[CQ-Contest] Transceiver transmitted composite noise at reduced output power

[donovanf at erols.com]

Hi Joe, 


I'll be pleased to email a pdf of Rob Sherwood's transceiver 
transmitted composite noise measurements to you or anyone 
who requests them 


73 
Frank 
W3LPL 

----- Original Message -----

From: "Joe" <nss at mwt.net> 
To: donovanf at erols.com, "CQ-Contest" <cq-contest at contesting.com>, "Elecraft" <Elecraft at mailman.qth.net> 
Sent: Thursday, April 1, 2021 11:09:50 PM 
Subject: Re: [CQ-Contest] Transceiver transmitted composite noise at reduced output power 

Hi Frank, 
Looks like the e mail machine strips attachments. 

Can you E-Mail this directly to me? 

Thanks 

Joe wb9sbd nss at mwt.ne 

On 4/1/2021 1:37 PM, donovanf at erols.com wrote: 
> 
> Rob Sherwood NC0B agreed to freely share his full transmitted 
> composite noise measurements (dBc/Hz). Rob's measurements are 
> limited to only transceivers he has access to. He'll be pleased to 
> measure the performance of any transceiver, but of course he needs 
> access for testing. 
> 
> 
> 
> Transmitted composite noise is only an issue in your immediate local 
> area -- such as interference to other hams within several miles if you 
> want to keep them as friends -- or to other transceivers in your own 
> station for SO2R, multi-op or Field Day. Transmitted noise can be 
> controlled by transmitter bandpass filters to reduce noise into 
> transceivers on other bands but a bandpass filter can't reduce noise 
> into a transceiver on the same band such as a CW and an SSB station 
> on the same band during Field Day. 
> 
> 
> Several hams asked about degraded transmitted noise power 
> when the output power is reduced to drive a modern amplifier. 
> Rob shared his data -- attached to this email -- for all of transceivers 
> he has tested for transmitted composite noise at 30 watts output. 
> Transmitted noise output from some transceivers -- such as the IC-7300 -- 
> is much worse at reduced output power, most others are degraded 
> from 3 to 6 dB. 
> 
> 
> K3S transmitted noise with 30 watts output power is increased by 
> 9 dB at 10 kHz from the transmitter frequency, but noise power 
> 100 kHz from the transmitting frequency is degraded only 3 dB, 
> the minimum degradation one would ever expect. 
> 
> 
> The top of the first page is Rob's transmitted composite noise 
> measurements at 100 watts output power. 
> 
> 
> 
> The bottom of the first page is composite noise measurements 
> at 30 watts output power. 
> 
> 
> The second page is six meter tests on the the TS-890S 
> 
> 
> 73 
> Frank 
> W3LPL 
> 
> 
> 
> 
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> 

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