/pl connectors on already.... wasnt bad i think....

 

[K5MAR]

LMR-400 is expensive, about twice the price of RG-8, but the same size. It is made with different material that reduces the attenuation. From my Belden Coax book: RG-8 has 7.6 to 12.8 db attenuation at 900 MHz on a 100' run (depending on which RG-8 you have, RG-8 is a generic term these days), LMR-400 has 3.9 db attenuation for the same run.
http://www.timesmicrowave.com/telecom/pdf/22-25.pdf
Here is a chart that has values for commonly used coax:
http://www.rfparts.com/commcoax.html
Looks like a 100' run of LMR-400 with UHF (PL-259) connectors installed is about $81 plus shipping: http://www.rfparts.com/coax.html
You would be well off getting your coax run shorter if you can. Note, I have no connection with RF Parts, it's just a site that came up on my Google search.

I'm sorry, I can't help you with amplifier information, maybe somebody else can. At this time all my coax runs are under 50', so I haven't needed an amp. If you get one, be sure and get a mast-mounted amplifier so you amplify the stronger signal going into the coax, not the weaker one coming out.

Mark S.

 

[LarrySC]

If you are having trouble w/ 800 then consider an antenna with GAIN. Using regular RG-6 with an antenna rated at 6 to 9 db gain works every time. If only one direction then a Yagi Beam is what to look for. It's not always the coax thats the problem, its the antenna. If you dont pump lots of signal down the coax then the type of coax dosent matter. Good Luck.

 

[mancow]

I'm surprised you are getting any 800 reception AT ALL through 100 ft of rg8 using 259 ends. I have a 7 element beam on 30 ft of LMR400. Without the 400 cable it was almost useless even at 30 feet of rg8.

The system I'm listening to is quite a distance away (50 miles). I don't know how this compares to what you're trying to do but it's an example.



mancow

 

[Aircargo]

when i 1st hooked myself up ...i went with the rg-8....was learning then...now that im more interested,i wanted more distance. ill probably replace my cable.
my antenna(rs 1 ctr whip 3 horizontal whips-16in. long) is on sold wood :!: ....8ft bean above house. about 2in. diameter....holds good and was there already(beam). antenna is on top. 45ft. or so totall.
think amp with wood mask make a prob? :?:

and...my rg-8 :idea: ....can i use it for CB unit and ant.? :?:

 

[mancow]

Your antenna is up considerably higher than mine so I'm sure that helps you out a great deal. I think you will be impressed if you do replace it with something rated for low loss at 800!

Yes, your RG should do fine for CB and lower frequencies below Vhf. I use a decent run for HF and have noticed no problems. The lower the frequency you go the less it matter as much.


mancow

 

[Aircargo]

what about wooden mask its attached to?