Posts: 15,819
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Remind me again, why this happens?
When tuned the signal is nice, but between stations it is buzzing.
Not much squealing, only a little and only in certain points. Mostly buzzing.
The effect is practically absent in my 20 or in 80jr.
It is the most pronounced in the 18 and also exists, though to a lesser degree, in my Zenith 9S262.
And as I said, when tuned, the sound is good.
At least in 18 I replaced the filtering caps from either line to the chassis with Y-caps, 10nF each.
Did not move much wires when recapping.
Posts: 1,108
Threads: 89
Joined: Jun 2011
City: Tacoma
State, Province, Country: Washington
Wish I could help you on this one, but I have that problem with ALL of my radios because of the noisy electrical grid here (fluorescent lights are nearly universal here).
Posts: 7,286
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
And if you short the ANT to GND do you still hear it??
Terry
Posts: 1,108
Threads: 89
Joined: Jun 2011
City: Tacoma
State, Province, Country: Washington
On all but the deafest sets. I think it gets in through the line..
Posts: 15,819
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
No, when I short them, it's all quiet.
And, as said before, when tuned in and the signal is strong, also no buzz there.
(This post was last modified: 04-03-2013, 10:42 AM by morzh.)
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Mortz, in your case sure sounds like something is radiating RF noise in your environment. Brenda sounds like she has something on the A/C line. But what do I know? 
Jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 7,286
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
Well unfortunately the RF environment isn't as good (clean) as it use to be. Using a coax feed ant may tend to help. Having a good earth gnd can't hurt. And a good long high up ant is a good thing to. Noise is everywhere!!! and it,s very annoying!!
GL w/it
Terry
ps A loop ant may be a good thing as you can use it to null out the noise as much as possible.
Posts: 15,819
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Good question is then, why the 18 with a hanging piece of wire is buzzing, whereas say my 20 (a TRF) also with a wire is not. Nor does 80.
....pollution...tell me about it! I have just come from a RF EMI sniffing session of my device, where I saw cell phone signal getting into unechoic chamber....
Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY
Probably the reason you hear the buzzing with the 18, but not the 20 or 80 junior is that the 18 has AVC while the 20 and 80 do not. When not tuned to a station, the 18 AVC line drops to 0 volts and the gain controlled stages are running flat out at maximum amplification. As soon as you tune to a station, the AVC voltage rises, reducing the gain and along with it the residual received RF noise level. The 20 and 80 with manual gain control do not automatically increase the amplification as you tune off a station, so the background noise level does not rise noticeably.
The 18 is also a much better receiver and has a lot more reserve gain than either the 20 or 80, so the off station background noise is more apparent than with the lower sensitivity sets.
(This post was last modified: 04-04-2013, 03:58 PM by Mondial.)
Posts: 15,819
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Yes, and this may be the same reason for the Zenith 9S262, as I think it also has the AVC. In fact I know it does as the AVC runs the Magic Eye tube.
I need to listen to my Westinghouse, as it also has the eye and AVC. If it does the same then this is probably the culprit.
Posts: 1,976
Threads: 147
Joined: Jan 2013
City: Westland, MI
Just a thought... have you tried running your set through a good surge protector? I had a problem with line noise with one of my televisions, and the surge protector cured it. Make sure it has pre-filtering in it. Can't hurt to try. Take care. Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
Posts: 15,819
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Gary
It is not line noise. Line noise is always present. You can't tune it out really.
It sounds excellent when tuned.
Also I have Y-caps 10nF from both line and neutral to chassis.
One thing I did not try is connecting Ground. But I don't hold my breath on this one.
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Philco 16B Parts
|
| Thanks for the reply. Unfortunately the radio was removed before bidding was over so I didn't get a chance to bid.dconant — 04:10 PM |
|
Philco 16B Parts
|
| Hi Dan,
Mike is correct, there's a lot of painted stuff on the chassis but it looks pretty good. The sm is all there,sp...Radioroslyn — 03:50 PM |
|
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
|
|
Hi Cap'n Clock,
Unfortunately, I do not have this radio. This is a shame because this should be a good performer. 2A...captainclock1988 — 03:43 PM |
|
Philco 42-390, code 121 speaker
|
| Using a 5W 1.5k ceramic resistor in place of the field coil and using a 4 ohm PM speaker, I was able to bring the radi...Stevelog — 02:57 PM |
|
Philco 60 Squealing
|
| I have taken out the 2nd IF and found a problem or not. I believe the coils are litz wire. There is a very small strand ...dconant — 02:13 PM |
|
Philco 6K7
|
| I am restoring a Philco 37-60. The am reception is very good, but the shortwave is very weak. Run 6 Philco removes the g...bobbyd1200 — 01:35 PM |
|
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
|
| Hi Cap'n Clock,
Unfortunately, I do not have this radio. This is a shame because this should be a good performer. 2A5...MrFixr55 — 06:48 AM |
|
American Bosch Model 802 auto radio
|
| I think it would come under either American Bosch or United American Bosch. American Bosch made sets for the American We...Arran — 05:53 AM |
|
trying to identify this wire type
|
| Thanks to all for the feedback. As Arran said, it is probably an older replacement and yes it has a grid cap so I will ...georgetownjohn — 09:32 PM |
|
trying to identify this wire type
|
| It's possible that the red wire, actually a grid cap lead, is a very old replacement, I can't remember seeing a pre 1939...Arran — 09:18 PM |
|
Who's Online
|
There are currently 5870 online users. [Complete List]
» 1 Member(s) | 5869 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
