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My philosophy regarding tuners, especially when contemplating a tuner for an "all band antenna" where impedances are likely to be quite high or quite low is to buy the biggest baddest tuner your budget allows even when running 100 Watts. The high power capable tuners will have larger components which translate to lower losses which become even more important as QRP power levels are approached. My current manual tuner is a Palstar AT1500DT (no longer made) which tunes my 200' doublet on the low end of 160m without complaint whereas the MFJ-986 it replaced was at the limit of the roller inductor (the Palstar still has turns to go).

One sign of being at a tuner's limit is the reflected power to the radio increases as power is turned up or during a longer transmission. It's likely that some component is heating up and it's losing the match.

You could always use it until it smokes and then you have an excuse, errr, reason to buy a new one!

<blockquote data-quote="N0NB" data-source="post: 237982" data-attributes="member: 15146">My philosophy regarding tuners, especially when contemplating a tuner for an &quot;all band antenna&quot; where impedances are likely to be quite high or quite low is to buy the biggest baddest tuner your budget allows even when running 100 Watts.&nbsp; The high power capable tuners will have larger components which translate to lower losses which become even more important as QRP power levels are approached.&nbsp; My current manual tuner is a Palstar AT1500DT (no longer made) which tunes my 200&#039; doublet on the low end of 160m without complaint whereas the MFJ-986 it replaced was at the limit of the roller inductor (the Palstar still has turns to go).One sign of being at a tuner&#039;s limit is the reflected power to the radio increases as power is turned up or during a longer transmission.&nbsp; It&#039;s likely that some component is heating up and it&#039;s losing the match.You could always use it until it smokes and then you have an excuse, errr, reason to buy a new one!&nbsp; <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":D" title="Big Grin&nbsp; &nbsp; :D"&nbsp; data-smilie="8"data-shortname=":D" /></blockquote>

[QUOTE="N0NB, post: 237982, member: 15146"] My philosophy regarding tuners, especially when contemplating a tuner for an "all band antenna" where impedances are likely to be quite high or quite low is to buy the biggest baddest tuner your budget allows even when running 100 Watts. The high power capable tuners will have larger components which translate to lower losses which become even more important as QRP power levels are approached. My current manual tuner is a Palstar AT1500DT (no longer made) which tunes my 200' doublet on the low end of 160m without complaint whereas the MFJ-986 it replaced was at the limit of the roller inductor (the Palstar still has turns to go). One sign of being at a tuner's limit is the reflected power to the radio increases as power is turned up or during a longer transmission. It's likely that some component is heating up and it's losing the match. You could always use it until it smokes and then you have an excuse, errr, reason to buy a new one! :D [/QUOTE]

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