Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Question about noise
Before leaving the topic of noise and quiet receivers, I have a
question. Tonight I was listening to a couple of Spanish language stations on 6185 and 6125 khz. On the Drake R8B, there was a background noise behind these signals and in fact behind most of the signals on this particular band. (It sounds like atmospheric noise--a vague, hissy sound that fades in and out a bit, just as the signal fades in and out). On the other hand, when I listened to these two stations on the Lowe HF-150, there was almost no trace of the noise. Both receivers were connected to the same antenna. I experimented with different power sources. Powering the R8B from it's internal power supply vs. an external power supply didn't have any effect on what I heard. This noise isn't always there, although I've heard it before. What puzzles me is the Lowe receiver's failure to be affected by it. Why was it interfering with the Drake, but not the Lowe? The receivers were sitting right next to each other (I tried separating them, just for the heck of it, but it made no difference.) Any thoughts? Steve |
#2
|
|||
|
|||
I'd hazard a guess that the digital circuitry in one radi does not exist in
the other and that circuitry is causing some noise in the other receiver. On the other hand, maybe the sensitivity of one receiver is different than the other. was the gain on both receivers set the same ? Peace We are the Providence of God + wrote in message oups.com... Before leaving the topic of noise and quiet receivers, I have a question. Tonight I was listening to a couple of Spanish language stations on 6185 and 6125 khz. On the Drake R8B, there was a background noise behind these signals and in fact behind most of the signals on this particular band. (It sounds like atmospheric noise--a vague, hissy sound that fades in and out a bit, just as the signal fades in and out). On the other hand, when I listened to these two stations on the Lowe HF-150, there was almost no trace of the noise. Both receivers were connected to the same antenna. I experimented with different power sources. Powering the R8B from it's internal power supply vs. an external power supply didn't have any effect on what I heard. This noise isn't always there, although I've heard it before. What puzzles me is the Lowe receiver's failure to be affected by it. Why was it interfering with the Drake, but not the Lowe? The receivers were sitting right next to each other (I tried separating them, just for the heck of it, but it made no difference.) Any thoughts? Steve |
#4
|
|||
|
|||
jimg wrote:
first disconnect the antenna from both receivers and short the antenna terminals...turn up the rf gain and audio...both real quiet, i bet? good. then it's from the antenna-ground-rf front end combo... are you using the 50ohm input on both, or the long wire input? lets say, the long wire inputs....well, i doubt they have the same input impedance...if your not using coax and don't have a reasonable impedance match, then the antenna's are going to act very diffferently...( how are they grounded? tied together? hmmmm) if your using the 50 ohm inputs, have a well designed antenna with good matching, then we have to discuss the reactive component at the antenna input...and even the selectivity of the first if stage.... you really want to know, we'd have to take 'em into a lab with very controlled conditions to trace out the diff...but it's not magik...just complicated wrote: Before leaving the topic of noise and quiet receivers, I have a question. Tonight I was listening to a couple of Spanish language stations on 6185 and 6125 khz. On the Drake R8B, there was a background noise behind these signals and in fact behind most of the signals on this particular band. (It sounds like atmospheric noise--a vague, hissy sound that fades in and out a bit, just as the signal fades in and out). On the other hand, when I listened to these two stations on the Lowe HF-150, there was almost no trace of the noise. Both receivers were connected to the same antenna. I experimented with different power sources. Powering the R8B from it's internal power supply vs. an external power supply didn't have any effect on what I heard. This noise isn't always there, although I've heard it before. What puzzles me is the Lowe receiver's failure to be affected by it. Why was it interfering with the Drake, but not the Lowe? The receivers were sitting right next to each other (I tried separating them, just for the heck of it, but it made no difference.) Any thoughts? Steve Are you saying the noise could also be heard on the Lowe but it was just lower? ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- jimg Oregon USA |
#5
|
|||
|
|||
Thanks for all of the input guys.
Although the noise sounded like atsmopheric noise, part of me thought it might be something else...and I turned out to be right. After staying up half the night, I discovered a laser printer that had been left turned on in a different room. I turned the printer off, not really thinking that it would be the cause of the noise on the Drake. But when I then walked into the room where the Drake sits, it was on and there wasn't a trace of noise. Just for the heck of it, I had to turn the printer back on to see if the noise returned...and it did. It's amazing to me that the Drake could have been affected so much more severely than the Lowe by the noise from this printer, but now I'm just glad that the noise is gone. Everything sounds the way it should now. Steve |
#6
|
|||
|
|||
|
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
vehicle noise | Shortwave | |||
Noise around 720 kHz | Shortwave | |||
Noise & UTE Dxing question | Dx | |||
Noise & UTE Dxing question | Dx | |||
CCIR Coefficients METHOD 6 REC533 // AUCKLAND --> SEATTLE | Shortwave |