looking for mar6

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on4bhm
Posts: 79
Joined: Mon Oct 24, 2011 5:52 pm

looking for mar6

Post by on4bhm » Mon Oct 24, 2011 6:01 pm

Hi,

i'm looking for 2 times mar6.
can someone supply them to me?
i can pay with paypal.

kind regards
73's

on4bhm (at) telenet.be

G0KTD
Posts: 45
Joined: Wed Jun 08, 2011 7:39 am

Re: looking for mar6

Post by G0KTD » Mon Oct 24, 2011 9:58 pm

Got mine from this Guy on Ebay http://www.ebay.co.uk/itm/390161593603? ... 500wt_1202

Keith G0KTD

g8ajn
Posts: 45
Joined: Sun Mar 16, 2008 1:59 pm

Re: looking for mar6

Post by g8ajn » Tue Oct 25, 2011 12:11 pm

They are available from http://www.ghengineering.co.uk
Other shaped devices can also be used hence the un-tinned section where the MMIC sits.
Dave G8AJN

w0fms
Posts: 23
Joined: Wed Oct 12, 2011 10:46 pm

Re: looking for mar6

Post by w0fms » Tue Oct 25, 2011 11:23 pm

MAR-6's are officially available from Mini-Circuits in the US. Everyone else is reselling them from "retail" since Mini-Circuits doesn't sell through distributors. Not an issue really except for the $50 minimum order. The only other reasonable place in the US cost wise is Down East Microwave. I can't vouch for the European sites. But then again at least initially the MAR's were relablled Avantek-->Aglient-->Avago parts. Maybe this isn't the case any more but the MAR-6 is the equivalent to a MSA-0685 and the substitute which I will use is a MSA-0886 or the equivalent to a MAR-8.

I ordered a couple of readily available (from distributors in the UK/Europe: Farnell #1085629) Avago MSA-0886 devices which have slightly better P1dB specs and similar gain at frequency. But to substitute those parts in, bias changes have to be done. This *should* work but is untested as of right now.

Why no one stocks MSA-0685's (MAR-6's) is a bit of a mystery to me.

The 7808 regulator appears to drive the 7805 which then drives that tiny 3.3V regulator. The +8V from the 7808 only seems to supply the MMIC bias. To use the MSA-0886 part, the 7808 needs to be changed to a 7810 .. calculating out the biasing from Avago's literature seem to mean for the 40ma bias recommended at 10V you need 63.4 ohms.. or probably two 130 ohm 1210 resistors in parallel is close enough. The 7810 for the first linear regulator should be not an issue with the regulators down stream as they are large compared to the current draw of the circuit.

Please Double check my math on this. (The Mini-circuits MAR-8SM data sheet confirms this.. they are the same part.) But the specs are similar and they are "more available" than the MAR-6. One could tack it on to the Farnell order (or Mouser if you are in the US).

I'm assuming the MAR-6 was picked because the high gain was needed to get to +0 dBm (-ish)? If so the MSA-0886 should get you there as well.

Hope this info is useful.

Fred W0FMS

G4OHV
Posts: 37
Joined: Sat Oct 08, 2011 10:31 pm

Re: looking for mar6

Post by G4OHV » Wed Oct 26, 2011 10:11 am

Got mine off ebay from Mainline Electronics

regards

Col

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