Roger,
I would assume the dielectric would be a limiting factor on a straight top
disk. However, the ones that use a stinger on top usually have a base
loading coil built into it to match the impedance of the stinger. The
stinger improves gain, but limits the overall frequency range. The normal
transmitting range of the Diskcone is 4x.
I built mine for a low frequency of 130 mhz and has respectable SWR from the
130+ aircraft frequencies all the way through the commercial 450 mhz band. I
do not have a coax connector at the gap. I use RG 213 connected directly to
the elements. I use a ceramic insulator and would suspect it to handle more
power than 200w. I have seen 1kw on a 6 meter version, but the spacing is
much larger between the disk and cone.
* 73's Jim W5IFP *
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com]On Behalf Of Roger (K8RI)
>Sent: Saturday, March 21, 2009 12:41 AM
>To: undisclosed-recipients:
>Cc: Towertalk
>Subject: Re: [TowerTalk] Discone Antenna
>
>
>
>
>Jim Hargrave wrote:
>> Bill,
>>
>> "Diamond" (tm) made a Discone antenna. They are now part of RF Parts.
>> You can get some info at:
>>
>> http://rfparts.com/diamond/
>>
>I note they list the maximum power on their "diskcone" at 200 watts (50
>- 1300 MHz). What on earth is in there that would limit the power other
>than spacing between the top and skirt beside the coax connector? I'd
>expect for the most part it'd handle the legal limit plus,
>until getting
>up around 1300 MHz where the dielectric *might* be a limitation.
>
>73
>
>Roger (K8RI)
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