The SontheimerBridge/TandemMatch//StocktonBridge?allows you to watch power and SWR
while the rig is in use.? ?So if your antenna breaks in the wind or you have an intermittent BNC connection,
the match can be monitored and measures taken to protect the rig.
A resistive bridge is simpler but only sends 1/4 of the available power to the antenna,
so must be switched out after tune up.
A wideband tandem match can be good over a decade or so, up into VHF.
A single resistive bridge can work well from DC to tens of GHz.
Bruene wrote a classic article on how many of the other (not resistive, not TandemMatch) SWR bridges work:
??"An Inside Picture of Directional Wattmeters" by Warren B. Bruene W0TTK in QST for April 1959.
That article is still very pertinent, highly recommended.
If you have a scope, you can figure out your SWR from first principles:
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I think the TandemMatch is ideal for an HF rig.
Diz does a good job of kitting them up, sells a TandemMatch for $12:
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The design of the TandemMatch is quite a bit older than most hams know, patented in 1966.
Stockton was several decades late in finding it.
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That link includes an analysis of how it works.
K6JCA has also put out a description of how it works, and notes on designing the transformers:
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Sontheimer is better known for developing the Cuisinart:
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Jerry, KE7ER
