Magnavox 537, 535, 533, 515, 513, 2160A, 2160, 2080 & Philips 3576, 3575 - Page 766

Good tip, I already did that = same result.
It,s just very puzzling that the Mag's internal splitter/amp goes both ways. And plugging into the OUT, although it reduces the signal strenght on most channels, actually performs better on a specific frequency (UHF 32) vs the "IN" which eliminates that same channel, while allowing another one on UHF 43 which doesn't come in at all when connected "OUT".

You'd of course assume connecting in the "OUT" is all wrong... but for some reason it's not necessary the case depending on the incoming signal.

Both these channels don't have adjacent or co-channels.

Wow, so they remain in memory, but are they tunable?

When I revert to "IN", PBS is still in memory on 33.1 (and sub channels 33.2, 33.3, 33.4) but has a signal indicator of "0" and so is not tunable.

I can't wait to see how you document this in the index of information.

Do you use a long coax run with an amp? If so maybe a tilt compensator would help.

hi folks....

ok, on this bass-ackwards issue, some technical points...

1 - depending on the design, these guys are bound to have reverse leakage. in a perfect design, there would be little to no
reverse leakage. in the real world, not so possible.

2 - the signals being fed to the ' OUT ' and lifted from the ' IN ' will be attenuated to some unknown degree, but due to leakage,
may still pass in the backwards direction in usable form.

3 - a buffer stage, such as might be in these tuners in order to compensate for a pair ( dvr processing & feed to the outside )
of loads, is likely of broadband design with some possible varactor based tuning. With or without any electronic tuning or
peaking, though, there are likely to be some frequency sensitive impedance or simple loss bumps along the entire tuning
range. Remember, these are NOT high dollar tuners.

given the above, i'm betting that what you are seeing is recoverability of weaker signals by virtue of the stronger signals
( not necessarily adjacent, mind you ) being attenuated due to the lossy reverse connection being used. by reducing
the level of the stronger signals, you are likely pulling otherwise unusable ( or undetectable ) channels out of the
mud ( read ' noise floor ' )...

i am not really too surprised by what you've been observing ... by-products of digital versus analog notwithstanding,
when you lower the noise floor, it's easier to pull a weaker signal sufficiently out of the mud to be completely usable ...

just thoughts...

rgds,
ron g

First of all, I'm indebted to Wajo for all the help I've received from reading here over the years. I first got the Philips 3575 five years ago and then the Magnavox 515 a year and a half ago. I continue to use them both every day. The 3575 gets only a few digital channels but I didn't realize it soon enough because I only had an analog TV when I bought it. Nevertheless, it's been very good for me. Lately, at most once a month, I've had to pull the plug out briefly after a "system error"; but rarely is anything lost. And the 515 seems to screw up if I try to record a digital channel immediately after a timed analog channel recording - at least that's what I think was happening. Now I always leave a dead minute in-between going from an analog broadcast recording to a digital one.

I'm so dependent on these recorders that I would have bought another one already if not for the remote control problem - having two units using the same remote. I can't remember what the workaround is. Can someone advise? I sure hope there is someway to operate two Magnavoxes side-by-side or I'm in big trouble. I'd hate to get stuck having to buy a Channel Master unit (I only need a harddisk recorder) as they get bad reviews and they're not what I want. Or perhaps another old Philips 3575/3576 is possible to find to replace mine when it finally quits?

It sounds like I shouldn't wait if I want to be sure to be able to still get a new Magnavox. Any advice or suggestions would be greatly appreciated.

On a side note, I read this sad news yesterday on techcrunch.com: "Philips, a brand well known for their televisions and optical media devices, is leaving the consumer electronics market and is now focusing on medical equipment and lighting. The company sold its CE business to the Japanese manufacturer Funai Electric Co. for $201 million."

Yeah. The whole consumer electronics division for a mere $200M. That says a lot about the whole consumer electronic industry, doesn't it?

Apparently, Philips has been losing hundreds of millions. "The whole consumer electronics division for a mere $200M" says it all.

I wouldn't wait to buy a new unit. The CM7400 would not be my first choice either. I had bad luck with mine and sent it back.

The method used to have two units close to each other involves blocking the ir signal. I use a small but well fitting piece of painted cardboard. Painted flat black and just covering the window is best. wajo has a method using part of a VHS tape which might be in the index post. It must be opaque and well fitting since any leakage can be bad. Since the power button is not the only button that can take a unit out of standby, you really must be careful.

Long cable.. I'd say yes since it must be about 100 ft. But I use a PRE-amp, outside next to the tower. No amp inside, just a regular splitter.

Thanks for this technical explanation. Although, the poor soul that I am still doesn't understand that this process would allow me to pick up a channel that's got a lower DB rate than the one it makes me lose. According to tvfool that is.

Thanks for trying it out Interesting results...


_ _ _ _

I wonder if anyone who has the newer 53x models would care to try it. Some people alledged these tuners are "better".

Yep, tried that too. Also tried different splitters. I can see some splitters are better quality than others but no significant changes in channels reception, just in the signal strength. Over the year I've been experimenting with this issue, I tried many, many things

Thanks much JoeKustra. I'm going to order a Mgvx 537 right now, while they still can be had. I don't need it yet but I will soon enough.

I really really appreciate ingenious KLUGE shield tips. I should have a couple vhs cases that should work and I might even consider the RF option. The warning about what can go wrong is now implanted in my brain. I might as well put the recorders together - I'm not sure I'd be able to put them far enough apart. But anybody like me that's got multiple recorders probably is using a lot of devices and remotes which gets confusing. I point the wrong remote in the wrong direction almost everyday and wonder why it's not working.

I use black painted cuts from 100 count green tea bag boxes. They're heavy enough, a handy size to cut from, and already have folds allowing need for no more than minor tweaking to ensure nice neat anti-leak fit.

hi rx...

ok... i just looked at tvfool to get an idea of your reference to DB rate (?) ... there are 2 references...

the first is NM or ' noise margin ' .. this number is a measure of the ' margin ' between a given signal at your location
and the ' noise floor ' ... the greater the number, the more usable a signal is... it must be above 0 in order to be
detectable from the noise floor... the number represents a theoretical value that may or may not actually exist,
depending upon any number of external factors, including things like broadband noise at your locale, other
non-tv stations in your immediate area, etc...

the 2nd is the signal strength expressed in -dBm ... this would be an actual measure of the signal level that SHOULD be
arriving at your antenna, given whatever parameters you made for your particular location... again, this is theoretical, and is
affected by things such as terrain, buildings ( even if they are not directly in the path of the signals you are trying to receive ),
and other strong RF sources not necessarily associated with the frequency bands that our tuner is used for.

for the sake of argument, lets use the following figures as an example :

in the normal connect configuration -

1 - actual noise floor at the point of detection inside the tuner = -63dbm
2 - station X with a signal level of -55dbm at the same point ( noise margin = 8db )
3 - station Y with a signal level of -66dbm at the same point ( noise margin = -3db )

in the above scenario, station X works, while station Y is below the noise floor, and does not work.

in the reverse connect configuration -

1 - actual noise floor is reduced by 8db and is now -71dbm
2 - station X signal level is reduced by 10db and is now -65dbm ( noise margin = 6db )
3 - station Y signal level is reduced by 1db and is now -67dbm ( noise margin = 4db )

the differences in the amounts of attenuation can be due to non-linearity across the bandwidth of the tuner,
especially given a reverse connection. it can also be due to reflections and impedence bumps created
by pumping a pair of output stages into each other, albeit separated by 100ft of feedline.

so in the reverse scenario, both stations are now ' above ' the noise floor, and with noise margins within 2db
of each other. both signals would theoretically be usable, but would have different characteristics than those
noted with a normal connect configuration. this would be due to how well the tuner itself was designed, as well
as possible bit error rate differences that might determine successful or failed station recovery and memorization.

again, these numbers are just random for purposes of the example. depending on the amount of noise margin
for each station, as well as the ' relative ' margins between the 2 stations in question, and along with how 1 or more
other uninvolved stations are affected in terms of their levels and margins, it all might be affecting the tuner's
ability to recover and use either of the 2 stations' signals.. indeed, the weaker station might prove more usable
than the stronger, or vice versa.

not really an exact science, here. having a spectrum analyzer would more than likely provide an accurate answer.

none of this even considers the effects of oxidized dissimilar metals close by or on the antenna structure, or feedline
condition. both of these can use incoming RF to create either broadband noise, or noise at a specific region in the
spectrum.

it also doesn't consider the effects of having a powered output stage ( your DVR tuner output ) feeding another output
stage ( your pre-amp's output stage at the other end of your 100ft cable run ) . you could be setting up various
reflections and impedence bumps along that whole route, some of which might produce ' adding ' or ' cancelling '
effects.

hopefully, this helps and does not confuse the issue moreso...

in essence, i don't really think you are observing something extraordinary, but rather the random anomolies associated
with the backwards connection setup...

rgds,
ron g
========

hi folks ...

after failed attempts at an IR solution, i think i would vote for using an RF path in lieu of IR, albeit kind of a kluge in its own right....

convert an IR remote into RF transmission using a switchable ' frequency ' RF carrier. then each dvr gets a companion receiver
tuned to its own RF frequency. if you wanted to stay outside the dvr, you'd take the RF receiver output and drive an IR LED
mounted at the DVR's IR receiver window....

of course this is just me... i would prefer a solution that does not require me to get off my butt and move IR covers around.....


best rgds,
ron g

@rkg22 : it's not confusing, it's very well appreciated. It could explain from a theorical perspective what's going on but, in a very practical way, there isn't much I can do. If the "noise floor" calls for more attenuation on one channel, while needing less for another one, there isn't much more I can do then physically attenuating (or not) the signal if I need X (or Y) channel.

So, it looks like it'll be : since I don't record FOX very often, but I do on PBS, I'll leave the cable plugged in the OUT connector allowing my timed recordings to do their thing, and in the odd occasion when I need to record FOX, I'll just switch the cable to the IN connector, and have to remember to switch it back to OUT after...

Just for kicks, here is my TV FOOL : http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d1dda1012783c84
You can see the difference between 32 and 43 is subtle. Hard to explain why such a big difference in reception results.
Edited by rxheaven - 2/2/13 at 6:44am

Well, you always will have the spectrum analyzer option. Or Cable.

Is there any noticeable difference between the two channels in the report with the antenna at ground level?

Hi, I've searched for the problem and found some information but still have some questions.

I have both a Magnavox MDR533 and a MDR535. The 533 dubs fine on several disks I've tried (including an ancient Taiyo Yuden DVD-R) but the 535 returns the following errors on disks that work fine in the 533.

When trying to dub to a new Sony DVD+R 1-16x disk in the 535, I received the error E4 54039000. I dubbed a short bit on this same disk in the 533. I then moved the disk to the 535, tried to dub and received the error E4 540043e02.

So I understand from the error that it's with the OPC. I tried the spit test after which the disk wouldn't even load (maybe I need to brush my teeth first) but I'm reluctant to open the machine and clean the spindle (at least I think I need to open it for cleaning).

Short of returning the machine for warranty work, are there any other options? I have a ton of stuff recorded on the HDD that I'd have to move via copy which I would prefer not to do (I will if I have to).

Any help would be very much appreciated. Thanks.

This happened to my 2160A I just swapped the drives between the 2160A and my 513 and now both work.

Thanks Wajo, the connection came back OK on the DVD.

Thanks for your reply. The MID is Ritek on the Sony's. I did try several different DVD-R and -RW that I have in the house - no luck.

At this point, it probably needs to be taken in for service.

Thanks again,
Cathy

hi mjw ...

also, if you have a PC with a dvd burner, you might want to try a full blown erase to re-virginize the RW discs...
i've had issues in the past that ultimately were attributed to the discs having been unusable between machines
without first turning them back into ' essentially ' virgins by performing a full disc erasure ( which these machines
do not do ) using a program like imgburn.

like others mentioned, i've also had issues whereby one machine would deal with given discs and another would not...
in some if these cases it was, indeed, a drive issue and i needed to replace the dvd drive...

good luck...

ron g