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I like the new output you created, majortom.

I tried to apply it, saving a majortom.diff file in the project directory and then running:

~/TV_Stuff$ sudo git apply majortom.diff
error: patch failed: channel_scan.sh:222
error: channel_scan.sh: patch does not apply

Any idea what I'm doing wrong?
 

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I dunno, it's probably not you.
I am more used to playing around with c projects, than bash stuff.
There's only 4 lines to edit, so just use the diff to edit your file manually.
 

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I'll give it a whirl. Thanks.

UPDATE: got it working. Have an HDHR4 arriving this week, which I'll use on another antenna. This new info will be great.
 

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nice...
yeah it's based on the info in that post, they are using a 60 dB range scale.
I placed a directional coupler inline earlier and connected the hdhr to the coupled port, which is 10.5 dB down on the coupled port, and the difference
between runs did seem to jive. Close enough at least.
If we knew what the range for snr in dB of that thing was we could do the same for that.
 

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Nice work. I've applied the changes to the script and have pushed the update to github.

I'll update the report script shortly.
 

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Cool...
I just read today in this blog post, that the SNR ceiling is around 33 dB.
Assuming that's the case we can add that in ur script too (I'd consider Trip's observations pretty reliable 'eh).
Seems about right when ya consider where the borderline 45 - 50% range lands.

http://pastebin.com/b2gnnY74

Code:
15 channels found
RF      Strngth dBmV    dBm     Quality snr     Symbol  Virt#1  Name            Virt#2  Name            Virt#3  Name            Virt#4  Name            Virt#5  Name
------------------------------------------------------------------------
7       96      -2.4    -51.15  56      18.48   100     67.1    WBBZ-TV         67.2    THISTV          67.3    METV            67.4    DAYSTAR
14      100     0       -48.75  86      28.38   100     29.1    WUTV-HD         29.2    TCN             29.3    GritTV
15      100     0       -48.75  56      18.48   100     15.1    WBNF-SD         15.2    WBNF-HD         15.3    TCT
17      100     0       -48.75  92      30.36   100     56.1    Cozi            4       56.2            5       56.3            6       56.4            7       56.5
19      75      -15     -63.75  64      21.12   100     19.1    TVO
20      77      -13.8   -62.55  67      22.11   100     5.1     CBLT-DT
25      84      -9.6    -58.35  77      25.41   100     25.1    CBLFTDT
26      100     0       -48.75  65      21.45   100     26.1    WNYB-SD         26.2    WNYB-HD         26.3    WNYBSD2
29      100     0       -48.75  95      31.35   100     39.1    WDTB-HD
32      100     0       -48.75  91      30.03   100     23.1    WNLO-HD         23.2    Bounce
33      100     0       -48.75  77      25.41   100     2.1     WGRZ-HD         2.2     WGRZ2.2         2.3     WGRZ2.3
38      100     0       -48.75  60      19.8    100     7.1     WKBW-HD
39      100     0       -48.75  73      24.09   100     4.1     WIVB-HD
43      100     0       -48.75  92      30.36   100     17.1    WNED-HD         17.2    Think           0
49      83      -10.2   -58.95  52      17.16   100     49.1    WNYO-HD         49.2    GetTV
 

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here is something else I was looking at, not sure what this is but for strong signals above SS=100, I think we can get an idea how much stronger they are by looking at this output. Keeping an eye on the numbers in bold. I am not sure exactly what it means, but possibly a reflection of what the AGC is doing??

Code:
~/src/TV_Stuff > hdhomerun_config 103AB6AA get /tuner0/debug
tun: ch=auto:32 lock=8vsb:581000000 ss=100 snq=100 seq=100 [B]dbg=-188[/B]/-7527
dev: bps=19394080 resync=0 overflow=0
ts:  bps=19394080 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0
and this is the same station, with the hdhr on the directional coupler coupled port (10.5 dB down).
Note it drops by about 100 with the 10 dB insertion loss, while your SS is still way above the 100% ceiling.
Point being, once ya hit that 100% strength, you'd have no other way of knowing how much higher than 0 dBmV
the signal really is. At least looking at that also will give ya some idea.
Code:
~/src/TV_Stuff > hdhomerun_config 103AB6AA get /tuner0/debug
tun: ch=auto:32 lock=8vsb:581000000 ss=100 snq=100 seq=100 [B]dbg=-283[/B]/-7530
dev: bps=19394080 resync=303223 overflow=0
ts:  bps=19394080 te=5005 miss=28 crc=0
net: pps=0 err=0 stop=0
I may try and see how that varies within the 0-100% SS range. Maybe we can use that to interpolate dBmV values higher than zero that way....
 

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I know you can currently choose the device if you have multiple tuners, but can the script command line be changed to choose the tuner? I know that it will choose an unlocked tuner, but apparently MythTV does not "lock" the tuner. As a test I had both tuners recording under myth and ran the script with the "-noscan" option and it said both were available for scanning.
 

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I'll add in the option to select a tuner. I've been meaning to switch over the command line options to use the built in bash getopts function, so I'll roll that change into it.
 

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Great. Thanks so much for your script.
 

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Change complete and pushed to github.

Code:
Usage: channel_scan.sh [option]

Options are:

-d <device id> (Provide a device ID instead of using auto discovery)
-t <tuner id> (Provide a tuner ID instead of using auto discovery)
-c Output scan results in CSV format
-l <filename> Log the output to <filename>
-n Report only what device and tuner would be used without running a scan
-h This help info
 

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Great! Thanks so much!
 

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I played around last nite varying signal strength from weak and strong signals throughout the 0-100 SS range, and recorded that dbg=
vs SS, dBmV, etc, and it is definitely a linear relationship.This means we can definitely use that to interpolate the dBmV, dBm values when SS is greater than 100%
 

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majortom, I would be very interested to know about the correlations for that dbg number, once you're ready to report on your findings.

- Trip
 

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I found a bug with the log output option and I've added a new -b "Brief" option that supresses the dB and all secondary channel results.

Code:
$ ./channel_scan.sh -h

Usage: channel_scan.sh [option]

Options are:

-d <device id>	// Provide a device ID instead of using auto discovery
-t <tuner id>	// Provide a tuner ID instead of using auto discovery
-c 		// Output scan results in CSV format
-l <filename>	// Log the output to <filename>
-b 		// Brief mode. No dB info or secondary channels
-n 		// Do not scan, only report devices and tuners available
-h 		// This help info
Code:
$ ./channel_scan.sh -b

Beginning scan on 105281ED, tuner 0 at 04/06/15 21:52:53

18 channels found
RF	Strngth	Quality	Symbol	Virt #	Name
-------------------------------------------------
9	100	98	100	9.1	CFTO
14	94	85	100	29.1	WUTV-HD
15	84	48	100	11.1	CHCH-DT
19	100	90	100	19.1	TVO
20	100	85	100	5.1	CBLT-DT
23	76	58	100	51.1	ION
25	100	100	100	25.1	CBLFTDT
32	100	100	100	23.1	WNLO-HD
33	100	85	100	2.1	WGRZ-HD
36	100	80	100	36.1	CITS-HD
38	100	100	100	7.1	WKBW-HD
39	100	100	100	4.1	WIVB-HD
40	100	100	100	40.1	CJMT
41	100	100	100	41.1	CIII-HD
43	100	100	100	17.1	WNED-HD
44	100	100	100	57.1	CITYTV
47	100	98	100	47.1	CFMT
49	100	98	100	49.1	WNYO-HD
 

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Tweaking HDHR4 setup

[Realize this could also be posted in one of the reception threads, but this post is more about wondering about differences between the tuners of the HDHR4 and 3 that might cause these issues.]

For the last four yrs I've been getting pretty great reception with an balcony antenna pointed at a build northeast of me in order to catch Toronto signals slightly SW through my apt building and SE to Buffalo.

This setup has enabled to get most of the Toronto, Buffalo and Hamilton stations just fine. I recently reviewed the AD Juice amp (and variable attenuator) and it improved things even further making a few more Buffalo's completely solid.

I just got my hands on an HDHR4 and so decided to aim an unamped antenna and my original HDHR3 at the reflector building to grab Toronto while the AD C2V antenna, Juice amp, variable attenuator and HDHR4 were aimed SE towards Buffalo. While the reflected setup has been fine all these years, the SE aimed setup took some doing. While ION popped up quite beautifully, WKBW took quite a bit of aiming to find a sweet spot where Symbol quality didn't keep dropping to red. WNYO was tricky too and isn't what I'd call particularly stable, though it used to be fine in the reflected setup. I'm still getting a few of my Toronto's through this antenna. WUTV isn't working with the HDHR4 setup right now, but it's still coming in with the reflected signal HDHR3 setup.

Any ideas why the Buffalo-aimed setup and HDHR4 a struggling with some signals? Anything about the newer tuners in the HDHR4? I really had to tweak both the aim and attenuation to get WKBW stable while both WNYO and WUTV still work better in the reflected/HDHR3 setup.

Here's my TVfool:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=2c156554532771

and a report from 905shmick's script:

Code:
26 channels found
RF  Strngth dBmV    dBm   Quality Symbol  
------------------------------------------------------------------------
9       100     0     -48.75  78     100     9.1     CFTO
13       76   14.4   -63.15  42     100
14       97   -1.8   -50.55  67     100     29.1    WUTV-HD
15      100     0    -48.75  41     100
17       66  -20.4  -69.15  41     100
19      100     0    -48.75  67     100     19.1    TVO
20      100     0    -48.75  55     100     5.1     CBLT-DT
22      100     0    -48.75  98     100     15.1    StarRay
23      100     0    -48.75  98     100     51.1    ION         
24       61  -23.4  -72.15  41     100
25      100     0    -48.75  74     100     25.1    CBLFTDT
27       71  -17.4   -66.15  41    100
28       72  -16.8   -65.55  42    100     31.1    WUHF-TV
32      100     0     -48.75  98    100     23.1    WNLO-HD 
33      100     0     -48.75  98    100     2.1     WGRZ-HD  
35       74  -15.6   -64.35  41    100
36      100     0     -48.75  68    100     36.1    CITS-HD
38      100     0     -48.75  98    100     7.1     WKBW-HD
39      100     0     -48.75  85    100     4.1     WIVB-HD
40      100     0     -48.75  63    100     40.1    CJMT
41      100     0     -48.75  69    100     41.1    CIII-HD    
43      100     0     -48.75  74    100     17.1    WNED-HD 
44       99    -0.6   -49.35  58    100     57.1    CITYTV
45       76  -14.4    -63.15  53    100     8.1     WROC-HD
47      100     0      -48.75  76    100     47.1    CFMT
49      89     -6.6    -55.35  42    100
 

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dheian,
which hdhr is the report from? hdhr3, or hdhr4?
one thing I notice is the quality for rf 19 and 20 look relatively low for having SS of 100. Comparing the report to tvfool confirms they are some of the strongest signals intensity wise. So back to my point earlier about the hdhr not letting ya know what the strength really is when SS = 100.
That's what I've been working on here, almost done with that, maybe tomorrow I'll be ready to post another mod to 905shmick's script.

Try tuning to CBLT RF 20 manually in the meantime, and run the debug command and note what the dbg = value is...Try it on both HDHRs to compare them.
Code:
hdhomerun_config device id set /tuner0/channel auto:20
hdhomerun_config device_id get /tuner0/debug
Then do the same on a channel that's less than SS = 100, but still locks and plays OK.
edit: you can also run this command after it's tuned...
'watch hdhomerun_config device_id get /tuner0/debug'
and it will poll kinda over and over until ya kill it...
 

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Sorry the report was from the SE facing HDHR4/C2V/Juice setup.

Here's the result for RF20 on the HDHR4:

tun: ch=auto:20 lock=8vsb:509000000 ss=100 snq=61 seq=100 dbg=-3975/-7079
dev: bps=19530944 resync=0 overflow=0
ts: bps=19530944 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0

Here's the result for RF20 on the HDHR3 reflected signal setup:

tun: ch=auto:20 lock=8vsb:509000000 ss=90 snq=55 seq=0 dbg=-455/-10198
dev: bps=3388512 resync=6370 overflow=0
ts: bps=3388512 te=1 miss=2 crc=0
net: pps=0 err=0 stop=0

Here's the result for RF14 WUTV on the HDHR4:

tun: ch=auto:14 lock=8vsb:473000000 ss=100 snq=69 seq=100 dbg=-4450/-7897
dev: bps=19401600 resync=0 overflow=0
ts: bps=19401600 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0

Here's the result for RF14 WUTV on the HDHR3 reflected signal setup:

tun: ch=auto:14 lock=8vsb:473000000 ss=74 snq=80 seq=100 dbg=-533/-11319
dev: bps=0 resync=0 overflow=0
ts: bps=0 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0
 

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Looking at my real trouble station, WNYO, I see it's the about the signal quality and not the strength:

HDHR4 (amplified, pointed toward Buffalo)

tun: ch=auto:49 lock=8vsb:683000000 ss=89 snq=43 seq=0 dbg=-5450/-7126
dev: bps=0 resync=0 overflow=0
ts: bps=0 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0


HDHR3 (reflected unamplified)

tun: ch=auto:49 lock=8vsb:683000000 ss=71 snq=61 seq=0 dbg=-554/-22678
dev: bps=0 resync=0 overflow=0
ts: bps=0 te=0 miss=0 crc=0
net: pps=0 err=0 stop=0

WNYO's strength is 89 on the Buffalo-aimed but only has a snq of 43 while the reflected has a strength of 71 but an snq of 61. Torrential rain's probably not the best day to be comparing signals and aims, but maybe I'll try the Buffalo antenna without the amp.
 

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here is a patch to 905shmick's latest script. This adds a 'Debug' option.
When ya run it, it will extrapolate signal strengths > 100% to dBmV and dBm. The assumption here is that the 'dbg=' value from the hdhr3 continues to be linear above SS = 100.

I think it's probably "close enough", since I have read the hdhr can handle an input signal of up to +40 dBmV. But, I have not verified how far the linearity continues beyond 100. So it's still just a guess. Someone with some real test equipment (ie a calibrated ATSC signal generator) can try that excercise.
I put some comments in there to explain what I had done.

http://pastebin.com/nE7BgX3r

It won't work on the hdhr4, since as you noticed the numbers are significantly different. But, I am sure someone could do a similar look at the dbg= vs SS within the hdhr4's usable 0 - 100 SS scale sometime.

Also, it's not likely that every hdhr3 device out there will have the exact same slope and intercept, but it's probably close enough for hobby work like ours... I don't think we are looking to split hairs over 2 to 3 dB of signal strength when looking in to issues caused by preamp overload.

Here is an example output from mine when running
./channel_scan .sh -D

http://pastebin.com/PBzB68jB
Edit: some time ago I removed channels 52 thru 69 from the source code of the libhdhomerun driver, so that scans wouldn't take so long
searching thru channels that will never have any ATSC on them.
 
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