Amplifier.

Once in a while a little extra help is needed to obtain a contact with a DX station.  That extra help can come in the form of a few more watts.  When a difficult DX contact is completed we call that being deserving, as in, “We are among the deserving” (Where Do We Go Next, Martti Laine, OH2BH).  Here is a photo of the new amp and my silly grin shows a combination of emotions.  Sheepish for adding power to a weak signal mode but thrilled at the same time.

IMG_2277

(Actually the emotion is more, “Can I get this damn cell phone to take a selfie”.)

Design contraints of a remote base off grid quickly narrow down the choices of linear amplifiers.  The SGC  SG-500 was the obvious choice because it changes bands automatically using rf sensing, runs the finals at 12 volts, and has a remote on/off switch ability.  Luck was with us when we found this pristine SG-500 at a good price online at QRZ Swapmeet.

The amp can draw up to 90 amps.  We rearranged the battery banks to dedicate one bank to the amp.  Everything else is on the other bank. Testing showed up no problems except a tired SO239 coax connector.  We escaped replacing that by using a PL259 with a slightly longer center pin so it would push against the solder cup at the back.  Deferred maintainance.  With 10 watts input the output is 150 watts with no complaints from anything else in the station.  On to the first on-air test.

First QSO

Wow, amazing, superlatives are not enough.  Noticing a big pileup for a station with the call 3D0AY (Swaziland) I found a clear frequency and clicked the transmit button.  Seven others were calling at the same time.  With only four calls, on the 4th transmission he came back to me!  Here is the proof.

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As soon as Swaziland anwered my call another station jumped on our frequency.   I found another clear spot and tried to complete the qso with Swaziland.   He came back again and we completed the contact.  Another station immediately jumped on the new frequency.  A difficult qso but my station joined the “deserving”, thanks to the new amp.  I’m hooked.  I’ll be using this whenever a pileup is tough.

Unfortunately there has been no second qso using the amp.  It seems to be malfunctioning.  It began immediately switching off and the high vswr warning light came on.  Changing to manual PTT got rid of the vswr alarm but no rf comes out of the amp.  It draws a large amount of current but where are those amps going?  It will probably have to go back to SGC for a look.  For the time being we are not using an amplifier.

 

 

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