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Re: [CQ-Contest] calculating CW duty cycle

To: AB2E Darrell <ab2e@hotmail.com>
Subject: Re: [CQ-Contest] calculating CW duty cycle
From: Robert Busch - DM4AO <sunnyrob@gmx.de>
Date: Tue, 5 Jul 2022 21:16:41 +0200
List-post: <mailto:cq-contest@contesting.com>
Hi Darrell,

What about vertical dipole(s) on a small fibre glass pole (I love the Mini from 
DXwire)? You can put as much power on it as your coax can cope and you can put 
it up everywhere. Omnidirectional, low take off angle, no radials, easy to 
construct and easy to carry!

Don‘t forget: The best amp is your prefix, hi!

73
Rob, DM4AO


Robert Busch   .iPhone
___________________
Mind is like a parachute, it only works when it's open.

> Am 05.07.2022 um 04:28 schrieb AB2E Darrell <ab2e@hotmail.com>:
> 
> Greetings John & the group,
> The antenna in question is the PreciseRF HG3 QRO, an MLA loop, advertised at 
> 1500W.
> When I dug into the actual specs, it's 50% duty cycle for CW at 800W, and 25% 
> duty cycle at 1500W.
> I would be using an SPE 1.5K-Series III amp, so will likely have to run it in 
> the low power position, driven by an Elecraft K3.
> That's OK, still 6db stronger than 100W.
> 
> Now that I'm 70, I'm having to rule out a lot of stuff I could do before due 
> some developing health issues.
> Now maybe I'm better off taking a chance and trying to string a dipole 
> between 2 palm trees rather than trying this MLA, but my recent
> experiences with AirBnb's in a couple islands, I've gotten negative responses 
> to my inquiries about putting up antennas.
> Most of the great rent-a-shacks are always occupied, or sky high in price.
> 
> The HG3 QRO takes up minimal space and could be set up easily in the back 
> yard of the villa without attracting attention.
> Yes, I know all these things involve tradeoffs, but may mean the difference 
> between getting to go somewhere and operate or not.
> 
> 73 to all,
> Darrell AB2E
> 
> ________________________________
> From: CQ-Contest <cq-contest-bounces+ab2e=hotmail.com@contesting.com> on 
> behalf of john@kk9a.com <john@kk9a.com>
> Sent: Monday, July 4, 2022 9:47 PM
> To: cq-contest@contesting.com <cq-contest@contesting.com>
> Subject: Re: [CQ-Contest] calculating CW duty cycle
> 
> I would guess that running a pileup your CW duty cycle would be closer to
> 25%.  What is the antenna and why is the power level so questionable?  FWIW,
> I have never had an issue setting up a Yagi, dipole or beach mounted
> vertical from a Caribbean villa.
> 
> John KK9A
> 
> 
> 
> AB2E wrote:
> 
> The consensus is that even with the variables, the duty cycle will not
> likely be over 50% at my regular contest speed of 30-35wpm.
> The reason for my question is that I am evaluating a portable antenna that
> claims a 50% duty cycle at 800W,
> but drops to 25% duty cycle for CW at 1500W. It appears I should be OK
> operating around 600-700W safely with the 50% duty cycle.
> This would be used on an island dxpedition where putting up regular (proper)
> antennas would not be possible, probably from a villa.
> 
> 73 and thanks again for taking the time to answer,
> Darrell AB2E
> 
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