[Elecraft] KX1 Spring Tune Up Update

[Jack Regan]

I purchased an Elecraft DL1 because of its' linearity and the built in VDC
test points. Here is the first set of test data.

 

Notes:

The SCOPE PWR was Vp-p * .3535 = Pav

The TP1 PWR was ((V * 1.414) + 0.15))2 / 50 = P(watts)

BAT: 1) DVM 11.93 UNLOADED 2) DVM 11.90 KX1 RECEIVE 3) KX1 11.6 KX1 RECEIVE
4) sDVM 11.72 KX1 TXMT 

 

FREQ  SCOPE P-P   SCOPE PWR   TP1         TP1 PWR     KX1 PWR     KX1 SWR

 3.55 30 VP-P     2.25 WATTS  7.60 VDC    2.424 WATTS 2.8-2.9     1.0

 7.05 28          1.96        7.22        2.146       2.5-2.8     1.0

10.12 32.5        2.64        8.25        2.79        3.8-4.0     1.0

14.05 27          1.822       6.80        1.79        2.3-2.5     1.0

 

In every case the scope power is lower than the DL1 power and the KX1 TUNE
power is higher than both!

 

The DL1 specification claims 10% Accuracy! Is that 5% plus or minus?

 

The scope used is a Tektronix 465. Its' self calibration shows that it is
functioning properly.

It was certified when I bought it. It uses a 10 Meg probe.

 

The rig is fully loaded. 4 bands, ATU, power mod and the SMD CW TUNING AID. 

 

Projects left to do. 

 

1.    Understand why the Scope and the DL1 are not showing the same results.

 

2.    Get the rig and the scope/DL1 readings to agree.

 

3.    If in fact the output is lower than spec for 20 for example, correct
that!

 

4.    Explore the possibility of increasing the power output to a full 5
watts.
      Don has pointed out the fact that more than just the oscillator, final
rf
      transistor and toroids are involved in putting out more than 4 watts.
Perhaps an
      out board power amp using the KX1 as a VFO would be the way to go!
QST has had several
      articles on power amp construction lately! 

 

Just for the record, the KX1 is working on all bands.

 

I'll be going over the KX1 manual next. In the mean time, if anyone has any
suggestions re: the data presented above, I would be glad to hear from you.

 

Jack AE6GC