Differences between RR database values and ArcPatrol values for modulation type

[ST-Bob]

ArcPatrol is designed for the Uniden HomePatrol scanner. It gets its data from a variety of sources including user input and the RR database. The information for each system is in similar columns to the RR dtabase but there appears to be some discrepancies.

This question is to find out whether regular users, premium users or admins see or have access to different levels of data which ArcPatrol seems to show and the RR database does not (apparently) show. Below is an example:

Massachusetts, Worcester County, Paxton

All 9 entries are shown as FM modulation though some of the frequencies appear to use different modulation schemes or bandwidths from my experience. The Paxton Fire VCall frequency 155.7525 comes in pretty garbled on my HP-1 when set to the default RR database setting of FM. Changing between FM, NFM, AM and Auto in ArcPatrol I was able to determine that this frequency is received clearly only when set to AM or Auto modulation. Auto is obviously something scanner-specific but appears to be somewhat flaky, mainly seeming to auto-detect analog or digital modulation, not AM, FM or NFM.

With the tight integration of the RR database into the HomePatrol and other new location-based preprogrammed scanners, is there something that needs to be changed in the display of the modulation types for the RR database?

Being severely limited in control panel options on the HP-1 I'm forced to play with the settings via ArcPatrol which was specifically written around the capabilities and limitations of the HP-1. It seems to have more optional data than the RR database contains (or at least more than it displays). Am I reading too much into this? Or am I just finding small errors which need to be submitted to RR.com?

 

[W6KRU]

AM is Amplitude Modulation. The auto setting uses a table internal to the HP-1 to select the proper modulation setting (AM,FM, or NFM) based on the frequency.

 

[ST-Bob]

Ahhh. I see (said the blind man as he picked up his hammer and 'saw').

The reason I mentioned it is that I get awful reception sometimes on systems which are set to Auto in the internal database. The Worcester Public Safety EDACS system has been giving me fits since a few weeks ago. Some site frequencies come in clearly and others garbled at time. I checked the Uniden database for Massachusetts by importing it into ArcPatrol and saw the modulation type was set to Auto. Setting it to FM seems to have cured this.

I also have trouble with Paxton MA fire V-Call system sounding garbled. DB says it's FM but my HP-1 seems to like AM.

Maybe my HP-1 needs a "clear User Data" and "Reset User Options" followed by reloading my favorites from the computer...

 

[W6KRU]

I also have trouble with Paxton MA fire V-Call system sounding garbled. DB says it's FM but my HP-1 seems to like AM.

Maybe my HP-1 needs a "clear User Data" and "Reset User Options" followed by reloading my favorites from the computer...

Something is very wrong. i am sure that that VHF-high frequency is not AM.

 

[ST-Bob]

This is my second HP-1. The first one had a blown backlight circuit after 3 days of use and was replaced by Scanner-Master. Dunno if this one is going bad too or not but I'm not too concerned. I've got one of those refurbished Pro-163's coming next week ($99 - how can you go wrong?) and it'll take all my attention for a while if I need to send the HP-1 out for repair/replacement. Hope it doesn't come to that though.

 

[loumaag]

Bob,

I took a look at the specific frequency that you mentioned and it would appear, based on the actual frequency being used and its reported use that it probably should be NFM in the DB along the two frequencies following it. I am basing this on the fact that the frequencies being used there are actually the reserved NFM frequencies for Public Safety Interoperability (you can see all of them in the RR Wiki); however, based on what is displayed on the DB page, they are being used in a non-standard manner. So...the best I can do is change the three entries to NFM. Several of the rest of the entries for that entity probably are also wrong, based on the displayed frequency; however, inspecting the two licenses displayed (what is up with that BTW ?!?) the use of the frequencies cannot be determined to be NFM or FM as both are on the license.

In the future, if you find specific problems with specific frequencies that appear to be wrong in the database, please submit the corrections via the <Submit> link (found on every page in the DB) on the page where the correction needs to be made. That way the regional DB admin will see it and take care of the problem.

Thanks for helping us get the DB in line with reality.

 

[ST-Bob]

Lou, I could possibly just be experiencing issues with the scanner itself. From my limited experience and the difficulty in testing changes with a totally pre-programmed scanner I cannot definitively say these V-Call frequencies are in-fact not WFM. If you'd prefer to hold off on any changes I'm expecting another scanner in a few days which can verify my findings more easily.

I didn't intend to try to get the DB changed with my post in this topic, but was just trying to bounce my findings off the experts here to see if there was something wrong with either my thinking, my radio, or the database. If I do find that the V-Call frequencies are either the wrong frequency or a non-standard modulation for their spectrum, I'll use the regular 'Submit' method to update the DB.

Thanks for looking into it though.

 

[ST-Bob]

On the same subject (sort of); I've been experiencing some poor reception on the Worcester Public Safety EDACS system which is still running EDACS-Wide here in Worcester, MA. It's not on all of the channels but seems to be on certain LCNs and may depend on whether it's the dispatcher's console or officer's mobile or portable unit that's sending at the time. I'm looking into it but will certainly have more luck with a 'regular' scanner than with the HP-1. I suspect there may be some testing going on with narrow-band audio on non-control channels or something.

I'll let you all know if I find anything once the PRO-163 arrives later this week.

EDIT: I did some research and see that the Worcester EDACS system is simulcast. The way I understand it simulcast transmitters on the same frequencies have to be VERY closely matched or receivers will hear distortion from the zero-beating between different site's transmitters. I'm fairly equidistant between the Green Hill and Asnebumskit Hill transmitting locations so I may be getting some strange reception due to tuning differences between the different LCNs. I guess I'll just live with it and stop worrying about it as it's probably not at my end. About all I could likely do is move my antenna or install a yagi pointed at one or the other. IOW, not a 'real' issue but a perceived one when I didn't have all the info.

 

[ecps92]

Is Paxton actually using the VCall/VTAC or an adjacent Wideband Freq?
what PL Tone would confirm VTAC vs.. ?

Ahhh. I see (said the blind man as he picked up his hammer and 'saw').

The reason I mentioned it is that I get awful reception sometimes on systems which are set to Auto in the internal database. The Worcester Public Safety EDACS system has been giving me fits since a few weeks ago. Some site frequencies come in clearly and others garbled at time. I checked the Uniden database for Massachusetts by importing it into ArcPatrol and saw the modulation type was set to Auto. Setting it to FM seems to have cured this.

I also have trouble with Paxton MA fire V-Call system sounding garbled. DB says it's FM but my HP-1 seems to like AM.

Maybe my HP-1 needs a "clear User Data" and "Reset User Options" followed by reloading my favorites from the computer...

 

[loumaag]

Is Paxton actually using the VCall/VTAC or an adjacent Wideband Freq?
what PL Tone would confirm VTAC vs.. ?

Actually that is what I referred to as the non-standard use of the frequencies. I can only act on the data given and those frequencies predate this thread. Based on the actual frequency there, they would be NFM. In any case I left a note for the regional DB Admin and I am sure he/they will look into it.

 

[ecps92]

Hopefully the OP can pass along the tone monitored.

Being just out-of-range for routine monitoring of Paxton FD [altho PD covers amazingly] I have not heard them on the Nationwide Interops, yet we have had a few other Depts pop up on them [actually adjacent freqs] with a Non Interop PL

Actually that is what I referred to as the non-standard use of the frequencies. I can only act on the data given and those frequencies predate this thread. Based on the actual frequency there, they would be NFM. In any case I left a note for the regional DB Admin and I am sure he/they will look into it.