Pro-95 problems in nj...

[Tech792]

I hate to repeat myself, but the antenna Erik is using is a VHF HIGH BAND mobile antenna. That would explain why he can only receive close-by 800 systems. A paper clip would probably work better.

 

[erikTromatowski]

Then please explain how I can pick up the conventional 500 freq.'s loud and clear, and the county 800 system (though I know the antenna is supposedly tuned). I have always been able to hear systems this far away with this antenna, so I don't believe the antenna is faulty. The coax has not been exposed to weather for 2 years. Most of the time its been inside sitting on my windowsill, with occastional trips on top of my car. Just recently have I put it outside semi-permenently. I thought maybe its because of the length of the run of coax (50'), so I took the antenna off of that 50' run, but I still cannot hear trunking systems other then the county. Maybe I should get a pre-amp? And if I cannot receive the other 800 systems, because the antenna is tuned, why is it then that I cannot pick up two VERY close 500 trunked systems, if I am able to recieve conventional 500 frequecies from as far away as Hillsborough (about 12 miles away)?

 

[loumaag]

Then please explain how I can pick up the conventional 500 freq.'s loud and clear, and the county 800 system (though I know the antenna is supposedly tuned). I have always been able to hear systems this far away with this antenna, so I don't believe the antenna is faulty. The coax has not been exposed to weather for 2 years. Most of the time its been inside sitting on my windowsill, with occastional trips on top of my car. Just recently have I put it outside semi-permenently. I thought maybe its because of the length of the run of coax (50'), so I took the antenna off of that 50' run, but I still cannot hear trunking systems other then the county. Maybe I should get a pre-amp? And if I cannot receive the other 800 systems, because the antenna is tuned, why is it then that I cannot pick up two VERY close 500 trunked systems, if I am able to recieve conventional 500 frequecies from as far away as Hillsborough (about 12 miles away)?

Erik,
You continue to refer to conventional frequencies as if they are somehow majically different than trunking frequencies. They are the same thing, RF! There is no difference in the reception of RF between a frequency assigned to a trunking system and an adjacent (or even the same) frequency assigned as a conventional frequency. NO difference. That fact being established, consider that you think hearing a 500MHz signal from 12 miles away as an accomplishment. I think it is abysmal! Given normal terrain and a nominal tower height for the transmitter, a UHF (which 500MHz is) should be clearly heard out to 20+ miles on the rubber duck that came with your scanner.

Listen to me, if you can hear something on a rubber duck inside your apartment and it goes away when you hook the outside antenna to the radio, the outside antenna system is broke. Now, I am not saying the antenna itself has problems or indeed the coax, I am saying by definition if it attenuates signals, it is not working for what you want it to. Someone else in the thread pointed out that the antenna you are using is a VHF antenna, well okay. I don't think that is a factor on UHF most VHF antennas will be an odd multiple on UHF. It does; however, approach an even multiple on 860MHz and hence will attenuate those signals some. So...given these facts the only conclusion to be drawn is something is wrong with the antenna system.

 

[robbinsj2]

[...] With my outdoor antenna (Maxrad MHB5800 with mag mount, I live in an apartment), I am able to recieve the Middlesex County EDACS system (it's an "800" system), but no other trunked system [snip] With the supplied rubber duck antenna, I can recive all systems (though not very well, since it is a rubber duck. Most of the time most of the systems are unreadable). (...)

Let's summarize. Your scanner works, albeit poorly, with the "all-band" stock rubber duck antenna. Your scanner doesn't work (on all but one of the systems, which is very nearby) using the Maxrad VHF-high antenna. The systems you are having trouble with are UHF and 800/900 MHz.

If, as you suggest, nothing else is changing in your setup then it almost must be the antenna, as that is the variable. Yes, you can receive conventional (analog, right?) signals in the same bands using the VHF antenna, but to decode CCs, which are digital, you need better reception. I can not notice an audible difference in reception of many CCs when using a stock antenna versus the RS 800 MHz antenna, but my Pro-96 sure knows the difference, as evidenced by the decode percentage on Mot systems.

I'd suggest you acquire a wideband antenna, or better yet one tuned to UHF and/or 800, and compare performance. Naturally make sure you can return it if the problem is not solved, but I would guess it will help immensely.

 

[erikTromatowski]

Ok, point taken. But, this question is still in my mind. Why am I able to receive a 500 system from 15 miles away, but not a 500 system from 3 miles away? I know that there is no difference between the two frequecies (as to loumagg's deffinaition, which I trust). Also, the maximum height I can get on my antenna is only about 8 ft. AGL, so that could explain for the short range.

 

[Tech792]

Not all systems have the same wattage or ERP. The 500 system thats 3 miles from you might be 25 watts ERP and on a smaller tower,where the one thats 15 miles might be 300 watts ERP.

 

[erikTromatowski]

Well, Piscataways tower is about 3 miles away and has a 300 watt ERP. And, according to the FCC database the tower site elivation is 26.0 meters.

 

[mikea7531]

Erik, Max ERP on the Piscataway TRS is 40. http://wireless2.fcc.gov/UlsApp/UlsSearch/licenseFreqSum.jsp?licKey=1222285

It's listed as conventional frequencies, which is strange since it's a TRS

 

[erikTromatowski]

I see... Sorry about that, got confuesed while looking at Loumaags post. But shouldn't I still be able to hear it? I'm about half a mile away from the Highland Park - Piscataway boarder. Considering that the New Brunswick PD dispatch channel (460.3) has a max ERP of 50 watts, and thier tower is about 3 to 4 miles away (and I am able to hear that with my outdoor antenna or without an antenna loud and clear). I guess I just don't understand why I am able to hear a 500 system from 15 miles away, but I cannot hear a 500 system from only 2 miles away, even if it is at a much lower ERP, I would think I should still be able to hear it given the close proximity.

 

[loumaag]

...Considering that the New Brunswick PD dispatch channel (460.3) has a max ERP of 50 watts, and thier tower is about 3 to 4 miles away (and I am able to hear that with my outdoor antenna or without an antenna loud and clear).

Okay, now you have proved your outdoor antenna system is broken! It operates as well as no antenna! :lol:

I fail to see why you think there is some other problem. You know the radio works; you know the rubber duck works; you know if you hear something on the rubber duck it disappears when you hook the outside antenna up; why do you continue to believe the outside antenna system is fine? :?: :roll:

 

[erikTromatowski]

Ok, thanks. Do you know where (online) I could get another maxrad antenna that would fit onto my magmount (so I can interchange the two)? I saw my antenna online without the magmount for only about $30. With the magmount it cost me $60.

 

[loumaag]

Ok, thanks. Do you know where (online) I could get another maxrad antenna that would fit onto my magmount (so I can interchange the two)? I saw my antenna online without the magmount for only about $30. With the magmount it cost me $60.

No I don't know. However, before you buy a new antenna to stick on that mount, might I suggest that you take the antenna off of the mount and use an alligtor clip to hook a piece of wire (try about 18") to the center of the NMO mount and see if the problem is the antenna or the coax/mount. Never fix the part that is not broken.