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Messages - K2BUG

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1
Equipment / Re: High SWR in a cushcraft A3S yagi
« on: January 17, 2016, 1240 UTC »
Ok, thanks

Since it is winter in upstate NY and the antenna is mounted on top of my 3 story house with a steep roof, this project will have to wait until late spring or early summer.

2
Equipment / High SWR in a cushcraft A3S yagi
« on: January 16, 2016, 2257 UTC »
Hi,

Measured SWR in my coax with an antenna analyzer into a Crushcraft A3S yagi which is tuned to 10, 15, 20 m.  I also have the 40m add on kit.  SWR is now 10-12 across bands.

Is this feed line contamination?  Other causes?

Thanks

3
Equipment / Re: Ameriton 80A will not transmit on 80m or 160m
« on: December 31, 2015, 1600 UTC »
Some additional symptoms with use over the past several days of use.

The current tube is declining in amp power.  A couple of bands have completely faded to a max of 300 w with 90 w in. (10, 15, 20m).  40m has reduced power to 500 w.

Two backup tubes that have been in storage for 5 years(?) do not provide any boost of signal at all ( one new unused and the original tube which was putting out 700 w when removed).  100 watts in and 100 watts out.

Bad tubes or something else going on?

Went back and carefully retested the original tube from storage and it exibited the same symptoms as the tube I was using.  200-300 watts output on 10, 15 & 20m and 500 w on 40 m.  Some other circuit failing.  Any suggestions?


4
Equipment / Re: Ameriton 80A will not transmit on 80m or 160m
« on: December 30, 2015, 1952 UTC »
Hi,

All connections on L1, L2 solid.  Also L3.  RFC3 replaced as was c17 which is on the 80 m circuit

Thanks

5
Equipment / Ameriton 80A will not transmit on 80m or 160m
« on: December 30, 2015, 1617 UTC »
Hi,

I am trying to recover from a newbe mistake of a couple of years ago.  I had purchased an Ameriton 80A amp used in good shape and I was setting up my shack for a higher power transmission.  Icon 746 into a 80A with a LDG AT 1000 pro tuner (1 kw) into a Cushcraft A3S 3-element beam (10-15-20m) with a 40 meter add-on.  Everything worked beautiful testing 10-40m with the 80a operating on 115v putting out 700-1000 watts depending on the band.  The tuner did not have to work hard since the antenna was tuned to these frequencies.

I then tried 80 m and apparently I did not have the antenna tuned properly with the tuner.  When I engaged the amp and started to transmit, all hell broke lose and the transmission was very short.  After that, the amp would not transmit anything.

I unplugged the amp and took off the cover to look for damage.  To make a long story short, the relay contacts were burned (replaced), a couple of diodes were burned on the PO/ALC detector board (all replaced), and the safety choke was smoked (replaced).  Put the amp back together and it worked as before on 10-40m.  No output on either 80 or 160 m into a dummy load.  Looked a little further and 80m contacts on the band selection switch were burned (replaced the whole switch).  Amp still only shows output on 10-40 m.

Checked the radio and it puts out RF at 80 m though a little weak.  Sent it in and no damage to the radio.  Substituted a different radio which has a robust 100 w on 80 into the amp (Icon 706) and still no output.  I replaced the pertinant doorknob caps within the 80 m circuit with no effect.  I even checked the tuned input components for 80 m but the RF would have to flash back through the tube.  No problem found.

Frankly, I am puzzled because I cannot find any component defective on the 80m circuit or I have replaced them all.

Any suggestions or help is requested.  The amp acts like no RF is entering the tube on 80 m and the output on 160 m is very small (20 w).

I am new to the forum so I have not figured out if I could post the schematic. 

Thanks

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