Originally Posted by andy.s.lee
Here's the radar plot using the new
FCC database code.
Thanks! Very nice! I very much like that "KW ERP" shown obviously tells you the ERP as calculated via taking the antenna pattern into account ... I've been doing that manually by using the formula : [relative field value in your direction Squared] x Max ERP(erp equivlilent to relative field value of 1.000] = ERP sent in your direction ....
And --- The co-channel warning for W36DG is certianly right on the mark -- W36DG is still analog at this time(the app is for flash cut to digital), and about 1/2 the time, CCI from WTVQ 36 Lexington is apparent to some degree, and it's not exactly unusual for it to just be a mess ....
I'm also glad stations like WDKY-DT+WSYX-DT were included, as I see some sort of an indication of signal from those two stations the majority of the time, and it is fairly common to occasionally achieve a lock(on an almost, but not quite daily basis for a few mintues at a time) and be able to decode at least a few minutes of video now and then from WDKY-DT and WSYX-DT(in case I didn't mention it, VHF antenna is Winegard PR5030, at about 30FT AGL) ... The situation isn't that much different for WBNS-DT+WTTE-DT ... WCMH-DT is a little more rare(due to co-channel WPTO 14 being 18 miles away+off backside of antenna), and oddly enough, WWHO-DT is even more rare -- I'd thought that was probably due to the terrain issues being worse in WWHO-DT's direction, and them being on higher frequency/shorter wavelength involved, so I'm a little surprised to see the predicted signal strength for WWHO-DT similar to for instance, WBNS-DT. Perhaps there is something going on with WRGT 45 being 1st adjacent channel, as 46 still looks a little messy from WRGT on a analog TV with antenna aimed at WWHO.
I have noticed that lowering the antenna a few feet makes quite an apparent difference in signal strength from the Cincy LP analog stations -- And, due to terrain I expect, the same is actually true for Dayton as well, especially on the higher UHF frequencies - to the extent that with my Dayton antenna(which is 31 element UHF yagi/corner reflector side mounted to tower about 8 feet lower than the XG91), Signal from WPTD-DT 58 seems to about match what I get from WCVN-DT(requires only about 15~20db extra attenuation added in feedline to get down to threshold levels) with the XG91, but with more fading+multipath issues with WPTD-DT ... Whearas, with the XG91 aimed at Dayton, it takes about 50db extra attenuation added into feedline to get down near threshold for WPTD-DT ....
I don't know if your software can show "terrain profiles" for the paths - in case not, Farther below I have attached terrain profiles(using Delorme's Topo USA) to WXIX-DT+WHIO-DT from my location(using NAD27 coordinates for the transmitter site as shown on FCC TV query from CDBS info+for my receive antenna location) ... I've drawn in a rough estimate of the TX antenna heights based on the "scale" you see for this+the height in AMSL given on FCC site. This doesn't take curvature of earth into account, so I've roughly estimated it with the "lower" line on each profile ... As you can see, the "LOS" for Dayton is a very "near" thing ....
So, in other(shorter) words - as should be evident by the "terrain profile" plots I've included -- there are certianly circumstances when terrain is involved when raising antenna a few feet can make a big difference!
I guess we'll just have to see how many errors are in there now.
As far as the stations listed on my "radar plot" -- The only thing I see that "might" be off is the ERP for WKRC-DT ... While this STA for 330KW ERP was shown as "granted" by FCC in 12/06 (and supposedly expired on 3/8/07) :http://svartifoss2.fcc.gov/cgi-bin/w...ion_id=1142636
-- WKRC Transmitter engineer told us in Cincinnati thread last summer that the request for STA was due to a failure of a transmitter component, and that they expected to have it replaced by sometime late last summer ... And, they told the FCC this when they filed for the STA in Late July as well, as you'll see in the info exhibited in the text described in "exhibit 21" near bottom of app, in the actual application which was filed, which can be accessed here :http://svartifoss2.fcc.gov/cgi-bin/w...ility_id=11289
Now, while I don't know for sure whether or not they are currently using that STA or not ... However ,given what their engineer told us+what they told the commission(that they expected it would be 8 weeks from end of july 2006 before they were back to full power) I suspect they are not and are back to their 800KW ERP licensed facility(non D/A). In fact, I suspect they were probably back to full power before FCC granted the STA in December, LOL. Doesn't matter much for my location, though, as all we're talking about here is a little bit less than 4db difference between 330KW ERP+800KW ERP ...
Besides that -- AFAIK
, Everything on the list looks to be right on, including involving the ERP/antenna patterns(and me being in the biggest null for WHIO-DT, and a pretty good "null" for WBDT-DT as well), and distances/azimuth headings to the transmitters from my location.
I do wonder however why W36DG and W27CT's (for channel 6DT) LD apps are "showing up", but WOTH-LD Cincinnati's CP for Channel 47 isn't showing up (see here) :http://www.fcc.gov/fcc-bin/tvq?state...&slon2=&size=9
There are a couple of others I might expect to see on there as well, given that W27CT's app for 6 is showing up -- Especially This one (for digital companion channel for W20CL, Springfield) - The others (such as W23DM-D LD translator) either probably wouldn't show up in a plot for me anyway as they'd probably be too weak, or haven't yet gotten beyond the "mutually exclusive apps" stage, to the extent that an actual "app" or CP shows up -- such as WBQC-CA Cincinnati digital companion channel app for 20, which just shows up as "new" with no app attached) :http://www.fcc.gov/fcc-bin/tvq?state...&slon2=&size=9
Most of the antenna patterns I need are available in the database.
Oh yes, I was just saying that the fellow who operates the dxfm website filters out some of that data(antenna pattern info/etc) from CDBS in his spreadsheets -- As I recall when he talked a little about how he does it(and what he filters out concerning "bad"/incorrect records/etc) -- he does download the CDBS info+use it with DBMS software(I think he uses MS Access, not sure) first before exporting it to excel spreadsheet - not sure where exactly he "filters out" the antenna info/etc.
There are some antenna IDs that are missing, but I think the majority of them are in there correctly. You would think this would be necessary for the FCC's own sake, otherwise they wouldn't be able to properly assess the coverage and interference of each broadcast.
Yes -- I'm trying to remember though, does that database show the beam tilt info in every case?
And, I suppose the big question is whether or not the antenna pattern shown in the FCC data/operating permits *actually* matches the performance of the "real" antenna in any/every given case .... I suspect, in some cases, there may be some differences in the "real world" involved .....
Also -- I'm sure you're aware of this, but in case not/in case it helps --- you can sometimes dig up more "detailed" info from elsewhere on FCC site, in PDF attachements to applications for CP's or CP mods/etc as submitted as interference studies supporting the applications themselves .. for instance, sometimes you can find info on the detailed longely-rice studies performed to support the applications, as well as more detailed info, such as on beam tilt/etc ....
Here's one for a CP mod from 2003 for WDKY-DT, entitled "comprehensive technical exhibit ---http://svartifoss2.fcc.gov/prod/cdbs...ibit_id=178781
The way to dig some of those up is to use TV query with the "detaled info+CDBS links" option, then click on the "application list" link (which in WDKY case takes you here) :http://svartifoss2.fcc.gov/cgi-bin/w...ility_id=64017
Then click on the blue "application" link for the app your interested in(in this case, this one is for file # BMPCDT 20020716AAI as granted by FCC on 9/29/2004), and in this case you'll get that app here, and if you scroll to the bottom of that app, you'll find the link to the lengthy "compreshensive techincal exhhbit" for which I included a link farther above :http://svartifoss2.fcc.gov/cgi-bin/w...ility_id=64017
Unfortunetly, that sort of detailed technical information isn't available for All stations on FCC site, only some of them .... I assume FCC has all the necessary info, however ....
Anyway, thanks again Andy -- hope some of this is useful to you in some way.