Railroad monitoring with Uniden SDS100

NS9710

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Is there any way to improve reception on the Uniden SDS100 or an antenna that won't risk damaging my scanner. I have everything set with no filters, NFM modulation.
 

N4DJC

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Is there any way to improve reception on the Uniden SDS100 or an antenna that won't risk damaging my scanner. I have everything set with no filters, NFM modulation.
An antenna tuned to rail frequencies will help, depending on how far you are from the tracks. A Smiley Slim duck 5/8 at 160 MHz performed better for me than the Diamond everyone recommends. An outside antenna is the gold standard, mobile or base.
 

NS9710

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An antenna tuned to rail frequencies will help, depending on how far you are from the tracks. A Smiley Slim duck 5/8 at 160 MHz performed better for me than the Diamond everyone recommends. An outside antenna is the gold standard, mobile or base.
Would that be a standard SMA Male, or the Motorola or Vertex version be the best fit, since the SDS100 has a unique fit?
 

N4DJC

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Would that be a standard SMA Male, or the Motorola or Vertex version be the best fit, since the SDS100 has a unique fit?
I use a BNC for simplicity (easy on and off). I don't know if their SMA male connector would fit the SDS100 properly.
 

Ubbe

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The filters for demodulation are so narrow in the SDS100 that using FM instead of NFM will give better audio quality with less noise when receiving very weak transmissions.

Also if you have strong transmitters nearby, like in the 155Mhz band that could be too close to the railroad band, then the SDS100 will reduce it's sensitivity to cope with that strong signal. You might want to look at pager filters if you have that problem that can be detected if you do a search of the band and note what the RSSI value says on the carriers it finds.

SDS100 measurements

/Ubbe
 

Nasby

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I don't care what others say, I've tried every filter setting using an RH77CA antenna and the SDS100 just plain sucks for railroad monitoring!
An old 10 channel, 25 year old analog scanner does a much better job.
 

wa8pyr

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I use my SDS100 for RR monitoring in situations where I can only tote one radio; it does a pretty respectable job monitoring railroads with the REMtronics antenna (better with a Smiley 5/8 duck RR antenna); I found that placing railroads in a separate system and increasing the hold time to around 1.5 seconds on that system made a considerable improvement in the radio being able to catch the stuff.

If I can carry more than one radio I'm more likely to use my Icom F3161 or Motorola XTS5000 for monitoring rail; for general rail and air monitoring a Uniden BC125AT works great.
 

NS9710

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What connection do you use, straight SMA Male, or one of the variants?

I use my SDS100 for RR monitoring in situations where I can only tote one radio; it does a pretty respectable job monitoring railroads with the REMtronics antenna (better with a Smiley 5/8 duck RR antenna); I found that placing railroads in a separate system and increasing the hold time to around 1.5 seconds on that system made a considerable improvement in the radio being able to catch the stuff.

If I can carry more than one radio I'm more likely to use my Icom F3161 or Motorola XTS5000 for monitoring rail; for general rail and air monitoring a Uniden BC125AT works great.
 

ko6jw_2

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Smiley antennas can be ordered with different bases. The bases screw on the the antenna. They sell the base connectors separately if desired. Thus, I have both SMA and BNC bases for some of my antennas. The Diamond RH77CA has a larger diameter base which I've heard is a problem on SDS100. Smiley's bases are small diameter. The RH77CA is basically a 2 Meter/ 440 antenna. Lots of people use them on scanners, but they are not optimized for 160MHz. What about just using a quarter wave whip adjusted for 160MHz? It will outperform any rubber duck. The Smiley "5/8" wave duck antennas may have a slight advantage when transmitting, but they don't really improve reception. Smiley sells whip antennas in both quarter wave and 5/8 wave. Adjusting them to less than full length will optimize them for higher frequencies.
 

Whiskey3JMC

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I use Comet W100RX antennae, SMA version on my SDS100 and BNC on my AOR AR-DV10 (native, no adapters). They do a nice job on rail, air, etc. As Ubbe mentioned, make sure you set the modulation to FM to bring in the more distant signals with less hiss. Plus they fold nicely alongside your radio so they don't protrude out if you keep your radios in your pocket or a bag
89311
 

wa8pyr

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What connection do you use, straight SMA Male, or one of the variants?
I have the BNC adapter for the SDS100 sold by jonweinke on this site, so I use the BNC base with the antenna. Smiley antennas can be ordered with different bases, so I have a selection of them to suit various radios I own.

The Smiley "5/8" wave duck antennas may have a slight advantage when transmitting, but they don't really improve reception.
YMMV. The Smiley 5/8 duck specifically cut for 160 MHz makes a noticeable reception difference on any radio I use it with.
 
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