Not so much on VHF.
I know that the attenuation will be less at VHF than UHF/700/800, but for somebody trying to improve reception, starting with a compromised setup isn't going to be necessarily helpful. That's all.
Not so much on VHF.
Does anybody here have experience with Mini-Circuits passband filters for railroad VHF voice? I see they are exponentially cheaper than the preselectors from STI-CO, Polyphaser and/or Sinclair. The model in particular I was trying to link was SXBP-162+, which is said to be a "Lumped LC Band Pass Filter, 155-169 mHz."
Lumped LC Band Pass Filter, 155 - 169 MHz, 50Ω | SXBP-162+ | Mini-Circuits
Mini-Circuits is a global leader in the design and manufacturing of RF, IF, and microwave components from DC to 86GHz.www.minicircuits.com
That one doesn't appear to be tight enough to block out NOAA weather radio or VHF paging transmitters.The model in particular I was trying to link was SXBP-162+...
That one doesn't appear to be tight enough to block out NOAA weather radio or VHF paging transmitters.
I don't but I have one of these and it seems to work well,
AIS 162 MHz Band Pass Filter Bandpass 160 MHz 161 MHz 162 MHz in Enclosure | eBay
This is a 3rd orderAIS bandpass filter in an enclosure, with excellent sideband rejection. This product is ideally suited for AIS receiver applications at 162 MHz . AIS uses the high side of the duplex from two VHF radio "channels" (87B) and (88B).www.ebay.com
He also sells one without a case for a little cheaper,
AIS 162 MHz Band Pass Filter Bandpass 160 MHz 161 MHz 162 MHz | eBay
This is a 3rd orderAIS bandpass filter with excellent sideband rejection. This product is ideally suited for AIS receiver applications at 162 MHz . AIS uses the high side of the duplex from two VHF radio "channels" (87B) and (88B).www.ebay.com
If you try the Minicircuts model let us know how it works. They both have some insertion loss even with the passed frequencies.
If there is one that can let the railroad frequencies through but block NOAA I would sure love to know about it!
Using an actual railroad transceiver like a Clean Cab Spectra or high end commercial radio should not require any filtering to keep out NOAA weather or anything else, just hook it up and enjoy beautiful reception.
how far are you looking to pick up
I agree, it is VERY rare that I ever have any kind of intermod with my Motorola CDM1550, I think I had NOAA bleed in once when I was literally right next to the tower and it only lasted for a few seconds.
RR build there base stations for about 20miles coverage. maybe try beam
You'll unfortunately have that when those HTs barely get two mile range. It's getting to the point trains are so long if a conductor is working a cut at the end of a long train their handheld won't reach the engine unless they step away from the train and stick their radio in the air.The base stations come booming in. The portable radios are the ones that come in weak. I am trying to improve those. I received my collinear antenna but the weather has not been cooperating. I will report back once I get to play with it.
You'll unfortunately have that when those HTs barely get two mile range. It's getting to the point trains are so long if a conductor is working a cut at the end of a long train their handheld won't reach the engine unless they step away from the train and stick their radio in the air.
An update...I have the Laird omni mounted on a tree in my yard at around 15’ at its base. Definitely an improvement over my discone in the attic. By switching among the antennas I can tell the signals on the Laird are much stronger and clearer even with my subpar cable run. The cable run needed to get to the antenna is about 150’. I rolled up the loss to be about 5 dB, which I realize is a lot.
This evening I installed a HPN-30118 and ZX60-P103LN at the antenna. The preamp has a gain around 24 dB at 160 GHz. At the radio I have a 10 dB attenuator and a 0-10 dB variable attenuator. With the variable atten at around 9 dB the gain of the preamp should roughly counter the cable loss.
I tuned into an extremely weak NOAA broadcast and played with the attenuation. I adjusted it until the signal peaked on intelligibility. It was not an exact science but it seemed like it peaks at total attenuation 15-16 dB so I set it there. Dialing back the attenuation further did not appear to help the desired signal quality. At this hour there are not too many rail signals for me to monitor so I can’t really assess how well it works.
Am I thinking about attenuation settings the right way? Is there a better approach to take when dialing in the attenuation?