FM hiss, vintage 1973 receiver

Nothing wrong with it, other than it should have been thrown out 20 years ago. Why are you still dicking with old recievers. Don't you have a girlfriend or a life?

It is impossible to guess at what can be wrong. There are many components involved to receive, and process the signal. An experienced tech who is knowledgeable in servicing tuners should be able to troubleshoot the tuner for you, and find the failed components.

--

JANA _____

Is this normal in a receiver of that age? If not, what components are likely to be deteriorating?

If the receiver has a multipath filter, try that.

Aaaah, shaddap before we bomb Dresden. Again.

Hugs & kisses, Francois.

I knew that already, except the "impossible" part.

How good is your antenna for the station that you are trying to receive? Do you have an outside antenna?

These symptoms are common for fringe reception (stereo not full quieting - but mono is better).

If you are trying to receive the signal with a small dipole in a tall steel and concrete high rise - then you are not getting sufficient signal strength to the receiver.

gb

That would be useful. ;-) Do you mean multiplex?

--
*Despite the cost of living, have you noticed how it remains so popular?

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

mc posted a question compliant with usenet standard: 3416554677697809809 section B, page 27, paragraph 8: Any initial question must omit at least one piece of vital information, otherwise it can not be considered for followups.

Noise in Stereo FM is out of phase between the channels, and thus disappears when the signalchannels are added to mono.

This is not about age - rather about quality, unless of course something is broken and age, if it was left unused for an extended period of time, may have caused some components to deteriorate. Have you just found or gotten it or do you know for sure that it has deteriorated. Try adding the elementary information: make and model, someone may then know whether it was likely to have been good or bad ex works.

Kind regards

Peter Larsen

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     *******************************************
     * My site is at: http://www.muyiovatki.dk *
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A 1/4 wave ground plane in the attic of a wood-framed house. Some of the local stations (within 5 miles) are very strong, and I can get some stations

80 miles away (not with good audio). The antenna is not the problem. What concerns me is that even the very strongest signals do not give full quieting on stereo.

That I knew...

Nikko STA-5010. FM stereo demodulator is a UPC554C chip.

Circuit diagrams somewhere on

Thanks!

Only on FM stereo. No problems with any other signal source, stereo or mono. Anyhow, would a dirty switch produce continuous hiss?

"mc" bravely wrote to "All" (03 Jan 06 00:00:37) --- on the heady topic of "FM hiss, vintage 1973 receiver"

mc> From: "mc" mc> Xref: core-easynews rec.audio.tech:186013 mc> sci.electronics.repair:353686

mc> FM stereo receiver, vintage 1973, has a noticeable background hoise mc> (hiss/white noise) on FM stereo regardless of the incoming signal mc> level. It disappears completely upon switching to mono.

mc> Is this normal in a receiver of that age? If not, what components are mc> likely to be deteriorating?

Vintage 70's equipment is making a comeback and is all the rage now. A big noise is absolutely normal between stations if there is no muting circuit but when tuned to a station the noise should drop dramatically. It is also normal to have a little extra hiss in stereo. However I have no idea how much hiss is normal for your particular receiver. If it seems excessive then perhaps the components to look at are electrolytic capacitors around the stereo decoder/demultiplexer circuitry. If you can find a separation adjustment trimmer, sometimes reducing the separation a little can lessen the hiss significantly without affecting the stereo effect too much.

A*s*i*m*o*v

... A stereo system is the altar to the god of music.

"null" bravely wrote to "All" (03 Jan 06 05:56:45) --- on the heady topic of "Re: FM hiss, vintage 1973 receiver"

nu> From: snipped-for-privacy@idiom.com ((null)) nu> Xref: core-easynews rec.audio.tech:186020 nu> sci.electronics.repair:353710

nu> In article , nu> Erich J. Schultheis, The Man with the 15 inch Cock. nu> wrote: >

nu> Aaaah, shaddap before we bomb Dresden. Again.

Don't feed the trolls!

A*s*i*m*o*v

... Your E-Mail has been returned due to insufficient voltage.

Don't be so sure. It used to be (and probably still is) that commercial FM transmitters were almost always horizontally polarized. A pair of crossed folded dipoles (made from 300 ohm twinlead) in your attic will probably have markedly superior performance to your vertical quarter-wave.

-- Dave Tweed

Asimov wrote: Vintage 70's equipment is making a comeback and is all the rage now. A big noise is absolutely normal between stations if there is no muting circuit but when tuned to a station the noise should drop dramatically. It is also normal to have a little extra hiss in stereo. However I have no idea how much hiss is normal for your particular receiver. If it seems excessive then perhaps the components to look at are electrolytic capacitors around the stereo decoder/demultiplexer circuitry. If you can find a separation adjustment trimmer, sometimes reducing the separation a little can lessen the hiss significantly without affecting the stereo effect too much.

Thanks. Several people are saying that. I'll also look at the power supply for the tuner section (which has its own regulator). The power may be noisy or not the correct voltage.

Thanks, I'll try that.

I thought they were going to vertical polarization because of car radios. I'm wondering where I read that, and whether it's true.

I'm pretty sure that commercial VHF services like FM radio and TV prefer horizontal polarization because of fewer problems with absorption and/or diffraction from vertical objects such as trees and poles.

Also, most customers for these services have fixed antennas, and can do horizontal just as easily as vertical. FM radio in the car is an exception, as you note, but most cars these days either have a horizontal dipole in the window glass somewhere, or a whip that has a significant amount of tilt.

On the other hand, VHF services that are intended *primarily* for mobile customers (public service bands, etc.) use vertical polarization because the car antennas really want to be vertical whips for mechanical simplicity.

-- Dave Tweed

Almost all commercial FM stations in the US are circularly polarized (1/2 power vertical; 1/2 power horizontal, 90 degrees out of phase). That covers both types of antennas, and if you have a CP receiving antenna, you can dramatically reduce multipath if it is oriented toward the transmitter.

Karl -

You beat me to that answer, which is correct. I installed a set of 2 horizontal staked loops for one college broadcast station (they had no desire for mobile users) and the antenna was free from a commercial station that upgraded to CP as pointed out by Karl).

gb