Power Strip/ extension cord

Status
Not open for further replies.
Joined
Jun 6, 2017
Messages
52
I have my Icom R75 plugged into a power strip that is shared with my desktop computer. I was wondering if this would be effecting my reception. Here in Alaska, I cant pick up most of the stuff you guys post on here about hearing. However, I am moving to the lower 48 this spring and was looking to set my radio up close to my computer at my next house. Just wondering how much interference this might cause. I see pictures all the time of people having them running with software on a computer. So do you think this interferes? Does using a separate power outlet help? Mostly trying to hear Shortwave broadcast and Ham operators.

thanks,
 

jonwienke

More Info Coming Soon!
Joined
Jul 18, 2014
Messages
13,416
Location
VA
The proximity of the computer to the SW antenna is a lot more significant than whether the radio is on its own branch circuit.
 
Joined
Jun 6, 2017
Messages
52
The antenna is about 20 feet across the room going out the window. However, the antenna slopes down the side of the house about 6ft above the houses electric boxes and meters. It was the only way to rig the antenna in this home. Maybe that is why I'm hearing so much interference.
 

ridgescan

Member
Joined
Apr 1, 2008
Messages
4,778
Location
San Francisco, Ca.
I run all my comms rigs on their own power strips with known RFI filters in them. However, the worst offender here is the high-speed/cable modem. This thing is nasty and I actually have it housed in a Faraday cage. Other than that, my cordless mouse can emit "pops" with each maneuver even on the R75 that's in the other room.
 

WA8ZTZ

Member
Joined
Feb 23, 2014
Messages
971
However, the antenna slopes down the side of the house about 6ft above the houses electric boxes and meters.

Keep the antenna as far away as possible from electrical wiring of any kind. Noise usually more likely to be picked up by your antenna than to be coupled in through the power line. However, if you think noise is entering via the power line, try running the receiver on a battery and see what happens.
 
Joined
Jun 6, 2017
Messages
52
Well, I raised the antenna up from the meters, didn't have as much electrical noise. So I'll keep that in mind at my next house. Just out of curiosity, how much coax could I run from the receiver to the antenna without losing signal, right now I have 18ft of coax. I've seen them sell it at 50ft in length.
 

prcguy

Member
Joined
Jun 30, 2006
Messages
15,230
Location
So Cal - Richardson, TX - Tewksbury, MA
Under matched conditions you can use the coax mfrs loss charts. If coax is used under extreme mis match conditions the loss can go through the roof at HF.

The worst case would be using a long run of RG-58 where 100ft might have 1.4dB loss in the 9Mhz SW band with a perfect match at the radio and antenna end and upwards of 6.5dB loss or 77% loss of signal if the match at the antenna is 20:1. This can easily happen with random length home made antennas.

If you use something like a PAR end fed SW or a 9:1 balun and 50 to 100ft of wire the match will probably be less than 10:1 and maybe better than 5:1 on most frequencies. Either way the coax loss will be more than stated in the mfrs catalog.
prcguy


HF has very little coax loss compared to UHF. 50 feet of anything will only make a few dB difference.

Welcome to Times Microwave | Coaxial Cable - Attenuation & Power Handling Calculator
 
Status
Not open for further replies.
Top