TopBand: ZJ Box Variants

[km1h @ juno.com]

Topbanders,

I received a number of replies to yesterdays post. It seems even more
versions exist.

So far units with MAR-1, MAR-3, MAR-6 and MAR-7 monolithic amps have been
reported.
Assuming that the proper bias resistors and wall warts are used we have
specs of:

Device	Gain	1dB Compression	 Intercept
(IP3)	NF

MAR-1	18.5	     +1.5		     
+14		5.5
MAR-3	12.5	     +10		     
+23		6.0
MAR-6	20.0	     +2.0		     
+14.5		3.0
MAR-7	13.5	     +5.5		     
+19		5.0
plus:
MAV-11	12.7	     +17.5		     
+30		3.6

All specs in dB and the gain is at 100 MHz per the MCL catalog. At 2MHz
the gain would probably be somewhat higher but MCL does not spec that
low. Other specs are measured at 500MHz.  The MAV-11 is the device
mentioned yesterday by Russ, NJ2L, and appears to be a much better choice
all around.    

I have not yet sketched out the complete circuit so cant say if a  filter
exists. If not, the unit is wide open from BC band to 1GHz .  Input AND
output filtering may be necessary at some locations. 

Now we just need a foolproof protection circuit.

73   Carl   KM1H
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