[Elecraft] K2 power anomalies

[Don Brown]

Hi

I did some testing with my DL1 and I found it to be quite accurate. At =
7.100 mhz I get 15.7 volts with 10 watts in. This correlates with the =
graph. Moving to 28.100 MHz I get the same reading at 10 watts in. I =
connected the DL1 to a leveled RF generator and ran the frequency from =
50 KHz to 250 Mhz and the output was the same within about 20 mV across =
the band. I used a WM-2 to measure the power out on the K2 and also =
checked it with a precision attenuator fed into a 400 Mhz scope. The DL1 =
matched up perfectly with the other metering methods. I connected the =
DL1 directly to the K2 BNC using the double male adapter I ordered  with =
the DL1. When connecting the other meters I used a 6 inch BNC cable to =
keep the connection as short as possible.=20

You should not have any reason to question the DL1 from what I am =
getting. I think the readings are really what your K2 is doing. Watt =
meters are notoriously inaccurate. Even the WM-2, one of the best, falls =
off about 10-15% at 10 meters. This is why I always used the precision =
attenuator and the scope to set up the K2-K2/100 tuners or anything that =
needs to be accurate. As simple as the DL1 is, it appears to be very =
accurate. I would say it is a must have if you do not have any other way =
to check the power out on a K2. It's inexpensive and simple.=20

In fact I would recommend anyone thinking of building a K2 to order the =
DL1, N-Gen and XG1 mini kits with the K2 and build them first. This will =
give you the experience and confidence to build the K2 and you get =
useful test equipment you will need to make setup and alignment easier =
once the K2 is finished.

Don
KD5NDB

  ----- Original Message -----=20
  From: Julian, G4ILO=20
  To: Elecraft List=20
  Sent: Sunday, January 04, 2004 11:21 AM
  Subject: [Elecraft] K2 power anomalies
  SNIP


  Does the voltage / power graph shown on the DL1 instruction sheet hold =
true=20
  across the whole frequency range the DL1 is specced for (0 - 225MHz), =
or=20
  even the whole HF bands? If so, my K2 is delivering considerably less =
power=20
  than I thought on the highest bands, as is my 6m transverter. This =
problem=20
  is not evident using my other homebrew power meter. For example, on =
40m at=20
  5.0W by the K2 display I am reading 11.5V on the DL1 test points. On =
10m=20
  when the K2 is reading 7.6W I am getting only 11.1V across the test =
points.=20
  At maximum output 11.9W according to the K2 I am only getting 12.6V =
across=20
  the test points, which if true would mean that at full output my K2 is =

  putting out little more than 5W according to the graph. My homebrew =
power=20
  meter does not show this significant fall-off in power compared to the =
K2's=20
  own readings.

  SNIP

  Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392)
  G4ILO's Shack: http://www.qsl.net/g4ilo



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