6U5/6G5 Tuning Eye Tube Questions

[jr_tech]

Originally Posted by Captainclock

I don't think that chart is very accurate though because most of those stations listed on there (except most of the chicago stations) are fairly powerful stations whoever compliled that chart I don't think did their research properly

The Radio-Locator information presented is calculated from the information presented on the FCC site, using established methods.

FCC data for WSBT:

https://transition.fcc.gov/fcc-bin/a...=0&facid=73985

Note that WSBT is only 5 kW and uses 4 towers to produce a directional pattern, to "protect" other stations.

From this data, the Radio-Locator computer calculates the following coverage map for WSBD:

http://radio-locator.com/cgi-bin/patg?id=WSBT-AM&h=D

Note that Elkhart is near the edge of the "local" plot, and the signal strength is adversely affected by the null in the directional pattern. I would not expect full closure of your 6E5 indicator on that station.

jr

[Captainclock]

Originally Posted by jr_tech

The Radio-Locator information presented is calculated from the information presented on the FCC site, using established methods.

FCC data for WSBT:

https://transition.fcc.gov/fcc-bin/a...=0&facid=73985

Note that WSBT is only 5 kW and uses 4 towers to produce a directional pattern, to "protect" other stations.

From this data, the Radio-Locator computer calculates the following coverage map for WSBD:

http://radio-locator.com/cgi-bin/patg?id=WSBT-AM&h=D

Note that Elkhart is near the edge of the "local" plot, and the signal strength is adversely affected by the null in the directional pattern. I would not expect full closure of your 6E5 indicator on that station.

jr

Well I realize its probably not going to completely close the eye, but I'm sure it would at least partially close it because it is considered a local station.
I'm aware that some stations even though they come in clearly won't necessarily completely close the tuning eye tube as I know for a fact that the 6FG6/EM84 tuning eye tube that's on my Silvertone stereo doesn't always completely close for some of the FM Stations near me even though they come in clearly but it does make the eye react enough though when tuning around on the dial none the less even if the station is an incredibly close by station that you know its working.
I know for a fact that the FM counterpart to AM 1270 WCMR here in Elkhart, which is 105.3 FM WCMR which is the FM Stereo version of AM 1270 doesn't completely close my tuning eye on my Silvertone Stereo, but yet the sister station to WCMR, WFRN 104.7 here in Elkhart (which both stations broadcast out of the same building and use the same towers) does in fact completely close the tuning eye tube on my Silvertone stereo, so does 97.7 FM (a local classic rock station out of South Bend, Indiana on the FM Band) and 92.9 (a local pop/top 40 hits station that is also from South Bend, Indiana) also completely closes the tuning eye on my Silvertone stereo as well as does the local country stations, the local 24 Hour Classical Station out of Berrien Springs, Michigan however, although it comes in clearly on the radio doesn't completely close the the tuning eye tube on the Silvertone, so I'm sure that the station's power does somewhat influence whether or not the tuning eye closes completely or not, but that doesn't mean its necessarily not going to come in at all, or not affect the tuning eye tube to some extent.
I have no idea how the AM Band is on the Silvertone and how the tuning eye tube on it reacts with the AM band as the original built-in loopstick antenna inside the stereo for the AM Band broke off of the chassis when I was working on recapping the unit so the AM Band doesn't work on the Silvertone currently until I can get a new loopstick antenna located for it and installed.

But really though trying to suggest that the stations aren't going to affect the tuning eye tube at all is kind of being a little presumptuous because I would think that a properly aligned tuner and properly working tuning eye tube would react to any sort of station its receiving whether or not its an extremely high powered station or not. If the tuning eye tube isn't responding or barely responding even to the most powerful and closely located stations then it has nothing to do with whether or not the station is extremely powerful or not, it has to do with the fact that something on the radio isn't working right whether the tuner is out of whack or the IFs are out of adjustment and need tweaking or something like that then obviously its probably going to affect whether or not the tuning eye tube is sensitive or not to picking up on signals and responding to them.

I think like OldCoot said more than likely the IF cans are out of adjustment and need to be tweaked back into adjustment again and it will probably fix my unresponsive tuning eye tube issue. Because like I said the tuning eye tube barely responds to even the strongest of stations on the AM Band, ironically though it is completely responsive on the SW band even when there's no audible signal being broadcast it picks up on it and completely closes the tuning eye tube on the SW band which tells me its probably something about the AM Band that isn't adjusted properly (whether it be the IF Cans or the Tuning Capacitor or the antenna adjustments.)

[old_coot88]

Originally Posted by Captainclock

...the tuning eye tube barely responds to even the strongest of stations on the AM Band, ironically though it is completely responsive on the SW band even when there's no audible signal being broadcast it picks up on it and completely closes the tuning eye tube on the SW band...

If that's the case, the IF stage has adequate gain. Don't mess with the IFs at all.

[Captainclock]

Originally Posted by old_coot88

If that's the case, the IF stage has adequate gain. Don't mess with the IFs at all.

Then what would cause it to barely respond on the AM Band and Respond extremely well on SW?

[old_coot88]

When you're on SW, does the eye respond only when a signal is being received? Or does it stay activated somewhat even with no signal received?
If the latter, do you hear a lot of birdies and whistles when turning the dial?

[Captainclock]

Originally Posted by old_coot88

When you're on SW, does the eye respond only when a signal is being received? Or does it stay activated somewhat even with no signal received?
If the latter, do you hear a lot of birdies and whistles when turning the dial?

Well the shortwave band is kind of odd because I will sometimes pick up a station from somewhere in Western Europe or even in Mexico or Central America, and the tuning eye will respond to those stations and almost completely close the eye in some cases, what's weird is that when I was picking up some shortwave stations on there one night there was a spot on the SW dial right around the 14-16 MHz area that made the tuning eye tube go completely closed but there wasn't any audio there that I could hear, which was kind of weird but yet when I use it in AM mode the tuning eye tube barely responds even to the stongest local signals, which is got me confused as to why the radio would do that...

[Electronic M]

Perhaps an un-modulated carrier is what closed the eye....Those are silent.

[Captainclock]

Originally Posted by Electronic M

Perhaps an un-modulated carrier is what closed the eye....Those are silent.

What's an un-modulated carrier? And are they common in Shortwave Broadcasts?

[Electronic M]

Originally Posted by Captainclock

What's an un-modulated carrier? And are they common in Shortwave Broadcasts?

Okay, really basic radio theory lesson time: Carrier wave = the radio frequency sinusoid that travels through space and normally carries information of some type, Modulation = modification of carrier to place information on it. Un-modulated means no modification of the carrier sinusoid is made.....Just an RF osc. (and probably a power amplifier) randomly radiating power out into space for no good reason.

Types of modulation include CW (turning carrier on and off to represent information normally in the form of Morse code), AM (changing the strength of the carrier instep with a signal that is normally a sound or video signal), FM (changing the frequency of the carrier instep with the signal), PM (changing the phase of the carrier instep with the signal...an integral/differentiation relationship exists between PM and FM signal encoding), QAM (Google it! most common example is color sub-carrier modulation scheme in NTSC TV), and various forms of digital modulation that I don't care to regurgitate, enumerate, and explain.....

As for how common un-modulated carriers are on shortwave...I can't say. It's been a few years since I was a regular SW listener, and even then it's hard to know since many radios (including my favorite SW set) lack a good signal strength meter, and unless the meter is looking directly at RF carrier strength you really have no way to know of their presence with a normal radio unless the band around them is VERY noisy...And even that is not a guarantee of their presence.
The only surefire way to find them is to plop down big bucks for a spectrum analyzer and use that to tune a radio to the frequencies of noticeable carriers....Or attach a measurement device to a TRF radio and learn the difference between atmospheric background noise and carrier waves.

If you don't know how the beast works your not an electronic technician, but a mechanic/parts swaper.

[Captainclock]

Originally Posted by Electronic M

Okay, really basic radio theory lesson time: Carrier wave = the radio frequency sinusoid that travels through space and normally carries information of some type, Modulation = modification of carrier to place information on it. Un-modulated means no modification of the carrier sinusoid is made.....Just an RF osc. (and probably a power amplifier) randomly radiating power out into space for no good reason.

Types of modulation include CW (turning carrier on and off to represent information normally in the form of Morse code), AM (changing the strength of the carrier instep with a signal that is normally a sound or video signal), FM (changing the frequency of the carrier instep with the signal), PM (changing the phase of the carrier instep with the signal...an integral/differentiation relationship exists between PM and FM signal encoding), QAM (Google it! most common example is color sub-carrier modulation scheme in NTSC TV), and various forms of digital modulation that I don't care to regurgitate, enumerate, and explain.....

As for how common un-modulated carriers are on shortwave...I can't say. It's been a few years since I was a regular SW listener, and even then it's hard to know since many radios (including my favorite SW set) lack a good signal strength meter, and unless the meter is looking directly at RF carrier strength you really have no way to know of their presence with a normal radio unless the band around them is VERY noisy...And even that is not a guarantee of their presence.
The only surefire way to find them is to plop down big bucks for a spectrum analyzer and use that to tune a radio to the frequencies of noticeable carriers....Or attach a measurement device to a TRF radio and learn the difference between atmospheric background noise and carrier waves.

If you don't know how the beast works your not an electronic technician, but a mechanic/parts swaper.

I have a basic running knowledge of how radios work but as far as why they do some of the strange things they do sometimes that I don't understand (after all I'm going to school for computer repair not electronics repair, seeing as electronics repair is more or less a dead artform since everything is more or less juts throwaway now, because I was born about 3 decades too late for electronics repair classes of any sort and I mainly dabble with radio and record player repair as a side hobby.)

Also there still hasn't been any definitive answers given yet as to why the tuning eye tube on my radio would be more sensitive on the Shortwave band than on Broadcast (AM) band, especially seeing as I've figured out that the tuning eye socket is getting the proper voltages its supposed to have but yet it barely responds on the AM Band but responds extremely well on the SW Band.