50-100Watt Dummy Load
This little homebrew 50W continuous 100w peak
dummy load has been a life saver and didn't run more than about 20$ in parts and a old case laying around the bin.
Parts:
Copper plate x 2
20 x 1000 Ohm Flame Proof 5w resistors (order extra)
Box (do not use plastic of any kind)
Wire (should use short coax)
UHF connector
The layout is simple but could be better, a round shape would be ideal for this but all I had was rectangular copper.
Over all I am pretty happy with it works great for qrp work and will handle 100W peak but added cooling should be used for 100W continuous.
dummy load has been a life saver and didn't run more than about 20$ in parts and a old case laying around the bin.
Parts:
Copper plate x 2
20 x 1000 Ohm Flame Proof 5w resistors (order extra)
Box (do not use plastic of any kind)
Wire (should use short coax)
UHF connector
The layout is simple but could be better, a round shape would be ideal for this but all I had was rectangular copper.
Over all I am pretty happy with it works great for qrp work and will handle 100W peak but added cooling should be used for 100W continuous.
Despite not using coax the swr was pretty darn good. One tip I would suggest is buy more resistors than needed to get the right 50ohm load. Going through all 60 I had ordered to get the values was a lot of time but well worth it. After pooling all the values I made sure to use values +/- to get the right 50ohm load. If I had one that was 1090 I would then use one that was 910ish to match the goal of 1k. This might seem like a lot of work but if you want a good known load its a must.
It's not fancy by any means and is not Bird/Motorola but it will do the job. Below you will find all the swr readings I took with my Fox Delta AAZ-0217MX.
The dummy load is 50.2-50.1 ohms.
SWR on the HF bands is as follows:
160=1.02
80=1.02
60=1.04
40=1.05
30=1.08
20=1.12
17=1.17
15=1.21
12=1.28
10=1.37
some fluctuation from top of the band to bottom but it was .01 of a point here and there from the values above.
The dummy load is 50.2-50.1 ohms.
SWR on the HF bands is as follows:
160=1.02
80=1.02
60=1.04
40=1.05
30=1.08
20=1.12
17=1.17
15=1.21
12=1.28
10=1.37
some fluctuation from top of the band to bottom but it was .01 of a point here and there from the values above.