Re: RF Power #chat


Andrew Lenton
 

Just Built and measured the 17M LPF J

 

Loss 0.5 dB looks like I need to rewind my 20 M coils!

 

73

 

Andrew

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Andrew Lenton
Sent: 02 September 2017 14:10
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] RF Power #chat

 

I have just measured the 20meter LPF, see below:  insertion loss 2.466dB !! L, I am making the 17,15,12,and 10 today so will measure each on in turn. And post for those who are interested. Maybe I am crap at winding the coils.

 

I normalised out the connection cables, which are 0.5M each.

 

So my U3S is 125mW ( adding 2.466dB) which is nearer the mark, I will check what the loss is on other LPF.

 

73

 

Andrew

 

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Andrew Lenton
Sent: 02 September 2017 12:42
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] RF Power #chat

 

Thank for this: I will measure power before the filter, see if it similar to below.

 

 

73

 

Andrew

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of SM7ETW Jan
Sent: 01 September 2017 23:16
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] RF Power #chat

 


The following is my U3S without any LPF, bias adjusted to keep overtones down.
The overtone values are dB down from main carrier.

 

U3S  all values in dBm

 

 

 

 

 

Frequency kHz

Power out dBm

2nd overtone 

3rd overtone

4th overtone

5th  overtone

137

22.6

-29.1

-8.9

-36.7

-14

475

23.6

-27.6

-9.4

-33.1

-14.1

1900

23.8

-35.5

-9.66

-39.8

-18.2

3600

23.9

-36.8

-9.9

-37.5

-14.6

5300

23.6

-36.5

-9.6

-35.1

-14.6

7100

23.9

-34.3

-10.1

-32.2

-15.1

10130

23.8

-30.8

-10.2

-26.8

-15.6

14100

23.5

-25.9

-10.4

-22.5

-22.3

18100

23.4

-22.9

-10.7

-19.2

-25

21100

23.2

-20.6

-11.2

-19

-26.9

25000

23.2

-17.6

-13.0

-19.7

-39.2

28500

23.1

-15.5

-15.3

-21.6

-39.1

50100

21.3

-17.3

-36.3

-28.3

-21.3

70100

18.8

-17.8

-23.8

-24.8

-18.8

145000

10.8

-13.3

-25.8

-10.8

-10.8

200000

9.1

-9.1

-9.1

-9.1

-9.1

220000

6.2

 

 

 

 

230000

8

 

 

 

 

 

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