OTA Signal Analyzers, Meters, Aimers, Bench Gear, Diagnostic Software - Page 4 - Canadian TV, Computing and Home Theatre Forums

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post #46 of 311 (permalink) Old 2009-12-13, 12:42 AM
 
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Digiair pro

I'm considering getting a DIGIAIR PRO to help aim tv antennas, and was wondering if their any good for the new digital channels, as I see no mention of ATSC in the manual.
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post #47 of 311 (permalink) Old 2009-12-13, 08:57 AM
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After a couple of seconds of hard Googling, it appears it does do ATSC. BTW, the name is also a clue.
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post #48 of 311 (permalink) Old 2009-12-13, 01:56 PM
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Witchdoctor, I moved your post into this thread mostly because of Post #45, which is a must read for someone wanting to buy a suitable OTA signal analyzer or meter for their needs and budget.
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post #49 of 311 (permalink) Old 2010-01-09, 08:04 PM
 
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Digiair pro

I have had my unit for nearly 2 years and - yes it works well for ATSC stations as well as NTSC. There is a selection which enables it to track both types of signal. I last used it to peak a Winegard 9032 antenna on CICT-DT here in Calgary. I must say that it is invaluable for use on the roof with no TV screen in sight or a body to shout the signal strength readings as you are adjusting!
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post #50 of 311 (permalink) Old 2010-01-10, 03:26 AM
 
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I had this DigiAir Pro, and it did not have a switch for ATSC, it was NTSC. So that the readouts were too low, to be of use.

Where is the switch for the ATSC?

Thanks! Id give it another shot if it worked for Fringe signals, and had an ATSC switch. Perhaps a new version was put out?
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post #51 of 311 (permalink) Old 2010-01-10, 12:39 PM
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Quote:
Originally Posted by JamesK View Post
After a couple of seconds of hard Googling, it appears it does do ATSC. BTW, the name is also a clue.
The site sponsor 'Save&Replay' sells them. Check their site online.
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post #52 of 311 (permalink) Old 2010-01-10, 02:11 PM
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Quote:
Originally Posted by EscapeVelocity
I had this DigiAir Pro, and it did not have a switch for ATSC, it was NTSC
Early model. As said, get the one sold by saveandreplay.com
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post #53 of 311 (permalink) Old 2010-03-13, 01:47 AM
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A Portable OTA Signal Finder Setup (See Post #53)

Here is a option for those who wish to hunt for OTA reception hotspots.



The heart of the setup is the 7 inch "MyGoTV" DPT170D+ battery-powered ATSC TV. Great TV for this because 1) it has a capable ATSC tuner, 2) it is lightweight and battery-powered (rechargeable proprietary only), 3) it has a signal strength indicator and a manual channel-add option, and 4) the 800 x 480 display is really quite nice. A bit pricey, yes, but try the "Big River". This unit is also sold under a different brand and model number at R. Shack (Auvio High-Resolution 7").



The idea was to maximize mobility (on foot), without worrying, for example, about dropping a $1000 laptop-USB tuner rig off the roof (yeah, you could use a netbook, but it's still a lot to wrangle). So I aimed for a stable lightweight platform that could hold an antenna and TV and free up one's hands to move it around, fiddle with the channels, etc.

I went the 1/2 inch PVC route, with lots of fittings ($15 worth!). There are certainly other ways to put something like this together. What's nice about the PVC and fittings is that they are snug enough to be secure without glue or screws, so the whole thing can be quite modular.



The antenna shown is the Fracarro-style X-032 4-diamond, built approximately to the specs supplied by Xauto Area 51 for Antenna Modelers & Builders (See Post #1) . I like this antenna because it is easy to build, has no eye-poking elements, and pulls in signals very well. You could swap in a different antenna, as long as it's not too heavy. The lower mast is metal electrical conduit, which works nicely because it is strong, and narrow enough to fit through the cross and into the T on the base. You can also shed the base and carry the rig around like a staff. Or do without the portable TV and connect it to your cable run into the house (but then you have to bug a family member to get on the phone with you and...well, it sort of defeats the whole purpose).
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post #54 of 311 (permalink) Old 2010-03-13, 12:55 PM
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That's a great idea, jpasadena, and a GH or M4 could be substituted for the 4-diamond with ease for UHF.

For VHF a person could use simple rabbit ears on top, but for longer distances there would be a need for at least a small LPDA - all a person has to do is manoeuvre one on a pole with a length of coax to where your base unit sits.
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post #55 of 311 (permalink) Old 2010-03-13, 02:01 PM
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Nice work ! Besides using it for locating the hot spots, it could also be used to tweak phasing lines and elements/reflectors in real time. For wi-fi, tweaking in real time using net stumbler helped me get another 2 dBi out of my bi-quad. Its amazing that little tiny changes did so much.

Quote:
A bit pricey, yes, but try the "Big River". This unit is also sold under a different brand and model number at R. Shack (Auvio High-Resolution 7").
Theyll be coming down in price. Ive seen some smaller ATSC units go on sale for less than $80. (dont know about the quality of their tuners though)

My builds/plans (not the latest models) are located here.
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post #56 of 311 (permalink) Old 2010-03-26, 07:37 AM
 
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jpasadena: That is one nice rig. Most only use a bowtie to find the hot spot.
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post #57 of 311 (permalink) Old 2010-04-29, 06:31 PM
 
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Signal measurement for overload.

I have a Tektronix 475 (DM44) and several multi-meters. The scope is 100MHz limited. I don't know about the multi-meters. Are the overload values quoted in this thread RMS or peak-to-peak. Is there a method to measure for signal at the antenna? I was going to attach a 75Ohm resistor across the inner core and the outer shield and connect a scope/meter across this. Is there a circuit, device, method to measure the antenna voltage?

I have a Kworld ATSC-110 which has a horrible front-end (12DB noise figure guesstimate). I also have ~70ft of cable and want to add an additional three devices. I am in the M8V xxx area of Toronto. Here is the femon summary output (from linux dvb wiki (signaltest.pl)).

Summary statistics:
Frequency Signal Ber Unc
========= ======== ======== ========
473028615 99.6 % 0.0 0.0
497028615 65.9 % 1443.6 182.3
509028615 99.3 % 0.0 0.0
527028615 98.2 % 0.0 0.0
533028615 94.7 % 0.8 0.0
545028615 67.2 % 9507.6 136.1
557028615 45.5 % 5952.8 133.0
581028615 99.0 % 0.0 0.0
587028615 97.5 % 202.4 8.5
617028615 99.2 % 0.0 0.0
623028615 97.4 % 152.0 0.0
629028615 99.1 % 340.8 0.0
647028615 99.4 % 0.0 0.0
653028615 99.2 % 0.0 0.0
659028615 63.5 % 3223.2 204.0
683028615 99.4 % 0.0 0.0
707028615 94.9 % 6507.2 0.0
773028615 98.1 % 0.0 0.0
779028615 99.4 % 0.0 0.0
785028615 99.4 % 0.0 0.0

I would order the Research Comms amplifier if I knew there would be no overload. I know that if I was to point my antenna directly at the CN tower, the CICA analog signal would overload it. However, I am pointing slightly east of grand island and expect about -25DB drop due to the side lobes. I would prefer to have some measurements before ordering. With the strength of the CAD the Research Comms and TinLee are about the same amount.

Calculations put peak signals at about 41dBm (from WNLO) and theoretically the RC amp should be ok.

Before I made my own ground, I had used the one Rogers installed. I was able to get sparks from the RG6. Rogers had connected to plumbing which contacts heating ducts which run millimeters from single strand knob and tube. With a ground stake and two separate ground wire, I don't seem to get this type of voltage anymore.

Thanks for suggestions.
Bill Pringlemeir.
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post #58 of 311 (permalink) Old 2010-04-29, 06:37 PM
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Quote:
Originally Posted by bpringlemeir View Post
I have a Kworld ATSC-110 which has a horrible front-end (12DB noise figure guesstimate).
I suggest that perhaps you look into upgrading the tuner before laying out for an expensive pre-amp. There are much (MUCH) bigger gains to be made that way.

And only then spring for the RC if the signal you want is teetering on the edge. Otherwise the Kitz ought to be just as good.

Cheers
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post #59 of 311 (permalink) Old 2010-04-29, 08:05 PM
 
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Replace PCI tuner card (was:how to measure antenna signal to check for overload)

Quote:
Originally Posted by mlord View Post
I suggest that perhaps you look into upgrading the tuner before laying out for an expensive pre-amp. There are much (MUCH) bigger gains to be made that way.
Err, ok. Do you know of a PCI ATSC Tuner card that works under Linux that has a better front end? Is there a thread for that? I also wish to add another capture card, an LCD Tv and an old NTSC set by splitting the signal four ways. Also, I still have 70ft of cabling in front of this. The cost of the PCI cards is about $80. Getting another is as much as a CM7777 and couldn't over-come the cable loss (and future splitters) like a pre-amp could.

Also, I don't see how 'much bigger gains' are to be made that way. I thought the first amp in the system was the dominate factor. If I amplify by 25dB gain with a 1dB NF, then most items coming after the pre-amp don't matter afaik.

Sorry, I am confused.
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post #60 of 311 (permalink) Old 2010-04-29, 08:33 PM
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Quote:
Also, I don't see how 'much bigger gains' are to be made that way. I thought the first amp in the system was the dominate factor. If I amplify by 25dB gain with a 1dB NF, then most items coming after the pre-amp don't matter afaik.

Sorry, I am confused.
I think you've hit the nail on the head. Just that mlord is also pointing out the fact that no matter the preamp, sometimes it's really hard to get over that cliff using some of the early generation tuners. I can attest to that.
My usb pc tuner quite often can't get over the cliff on weak stations, yet every other tuner in the house can.
Also kinda depends on what environment ur in, Like if ur in a rural area, far away from nearby transmitters, urban trash,
A pre-amp will help immensly, because your are most likely "noise limited". When your in the city, close by to transmitters
and other sources of trash, you may be "interference limited" when using a pre-amp. No pre-amp is gonna help ya overcome interference.
in fact may just make a bad situation worse. There is also the factor of some tuners are not able to handle really strong signals as well as others. At least I think that's what he's gettin at.

I live in the suburbs south of Buffalo, and there is no way I can receive canadian digital stations reliably without a pre-amp.
(Very low Noise Margins, 1 EDGE IN MY tvfool)
I'm almost there, but still room for improvement in my setup. Mainly due to sloppyness/laziness on my part.

Noise limited: Where reception is most limited by the noise floor, i.e. - just plain weak signals
Interference limited: Decent strong signals in the area, yet still poor quality / bit errors.

Everyone's environment is different which is why you'll get so many seemingly contradictory results/opinions.
What really matters is what works for you, not what works for the other guy...

have a look at this sheet, and try plugging in ur own numbers...

http://docs.google.com/fileview?id=0...OTFlMTNj&hl=en
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