HFU HF Underground

Technical Topics => Equipment => Topic started by: Rusty on December 21, 2016, 0100 UTC

Title: HI, first post, antenna question.
Post by: Rusty on December 21, 2016, 0100 UTC
Hi, I'm retired, mostly, married, with children (grown), and have gotten interested in radio. I've got several Baofeng radios that I use for scanners and weather and such, but they are limited in my area. So, I got  Tecsun PL-660 a few days ago and I like it. But, I can't get any SW on it. So, today I re-did my computer room and ran the external antenna it came with and put it outside. The radio is sitting right beside all three of my computers and monitors, and the static is, well, bad. I can't get anything unless I move the radio and then the antenna wire does not reach.

So, it looks like there's just one wire inside the insulation and I thought I could just go buy a similar gauge wire and splice it on to it, and then move the radio to where it will work. I just didn't want to screw anything up seeing how I really don't know how antennas work. I feel I can just cut the wire a foot or so back from where it jacks into the radio and add a piece of wire, soldered and heat shrunk. Am I wrong?

Thanks.
Title: Re: HI, first post, antenna question.
Post by: MDK2 on December 21, 2016, 0442 UTC
Hi Rusty. I'm not much of an antenna expert, but I don't see why extending the length of the wire shouldn't work if you do it the way you're planning. But I will point out that today's home environment is often a radio frequency interference wasteland, with noise being generated by all kinds of sources. My PC can be a terrible source, for example, and if I'm watching a video or my daughter is playing a game on my Mac, you can often hear a very distorted copy of that audio on my receiver. So you may want to find a better place than next to your computers for your radio.

I'll also let you know that we're just about at solar minimum for this solar cycle, and some recent days and nights have had truly abysmal propagation conditions. So there may be more preventing you from hearing much than your antenna or receiver placement. Also, if you're new to short wave listening, you'll need to learn about propagation, because different parts of the frequency bands are listenable some parts of the day, but not others, and also time of year is a factor as well.

In the meantime, some easy to catch stations to look for include Radio Habana Cuba (in Spanish on many frequencies all day, plus select other languages including English), Radio Nacional da Brasilia (6180 later afternoon and into the night), Radio Australia (9580 in the morning, but only until it goes permanently off the air at the end of January), WWV or WWVH time signals (2500, 5000, 10000, 15000, and 20000 - time of day will determine which one comes in best, and hopefully you don't live as close to their transmitters in Fort Collins, Colorado, like I do), and various program carried by American broadcasters WRMI, WBCQ, and WTWW. The last one often has good music on 5085 evenings, but sometimes it's not on the air. I'll link a few online shortwave schedule pages below.

Good luck!

http://www.short-wave.info   - easy to search and easy to read site which provides a great map showing grey line and location of broadcasters, and allows you to put in your own location as well. But some of the information doesn't get updated regularly

http://www.eibispace.de  -  probably the most accurate and up to date listing, but it's just a big list of everything. That's handy for confirming a station you have found from random scrolling but hard if you want an idea of what's on now. (I'd love it if I could merge this info into the above site's database.)

https://www.shortwaveschedule.com/   

http://www.primetimeshortwave.com/
Title: Re: HI, first post, antenna question.
Post by: Rusty on December 21, 2016, 1136 UTC
Thank you very much! I will move the radio which is the reason I want to make the external antenna longer. I just need to find a place in my room where it will work. And I forgot to mention, yesterday I had all the computers and monitors unplugged and I turned on the radio with the antenna plugged in and I could hear some SW from different stations! So I got all excited and went ahead and re-arranged everything and hooked all the computers up and Buuuuuuuzzzzz! :)
Title: Re: HI, first post, antenna question.
Post by: Pigmeat on December 21, 2016, 1958 UTC
CFL's are nasty little noise generators, too. The LED's I use don't seem to cause RF problems.

I miss the days when all you had to worry about were wall warts.
Title: Re: HI, first post, antenna question.
Post by: BoomboxDX on December 22, 2016, 0331 UTC
Hi, I'm retired, mostly, married, with children (grown), and have gotten interested in radio. I've got several Baofeng radios that I use for scanners and weather and such, but they are limited in my area. So, I got  Tecsun PL-660 a few days ago and I like it. But, I can't get any SW on it. So, today I re-did my computer room and ran the external antenna it came with and put it outside. The radio is sitting right beside all three of my computers and monitors, and the static is, well, bad. I can't get anything unless I move the radio and then the antenna wire does not reach.

So, it looks like there's just one wire inside the insulation and I thought I could just go buy a similar gauge wire and splice it on to it, and then move the radio to where it will work. I just didn't want to screw anything up seeing how I really don't know how antennas work. I feel I can just cut the wire a foot or so back from where it jacks into the radio and add a piece of wire, soldered and heat shrunk. Am I wrong?

Thanks.

If you are just adding wire to a wire antenna, it will also act as an antenna and pick up the computer hash.

That said, you could still try adding the extra length of wire and moving the radio that way, and see if it still works. The actual signals supplied by the antenna may outstrip the RFI hash coming from the computers, and it may work.

It's been my experience that the noisiest part of an actual computer is the monitor. Switch it off and RFI is reduced. The computer itself will put out carriers here and there throughout the HF spectrum. Sometimes the RFI is not that much in the way of SW broadcasts.... sometimes it is. My computer is always on, monitor off unless I'm using it. My SW radios are maybe 40 feet from my two computers (a laptop which is usually off or in sleep mode, and a desktop with a monitor that's always off unless I"m using the computer), and I'm using SW digital portables connected usually to a 25 foot indoor wire. I have no trouble DXing the SW bands with that set up. Whatever RFI I have isn't exactly overpowering....

If you have and ethernet cable running from your router to the computer, that will act like a transmitting antenna and wipe out sections of RF spectrum with hash. That is my worst RFI generator, worse than the computers themselves.

Switching power supplies, like the ones used to power routers and other devices, also throw out hash, and I've only had issues with mine when the ethernet cable is engaged.

Maybe you could use the external wire that came with your radio in another part of your home, away from the computers?
Title: Re: HI, first post, antenna question.
Post by: Token on December 22, 2016, 1741 UTC
Welcome to the hobby, it can be an addiction.

Your PL-660 is a pretty decent little portable, pretty good bang for the buck.  Don’t expect it to act like a $700 desktop radio and you will not be disappointed.  However one of the issues the 660 can suffer, as do many other portables, is front end overload when hooked to a decent sized external antenna.

I am not saying that is the source of your noise, and I am not saying to not try a larger antenna, I only say the above to make you aware that there is the potential for odd operation when on a larger external antenna.  However there are also large benefits to such an antenna.

Next, noise can be a tough nut to crack, and in today’s urban world that is more true than ever before.  I would start by finding out exactly what is causing the worst noise issues.  Shut stuff off around the house and see if the noise reduces or goes away.  Depending on what the noise sources are they are addressed in different manners.

Get the antenna as far from any noise source in the house as possible.  The antenna you describe sounds like it is a random wire that starts right at the radio.  This means it is picking up noise from right there till the end of the wire.  A more advanced antenna would use coaxial cable to connect with the antenna element.  That way the shielded coax is inside the house, and closer to the noise sources, while the actual receiving element is outside and potentially further from noise sources.

Also, don’t assume that noise is from a computer just because the noise is in the same area of the computer.  Many of us use radios that are attached to, and sometimes mounted inside of, computers.

T!
Title: Re: HI, first post, antenna question.
Post by: Rusty on December 22, 2016, 1929 UTC
Thank you all for helping. I have extended the length of the antenna by about 20 feet and I have moved the radio. I can get some stuff, but I think I need to wait and see for a while before I rush to judgment because the atmo my not be cooperating. So, we''ll see. One thing about the antenna wire, it runs right by the modem cable, monitor cables and power cable. I don't know if that will affect it. So, I'll wait a few days and then if it still is not picking up much I'll move the antenna and the radio to another part of the house.
Title: Re: HI, first post, antenna question.
Post by: Looking-Glass on December 31, 2016, 1119 UTC
The main culprits for generating noise that comes through your radio and affects reception, usually are one of, or some of the following:

1.  Mobile phone chargers (especially the cheap Chinese ones, Nokia and Samsung seem OK).

2.  Energy Saver indoor light globes, especially the curly ones.

3.  Solar garden path lights.  These generate RF at night when they are lit.

4.  Modern flat screen Televisions.

5.  Computer Gaming consoles.

6.  Touch screen programmed washing machines, when in operation.

7.  Old fluro light tubes, especially when they are on the way out and start flicking. Also the "starters" cause RF when faulty.

8.  Computer hard drives and monitors, some brands are worse than others.

9.  Water feature pump in the garden, especially cheap Chinese rubbish.

10. Swimming pool filter/pump.

11. Rechargeable battery chargers when running.

12. Power line interference from your external mains supply overhead wires to the house, cracked insulators and broken splitter joints. Usually disappears in wet weather.

13. Christmas tree lights, again the cheap Chinese rubbish give heaps of RF, especially the ones that flash.

14. Television reception mains operated amplifiers (indoor near TV), most are pretty good but some do cause RF interference.

Sometimes, if you change direction of the external wire antenna some interference can be reduced.  I get RF from something the neighbour runs.  I changed the direction of my wire away from his property, problem solved.

Easy way is to walk around unplugging, or turning off at the power point each suspected device until noise either abates or disappears.  ARRL Handbook for Radio Amateurs is a good self help reference source in dealing with RF interference issues.

Good luck and good DXing... 8)
Title: Re: HI, first post, antenna question.
Post by: MDK2 on December 31, 2016, 1509 UTC
I understand that plasma and LCD flat screen TV's generate RFI, but not LED TV's. I can't speak from any real experience, but we have an LED TV and I can't say that I have ever noticed any RFI when it's on. So, take that anecdotal evidence for what it's worth.

The worst source of RFI that I found in my house is our swamp cooler. Not a problem in winter obviously, but something to contend with in the summer. I could put my receiver next to the thermostat and hear the most godawful combo of static and feedback whine. I threw the breaker when we shut it down for the season.

I still need to do a more thorough rundown, but I can't say that there's much else that's an obvious source, where a difference is apparent when a given appliance or light is off, or a wall wart unplugged, or power strip turned off. But I haven't tampered my modem or routers and I do wonder if their wall warts are doing anything.