[NLRS] Power on 5760 MHz

[tosca005 at umn.edu]

Jerry:

Thanks for setting me straight on this. It sounds like it is well beyond my 
abilities to work with, so I should scrap the idea. I guess it's like they 
say, if it sounds too good to be true, it probably is exactly that! :)

73 de W0JT

On Nov 8 2012, Dr. Gerald N. Johnson wrote:

>
>
>The QFN package is tiny, terminations on 1/2 mm centers and about 1/3 mm 
>wide. The terminations are not exposed to a soldering iron. There's also 
>a center pad, generally bigger that is often ground and most often heat 
>sink. The only way to mount is by solder reflow, hand soldering can't be 
>done to mount them the way the maker intended. I suspect they might 
>mount well dead bug style in a hole in the PC board with #30 single 
>strand wire bridging from board to pads and copper foil to the multiple 
>grounds and heat sink pad.
>
>Big SMT resistors and capacitors are 1/8" long by 1/16" wide, often 
>boards these days are using 0805 parts 80 thousandths (2mm) long and 50 
>thousandths wide. They can be hand soldered, but for RF some parts get 
>smaller down to 0201 and even 10 thousandths long by 5 wide. Those get 
>to be hard to see with a good binocular microscope. And harder to hand 
>solder.
>
>There is a good article on reflow soldering in the latest MUD proceedings.
>
>73, Jerry, K0CQ
>
>On 11/7/2012 11:15 PM, tosca005 at umn.edu wrote:
>>
>>
>> My 5760 transverter is an older 10 mW Down East Microwave model. I have a
>> few options for boosting the power up to a more competitive level, but
   while browsing the listings on eBay, I came across a few items that 
looked
>> appealing to me and might interest other folks in the same boat as I:
>>
   Item 400182916307, a pair of PC boards for a RFMD/Sirenza 4.9-5.9GHz 
1Watt
   SZA-5044Z RF MMIC Power Amplifier in 4mmx4mm QFN Package -- $11.99 for 
the
>> pair, has "more than 10 available", has sold 110 of them so far.
>>
>> Item 260605336283, a package of 5 of the MMIC chips that fit on the above
>> boards -- $13.99 for the set of 5, 3 sets available, 5 sold so far.
>>
>> These would provide about 22 dbm maximum output power at 5760 MHz, so a
>> noticeable bump from 10 mW (10 dbm), but still pretty low. So why bother?
>> Because the next item below needs 18 dbm in to produce a pretty healthy 5
>> watts or 37 dbm of output power.
>>
>> Buy 5 of the board sets and 2 of the MMIC sets and you could build 10
>> boards... Strange choice of grouping the sales if you ask me. And of
>> course, you would need to add the various chip caps, chip resistors, chip
>> inductor, and SMA in and out connectors, and be comfortable with surface
   mount components (which I'm not). But could be a group project if a 
number
   of people wanted assembled boards and someone in the group wanted to 
tackle
>> it for those of us less adept at assembling microwave components...
>>
   Then, I also saw the following item that would nicely complement the 
above
>> pre-driver boards to bring them up to a genuine 5 watt level:
>>
>> Item 250983172827, a 4.8-6.7 GHz 5W Power Amplifier M/A-com MAAPGM0060 --
>> from the spec sheets, it appears that 18 dbm in would give the 37 dbm (5
>> watt) output that the part is capable of generating, and since the prior
>> item could provide up to 22 dbm, it seems that 5 watts from 10 mW is
   doable. Unfortunately this last item is selling for $120, whereas the 
prior
>> ones are priced low enough to entice me to experiment. As far as I can
>> tell, this item is just the module itself, so a board would need to be
>> created to use it.
>>
>> Anyone want to offer comments on these items? Or is everyone else already
>> at power levels above a watt or 5 on this band?
>>
>> 73 de W0JT/5
>>
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