[morzh]

OK, so I have them side-by side.

One thing I cannot understand: in the morning, any time since when I get up, say 8 or 9am and about 11am to lunch, when I turn on Zenith and tune to the local station, the reception is clear, no noise, and so it is for the Philco 18.

In the evening the same station reception is still fairly clear for Philco, but for Zenith there is some noise, like a light scratching.

I started paying attention to that just recently, and so far I have no clear explanation.

Any ideas?

[Electrothaumaturgist]

Move the Zenith where the Philco is, and move the Philco to where the Zenith was, to determine if it simply is a matter of antenna misalignment. I know on the 42-400, a slight turn of the antenna (or perhaps any linear movement of the radio itself) can cause noise, or clarify the signal, especially in the evening. Or if not, maybe the Z brand is just more sensitive to rogue noises than the Philco. That is one thing I noticed when I powered up the 42-400 (my phirst philco), there was dead silence between stations. Philco may have more filtering power than the Z's, as I've heard that "scratching" sound you speak of (under similar situations) on other Z sets.

[BrendaAnnD]

Given that you are talking about evening, and therefor skip reception is present, it could well be an adjacent channel station bleeding over. This could be a function of needing alignment, or it could just be that the Zenith IF's are a bit broader (good for fidelity, not so good for selectivity). It could also be IBOC interference.

[morzh]

Yep, that could be it, some sort of skip reception effect, as it is strongly day/night dependent. Could be coupled with the IF alignment.

ET: same was the case in my upper room where they resided before.

One thing I did not check: the Z-antenna is a loop of wire inside the cabinet and Philco has a dangling wire. May do it out of interest.


PS. this is also absent on my Philco 37-116.

[Electrothaumaturgist]

Well, there you have it! The highly advanced Philco circuitry is superior in eliminating unwanted signals, compared to its' contemporary Z brand. The classic "taste test". You have me sold!

[morzh]

Yeah, but the sound so far is totally owned by Z.

[Eric T]

A lot of AM stations switch to lower power at dusk. That might have something to do with it.

[BrendaAnnD]

Morzh,

A loop antenna would tend toward a lower noise floor. For longwires/random wires, vertical orientation tends to be quieter than horizontal.

[morzh]

Good to know.
Hadn't tried that vertical hanging wire on the Z yet - I am battling 37-116 dial assy. (Although I did have it in there first but then I noticed that internal antenna and connected it. And now I don't remember how the long wire behaved...maybe it was better and maybe I did not try it when it was noisy.....)
Plus other headaches that are many
Que dolor de cabeza!

[morzh]

For example, take this morning.
First thing around 9 or so AM I turned the local station to listen to news on and I had a really audible buzz, I even thought for a sec there was something at play locally, but then I roamed around the band and the buzz was not in other places....so I went back, and within an hour when they changed the program, the buzz disappeared at once and the broadcast was clear with no noise at all.

What can a station do to produce this kind of buzz?

Just thought I should've listened to the same station on the other radio, just to see if it is also radio-dependent.

[BrendaAnnD]

Broadcasters are not immune to the same sort of problems we have. Bad connections on patch panels, noisy feeds, etc. plague them as well. Some speech I watched on CNN the other day had a ground loop in the mic circuit, and there was a goodly hum during the entire speech.