Re: Transmit Output Power (CW) #v5

Andy_501 <andrew.webb.501.ve4per@...>
 

Here are a couple of tone clips that might be useful; 700-1900 is 2 tone  300 and 3000 are voice BW max & min. I use another SDR spectrum display to check spectral purity for things like harmonics. depending where you feed it into system you might have to fashion an atten pad

cheers


On 2020-03-11 10:05 p.m., Matthew Chambers NR0Q via Groups.Io wrote:
why? he already did the test with CW which will give the maximum power out vs a whistle which will vary and may have a complex signal component and reduce how much power you see on a non-peak reading meter. in radio shops we always test in either CW or FM for max power out, and then in AM to set the carrier level.

Matthew Chambers, CBT, NR0Q
Owner/Engineer
M Chambers Communications Engineering LLC
PO BOX 855, Moberly, MO 65270
Mobile (660)415-5620


On Wed, Mar 11, 2020 at 9:57 PM Joe Puma <kd2nfc@...> wrote:
Do the same test but in SSB. Give a steady whistle.  

Joe
KD2NFC 



On Mar 11, 2020, at 10:13 PM, Rob French (KC4UPR) <kc4upr@...> wrote:



I've collected all my parts to do Allison's transmit chain modifications (BFR106, 2N2222, 11 ohm resistors...).  I'm ready to go... but I wanted to QC my output power first.  Now, I have noticed on 40 meters (where I spend most of my time), that the output power is low, so now that I finally have a power meter, I went ahead and tuned RV1 while transmitting into a dummy load.  I tuned RV1 to get 12W output on 3.500 MHz, and then checked the output power across the rest of the bands.  This is what I got... is this representative of what other people have seen?  I know I'd seen reports of crazy low output power (<1 W) on 10 meters, which I did NOT observe here, obviously.  (Note, all of these were done with CW.)

Frequency

SWR

Power (W)

3500000

1.00

12

4000000

1.00

9.4

5332000

1.00

6.3

5405000

1.00

6.2

7001000

1.00

6.7

7300000

1.00

5.6

10100000

1.00

5.2

10150000

1.00

4.7

14000000

1.01

6.6

14350000

1.01

6.2

18068000

1.02

5.5

18168000

1.02

5.5

21000000

1.04

5.8

21450000

1.05

8

24890000

1.04

4.1

24990000

1.04

4

28000000

1.04

4.8

29700000

1.03

4

Any thoughts?  (a) Are these typical of what others have observed?  (b) What can I expect from the transmit modifications, relative to this?  Higher output on 30, 20, 17?

Thanks!

-Rob KC4UPR

PS - Random aside.  So I am using KD8CEC firmware version 1.2.  I noticed something weird on 40 meters... If I tune to exactly 7.000.000 MHz, or lower, in the 40 meter band, I hear the T/R relay switch and the display indicates in CW transmit, but there's 0 W output power.  But if I tune to 7.000.010 or higher, it's fine.  It's kind of like it's enforcing transmit restrictions, except that the ONLY place that it seems to do this is on the bottom end of 40 meters!  I've tried to trace code behavior for the band limiting, and could not identify anything that would make this happen.  Has anyone else observed this???

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