DPRG
DPRG List  



Request For 310 Mhz Cheap Yagi Dimensions

Subject: Request For 310 Mhz Cheap Yagi Dimensions
From: Kent Britain wa5vjb at flash.net
Date: Sun Nov 7 11:41:27 CST 1999

Take the 445 MHz version and just multiply all dimensions by
445/310 and that will get you very close.  There are a few
"Techalicalties" changing the antennas on Part 15 stuff.

73's  Kent

Douglas Kilgore wrote:
> 
> Kent -
> 
> The Dallas Personal Robotics Group made a group buy of some Ming 310 Mhz
> radio remote control modules.  Some of them would like to extend their
> range.  I suggested a 3 element yagi on the operator end.  I referred
> them to your article on the CLARC web page  to show them a cheap yagi.
> 
> Could you  provide dimensions for a 3 element 310 Mhz cheap yagi?
> 
> Doug Kilgore KD5OUG
> 
>   ------------------------------------------------------------------------
> 
> Subject: Re: DPRG: Ming Modules?!@$#@@!
> Date: Sat, 06 Nov 1999 02:51:18 -0600
> From: "Robert L. Jordan" <rljordan at airmail.net>
> Reply-To: dprglist at dprg.org
> To: dprglist at dprg.org
> References: <991105063707.22800c63 at DEVEL.USA.ALCATEL.COM> <3823442E.6C7A855 at home.com>
> 
> Doug,
> Do you have easy access to the length for the 1/4 and 1/2 wave antennas for the
> ming transmitter frequency? I've see freeware around like Yagimax (?) that
> calculates it easy. Any of your often talked to contacts have that info.
> 
> The Ming site (http://www.ming-micro.com/tx.htm) says
> "The TX-66 is a SAW based 310MHz AM RF transmitter board
> We recommend using 22 gauge wire cut to 9.06" (1/4 wave)  "
> 
> The dimensions and info for the yagi for use at the receive end would
> help as receive distance should be much (?) farther
> 
> Regards
> Robert L. Jordan
> 
> Douglas Kilgore wrote:
> 
> > I can understand the use of a 1/4 wave or 1/2 wave antenna with the board but
> > I don't understand the benefit of using a full-wave end-fed antenna.  It seems
> > the VSWR would be high.
> >
> > I don't know the impedance of the Ming circuit but I would think that a
> > vertical 1/4 wave whip over a ground plane would radiate a better
> > omni-directional pattern.  A similar antenna is used for vehicle antennas.
> >
> > To increase the communication range, a directional antenna could be used at
> > the operator end and an omni-directional on the robot.  A cheap, simple 3
> > element home built yagi is described at the following URL:
> >
> > http://www.clarc.org/Articles/uhf.htm
> >
> > The article describes antennas for use on the Ham bands but if someone is
> > serious about wanting to build one  for  300Mhz, I could ask the author to run
> > his computer program for that frequency.
> >
> > Doug Kilgore KD5OUG.
> >
> > MIKE MCCARTY -- 93789 wrote:
> >
> > > I don't recall the precise length, but something like 30 inches. Why?
> > >
> > > )What is the physical length of the antenna?
> > > )
> > > )Doug Kilgore  KD5OUG
> > > )
> > > )MIKE MCCARTY -- 93789 wrote:
> > > )
> > > )> That is with full-wave antennas on both the transmitter and receiver.
> > > )>
> > > )> ----------------------------------------------
> > > )>
> > > )> Is that with or without the optional antenna that the instructions
> > > )> reference?
> > > )>
> > > )> -----Original Message-----
> > > )> From: owner-dprglist at dprg.org [mailto:owner-dprglist at dprg.org]On Behalf
> > > )> Of MIKE MCCARTY -- 93789
> > > )> Sent: Thursday, November 04, 1999 9:32 AM
> > > )> To: dprglist at dprg.org
> > > )> Cc: JMCCARTY at DEVEL.USA.ALCATEL.COM
> > > )> Subject: RE: DPRG: Ming Modules?!@$#@@!
> > > )>
> > > )> My experience is that they provide reasonably reliable communication
> > > )> over a distance of 3 to 4 meters, but not more.

- --------------B4B69C5BA01471000BEE3421--

------------------------------

More information about the DPRG mailing list