What is the balun doing in this case? What would happen if you removed the balun?
I have never used one, as I think they would just be another thing to fail or loose power in. Also, baluns are rated in pep watts and duty cycle, both are very high on AM. The 'legal limit' B+W folded dipole was only good for 150 watts carrier of AM and that was pushing it. Brett N2DTS > > Reply by Jim, WD5JKO > > Donn, everything you say is true. I will take a differing > point of view > for a specific exception. What if the coax to be used is very short? > By short, I mean like 6-12 feet long like you might have in a > mobile, or at > home where an outside balun resides. > > Consider the case where you have a 100 watt class rig feeding > a ATU, and > then 10' of coax to a legal limit rated balun. The balun can handle > considerable reactance, and miss match since it is being used > at 1/15th the > power rating. The feedline SWR might go upwards to 10:1, and yet the > transmitter is happy, and the losses are low, so therefore > the radiated > signal will be fine. The loss from the coax as calculated > from this web page > is: > > http://www.ocarc.ca/coax.htm > > .12 db at 3.880 for Belden 9913 / RG-8 @ 10:1 SWR > > The remaining question is the efficiency of the balun. If the load is > primarily resistive (= or > balun ratings), then I bet the > balun will behave > pretty well. Now take this scenerio and add a linear > amplifier, and all hell > will break out!!! > > Regards, > Jim > JKO > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.446 / Virus Database: 268.18.9/719 - Release > Date: 3/12/2007 > 8:41 AM > > ______________________________________________________________ > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Partner Website: http://www.amfone.net > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. > ______________________________________________________________ AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
