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Hello Laura,
The idea of walking around your area (and the roof) with your radio in hand to see if interference is greater or lesser at various locations is sound. See if you can find a place which is relatively noise-free. I'm afraid a length of wire just lain on the roof will probably be unsatisfactory; it should be raised much higher and must not touch anything. It should be attached to ceramic (or similar) insulators and those insulators affixed to supports, with suitable strain-relief. You can use coaxial cable (RG-6 or RG-8) as a lead-in, or you can even try a twin-lead (300 Ohm) wire and terminate that in a 3.5 mm plug. If you do use coax, I have found that Radio Shack does indeed sell adapters for attaching it to your radio. I have used a BNC connector at the end of coax, then a BNC to RCA adapter, and finally an RCA to 3.5 mm plug adapter to connect an outdoor antenna to a portable radio (I did this years ago when I was able to have an outdoor antenna; it worked just fine.) I have done something similar to allow my Wellbrook antenna to be used with my Sony ICF-SW7600GR. If, however, you find that in your location there is nowhere without electrical noise, you've got problems. Are those restaurant ventilators ever turned off, perhaps in the middle of the night? If you try your radio then and find no interference, you've found its source. If those machines are indeed the cause of your interference, the only type of antenna which can overcome that (to a greater or lesser extent) is a balanced loop design, such as the Wellbrook, and, as you know, they are expensive (but well-worth the money if you can afford them). What you'll spend or do depends just how serious you are about short wave listening. If you find that placing your radio (using its whip) near a window on the side of your house farthest away from the ventilators results in lower noise levels, you might try an AOR WL500 Window Loop Antenna which can be mounted in that window. It is a loop of unbalanced design, according to PASSPORT, but may help reduce some local electrical noise. In my case, I tried it before I bought the Wellbrook ALA 330S and found it to be a great help in my location, better than any other antenna I had previously tried (I still use it with my Satellit 800), and it is a great match for a portable radio (the Sony AN-LP1 is also a good antenna for portables, but, in my experience, does not reduce local electrical noise at all). It terminates in a BNC so the Radio Shack adapters I mentioned above will easily adapt that antenna to your radio. It may be worth a try though it, too, is expensive and, frankly, is no match for the Wellbrook. If the WL500 works fairly well, then the Wellbrook will work very well. I hope that is of some help to you. Some of the other posts here also have good ideas. Antennas are "scientifically" designed. But "science" is no good at all when it comes to determining what will work at a specific location. Only trial and error will tell you that. All the best, Joe laura fairhead wrote: Hi, Can Joe or anyone else explain to me a few things; I am trying to set up a antenna on the roof as reception is really bad using the indoor whip (lots of interference I live next door to a restaurant ventilator farm and I think that may be a problem). Anyway I am thinking of getting a length of wire and just laying it on top of the roof under a couple of bricks to stop it getting blown around. The thing I don't get is the connection down the side of the house - I need to use a different cable yes? I have heard people specify a length of "radio coax" is suitable but I do not understand how this could be any use without the shielding being grounded - could someone explain? My roberts R861 has a minijack anntena input - which has 2 connections on the plug - are they both used or is only one? If I use a thick cable to run into the house would I need any special attention to connect that to the minijack? What sort of length wire should I use on the roof, is it just a case of the longer the better? Thanks in advance for any advice bestwishes laura I have never owned a Sangean ATS 909 nor do I know anyone who does. According to PASSPORT TO WORLD BAND RADIO, the Sangean/Roberts works BEST off its AC adapter as it "eats" batteries. An external antenna is necessary also, as it lacks sensitivity with its whip (according to them). A long wire, or loop antenna, mounted on your roof would be ideal. Try buying a length of insulated wire, two ceramic or equivalent stand-off insulators (to isolate the antenna from whatever support you use) and some lead-in wire; attach the appropriate plug to the lead-in to attach to the radio and you're in business. No separate ground is necessary, but make sure you DISCONNECT the antenna whenever the radio is not in use and, especially, during local thunderstorms. (NEVER use ANY electronic appliance during a thunderstorm; storms only last a half-hour or so.) Do NOT let your antenna proper or the lead-in touch anything metallic; that will degrade the signal. -- echo |sed 's/\(.\)\(.\)/\2\1/g' |
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