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Magnavox 515 what is the DB TV antenna signal gain

post #1 of 20
Thread Starter 
my internet connection has gotton so weak I can't open the stickie thread.however I can type this.

some of my regular OTA TV stations won't come in w/ the TVs tuners however they will come in on the 515.

I understand that the 515 has a builtin gain amplifier so what is the BD gain on this amp?


I'm concidering a signal amplifer for my antenna. some claim 35+BD gain others claim much less so what BD gain is preferred

Thanks STB

http://www.ebay.com/itm/EMERSON-10dB-DIGITAL-TV-SIGNAL-BOOSTER-AMPLIFIER-AMP-INDOOR-OUTDOOR-ANTENNAS-/270834480453?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D1180782090816557255%26pid%3D100015%26prg%3D1006%26rk%3D1%26
post #2 of 20
A 3db gain is doubling the input, my guess is the passthru on your DVDR might increase the signal by anywhere from 2-6 db(again this is only a guess). 35db is way overkill and will only add noise and possibly overdrive things. IMO the only use for such a large amp is if your powering a 8 or 16 way splitter or trying to run your cable 1000 ft or more.
In your case I'd look for a amp ~10db gain which your link is, Emerson probably more a low end product but it might do the trick. I like Winegard and Channel Master but have also used lower cost amps and sometimes they work fine.
I like the RCA towards the bottom of my link or even the similar looking Philips 18db towards the top which seems to indicate it might be bi directional for internet or cable use.
http://www.amazon.com/s/ref=nb_sb_ss_c_0_9/188-0500169-7015662?url=search-alias%3Delectronics&field-keywords=antenna+amplifier&sprefix=antenna+a%2Caps%2C213
Edited by jjeff - 8/8/12 at 6:11am
post #3 of 20
Thread Starter 
Jeff I'm using Y-tube homemade antenas they work kindof good (better than the old rabbit ears) if positioned prefectly (like some channels come in great others require repositioning of antena, I'm seriously concidering putting the antena up in the attic (currently there directly behind TV) but am concerned about a long probabley 40' coax cable).

my requirements are 4 input feeds TV, 515, and two for the PC (I have 2 separate PC tuners) so I have two Y-tube antennas each has a 2 way splitter antena 1 feeds PC w/ 2 way splitter, antena 2 feeds TV & 515 w/2way splitter.

The 515 works fine usalley however sometimes (ocasionalley) it dos'nt recieve a clear signal.

it's the rest TV & PC that need a boost. so maybe a good plan would be to use unamplified antena w/ the 515 then use a amplified w/ 3 way splitter for the rest. I don't have a 3 way splitter but do have two 2 ways.

edit: I have being reading a little on antenas now I'm wondering about a FM trap I'm thinking my small FM antena that came w/ my AVR (just a very thin coax cable) is located very close to the TV antena maybe it's interfering w/ TV reception?

edit 2: I'm assuming the Channel Master 7778 is so expensive because it's designed for outdoor use?

nice link from Amazone I'll look it over.

Thanks STB
Edited by stevethebrain - 8/8/12 at 8:48am
post #4 of 20
Steve,

I too have noticed that the tuner in the Magnavox is superior to the one in either of my televisions. If this is due to an amplifier, it's not likely to bee too effective. An amplifier just before the tuner would amplify the signal, and whatever noise is on the line as well. You would get a loud, noisy signal. You need to put an amplifier as close to the signal source (antenna) as possible to get the signal above the noise. Once the signal is corrupted by noise, amplifying it won't improve the signal to noise ratio.
post #5 of 20
Quote:
Originally Posted by Church AV Guy View Post

Steve,

I too have noticed that the tuner in the Magnavox is superior to the one in either of my televisions. If this is due to an amplifier, it's not likely to bee too effective. An amplifier just before the tuner would amplify the signal, and whatever noise is on the line as well. You would get a loud, noisy signal. You need to put an amplifier as close to the signal source (antenna) as possible to get the signal above the noise. Once the signal is corrupted by noise, amplifying it won't improve the signal to noise ratio.

 

The Mags have a +4dB amp>Low Pass Filter (LPF)>+2db Amp cicuit that results in ~1dB stronger signal to the tuner or line imputs, rather than the typ. ~1dB loss thru passive circuits.. The LPF helps reduce any noise encountered. More info here.

post #6 of 20
In your case I'd really look into a attic antenna. I used to futz with indoor antennas but having one antenna cabled to all devices is much better. In your case I'd guess a decent small to mid sized UHF(/ VHF if you market dictates) would feed all 4 of your devices.
I'd run the cable to a centrally located place(preferably near a electrical outlet) and first try it with a 4-way passive(non amplified) splitter. I used to use a amplifier and 4 way splitter but with the switch to digital I found I had far less problems w/o the amplifier than with it. If your still having issues you should get either a ~15db amplified 4-way splitter or a 1 in 1 out ~15db amplifier along your passive 4-way splitter.
If it's more convenient you can place a splitter in your attic but if you do then you need a amplifier that allows you to place the power supply in a remote area and use the coax cable to carry power to the amplifier(the amplifier should be before the splitter).
While you can use a amplifier with a indoor antenna it's generally not the best way to go, if you plan on splitting a indoor antenna it's best to get a amplified indoor antenna, if not splitting the indoor antenna a amplifier isn't really needed.
For your antenna cable it's best to use RG6 cabling although for runs under 50' I've been known to use RG59.
I doubt your FM dipole antenna is causing your problems, it probably more due to multipath or just weak signal, it's generally not a good idea to split a indoor non amplified antenna.
Good luck! Oh and if your wondering what kind of outdoor antennas to look at you might want to check your local thread for the city you live near, if you don't know they are bound to know if you have any VHF channels in your area(note not all channels under 13 are VHF, with virtual channel mapping you really don't know what channel your stations are broadcasting on without being told or through diagnostics).
The antennas will be much smaller if you don't have VHF to contend with.
http://www.avsforum.com/f/45/local-hdtv-info-and-reception
post #7 of 20
See wajo's post for the straight info on the Mvox amplified signal gain. Allow me to join in with Church Guy & others about the Mvox tuner. We recently- after years of BS from the cable co.- began getting digital simulcast of all the channels we had before(numbered 3 to 57, with holes here & there). Plus- allegedly- on the digital "side" only, a new block of about 7 channels more & about 20 audio-only music channels.

Tried a scan w/Mvox on an evening when signal looked pretty bad on upper-numbered ch's, got 3-47. A few days later, went to cable ofc & got new cable box/decoder, installed it inline between Mvox 2160A & TV. Did scan on box, & again on Mvox- m-vox now got ch 3-57(the old com;lete listing), but none of the new channels. The cable box got ch 3-47. Several tries over several days with both, the 2160A now got the block of new channels(cable #s 58-69 with holes) at 55.1 thru 55.7. The cable co box- still stuck at ch 47.

So the 2160A's tuner is 17 channels better than Suddenlink's own cable box. I've been patient, & delayed because of wanting to record stuff last Thurs/Fri/Sat & KNOWING they would screw things up somehow. But tomorrow the calls start. wink.gif
post #8 of 20
Thread Starter 
? besides driving a ground rod 6' into the earth or attaching a wire to a cold water pipe.

how to ground a 2 way spltter inside the house? maybe grounding will improve the situation?

most of the channels work fine usalley I have been experienceing bad reception mainly w/ NBC and the Oylimpics when watching the bicycles race the recption was real bad they explained that when the motorcyclists where fliming line of site for the satilite was being obstructed thats understandable.


outside the Oylimpics what I can't understand is NBS sometimes does'nt work at all w/ my Y tube anteana however the other TV w/ a amplifed Terk antena recection is good.

I have recorded antena signal strenght w/ the 515 though it's display.
CBS 72-76 4 bars

NBC 0

Fox 49-61 3 bars

This 58-64 3 bars

CW 20-22 1-2 bars

ABC 55-70 3-4 bars

PBS 66-70 3-4 bars

regilious 61-67 3 bars

I'm thinking the solution is relocating the antena to the attic for right now trying to avoid the hot attic temps I also require a wallfish to run the wire up in attic.

Thanks Guys for the helpfull advice STB
Edited by stevethebrain - 8/11/12 at 8:00am
post #9 of 20
Thread Starter 
Quote:
Originally Posted by jjeff View Post

In your case I'd really look into a attic antenna. I used to futz with indoor antennas but having one antenna cabled to all devices is much better. In your case I'd guess a decent small to mid sized UHF(/ VHF if you market dictates) would feed all 4 of your devices.
I'd run the cable to a centrally located place(preferably near a electrical outlet) and first try it with a 4-way passive(non amplified) splitter. I used to use a amplifier and 4 way splitter but with the switch to digital I found I had far less problems w/o the amplifier than with it. If your still having issues you should get either a ~15db amplified 4-way splitter or a 1 in 1 out ~15db amplifier along your passive 4-way splitter.
If it's more convenient you can place a splitter in your attic but if you do then you need a amplifier that allows you to place the power supply in a remote area and use the coax cable to carry power to the amplifier(the amplifier should be before the splitter).
While you can use a amplifier with a indoor antenna it's generally not the best way to go, if you plan on splitting a indoor antenna it's best to get a amplified indoor antenna, if not splitting the indoor antenna a amplifier isn't really needed.
For your antenna cable it's best to use RG6 cabling although for runs under 50' I've been known to use RG59.
I doubt your FM dipole antenna is causing your problems, it probably more due to multipath or just weak signal, it's generally not a good idea to split a indoor non amplified antenna.
Good luck! Oh and if your wondering what kind of outdoor antennas to look at you might want to check your local thread for the city you live near, if you don't know they are bound to know if you have any VHF channels in your area(note not all channels under 13 are VHF, with virtual channel mapping you really don't know what channel your stations are broadcasting on without being told or through diagnostics).
The antennas will be much smaller if you don't have VHF to contend with.
http://www.avsforum.com/f/45/local-hdtv-info-and-reception
Hello Jeff well the attic temps have cooled so I'm ready to move the Y tube antenna up in the attic and try you'r advice with a 4-way passive(non amplified) splitter behind TV out the 4 way to each device.

?1.my home is a ranch style home only one floor home is 60' wide so where is the ideal spot in the attic as high as possiable w. the shortest length of cable? or lenghten the cable and have the antenna located at either side of home inside attic? I really don't want this fugly looking thing mounted outside.

?2.please recommend w/ link a decent 4-way passive(non amplified) splitter.

?3.or will the two 2 way splitters I allready have work the same as a 4 way.

I'm not sure on what to look for in a splitter like 1GHz/2 GHz ect.
how doe's this look?
http://www.lowes.com/pd_144227-12704-85-137_0__?productId=3363114&Ntt=splitter%3B+rf+4-way&pl=1&currentURL=%3FNtt%3Dsplitter%253B%2Brf%2B4-way&facetInfo=


or maybe this will work http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10422&cs_id=1042206&p_id=8217&seq=1&format=4#feedback
Thanks for all responses STB
Edited by stevethebrain - 10/5/12 at 5:59am
post #10 of 20
Quote:
Originally Posted by stevethebrain View Post

?1.my home is a ranch style home only one floor home is 60' wide so where is the ideal spot in the attic as high as possiable w. the shortest length of cable? or lenghten the cable and have the antenna located at either side of home inside attic? I really don't want this fugly looking thing mounted outside.
I would mount the antenna in the most direct line of site to your stations even if this means mounting the antenna at one end of your attic and your TV is on the furthest side of your house. Good RG6 cable loses very little on a 60 ft. run but having your antenna shoot through the rafters the full length of your house will lose more signal. If your stations are perpendicular to your house then I'd mount the antenna closest to your TV.
Quote:
Originally Posted by stevethebrain View Post

?2.please recommend w/ link a decent 4-way passive(non amplified) splitter.
Either of the splitters you linked should work just fine. If they were similar priced(including shipping) I'd probably go with the Lowes one, looks nicer made.
Quote:
Originally Posted by stevethebrain View Post

?3.or will the two 2 way splitters I allready have work the same as a 4 way.
You'd need 3 2-way splitters to do what a 4-way splitter would do, 2 2-way splitters could replace a 3 way splitter but one of the outputs would have less loss than the other two.
Quote:
Originally Posted by stevethebrain View Post

I'm not sure on what to look for in a splitter like 1GHz/2 GHz ect.
how doe's this look?
Anything about 1GHZ is only useful for things like satellite TV. Of course it doesn't hurt for OTA but it's not really needed either.
Again either of those splitters should work, the Lowes one might have less loss but probably not enough to make a difference. Antenna and placement is your main consideration.
post #11 of 20
Thread Starter 
Quote:
Originally Posted by jjeff View Post

I would mount the antenna in the most direct line of site to your stations even if this means mounting the antenna at one end of your attic and your TV is on the furthest side of your house. Good RG6 cable loses very little on a 60 ft. run but having your antenna shoot through the rafters the full length of your house will lose more signal. If your stations are perpendicular to your house then I'd mount the antenna closest to your TV.
.
Jeff are you saying that I should locate on a map where the one weak station is (NBC) then try to locate or aim in that direction?what real strange is I only have to move the y-tube ant. a tiny bit closer to front of house and wala good NBC reception however ABC and CW is terriable.

or should I just go up in the attic w/ TV tuned to NBC and find the good recption spot then nail it to a rafter?

edit doe's it matter if the Y-tube antena is mounted verticalley or diaangley nailed right to rafter.

yes I have have RG6 I also plan to use the leftover to conect all devices out of splitter.

Thanks STB
Edited by stevethebrain - 10/5/12 at 2:14pm
post #12 of 20
I'm not familiar with that type of antenna but generally I'd move the antenna until your weakest channel comes in. Of course if your stations are in different directions and this causes you to lose other stations, you'll either need to use some type of rotor or decide what stations you like the most. If you have a small portable TV you might want to bring it up into your attic, that or have someone watching your TV while you turn things in the attic.
post #13 of 20
Thread Starter 
Quote:
Originally Posted by jjeff View Post

I'm not familiar with that type of antenna but generally I'd move the antenna until your weakest channel comes in. Of course if your stations are in different directions and this causes you to lose other stations, you'll either need to use some type of rotor or decide what stations you like the most. If you have a small portable TV you might want to bring it up into your attic, that or have someone watching your TV while you turn things in the attic.
Jeff I probably relocate the Y-tube antenna Wensday or Thrusday I report back w/ results thanks for advice.

the Y-tube antenna is a coat hanger wire 4 whiskers on each side works real good just not NBC.
post #14 of 20
Thread Starter 
update onTV reception

well I finalley got the wall fish completed and now don't have to look at the Fugly antenna any more.

made a deal w/ a cable Guy at the gas station I wanted RG6 coax he had a almost empty roll that he said he was gonna throw out anyway the cable was free I asked nicely and he terminated both ends for me.$10. for 8 RG6 connectors and a 4way passive splitter 0-1GHZ.

The Y-tube coat hanger wire antenna worked good on the first level however it did'nt work that good in the attic so connected my old $15. archer rabbit ears.

Day one rabbit ears working kindof good then I read on the net about antennas in the attic I had about 20' of extra cable the problem was this 20' of cable was coiled up so I cut the excess cable and straightened the rest of the cable.

Results w/ TVs tuner are all channels come in clear even NBC & CW the 2 problem channels now experiencing bad reception on CBS however w/ the 515 & the PCs tuners all channels come in good which is good because most of the stuff I watch is prerecorded only time I watch live TV is local news or football so I maybe forced to use the 515 or the PCs tuners.

I was concidering a antenna upgrade

http://www.pcrush.com/product/HDTV-Antennas/318785/Channel-Master-4221HD-UltratennaTM-HDTV-UHF-Antenna

however this antenna won't go to the low channels below 14 only recieves 14-69 so I'm assumming it will preform as good as my old $15. archer rabbit ears.

I have observed that some splitters have differnt output -3 -7 ect. this 4 way I obtained from the cable Guy all 4 outputs are the same -7 so why are some splitters outputs differnt? maybe one device requires more or less signal?

Lastly is it true or false that TV stations turn up the transmitting power for commercial and also during prime time?

Thanks STB
Edited by stevethebrain - 10/13/12 at 7:23am
post #15 of 20
Your Archer rabbit ears antenna is mainly for VHF(below channel 14) where as the 4 bay bowtie you linked is, as you said, mainly for UHF. A bowtie type antenna does tend to cover high VHF(channel 7 and above) but won't be too good for the low VHF channels.
2 or 4 way splitters(even splits) will almost always be equal on all outputs, odd number of splits(3 way for example) sometimes have two of the outputs -X db while the other will be less. If this is the case then the less - output should go to your longest run.
Some stations may turn power down during off hours(for example after midnight) but I doubt they would be changing power for other times. I'm not even positive any stations do drop power, AM radio stations do this but I'm not so sure about TV stations. The reason AM stations did this was because at night AM travels much further and a larger market station wouldn't want smaller market stations interfering with their signal.
post #16 of 20
Thread Starter 
during day 2 of testing it out, was'nt for an extended period of time yesterday was, I wrote to soon CBS is improved w/ using the 515 tuner but still is'nt 100%

Maybe this antenna will work better than a bowtie type?

it's advertising channels 7-69 compared to the bowties 14-69

Thanks STB


http://www.amazon.com/International-CM2016-Channel-Master-Television/dp/B0018BZJNS/ref=cm_cr_pr_product_top

this antenna has excellent feedback however they don't mention which channels I can recieve.
http://www.amazon.com/RCA-ANT751R-Outdoor-Optimized-Reception/dp/B0024R4B5C/ref=cm_cr_pr_product_top
Edited by stevethebrain - 10/14/12 at 7:28am
post #17 of 20
It's interesting to read those comments about Maggies tuners improving the reception. In my case, all the OTA channels (23 of them on 14 different physical channels) come in weaker on the Mag than in the 3 television sets we have. Actually, of the 23, only 18 are even detected by the Mags, and at least 8 others have very unstable (below 20%) locks.

We have 3 TVs, 2 Mags.

I have a CM4228HDC along with a CM7778 pre-amp, and a single 4-way splitter (lowest dB figure I could find) to split the signal to the 4 devices (the 4th one is because I ended up giving up on picking up those 5 + 8 weak stations on the Mag on the main TV and opted to have a 4th split which I connected directly to the RF input of the TV. At least I can watch these channels, but can't record. It was important to me because one of those is FOX, and I need my football.

I had to find that workaround because even using the Mag's passthrough connexion, the signal loss affected my TV's tuner. Had no choice but to have a connexion that completely bypassed the Mag and went directly to the TV. On the secondary TV, the antenna first feeds the Mag, then through its passthrough to the TV. The reception still ends up better on the TV's tuner than the Mag (20 on TV vs 10 + 8 very unstable on Mag). Upstairs the TV rarely gets used for anything else than Blueray movies, yet it still picks up 20 channels (longer cable run), doesn't have DVDR equipment.

That's been the only major inconvenience of my Mags though, I just love'em and for the price, I still recommend them to everyone I know (without much success, most people complain all the time about the cable costs and poor service, but think they couldn't live without it... oh that's another story!).

So I guess the results can vary, but I personally (because of my own experience) would NOT recommend relying on the Mag's amp to improve your signal. You could end up thinking you have a bad signal, when the problem is really the Mag introducing noise in it. Sure, local channels might actually improve, but any weaker signal will be degraded. In my case, even local signals get downgraded by the Mags.
post #18 of 20
Thread Starter 
well I finially spent a little $ on a hopefully excellent TV antenna, from Walmart online $40.99 plus tax.

will install it Sunday and report back w/ details.

?1. the RG6 coax I obtained from the cable Guy at the gas station the center conducter is'nt soild copper it's steel w/ just a copper coating how doe's this cable compare to soild center conducter?

?2.it seams like splitters come in differnt sizes 2,3,4 way then jumps to 8 way are 5 way splitters available?

3.I would'nt mind connecting the second TV up to this RCA751( if it works well) if I'm forced to use a 8 way will I lose any signal strenth to the primary 4 devices? or will capping the 6.7,8 ports reduce any signal lose?


?4.lastly how do I know if this RG6 coax is quad shield or just double shield and how do the two types of cable compare to each other?
Thanks STB

http://store03.prostores.com/servlet/dennysantennaservicestore/the-EZ-dsh-HD-Antenna/Categories
post #19 of 20
Quote:
Originally Posted by stevethebrain View Post


?1. the RG6 coax I obtained from the cable Guy at the gas station the center conducter is'nt soild copper it's steel w/ just a copper coating how doe's this cable compare to soild center conducter?

?4.lastly how do I know if this RG6 coax is quad shield or just double shield and how do the two types of cable compare to each other?
Unless you are hopelessly strapped for cash, get yourself to Lowes and buy some real quad-shield cable with solid copper core and a pack of quad-shield F-connectors.
post #20 of 20
Thread Starter 
update on reception

the new antenna was a joke I spent hours aiming this thing and never recieved all the channels.

I rebuilt my Y- tube coat hanger wire antenna went from 7" whiskers to 8" now my TV tuner and 515 recieve all channels however the PCs tuners won't pick up ABC or CW.

so looks like I'm forced to record ABC and CW w/ the 515.

edit: I'm planning to add reyonlds wrape or chicken wire to back of antenna as a reflector.

Kelson do you think the soild copper center conducter type coax would be the solution for ABC and CW on the HTPC? all the other stations come in excellent.

STB
Edited by stevethebrain - 11/3/12 at 6:48am
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