SDS

[ScubaJungle]

I really am considering buying a second scanner, so I can have one dedicated to PS while another scans other things like local business, security, hospital, airband/milair, etc, (although I could always just use the 436 for VHF/UHF and SDS for PS). I see so many conflicting reports regarding analog VHF/UHF with SDS so, two main things that I haven't been able to come to a conclusion on in my research:

1. Has anyone seen the SDS available on Amazon or another site for a more reasonable price?
The reason I say this is because, on scanner master and similar sites, the 436 is priced at a ridiculous $470-$500, whereas the price on Amazon is regularly between $350-$400 (I got mine for $378). So, if they have the 436 for $100 more than it could be, how much more is the SDS than it could be..

2. The other thing that is a bit of a worry for me is, how has VHF/UHF coverage been with the SDS100 for everyone?

 

[hiegtx]

I really am considering buying a second scanner, so I can have one dedicated to PS while another scans other things like local business, security, hospital, airband/milair, etc, (although I could always just use the 436 for VHF/UHF and SDS for PS). I see so many conflicting reports regarding analog VHF/UHF with SDS so, two main things that I haven't been able to come to a conclusion on in my research:

1. Has anyone seen the SDS available on Amazon or another site for a more reasonable price?
The reason I say this is because, on scanner master and similar sites, the 436 is priced at a ridiculous $470-$500, whereas the price on Amazon is regularly between $350-$400 (I got mine for $378). So, if they have the 436 for $100 more than it could be, how much more is the SDS than it could be..

While, sporadically, we've seen one or the other of the SDS scanners at somewhat of a discount, but for the most part, they are selling for about the same cost at most dealers. This dealer has on occasion listed a "store demo" available at a lesser price, supposedly with only one available. But some of those that have purchased one of these 'demos' have said that the one they got appeared to be brand new, never used, with the plastic still over the display. And magically, in a day or two if he has stock (appears to be out on both SDS scanners right now), another 'one only store demo' pops up.

2. The other thing that is a bit of a worry for me is, how has VHF/UHF coverage been with the SDS100 for everyone?

I have both the SDS100 and SDS200. While there are a number of 700 & 800Mhz trunked systems here in the DFW metro area, Dallas (city) still primarily uses Uhf. Dallas County, and a number of smaller suburbs in southern Dallas County, as well as in Ellis County (just to my south) use Vhf-high. I don't see a significant difference in sensitivity versus other scanners using the same antenna (using the Remtronics 800Mhz antenna that is specifically for the SDS100, the other handhelds mostly the Remtronics (or Radio Shack labeled versions) 800Mhz antenna, which is not the best choice for Vhf. I get the agencies I can reasonably expect to hear on the SDS100. When I travel to visit a friend who lives about 100 miles west of DFW, I usually take the SDS100 & one of my 436HP's. Both are on magnetic mount antennas on the roof of my SUV. In that area, west of here, just about everything is Vhf-high. I'm not seeing the 436 grab a channel that the SDS100 overlooks. No noticeable difference.

Unless you have a ton of 700 & 800Mhz trunked systems, especially if most are simulcast, I would not buy another SDS scanner. You would not need it for Vhf, Uhf, and aircraft. If you like the versatility of having the main database in the scanner for possible traveling with a GPS, then go with the 436HP (or 536HP). Amazon had the 436HP, within the last couple of weeks, at about $370. (It's back up to $429 right now.) The 325P2 is currently $369, and usually stays reasonably close to that. If they were roughly the same cost. then I'd get the 436 instead of the 325 if I wanted another scanner other than the SDS series. The 325P2 is a good unit, as long as it doesn't have to wrestle with simulcast trunked systems. But you only have one programming file, not your choice of more than one Favorites lists with a different assortment of systems and frequencies.

Use Keepa or CamelCamelCamel to watch the prices on Amazon to catch the 436HP when it drops down below $400 again om Amazon.

You already have an SDS scanner, so that jump starts you on programming for a 436 or 536HP scanner.

 

[ScubaJungle]

While, sporadically, we've seen one or the other of the SDS scanners at somewhat of a discount, but for the most part, they are selling for about the same cost at most dealers. This dealer has on occasion listed a "store demo" available at a lesser price, supposedly with only one available. But some of those that have purchased one of these 'demos' have said that the one they got appeared to be brand new, never used, with the plastic still over the display. And magically, in a day or two if he has stock (appears to be out on both SDS scanners right now), another 'one only store demo' pops up.


I have both the SDS100 and SDS200. While there are a number of 700 & 800Mhz trunked systems here in the DFW metro area, Dallas (city) still primarily uses Uhf. Dallas County, and a number of smaller suburbs in southern Dallas County, as well as in Ellis County (just to my south) use Vhf-high. I don't see a significant difference in sensitivity versus other scanners using the same antenna (using the Remtronics 800Mhz antenna that is specifically for the SDS100, the other handhelds mostly the Remtronics (or Radio Shack labeled versions) 800Mhz antenna, which is not the best choice for Vhf. I get the agencies I can reasonably expect to hear on the SDS100. When I travel to visit a friend who lives about 100 miles west of DFW, I usually take the SDS100 & one of my 436HP's. Both are on magnetic mount antennas on the roof of my SUV. In that area, west of here, just about everything is Vhf-high. I'm not seeing the 436 grab a channel that the SDS100 overlooks. No noticeable difference.

Unless you have a ton of 700 & 800Mhz trunked systems, especially if most are simulcast, I would not buy another SDS scanner. You would not need it for Vhf, Uhf, and aircraft. If you like the versatility of having the main database in the scanner for possible traveling with a GPS, then go with the 436HP (or 536HP). Amazon had the 436HP, within the last couple of weeks, at about $370. (It's back up to $429 right now.) The 325P2 is currently $369, and usually stays reasonably close to that. If they were roughly the same cost. then I'd get the 436 instead of the 325 if I wanted another scanner other than the SDS series. The 325P2 is a good unit, as long as it doesn't have to wrestle with simulcast trunked systems. But you only have one programming file, not your choice of more than one Favorites lists with a different assortment of systems and frequencies.

Use Keepa or CamelCamelCamel to watch the prices on Amazon to catch the 436HP when it drops down below $400 again om Amazon.

You already have an SDS scanner, so that jump starts you on programming for a 436 or 536HP scanner.

Thanks - thats exactly along the lines of what I was looking for. I don't mind a newly used, or slightly used one as long as its been manufactured recently. Ill keep an eye on there.

Sorry if I mixed up the wording - I already have a 436 (got it for $378 on amazon), thinking about an SDS as a second. I see what you are saying though. The main reason for considering adding an SDS is that my county does have a new P25 system set to be used possibly next year, and seems to be simulcast. If it weren't for that, and the possibility that I will be moving after I finish with my university (and possibly to a simulcast area), I would definitely just grab another 436.
I think what I would do then, is use the 436 for VHF/UHF and all the other things I listen to(business,security,hospital,airband/milair), and then use the SDS for primarily PS/trunked 700/800/900, although Id probably play around with both to see which one works better.

I appreciate the input!

 

[N4DJC]

My SDS200 is pretty good for analog UHF, good enough to catch most of three adjacent counties with the stock telescoping antenna. It's not doing well for AM Airband or Railband at my location. But I use a BC125AT for those bands.

 

[hiegtx]

Thanks - thats exactly along the lines of what I was looking for. I don't mind a newly used, or slightly used one as long as its been manufactured recently. Ill keep an eye on there.

Sorry if I mixed up the wording - I already have a 436 (got it for $378 on amazon), thinking about an SDS as a second. I see what you are saying though. The main reason for considering adding an SDS is that my county does have a new P25 system set to be used possibly next year, and seems to be simulcast. If it weren't for that, and the possibility that I will be moving after I finish with my university (and possibly to a simulcast area), I would definitely just grab another 436.
I think what I would do then, is use the 436 for VHF/UHF and all the other things I listen to(business,security,hospital,airband/milair), and then use the SDS for primarily PS/trunked 700/800/900, although Id probably play around with both to see which one works better.

I appreciate the input!

I guess I misunderstood what you had, thinking that you already had an SDS series scanner, and was thinking of adding an additional scanner other than an SDS.

Getting one of the SDS series scanners would likely be your best move, along with, as you noted, using your 436 for Vhf, Uhf, and non-simulcast systems. With your county set to move to a P25 system, probably simulcast, the SDS would be a better fit for the additional scanner.

My SDS200 is pretty good for analog UHF, good enough to catch most of three adjacent counties with the stock telescoping antenna. It's not doing well for AM Airband or Railband at my location. But I use a BC125AT for those bands.

I'll defer to your experience on that, since I don't use either of my SDS scanners for those bands. I have several other, older, scanners that do well on analog Vhf & Uhf, so their falling short on 700/800Mhz systems is not a factor, as I have that covered with newer models (x36HP & SDS series scanners).

 

[Para078]

I'm east of DFW area in Kaufman County.. I had all the surrounding counties and the Kaufman County simulcast system in my SD S200. It was doing so good on VHF and UHF(Dallas) that I had to lock them out to hear Kaufman County. I left all those in my Pro-2053.

 

[ScubaJungle]

Thanks guys, that seems to be many peoples experience. I think this is my best move, for all of those reasons. My 436 does well on airband, VHF, and UHF, so using it for this will probably be what I do. The only thing I haven't had much luck with is milair and VHF low. Of course, antenna has a lot to do with this though, and I think the huge swath of spectrum/1 antenna (for milair) is a bigger factor.

I'd like to get a duplexer/triplexer or something that I can hook up multiple antennas and get the benefits of either my 800mhz yagi with my dipoles, or just multiple dipoles adjusted specifically to get all around coverage.

Are there any drawbacks to hooking up multiple antennas to one receiver, or will it work as it should in theory (covering multiple specific bands at once)?
If anyone does this, do you have recommendations for specific ones or manufacturers? Im having trouble finding any, most are labeled for the opposite - splitting one antenna to multiple receivers, so I have no idea if this will work the same way or if I need one specifically for combining rather than splitting. The one I have found for a reasonable price that states it can be used for combining is this MFJ:

MFJ-916B HF-2m/70cm Duplexer

Duplexer: 1.3-225MHz/350-540MHz, UHF

www.gigaparts.com

Two would work, but if I can find one with three connectors, that would be even better.

 

[Ubbe]

Those diplexers that combine different inputs for different frequency bands and combine them into one output, works great . They have almost zero loss in them. Most of them are made for transmitter use so are super epensive as they need to handle high power transmitters.

There are filter calculators on the web where you specify the frequency ranges and get the component values to use and how to connect them together. It's probably $5 for each bandpass filter and you can buy a 3 or 4 port $10 splitter and throw out its circuit board and build the filter inside that box and using its connectors.

Building it yourself if you can solder, or ask someone else to do it for you, will enable you to specify the exact frequency ranges you want.

/Ubbe

 

[hiegtx]

Thanks guys, that seems to be many peoples experience. I think this is my best move, for all of those reasons. My 436 does well on airband, VHF, and UHF, so using it for this will probably be what I do. The only thing I haven't had much luck with is milair and VHF low. Of course, antenna has a lot to do with this though, and I think the huge swath of spectrum/1 antenna (for milair) is a bigger factor.

I'd like to get a duplexer/triplexer or something that I can hook up multiple antennas and get the benefits of either my 800mhz yagi with my dipoles, or just multiple dipoles adjusted specifically to get all around coverage.

Are there any drawbacks to hooking up multiple antennas to one receiver, or will it work as it should in theory (covering multiple specific bands at once)?
If anyone does this, do you have recommendations for specific ones or manufacturers? Im having trouble finding any, most are labeled for the opposite - splitting one antenna to multiple receivers, so I have no idea if this will work the same way or if I need one specifically for combining rather than splitting. The one I have found for a reasonable price that states it can be used for combining is this MFJ:

MFJ-916B HF-2m/70cm Duplexer

Duplexer: 1.3-225MHz/350-540MHz, UHF

www.gigaparts.com

Two would work, but if I can find one with three connectors, that would be even better.

Here's a similar item from Amazon:

Amazon.com: Linear 2512 ChannelPlus DC & IR Passing 2-Way Splitter/Combiner: Electronics

Buy Linear 2512 ChannelPlus DC & IR Passing 2-Way Splitter/Combiner: Splitters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

smile.amazon.com

While they are labeling that as a "combiner", it's basically the same thing as a cable TV splitter, just being used "reverse" of how a splitter is used.. You'll end up with with a signal, to each scanner, about 50% of what you'd be feeding to only one scanner without the combiner. If you got one with three ports instead of two, each radio would get about one third of the signal from the antenna. You could mitigate that somewhat if you added a preamp between the combiner your antenna, but sometimes the preamps amplify too much noise as well as the signal you want.

While much more expensive, one of the amplified multicouplers have just enough amp so that the scanners get basically the same signal strength as if a single scanner was all that the antenna was feeding.

 

[ScubaJungle]

Those diplexers that combine different inputs for different frequency bands and combine them into one output, works great . They have almost zero loss in them. Most of them are made for transmitter use so are super epensive as they need to handle high power transmitters.

There are filter calculators on the web where you specify the frequency ranges and get the component values to use and how to connect them together. It's probably $5 for each bandpass filter and you can buy a 3 or 4 port $10 splitter and throw out its circuit board and build the filter inside that box and using its connectors.

Building it yourself if you can solder, or ask someone else to do it for you, will enable you to specify the exact frequency ranges you want.

/Ubbe

I didnt even consider building it myself. I can solder so that's not an issue, I'll just have to see what parts I can grab and make sure I have everything I need.
So I would basically just need to replace the existing insides and solder the new bandpass filters to the correct connectors to be used with a frequency range? If so, that sounds really simple.

Here's a similar item from Amazon:

Amazon.com: Linear 2512 ChannelPlus DC & IR Passing 2-Way Splitter/Combiner: Electronics

Buy Linear 2512 ChannelPlus DC & IR Passing 2-Way Splitter/Combiner: Splitters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

smile.amazon.com

While they are labeling that as a "combiner", it's basically the same thing as a cable TV splitter, just being used "reverse" of how a splitter is used.. You'll end up with with a signal, to each scanner, about 50% of what you'd be feeding to only one scanner without the combiner. If you got one with three ports instead of two, each radio would get about one third of the signal from the antenna. You could mitigate that somewhat if you added a preamp between the combiner your antenna, but sometimes the preamps amplify too much noise as well as the signal you want.

While much more expensive, one of the amplified multicouplers have just enough amp so that the scanners get basically the same signal strength as if a single scanner was all that the antenna was feeding.

I actually do want to use them as a combiner, not a splitter (sorry, I'm still learning the correct terminologies) - Id like to have 2 or 3 of my dipoles at different lengths fed to one 436.
That one you posted the link to looks like it would be perfect for this/doing what Ubbe posted above - I haven't seen that one in my searches.
It does say 5-1000mhz though, so maybe it wouldn't even be necessary to change anything with it (maybe it would be more efficient with specific filters?)?
Either way, I think Ill give that one a shot.. I cant go wrong for $11.

Thanks!

 

[Ubbe]

You have to use exact values so you need a complete set of coils from uH to nH and capacitors from 5pF to 470pF. It's better to calculate the components and then order the exact ones. It's really super simple to make customised filters if you know how to solder, and much cheaper than buying filters that often doesn't have the exact frequencies you'll need and have to compromise.

Try to use Butterwort type of filter as it isn't as critical with component tolerances and also select to have series first as it will not load and shortcircuit the other filters in parallell when the frequency goes out of the filters range.

If you can have a gap in frequency between filters then they do not need to be so sharp and a 3 order filter will do that uses less components.

RF Tools | LC Filter Design Tool

An online tool for LC filter synthesis. Calculate LC filters circuit values with low-pass, high-pass, band-pass, or band-stop response.

rf-tools.com

/Ubbe