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Transmitter Antenae, Ups and Downs

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  • Member since
    July 2006
  • From: South Western PA
  • 139 posts
Posted by Smoke Stack Lightnin' on Tuesday, August 1, 2006 8:36 PM

Thanks Ralph.  I guess awkward and unbalanced is better than fried and useless.  This week has been tough.  First I find out 3 in 1 oil is not good to use, after 30 years of use, and now the antennae thing, which the tx has probably 10 hours use.  Its a wonder anything still functions!  Next, someone is going to tell me I shouldn't wash rolling stock and engines in the tub with me during Saturday night bath time!  I can't win.

Seriously, I need a rubber duck! 

Thanks for the advice,

Rich F.

  • Member since
    February 2005
  • From: Peak District UK
  • 809 posts
Posted by cabbage on Tuesday, August 1, 2006 2:11 AM
Well here I speak as one of my alternate personae! I have a G8 and G3 radio licence.

The effect you have been warned about is true.

It has to do with the length of the transmission antennae not being a exact fraction of a wavelength of the radio and the energy being 'reflected' back to the transmitter. Standing Wave Reflection as it should be called.

The commonest is a 1/4 wavelength antennae. I use a replacement 'rubber duck' on my Futabas -this is due to rough handling by offspring / nieces / nephews (4 to 11). On modern model transmitters this is not too rough on the output trannies. At some of the powers that I use -it would be spectacular!!!

regards

ralph

The Home of Articulated Ugliness

  • Member since
    July 2006
  • From: South Western PA
  • 139 posts
Transmitter Antenae, Ups and Downs
Posted by Smoke Stack Lightnin' on Monday, July 31, 2006 10:46 PM

In one of the threads prior to the change at Trains.com, someone had warned about possibly damaging the tx with use without telescoping the antenae, if not all the way, at least partially.  Due to the antenae being awkward and unnessesary (until battery power starts bottoming out), I leave the antenae retracted.  I contacted the site of purchase by email, and did not get a reply, which is par for this ex-vendor of mine.  So I hope somebody can shed some light on the topic for me.  Does tx antenae need to be extended during use?  There is nothing in the documentation with the Hi Tech, Laser 4 Tx that warns of damage in this regard.

Thanks,

Rich F.

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