Seeking Feedback on Rail Band Reception Improvement Options
- Thread starter MDScanFan
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- Feb 6, 2014
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Hi all,
I read this and many other similar topics on RR with great interest, trying to gain some insight on improving my own railroad listening setup. I was going to try the AIS bandpass filter suggested above, but thought I would try Par Electronics first... I now have a Par railroad bandpass filter and I was informed that rail band filters are now part of the catalog.
HTH,
Michael
I read this and many other similar topics on RR with great interest, trying to gain some insight on improving my own railroad listening setup. I was going to try the AIS bandpass filter suggested above, but thought I would try Par Electronics first... I now have a Par railroad bandpass filter and I was informed that rail band filters are now part of the catalog.
HTH,
Michael
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Do you have any specs for the par rail filter? As others have pointed out, one of the common challenges with the rail band are signals adjacent to the rail band, such as the pager bands at 152 and 158 and noaa at 162. If those signals are the issue, or one of the issues, then it is hard to mitigate them with a bandpass filter while maintaining a reasonable passband insertion loss. In my location both of those pager bands, noaa, and the fmbcb come in real strong and cause problems.
If funds are not a problem,
Still won't help with NOAA though.
Still won't help with NOAA though.
Michael, if you end up using Par, let me know. I had a friend recommend them to me and I sent them an e-mail tonight, waiting on a reply back. I'm looking to see if they can make me a couple ATCS filters, some of my site sit in high RF environments and I'd like to squeeze a little extra reception with a preamp, so I'm hoping their filters could do the trick.
Mike
OP back with an update on my setup...The Laird FG1563 collinear is my primary railband antenna. At the antenna I have a PAR FMBCB notch filter followed by a minicircuits LNA (ZX60-P103LN). The LNA is powered by a set of Commscope power inserters (CSHMPI). The coax I am using is a flooded RG6 from Commscope (F677TSEF) at around 100-125’ long. In the shack the coax goes into a 0-60 dB step attenuator (likely to be replaced with a fixed attenuation at some point) and then a two way minicircuits splitter (ZSC-2-1+) and then to a Kenwood TM-281A. Between the radio and the splitter I have a 2-way Daiwa switch that allows me to switch to a fixed position 150-165 5 element yagi. Right now, the yagi is connected directly to the switch via coax - no preamp.
For my secondary setup...the other path of the splitter goes to a pager band notch filter (PAR VHFSYM152HT) and then a 780XLT or 125AT. Without the filter all of my scanners exhibit significant intermod issues. Even with the 152 notch I still notice intermittent intermod products. If I add a 162 notch filter (VHFSYM162HT) the issue goes away completely. The trade off is an additional ~ 3 dB of loss in the rail band. For the specific rail channels i tend to monitor the 162 filter is not needed.
This setup offers a dramatic improvement in reception. I smile when I do a side by side reception comparison with my initial configuration (attic discone - coax - scanner). The difference is like night and day. Weak signals are much stronger and I get a lot more traffic than before.
Of course, never content, I am planning to try a couple setup tweaks for the fun of it. I will report back when I do...
For my secondary setup...the other path of the splitter goes to a pager band notch filter (PAR VHFSYM152HT) and then a 780XLT or 125AT. Without the filter all of my scanners exhibit significant intermod issues. Even with the 152 notch I still notice intermittent intermod products. If I add a 162 notch filter (VHFSYM162HT) the issue goes away completely. The trade off is an additional ~ 3 dB of loss in the rail band. For the specific rail channels i tend to monitor the 162 filter is not needed.
This setup offers a dramatic improvement in reception. I smile when I do a side by side reception comparison with my initial configuration (attic discone - coax - scanner). The difference is like night and day. Weak signals are much stronger and I get a lot more traffic than before.
Of course, never content, I am planning to try a couple setup tweaks for the fun of it. I will report back when I do...
There are some railroad control or ATCS signals sent over the normal ARR channels, as far as I know only BNSF uses these. The protocol is ARES or ATCS over ARES.
However since the poster said he is trying to "see" if they can make a filter for ATCS my guess is he is seeing if they can make a filter in the 896-937 range that most ATCS uses.
I'm actually working on getting a filter myself tuned for 928-933, since UP changed their protocol to the new 19200N from RFL in my area, which increased the baud rate from 300 to 19,200 I'm having a really hard time decoding some more distant signals. I have a BCP tower literally 1000Ft. from my antenna broadcasting at 952MHz, so I'm hoping the filter might help my reception some. I found one on ebay that has a claimed insertion loss of only 1.5db, I've sent it to a friend who has a spectrum analyzer for fine tuning.
Maybe were not referring to the same thing, but there is for a certain ATCS data that is over the VHF band, I've used and monitored it myself many times, I have 2 VHF radios dedicated just for this use in my mobile ATCS kit. The signals signals on the VHF band control switches, line routes, send track occupancies to the dispatcher etc. It isn't as common as the ATCS used over the 896-937 band, but it certainly is there, I can think of 4 different subdivisions here in Missouri that use it. The protocol is ARES, it is sent at 2400 baud. Some areas use the ATCS protocol over ARES.
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Hi all,
First, I am a novice.
The filter I had made by Par, I had it include the NOAA bands... As for my use case, I wanted full coverage of the NOAA band. Obviously, this is not the use case for a majority of listeners, and I was told a filter could be made narrower. So, I present the statistics for my filter with that caveat. These are the numbers provided to me by Par:
Passband: 159.57-162.5MHz (again, this could be made narrower but was done at my request)
Loss in the passband: under -3dB
Loss at 144MHz: -46dB
Loss at 180MHz: -41dB
3 cavities
HTH,
Michael
First, I am a novice.
The filter I had made by Par, I had it include the NOAA bands... As for my use case, I wanted full coverage of the NOAA band. Obviously, this is not the use case for a majority of listeners, and I was told a filter could be made narrower. So, I present the statistics for my filter with that caveat. These are the numbers provided to me by Par:
Passband: 159.57-162.5MHz (again, this could be made narrower but was done at my request)
Loss in the passband: under -3dB
Loss at 144MHz: -46dB
Loss at 180MHz: -41dB
3 cavities
HTH,
Michael
That loss sounds about right for the bandwidth and filter style. Yes, it can be made narrower but that usually comes at the expense of increased passband loss. So it is a trade.
Out of curiosity, what interference are you trying to mitigate with that filter?
Out of curiosity, what interference are you trying to mitigate with that filter?
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