MKARS-80: Improved and upgradeable

MKARS-80

A bit over a year ago I built two MKARS-80 kits developed by Steve G6ALU – one for myself and one for a local ham. Not being a phone op, I sold mine, having ordered it just for the experience of building something different from all the CW kits that have found their way to my soldering iron over the years.

In my short time with each completed radio, I was duly impressed with the receiver. They reminded my of the OHR-100 series of CW kits in that there is little background noise while tuning between stations. Once tuned to a station, fidelity is fantastic and there is sufficient volume to drive a speaker to room-filling volume.

Five minutes or so of warm-up time is necessary to allow the rig to stabilize on freq.

Since my build, the MKARS-80 has gone through two generations of improvements, but even better, it can now be adapted to be a dual-mode rig with the addition of the CW Adaptor kit.

I’m not sure how practical this would be in actual use since the freq coverage of the rig is such that it will not cover both the phone and CW portions of the 80m band without internal adjustment. But at any rate, the option is there for you ti choose modes – just not “on the fly”.

To get around this problem, Ron PA0RCL developed a mod that divides the MKARS-80’s band coverage into three switchable segments. Other info describing his construction and mods can be found here. Check out the “photo” of his DRAKARS-80!

And Ron’s 40-watt amp for the MKARS-80 can be found here (with excellent photography, btw).

At the current exchange rate, the kit with the CW option goes for $160 delivered Stateside.

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  2 comments for “MKARS-80: Improved and upgradeable

  1. KL7P Dave
    January 22, 2012 at 11:15 pm

    Did you try to see how high in the band this could be tuned above 3.8 MHz, or see anything on the net regarding that? I have a kit on order and will be building it this spring. Thanks!

    • October 31, 2013 at 6:45 am

      THe kit can be rebuilt as a 40m transceiver. THe kit vendor will send you the PIC code to allow this to be done but will not support the rebuild effort. You have to change out all the RF filters after the mixer to the final PA. You have to replace the PIC. YOu may be able to get Steve to sell you a PIC burned with the replacement code. You also have to change out the incoming RF Rx tuned circuits , only one I think and change all the Xtal filters over to 12 Mhz, were 10 Mhz. So it is a fairly basic job but still requires some engineering skills to get it right. Of course the LO analogue osc frequency has to tune 5 Mhz down to 4.7 so you have to at a min, rewind the LO coil (but for good engineering you would want to keep the Lx to Cx ratio the same in the tank circuit – Its a Colpitts osc, from memory) You might be able to get a set of 12 Mhz computer xtals all from the same mafr and batch and get them to work with out matching. If you type Ashan Farhan into Google you will eventually come up with some recommendations on Cohn xtal fllters where you mod the caps based on the degree of mismatch between the nominally same xtals or findout Ashan’s email address and get him to point you to the article. He is in India as you may know. Hydrabad.

      have fun.

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