Looking for SDS200 Solution for Conv UHF/VHF & 800Mhz

[upstatesc]

I'm hoping someone can point me to a solution for my situation with my SDS200. I live in an area where all of the local county communications are on VHF & UHF, but the state trunk system is on 800mhz. I've tried all of the various Remtronics antennas and only the dedicated 700/800mhz models can successfully pick up the Trunk system. The signal is a bit weak on it at my location, so their Triband antenna is out. It works great on improving the local VHF/UHF, but not the 800mhz system. The catch is the VHF/UHF reception on the 700/800mhz models obviously suffer.

The factory antenna that comes with the SDS works perfect for the local UHF/VHF systems. Ideally I need to combine two antennas in order to effectively receive both systems. Looking online I see a few options:

Amazon has a dual BNC adapter which makes it possible to connect both antennas at one time. Looking on eBay I found a filter that seems to pass 800mhz and up fairly reasonably, but it goes into the HF bands as well: Mini-Circuits BHP-800 High Pass Filter Center Freq 800 MHz | eBay

Hooking that up in front of the Remtronics antenna should filter out any VHF/UHF interference that would affect my local systems, but I still have the issue of the factory antenna possibly passing some 800mhz signal on. Looking on Scanner Master I see a filter that filters out everything above 485mhz but it is almost $70. Looking on Amazon I see the new LTE filters designed for HDTV antennas passes from 0 to 700mhz in most cases. Does that seem like a reasonable substitute, or does anyone have any better ideas?

My plan right now would be:

Factory SDS200 Antenna--->LTE FILTER (w Coax to BNC adapters)--->BNC Combiner <--- eBay Mini Circuits Filter <--- BNC to SMA adapter <---- Remtronics 800mhz antenna (from my previous SDS100)

Anyone have any suggestions or better solutions? Clearly that is a lot of combining, filtering, adapting.

 

[ind224]

I'd go discone with the caveat you did not mention simulcast 800. Yes thats a lot of filtering connections and work imo.
I'm always a function over form guy and I hate splices like a sharp stick in the eye. A single antenna a single run and hopefully some savings. I say frugal they say cheap.

 

[mmckenna]

Combining antennas can get tricky. It's not as simple as getting a T-adpater and hooking up two antennas.

If coverage is an issue, one of the best things you can do is get your antenna outside. One thing you could do is take your scanner outside, and if possible, up on the roof. See if your reception improves.

Trying to make an antenna work indoors can be difficult. Building materials can impact reception. There's also lots of sources of interference in most homes. Getting the antenna outside can make a big difference.
If going outside isn't an option, then getting an external antenna and putting it near the window can help quite a bit.

 

[Ubbe]

Anyone have any suggestions or better solutions?

That's an excellent and not so expensive solution. Those filters seems to be perfect. I looked at the Philips LTE filter and it attenuates 40dB above 650MHz and the BHP-800+ attenuates 40dB below 500MHz.

Use a BNC T-adapter, either directly to the scanners BNC connector or more practically with a coax between them, and attach the filters to that, so it will isolate the whole coax lengths to the antenna that are filtered out.

scanner-T_adapter_out1-filter1-coax-antenna
scanner-T_adapter_out2-filter2-coax-antenna

Use the appropriate adapters for F and SMA and BNC and try and plan ahead what male and female connectors, and possible pigtails, are needed before purchase. There are even T-adapters with F connectors.

You can use RG6 with F connectors for all coax and have the flexibility to experiment with different placement of antennas as coax attenuation will be low even with 30ft lengths.

/Ubbe

 

[trentbob]

I understand your dilemma and there are ways to attempt to solve your problem, I'm not sure that the approach that you're thinking about is the only solution.

It would be good to know your location, County and State and what is the 800 MHz trunked system that you're talking about. Judging by your username could it be the Palmetto phase ll simulcast system and if so what site or sites do you listen to, hopefully, it's only one or two?

Obviously the answer is to put up a rooftop antenna but we're going to assume you're unable to do that for some reason or you wouldn't be here.

Depending on what type of dwelling you live in, you could always purchase the rooftop tri-band antenna of your choice like a mini discone and mount it on a floor lamp that you can get cheap at Walmart using low loss coax. You would be able to move the floor lamp around and rotate it as needed, as has been said, near a window preferably.

Also, as has been said the type of dwelling you live in because of insulation, coating on windows ect. your planned set up could be affected.

With a phase ll simulcast system they usually benefit from the use of filters, all of the systems in my area local and state are Phase ll simulcast.

In settings, on global filters which are set to normal as default, while listening to your system, you sample wide normal, wide invert and invert. Do not use Auto. You do this on the radio itself through the menu because you want to see real time reception results. You look at reception indicators like noise level and error rate and if you see an improvement with one of those three filters then return Global filter to normal as it affects every object in the radio and you don't want to compromise reception on any other objects.

You then drill down with the menu to the sites that you listen to and set the filter that worked the best in your sampling directly to the site or sites you use.

Obviously because you've done this directly on the radio you have to hook up to Sentinel and immediately transfer the information on the data card to your profile so as to save the changes permanently. You can put the filter indicator on your display, that's a good way to keep track.

As has been said using two antennas together, LTE filter or not, can be rather tricky and you very well might find it doesn't work. A whole new approach might be the solution.

 

[popnokick]

Take a good look at this thread from another forum here on RR reference using a simple, inexpensive yet effective HDTV antenna you can buy in nearly any hardware or "big box" store. It will cover the range of frequencies you're looking to listen to on your scanner. And it doesn't involve expensive multiple filters, couplers, outdoor and rooftop antennas, or camera tripods in the house with antennas to poke your eye out. Given the price and simplicity of this solution you can try it and if you don't like it for any reason you'll only be out of pocket for $15-$25 or less. Here's the link: Best $15 Scanner Antenna - By Accident

 

[devicelab]

Anyone have any suggestions or better solutions? Clearly that is a lot of combining, filtering, adapting.

Why can't you go discone? I don't understand. That solves your problem 100%. Be sure to use quality coax (LMR-400) and keep the run under 100ft if possible. A D130 or D3000 Diamond are good choices.

Why are you stuck using portable antennas with the SDS-200? It's a base scanner and should be used with an external antenna.