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Long wire to SO-239 50 ohm?
In article .com,
"RHF" wrote: On Jan 25, 6:03 pm, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...103912&cp=&sr=. .. gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component?I didn't go as far as that. This unit is made of a ferrite core and a couple of very small value capacitors. I would guess the core was the problem. Some of the better 300 Ohm to 75 Ohm TV type Matching Transformers are labeled as being good down to 5 MHz. Usually these are the {Gold Plated} ones designed for Cable and Satellite TV used. ? Honestly ? What good does the Gold Plating do on the "F" Connector and the Spade Connectors : When it is the internal components that will determine the real quality of the signal entering one end and exiting the other. The gold plating on the contacts is so there is no corrosion or oxidation on the connector mating surface. If you don't have a good DC connection you don't have a good circuit for RF either. Gold is a nobel metal that does not oxidize. They work 'ok' for a basic Shortwave Listener (SWL) Random Wire Antenna "Matcher" with moderate size {Lenght} Antennas in the range of 20-60 Feet. Plus they have the extra advantage of attenuating those High Power AM/MW Radio Stations below 1.8 MHz. at least this has been my experience - speaking of "quick and dirty" - hey that's me - iane ~ RHF Yeah they will do that. Problem is they will not work so well on 41, 49, 60, 75, 90, and 120 either. -- Telamon Ventura, California |
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