My father's keep buying radios for the kitchen, but each one has the problem of poor reception (he listens to AM). Is there anything that will help boost the range of the antenna or maybe even an add-on or something? Thanks
Put out a wire antenna of about 40 yards,as high as it goes, take the wire down into the kitchen, wrap it 4 times around your radio, and attach the wire to the (hopefully metal) water supply tube. To prettyfy this, you can hide the 4 turn coil(radius > 10") behind some wooden or plastic panel, as long as you put the radio close to that. Try radio orientation for best reception.
That might work, but you might need to try top-back-bottom-front-top and left-front-right-back-left wrapping to get it right. Top-front-bottom-back-top won't be necessary; the internal antenna coil undoubtedly isn't oriented that way.
Isaac
Hi!
On many modern radios, the AM antenna is inside. It's a ferrite bar wrapped with many turns of fine wire.
I would suggest looking for a radio that offers the ability to connect an external antenna for AM, FM or even both bands. You can then hook up a long wire antenna and this should improve the reception.
Also check for common sources of interference to AM broadcasts, such as fluorescent lighting, motors and some switching power supplies.
William
David D hath wroth:
The obvious answer is an external antenna. The radio(s) should have an external AM antenna connector. It should also have an antenna ground connection, which should be connected to a *METAL* cold water pipe.
However, I'm a bit worried about your vague description. My guess(tm) is that your father is experimenting with varying quality of radios and that there's a problem across the entire AM band. It could be that your location is useless for AM, but I suspect that something else is going on. My guess(tm) is that you have some local source of AM interference, such a motor noise, power line arcing, computer RFI/EMI, light dimmers, fence chargers, etc. Should be something in the internet.....yep:
An easy test is to drag one of the radios to a very different location several miles away. If it works properly at that location, there's a fairly good chance that there's a localized RFI/EMI problem around your kitchen, house, or neighborhood. If this is the case, then adding an external antenna could easily make the problem worse, as it will pickup a stronger AM station signal, but also pickup a stronger RFI/EMI signal.
Incidentally, we have a local RFI/EMI problem. There are a substantial number of solar arrays in the area. The inverters run a rather high power levels and are capeable of generating quite a bit of RFI/EMI. We're slowly dealing with the problem, but meanwhile, weak signal HF ham radio operation is a dubious proposition. Look around for solar power arrays and bring a portable AM radio to check for RFI.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Just go to Web Site
Are the invertors for the solar systems meeting the FCC Part 15 rules on emissions??
H. R. (Bob) Hofmann
Have them buy the Grundig YB 400PE or equivalent radio. It comes with an external reel in and out antenna. Or at least something with an external antenna connection. Then help them erect a longwire antenna which you can look up on google.com.
"hr(bob) snipped-for-privacy@att.net" hath wroth:
The few I field tested locally obviously did not. I do not have the full antenna kit necessary to make the determination. However, my back of the envelope calculations based on received signal strength to a small loop antenna seems to indicate that it's not even close. I need to drag over a spectrum analyzer and see what's really being radiated. I built a small power line coupling circuit so that I can look at the AC power waveform. I could see roughly 200mv switching hash on an oscilloscope so I suspect that this system wasn't compliant.
The owner of one private solar system is working with the manufactory on reducing the interference and has installed power line EMI filters. These were a huge help. These filters are allegedly standard on all their current installations but were not when he purchased his[1]. A different owner just received what I suspect may be the worlds biggest clamp-on ferrite bead. He says it's about the size and weight of a brick and goes on the solar panel leads. That was installed about a month ago, and helped somewhat.
Meanwhile, the ham operators that have been affected are making measurements, running tests, and playing with different types of antennas. There's been some success. Weak signal DX is out, but contesting, RTTY, PSK31, and other modes operate normally. At this point, radio reception is functional and not a crisis.
The big problem is that almost all the EMI is being conducted (and radiated) through the power lines. We can turn off one source of switching noise, and there's very little effect as the other noise sources are just as strong over the shared power lines. At one point, we obtained the cooperation of everyone involved, except the water district, to turn off their solar systems completely for an hour so we can make measurements. We then found yet another solar system noise source we had not known about and possibly two more. We also determined that the major source of EMI was the water district system. At this point, we know of about 7 solar systems within about a 1 mile radius. Most of them were found by sniffing, but others by accident or with an airplane flyover. We tried Google Earth, but the images are too old. What was interesting is that many of the solar systems we found were fairly RF quiet, while others were very noisy. The difference seems to be the amount of EMI/RFI filtering on the various wires going in and out. The quiet ones are liberally equipped with filters on the panels, AC mains, and control panels. The noisy ones do not.
Much of the testing and sniffing has been done with portable AM radios and a SW AM radio. The noise is continuous, very strong near the power lines, and very obnoxious on AM. My guess(tm) is that the original problem might be one of these solar inverter noise sources.
[1] I suspect that the installer "forgot" to install the filter or lost it since it's a separate box and did not fit neatly into the installation.-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
I am assuming that you mean the invertors that change the DC from the charged batteries to 120-240V AC, not anything associated with the solar cells charging the batteries. Am I right?
If there are any clocks associated with the invertor control circuitry, the entire installation falls under the FCC Part 15 Rules. These apply to any "noise" from 150 kHz up to 30 MHZ for conducted noise from the installation onto the power lines and you should notify the nearest FCC Feld Office.
I am a past president of the IEEE EMC Society and am still very active on IEEE and ANSI C63 (TM) EMC committees. Let me hear from you, either here or directly to me.
H. R. (Bob) Hofmann
"hr(bob) snipped-for-privacy@att.net" hath wroth:
Correct. All these installations are grid connected synchronous inverters. No batteries. There usually is a small generator and disconnect switch, to simulate the AC power from the grid during power outages. Without it, the system would not run. At night, the house runs on grid power. However, the inverter is still running to remain in sync with the grid power. I would think that it would be best to shut down the inverter if there is no solar power available, but this is apparently (my observation) not the case. The noise is there 24 hours per day. I'll see if I can obtain an equipment list.
I have no clue what's inside the water district system. It may have batteries.
I think (not sure) that this was already done. I wasn't party to this part of the exercise. None of the local hams involved seem to consider involving the FCC as a useful strategy. All of the solar system owners involved are being very cooperative, as are the manufactures of the equipment. The water district is kinda marginal, but without a proper field test (that's me and my borrowed spectrum analyzer), they're not interested in doing much.
Sure. I can supply names and possibly vendors, but I don't think any high level action is required. Things are blundering along slowly, as various participants find the time. I'll send you some email but I think I've supplied most of what I know.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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