SDS Discone help

[raf1919]

Hi All, Long time lurker first post... total noob here.

I have a SDS100 and felt like tinkering to see what Antenna upgrade would bring in, from reading on here seems like another duck is waste of time and discone would be better. Going to get a D130JN or D3000N (still deciding) attic mount, but I need help with the cabling and connection to make it work. Going to use 25ft LMR400UFUMUM25 but what do i need to make the connection to the SDS100 (SMA)? Is it just a simple N to SMA connector, I've seen mention of using 240. Also if only running 25ft do i Need LMR400 or can I use 240. If no improvement on SDS I can always use this for my ADS as well but want to see what kind of range improvement I'd see.

 

[Whiskey3JMC]

Hi & Welcome to the RR forums. What band(s) are you looking to bring in better?

 

[raf1919]

Hi & Welcome to the RR forums. What band(s) are you looking to bring in better?

Honestly I'm just tinkering to see what I can pull in and experiment. I mainly I Listen to my local (chicago area DUCOMM) Central dispatch which is P25 and I get that in pretty good. But the tinker in me wants to see what else I can pull in and eventually maybe use the setup for my ADS Pi system.

 

[Ubbe]

Going to use 25ft LMR400UFUMUM25 but what do i need to make the connection to the SDS100 (SMA)?

A pigtail would be the best. It makes it easier to handle the scanner and will not strain its connector with a thinner much more flexible coax. SMA male at one end, preferable an angled one, and the other end to match whatever the bigger coax will use.
If you have the SMA-BNC adapter you could have an angled BNC connector at the coax instead of the SMA one.

Pigtails

/Ubbe

 

[iMONITOR]

If by P25 you mean frequencies above 700MHz a discone would not be my first choice.

 

[raf1919]

A pigtail would be the best. It makes it easier to handle the scanner and will not strain its connector with a thinner much more flexible coax. SMA male at one end, preferable an angled one, and the other end to match whatever the bigger coax will use.
If you have the SMA-BNC adapter you could have an angled BNC connector at the coax instead of the SMA one.

Pigtails

/Ubbe

perfect thank you.

 

[raf1919]

If by P25 you mean frequencies above 700MHz a discone would not be my first choice.

open to other options. Would consider placing 2 in attic can always use the discone for my ADS

 

[iMONITOR]

Hi & Welcome to the RR forums. What band(s) are you looking to bring in better?

OmniX Scanner Base Antenna

Specs Gain: 3 VHF 4 UHF dBi Pattern: Omni-directional Wavelength: 1/2 Elements: 3 Tuned: 118-137, 148-175 & 225-900 MHz Band: UHF & VHF Connector: N Female Cable: RG8X Cable Length: 16 Inches Height: 45" Width: 30" Weight: 2 lb Features Multi Band-Wide Coverage: The uniquely...

dpdproductions.com

 

[lzielasko]

OmniX Scanner Base Antenna

Specs Gain: 3 VHF 4 UHF dBi Pattern: Omni-directional Wavelength: 1/2 Elements: 3 Tuned: 118-137, 148-175 & 225-900 MHz Band: UHF & VHF Connector: N Female Cable: RG8X Cable Length: 16 Inches Height: 45" Width: 30" Weight: 2 lb Features Multi Band-Wide Coverage: The uniquely...

dpdproductions.com

Switched from a discone to the OmniX a year ago. Big improvement.

 

[togo54]

I'm using a discone in my attic and running rg6 coax to boot. Why? Because the coax was already there. Not sure what, if anything I might be missing out on but attached is a partial screenshot of some of what I do receive.

 

[jonwienke]

I use a discone and 20 feet of LMR400 for my scanner reception, and that works pretty well. RG6 means extra loss at each end of the cable due to impedance mismatch, but not a huge amount. I wouldn't buy RG6, but I've used it when I had a bunch lying around, and it worked reasonably well.

 

[darkness975]

Though there are antennas that handle over 700mhz better , discones can still work well depending on your configuration.

 

[togo54]

I use a discone and 20 feet of LMR400 for my scanner reception, and that works pretty well. RG6 means extra loss at each end of the cable due to impedance mismatch, but not a huge amount. I wouldn't buy RG6, but I've used it when I had a bunch lying around, and it worked reasonably well.

The RG6 in my house is from past satellite tv installations and and in all 5 locations in my house that the cable it run it is in interior walls. I'll live with a little signal loss as opposed to trying to run new cable

 

[jonwienke]

That makes sense if the RG6 is already installed.

 

[Ubbe]

Though there are antennas that handle over 700mhz better , discones can still work well depending on your configuration.

If you use the discone at 400MHz and lower it will probably work fine. At 900MHz its directivity points up at a 60 degree angle and at the horizon the signal are down 10dB or more. But if you only have strong signals then 10dB loss are no problem, or cut all elements down to half size.

/Ubbe

 

[R0am3r]

@Ubbe - Just wondering, what discone antenna did you model? I routinely "see" aircraft ADS-B signals from 100 - 125 nm (185 - 232 km) away from me. Because of the aircraft altitude, that certainly isn't a horizontal distance. Based on these distances, it is obvious the antenna isn't limited to seeing signals directly above it. For reference, I use the MP Antenna 08-ANT-0861 discone.

 

[TailGator911]

The Diamond D-130J wideband discone serves me well for all but my local MARCS P25 Phase 1 system, for which I use a Terrawave directional yagi (Scanner Master) aimed at my local site about 5-6 miles away. My discone does very well for vhf/uhf and mil-air. I have both on a mast at the side of my house about 25ft high. I am in a sweet spot here for everything, so the 130J is all I need.

 

[Ubbe]

For reference, I use the MP Antenna 08-ANT-0861 discone.

You use the "spider" antenna 08-ANT-0861, which could perhaps work as discone but more like a multifrequency GP. I have a 100cm telescope antenna on my desk that catches ADS-B from 100km and doesn't seem too hard to receive signals inside a room.

The diagram comes from Sirio and are for their SD2000 discone.
Discone works well for frequencies up to 400Mhz, incl VHF air and MIL air.

/Ubbe

 

[N9JCQ]

You use the "spider" antenna 08-ANT-0861, which could perhaps work as discone but more like a multifrequency GP. I have a 100cm telescope antenna on my desk that catches ADS-B from 100km and doesn't seem too hard to receive signals inside a room.

The diagram comes from Sirio and are for their SD2000 discone.
Discone works well for frequencies up to 400Mhz, incl VHF air and MIL air.

/Ubbe

I use its little brother for ham and aircraft. Works great!