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RE: Can you run a Nautel Xmtr at 110%?
To: "'CRTech'" <crtech@crtech.org>
Subject: RE: Can you run a Nautel Xmtr at 110%?
From: "Bill Hurne" <billhurne@pilgrimradio.com>
Date: Wed, 9 May 2018 11:30:52 -0700
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We’re running a couple GatesAir FAX 3K, 3KW transmitters, one at only 1250 watts, and one at 1950 watts.   The PA efficiency at full 3KW is a bit over 70 percent, but at 1250 watts is only 50 percent.  At 1950 watts the PA efficiency is 63 percent.    I haven’t seen any charts, but these are my real measured values, Output Power/PA Volts X Amps.    Have been able to improve the lower power efficiency a bit by reducing the adjustable supply voltage, and doing a re-bias procedure.

 

Bill

 

From: Kevin Kidd [mailto:kkbroadcastengineering@gmail.com]
Sent: Wednesday, May 09, 2018 10:52 AM
To: CRTech
Subject: Re: [CRTech] Can you run a Nautel Xmtr at 110%?

 

Just curious, is there a chart or curve available to check out for the various products efficiency vs tpo and the max recommended power?  Most of my client's Nautel TX's are running close to nameplate power but some aren't.


Kevin C. Kidd, CSRE/AMD
Lawrenceburg, TN
AM Ground Systems Company  -  WD4RAT
kkidd@kkbc.com  --  866-22-RADIO -- 866-227-2346
www.amgroundsystems.com

 

On Wed, May 9, 2018 at 12:00 PM, Gary Liebisch <glieb01@gmail.com> wrote:

We get that question all the time and you can certainly run it at 110%.   In the days before software was used to limit power, it was common for folks to use all kinds of modifications and tricks to "juice up" tube transmitters beyond their rated power. But now software is the gate keeper on excess dissipation, and our components are conservatively rated.  You get best efficiency on a solid state transmitter when it is run at rated power or above.  If your licensed TPO is 5500 w and you follow the advice of buying the next larger transmitter (a 7.5) then you are taking a double hit on efficiency, not running it near rated power, not to mention that a 7.5 is really a 10 internally anyway, so you're only at about 50%.   We may not talk you out of doing that, though, because it puts more commission in our pockets!  :)

 

References: Can you run a Nautel Xmtr at 110%?
(Dave Land <dave@klvv.com>, 9 May 2018 14:30:32 -0000)
RE: [CRTech] Can you run a Nautel Xmtr at 110%?
("Laverne Siemens" <lsiemens@goldenwestradio.com>, 9 May 2018 14:34:13 -0000)
RE: Can you run a Nautel Xmtr at 110%?
(nathaniel.steele@icloud.com, 9 May 2018 14:45:03 -0000)
Re: Can you run a Nautel Xmtr at 110%?
(Dave Land <dave@klvv.com>, 9 May 2018 14:55:45 -0000)
Re: Can you run a Nautel Xmtr at 110%?
(RADIO DOCTOR <lylehenry@fastmail.fm>, 9 May 2018 16:38:08 -0000)
Re: Can you run a Nautel Xmtr at 110%?
(Gary Liebisch <glieb01@gmail.com>, 9 May 2018 17:01:58 -0000)
Re: Can you run a Nautel Xmtr at 110%?
(Kevin Kidd <kkbroadcastengineering@gmail.com>, 9 May 2018 17:52:01 -0000)
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