[Antennas] Antennas Digest, Vol 67, Issue 13

Sun Aug 30 19:44:54 EDT 2009

Elwyn,

If you are using low-power on two meters (just a few Watts), I just built
and tested, using a network vector analyzer, a diamond antenna made from
.045 mil aluminum welding wire.  It is 35 inches each leg and ten
inches high.  The feed point is on either of the long sides, 17 inches from
the pointed end. SWR was better than 1.3-to-one at center band (146 mHz),
and the radiation seems to be maximum broadside.  I mounted mine using
patches of clear packing tape onto an acrylic sheet, yet cardboard or
fiberglass screen would work just as well.  I fed it with 18 inches of 300
Ohm TV twin lead and a 300:75 balun on an F-Series-to-BNC adapter, connected
to the 2 meter HT.  A longer twin lead should not be a problem.  Better yet
would be to use 70 Ohm TV coax to bring the connection after the balun
on into your flat.   This would be ideal on a balcony as you describe as it
appears to be near omni-directional.  It can be as close as one foot to
surrounding objects with out affecting the SWR significantly.   Suspended
above your railing as a sunshade it would not stick outward at all.
 Measured SWR is well under 1.5 across the entire 2 meter band (144-148
mHz).  Good luck & I would appreciate knowing how it worked out OK for
you.    Sincerely,  George  AF6JT

> ------------------------------
>
> Message: 8
> Date: Sun, 30 Aug 2009 10:32:43 +0100
> From: Elwyn <M6GKX at Elwyn.org.uk>
> Subject: [Antennas] Small space antenna
> To: antennas at mailman.qth.net
> Message-ID: <4A9A473B.1040208 at Elwyn.org.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hiya Folks
>
> I've got a specific requirement for an antenna.
>
> I'm in a towerblock, with the balcony being the only place I can put the
> antenna. It is flush with the side of the building and I would be sat
> less than a meter from where it would stand normally, ruling out most
> main choices.
>
> I cannot put it lower or higher as other people live in the block too
> and I'm right in the middle. I cannot put it on the roof and run the
> cable down, although that would be nice!
>
> A yagi was suggested but I was wondering if there were other choices. I
> have also been informed that I cannot have anything extruding over the
> edge of the balcony but if needs must then I might be able to disguise
> something as long as it's not too big.
>
> As for bands, at the moment it is only 70cm and 2m. It may well be
> several years before I reach the HF bands (low finances).  I'm UK based
> with Foundation level, so most bands have a 10w limit at the moment.
>
> So, what can you suggest or advise I do?
>
> Thanks in advance ;)
>
> Elwyn M6GKX
> --
> Regards, Elwyn
>
> Ita erat quando hic adveni.
> VxC2, KM5D at 45k
>
>
> ------------------------------
>
> Message: 9
> Date: Sun, 30 Aug 2009 10:52:11 GMT
> From: "w3bj at juno.com" <w3bj at juno.com>
> Subject: [Antennas] 40 M antenna
> To: antennas at mailman.qth.net
> Message-ID: <20090830.065211.11496.0 at webmail06.dca.untd.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> I now have a G5RV that I use for 40 M. Was wondering if anybody had any
> suggestions for a beam on 40. How much difference it would make and what
> brand would be good. I know a beam is always better, but I have never used a
> beam on 40. Tnx for any advice
>
> ____________________________________________________________
> Lights, Camera, Career?
> Enter the fast-paced film industry with a degree from top film schools
>
> http://thirdpartyoffers.juno.com/TGL2131/c?cp=6xbKiXTocxpgeW_R9lVvcAAAJz1uFo4iW2BF213RHLdmL-vOAAQAAAAFAAAAAIXrUT4AAAAAAAAAAAAAAAAABgAYAAAAAA==
>
>
> ------------------------------
>
> Message: 10
> Date: Sun, 30 Aug 2009 08:58:08 -0400
> From: "Brian  Cake" <bcake at bellsouth.net>
> Subject: Re: [Antennas] Small space antenna
> To: "Elwyn" <M6GKX at Elwyn.org.uk>,       <antennas at mailman.qth.net>
> Message-ID: <0F55010771D742A1B363FB0143A6D2F6 at BRIANSLAPTOP>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>        reply-type=original
>
> Hello Elwyn,
>
>    I have designed a series of "boxkite" yagis that give good performance
> on both 2m and 70cm. These are single-feedpoint designs, and have much
> higher gain, for a short boom, on 70cm than a conventional yagi. For
> example, the 9-element version has a boom length of a fraction over 1m, but
> has a gain on 70cm of 15.7 dBi, which is about the same as that of a
> conventional yagi on a 2.4m boom. Gain on 2m is the same as that of a
> conventional yagi on a 1m boom, at 9.9dBi. SWR is <1.3:1 across the 2m
> band,
> and is < 1.5:1 from 422 to 439MHz.
>
>    These are not available commercially - yet, but I would be happy to send
> you more details of the performance, plus construction details if you are
> interested.
>
>    73
>
>    Brian KF2YN
>
> ----- Original Message -----
> From: "Elwyn" <M6GKX at Elwyn.org.uk>
> To: <antennas at mailman.qth.net>
> Sent: Sunday, August 30, 2009 5:32 AM
> Subject: [Antennas] Small space antenna
>
>
> > Hiya Folks
> >
> > I've got a specific requirement for an antenna.
> >
> > I'm in a towerblock, with the balcony being the only place I can put the
> > antenna. It is flush with the side of the building and I would be sat
> > less than a meter from where it would stand normally, ruling out most
> > main choices.
> >
> > I cannot put it lower or higher as other people live in the block too
> > and I'm right in the middle. I cannot put it on the roof and run the
> > cable down, although that would be nice!
> >
> > A yagi was suggested but I was wondering if there were other choices. I
> > have also been informed that I cannot have anything extruding over the
> > edge of the balcony but if needs must then I might be able to disguise
> > something as long as it's not too big.
> >
> > As for bands, at the moment it is only 70cm and 2m. It may well be
> > several years before I reach the HF bands (low finances).  I'm UK based
> > with Foundation level, so most bands have a 10w limit at the moment.
> >
> > So, what can you suggest or advise I do?
> >
> > Thanks in advance ;)
> >
> > Elwyn M6GKX
> > --
> > Regards, Elwyn
> >
> > Ita erat quando hic adveni.
> > VxC2, KM5D at 45k
> > ______________________________________________________________
> > Antennas mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/antennas
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Antennas at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 4380 (20090829) __________
> >
> > The message was checked by ESET NOD32 Antivirus.
> >
> > http://www.eset.com
> >
> >
> >
>
>
>
> ------------------------------
>
> ______________________________________________________________
> Antennas mailing list
> Home: http://mailman.qth.net/mailman/listinfo/antennas
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Antennas at mailman.qth.net
>
>
> End of Antennas Digest, Vol 67, Issue 13
> ****************************************
>