I am looking for some input on filters for the SDS200 The internal ones and the Military Low band 30-50

[tnbound]

I am hoping someone can share the settings for the 200's filters on the 30-50 Military band? I am too far away from Ft. Campbell to get any real traffic on those frequencies but occasionally get a couple helo's flying by but have never caught any voice traffic. I am hoping if I can tweak the filters it may help. I am using an outdoor Diamond D130J wideband antenna about 25 feet up? I also use Procsan to monitor and record communications so I am just not getting any.

Thank you in advance as always

 

[trentbob]

Just my two cents but I have a lot of experience with the filters but I have zero experience with the filters and low band.

You can add to your display a filter indicator so it will indicate what filter is applied to what frequency. We will avoid systems for now since you are talking about individual conventional frequencies. Note that the filters cannot be applied to a specific analog frequency, they are applied to group options of the group of conventional frequencies you want to improve.

Regardless of what people might say you want to apply filters using the keyboard of the radio while listening to real time reception indicators.

There are two ways to apply filters, you can use global which by default is set to normal which is called normal for a reason. If you're not getting good reception on normal we can eliminate that option right away.

Global filters affect every object on the radio so if you change Global from normal to wide normal or something else you are affecting every object on the radio, many of them working well with normal so you will be compromising a great deal of reception on other frequencies and systems. We use Global just for sampling. If we see improvement with a filter then we return Global to normal where it belongs and then use the keyboard to drill down to group options and apply the filter that worked better there.

You will want to avoid the auto filters as they sample all the filters wide or otherwise and slow down scanning so you are basically looking at the choice of wide normal, wide invert, invert or no filter at all to sample in global filters.

Remember if you find an improvement don't leave that filter on global, write it down and return Global to normal so as not to compromise every object on the radio.

You then drill down on the menu, just follow the prompts and apply the better filter to group options of the group of military frequencies, if it works for one it's going to work for all of them.

To answer your question about advice on what filter to use, who knows? It depends on your area, your topography, RF interference, what works for you isn't going to work for the next guy. Keep track with a pencil and paper and use reception indicators since you are listening with real-time reception while sampling.

You're going to find your ear is one of your best reception indicators. Work along those lines, it really depends on how familiar you are with the operation of your radio using the keyboard.

You also may get comments that it's willy-nilly and hit or miss and so forth, it's really not, if you follow the system strictly and keep track with a pen and paper you have the best chance of reaping benefits from filters.

My personal opinion, don't expect much, get a rooftop antenna made for low band😄

 

[merlin]

The specs for the SDS-200 show a full compliment of filters, most, atomatically set by band and emission type.
You can select any filter manually. Specifically for low band VHF, RF filter is 30 to 50 MHz, Military low band, IF filter of 6 KHz (AM) or 2.5 KHz (USB) is ideal.
What I use as a scanner is a Quansheng UV-K5(8). 7 bands from 20 MHz to 1000 MHz fixed filters. AM IF default is 6 KHz but can select wide (20 KHz) or narrow (2.5 KHz) Default works great for MIL AIR and air band.

 

[trentbob]

The specs for the SDS-200 show a full compliment of filters, most, atomatically set by band and emission type.
You can select any filter manually. Specifically for low band VHF, RF filter is 30 to 50 MHz, Military low band, IF filter of 6 KHz (AM) or 2.5 KHz (USB) is ideal.
What I use as a scanner is a Quansheng UV-K5(8). 7 bands from 20 MHz to 1000 MHz fixed filters. AM IF default is 6 KHz but can select wide (20 KHz) or narrow (2.5 KHz) Default works great for MIL AIR and air band.

Well what I think the poster is referring to for the SDS-200 is the filters that are selectable to be applied to the site or sites of a system or department options of a conventional group of conventional objects. You have normal, wide normal, invert, wide invert, Auto and Wide Auto or no filter applied at all and these can be applied to any frequency or band offered by the SDS radios.

The reason that there isn't a whole lot of official explanation other than Paul Opitz initial firmware comments is that the filters were added in two steps through two different firmware upgrades. First we had normal, invert, Auto and no filter. The second firmware update was wide normal, wide invert, Wide Auto and no filter at all and there really wasn't a whole lot of explanation in writing especially in the manuals.

Sadly this is when Paul Opitz, the product manager and developer of the SDS series was grappling with progressive, aggressive, metastasized cancer, yet he kept plugging on and working but had medical treatments and intervention ongoing through the spring of 2019.. ended up being hospitalized to remove a neck tumor much longer than expected but stayed on the job as long as possible. He passed in late December of 2019.

"UPMan" was very proactive with the members of radio reference, pretty much always available for expert advice and instruction as the SDS radios were his.. babies.

All this information comes from him as he had a open blog that he posted on regularly for anyone to see. But that might explain a lot of why there isn't more official information on filters and other potential for the SDS scanners that may have actually gone with him.

He was very vested in these radios and had his share of disappointments and proud moments of accomplishment.

 

[trentbob]

@merlin, I know you know all of this because of the amount of time you've been a member but a lot of people don't know the history of the beginnings of the SDS radios. It's been over 5 years now.😉.

 

[tnbound]

Just my two cents but I have a lot of experience with the filters but I have zero experience with the filters and low band.

You can add to your display a filter indicator so it will indicate what filter is applied to what frequency. We will avoid systems for now since you are talking about individual conventional frequencies. Note that the filters cannot be applied to a specific analog frequency, they are applied to group options of the group of conventional frequencies you want to improve.

Regardless of what people might say you want to apply filters using the keyboard of the radio while listening to real time reception indicators.

There are two ways to apply filters, you can use global which by default is set to normal which is called normal for a reason. If you're not getting good reception on normal we can eliminate that option right away.

Global filters affect every object on the radio so if you change Global from normal to wide normal or something else you are affecting every object on the radio, many of them working well with normal so you will be compromising a great deal of reception on other frequencies and systems. We use Global just for sampling. If we see improvement with a filter then we return Global to normal where it belongs and then use the keyboard to drill down to group options and apply the filter that worked better there.

You will want to avoid the auto filters as they sample all the filters wide or otherwise and slow down scanning so you are basically looking at the choice of wide normal, wide invert, invert or no filter at all to sample in global filters.

Remember if you find an improvement don't leave that filter on global, write it down and return Global to normal so as not to compromise every object on the radio.

You then drill down on the menu, just follow the prompts and apply the better filter to group options of the group of military frequencies, if it works for one it's going to work for all of them.

To answer your question about advice on what filter to use, who knows? It depends on your area, your topography, RF interference, what works for you isn't going to work for the next guy. Keep track with a pencil and paper and use reception indicators since you are listening with real-time reception while sampling.

You're going to find your ear is one of your best reception indicators. Work along those lines, it really depends on how familiar you are with the operation of your radio using the keyboard.

You also may get comments that it's willy-nilly and hit or miss and so forth, it's really not, if you follow the system strictly and keep track with a pen and paper you have the best chance of reaping benefits from filters.

My personal opinion, don't expect much, get a rooftop antenna made for low band😄

Great advice and thank you for your input

 

[tnbound]

@merlin, I know you know all of this because of the amount of time you've been a member but a lot of people don't know the history of the beginnings of the SDS radios. It's been over 5 years now.😉.

I knew something had happened to him and he passed but that was a great explanation of how the filters work. The SDS200 is a great radio for sure.

 

[tnbound]

The specs for the SDS-200 show a full compliment of filters, most, atomatically set by band and emission type.
You can select any filter manually. Specifically for low band VHF, RF filter is 30 to 50 MHz, Military low band, IF filter of 6 KHz (AM) or 2.5 KHz (USB) is ideal.
What I use as a scanner is a Quansheng UV-K5(8). 7 bands from 20 MHz to 1000 MHz fixed filters. AM IF default is 6 KHz but can select wide (20 KHz) or narrow (2.5 KHz) Default works great for MIL AIR and air band.

Quansheng UV-K5(8) I will Google that and check it out where did you buy yours

 

[trentbob]

I knew something had happened to him and he passed but that was a great explanation of how the filters work. The SDS200 is a great radio for sure.

Thanks, the same theory applies to systems except you change the filter in site options on the radio menu. You want to have as little sites as possible because it has to be applied to each site so one or two is the max for me if possible. It wouldn't be unusual to have one filter on one site and another filter on another site.

 

[merlin]

Well, I will be silent key soon enough, but for 50 years, I have been a hardware man. I saw scanners go from a few crystal controlled channels to PLL synthesyzers, then marrying CPUs and full programability, additions to band coverage to a couple GHz. Today, you find multi core risc processors, a few hundred Gb of memory, (AOR comes to mind). Filters today are no longer little metal cans with tuning slugs, they are discreet ICs that tune with softpots/software/firmware. All the size of pencil dots, on boards with SMT technology.
Never touched an SDS scanner but that is how they work today. Keyboards are giving way to touch screen and menu maps that choke a horse.

 

[merlin]

"Quansheng UV-K5(8) I will Google that and check it out where did you buy yours."

A couple years ago, SWLing and DXunderground did evaluations, there were hotlinks to official sales outlets, and boasted as being the most hackable tranceiver, I bought one. Takes a bit to impress me but this radio exceeded my expectations. There are 3rd party firmwares that change the whole personality and only takes minutes to swap firmwares. The build I find matches that of the Yaesu FT-60, not like the typical CCRs.
Should you buy, the (8) model has improved speaker and sound. Firmwares can be found on github.

 

[merlin]

@merlin, I know you know all of this because of the amount of time you've been a member but a lot of people don't know the history of the beginnings of the SDS radios. It's been over 5 years now.😉.

Already getting to be old radios.