Collins KWS-1 and the MFJ-267 Dummy Load

The MFJ-267 Dummy Load / Wattmeter

MFJ makes a lot of great little boxes, and yes, they are “cheap” when compared to other manufacturers. For example, this product only costs $139.95. Because of their low price, they are ripe for modifications to improve them – which I wouldn’t do to more expensive gear.

You can switch the unit so it is just a dummy load or an inline SWR / wattmeter

The DL2K is nice, but is $379 and does not have the feature where you can use it as a “through” SWR / Power Meter

Now, Phil, AD5X has a fantastic article on how to add a fan to the MFJ-267 that now makes it very competitive to the much more expensive Palstar DL2K:

http://www.ad5x.com/images/Presentations/MFJ267.pdf

I purchased 5 small “muffin fans” for only $8.98:

I’ll use 2 of these the way Phil did:

Phil, AD5X took an MFJ-267 and made it better than a Palstar DL2K for less than half the price

This is one case where the “beefier” Palstar does not work out – because I really do need the dual features of the MFJ – switchable Dummy Load and through SWR / Wattmeter for my Collins KWS-1. As I understand it, it takes a while to get used to learn how to tune the KWS-1, and also – because I have resonant antennas on all bands – with low SWR, it doesn’t make sense to put my Palstar AT2K tuner in line (which is what I was going to do).

Even when I switch to an all band wire antenna some day – I will use the Collins 180S-1 antenna tuner remotely – at the antenna. The other thing is that while this meter is rated at 10 minutes for 100 watts, Phil says that at 600 watts, he can tune up for 10 – 20 seconds at a time and not have to wait in between tuning “sessions” as he did before he installed the fan. Since the KWS-1 is 1000 watts input, I expect that I will get 500 – 600 watts output, so I should be in the same ballpark as what Phil was when he measured the success of his mod – he said adding the fan was an amazing (and inexpensive) upgrade.

This meter will:

  1. Help me learn how to tune the KWS-1
  2. Keep me from polluting the airwaves as I learn
  3. Make my tune ups quicker when I am on the air
  4. Offer a “safety” measurement – if any antenna fails and SWR spikes, I will see it immediately and know its the antennas and not something going wrong with the KWS-1
  5. Let me “preserve” the EIMAC 3CX250B final tubes – which are not that expensive, but are NOS – so I want to be kind to these old tubes

I will have this mod done this weekend – and also build whatever cables I need before the KWS-1 arrives – which will be this coming week.

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