Frederick / Montgomery 154.280 VFIRE21

c5corvette · #1 (**permalink**) 10-31-2011, 05:02 PM

154.280 appreas to be used by several border counties in Maryland.
154.280 is listed in NIFOG for interop as VFIRE21.

When programmed for interop, 156.7 is the NIFOG suggested PL tone.

Question here is when Frederick or Montgomery broadcasts mutual aid, are they using this or any other tone?

ka3jjz · #2 (**permalink**) 10-31-2011, 05:16 PM

Actually most all counties in Maryland, AFAIK, has this channel as a mutual aid channel (certainly the ones in Central Maryland up and down the I-95 corridor do). I have no idea whether they are following the NIFOG recommendation (in fact I rather doubt it, but would be nice to be proven wrong). Many jurisdictions, and I'm sure Frederick and Montgomery do this, make a patch from their trunk system without using PL.

best regards...Mike

c5corvette · #3 (**permalink**) 10-31-2011, 05:24 PM

Yes, I sometimes hear Frederick and Montgomery talking to Loudoun (VA) and Jefferson (WV) on this.

I want to program these into my scanner with the PL instead of CSQ, to filter out some of the intermod while driving through the big cities, but am afraid if I do this it will actually prevent me from hearing some of the counties around here that are supposed to be on these channels.

I will be monitoring with PL for a while to see what I get. If anyone knows for sure - please reply.

ka3jjz · #4 (**permalink**) 10-31-2011, 05:52 PM

Well you could check the database (hint hint) - I did and I think you'll find that at least in Frederick and Montgomery there's no PL on that frequency.

An old friend of mine (a fellow ham who passed away about a year or so ago from a major stroke) was on the committee that was discussing interop in Maryland. The Eastern Shore is much better in this regard than we are - too many areas are still in the NIMB mode at that time. Probably still are.

I put a PAR filter on my dual band ham gear in my car - I get virtually no intermod junk on that anymore. Time for an investment. Pricey but you get what you pay for

best regards..Mike

c5corvette · #5 (**permalink**) 10-31-2011, 07:02 PM

Quote:

Originally Posted by ka3jjz

Well you could check the database (hint hint) - I did and I think you'll find that at least in Frederick and Montgomery there's no PL on that frequency.

An old friend of mine (a fellow ham who passed away about a year or so ago from a major stroke) was on the committee that was discussing interop in Maryland. The Eastern Shore is much better in this regard than we are - too many areas are still in the NIMB mode at that time. Probably still are.

I put a PAR filter on my dual band ham gear in my car - I get virtually no intermod junk on that anymore. Time for an investment. Pricey but you get what you pay for

best regards..Mike

The database shows CSQ on almost all the FMARS channels around the MWCOG area, but I was hoping for a little luck with PL tones.

The IM in NoVA and Baltimore seems to be the worst. Most of the scanner fiters focus on notching out FM broadcast, Paging, and NOAA. Unfortunately, I dont want to loose up to -35db at some of those areas.

I could tone things down by using a basic multi-band scanner antenna, but I usually have a specifically tuned antenna on each scanner. For example, when listening to the higher side of the VHF-Hi spectrum ;-) my mobile antenna picks up NOAA on 6 of the 7 different weather frequencies from any given point in northern Fairfax County.

ka3jjz · #6 (**permalink**) 10-31-2011, 07:19 PM

I'm in the Baltimore County (Woodlawn) area when I'm at work, and where I am, paging is a royal PITA. I put a PAR paging filter on it, and have absolutely no trouble receiving the mutual aid freqs when they're active. You should take another look at them - the notch depth is listed as -35db, but it's only for a very narrow bandwidth. I also have AA, PG and Howard county's fire dispatch, along with the MSP Portables frequency, in my IC 207, and have no problems at all with the filter in line.

Like I said before, the PAR filters are pricey but you get what you pay for. These ain't cheap in construction, for sure...best regards..Mike

[edit] It sounds very much like you're being seriously overloaded. Did you try just using a 1/4 wave whip, which would cut your response down considerably? I used to drive from Glen Burnie down to Tyson's Corner Virginia a few years back and found that I had to use a less responsive antenna to get a reasonable response without a lot of the overloading (this was before I put the PAR filter in line...)

ka3jjz · #7 (**permalink**) 10-31-2011, 07:56 PM

Another thought here - if you are using your PSR800 with a VHF gain antenna you're asking for trouble. It's been well documented that GRE radios are far and away more prone to problems in the VHF hi band. I can't remember exactly, but I think the passband filter in that radio stops at 88 mhz or so - so guess what, FM broadcast blasts right in and you get overloading all over the place.

I seem to recall that folks that have put a bandstop filter for the FM broadcast band have reported that this settles down the GRE radios pretty well. Makes sense, with the density of FM broadcasters we have in the area.

Just a thought...best regards..Mike