138DP vs 148DP
02-11-2003, 09:05 PM
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138DP vs 148DP
Looking to buy a couple of receivers for my 9c. Been using 127DF
receivers but would like to move "up" to PCM. Don't want to pay 160.00 for 149DP and I don't use all 9 channels anyway. I have been looking at the 138DP and the 148DP. Went to the futaba site and all but nowhere does it tell me what the differance is between these two receivers besides the price and physical size. Both appear to be 8 channel 1024 PCM receivers. Can someone enlighten me ?
Thanks
Roger
receivers but would like to move "up" to PCM. Don't want to pay 160.00 for 149DP and I don't use all 9 channels anyway. I have been looking at the 138DP and the 148DP. Went to the futaba site and all but nowhere does it tell me what the differance is between these two receivers besides the price and physical size. Both appear to be 8 channel 1024 PCM receivers. Can someone enlighten me ?
Thanks
Roger
02-11-2003, 11:47 PM
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138DP vs 148DP
Roger,
Explanation is for PPM receivers.
Both the 138 and 148 use the same circuit components after the RF input side of the receiver.
The 138 uses AGC sensed from the output of a Dual Gate MosFET 1st mixer, before it enters its main FM demodulator IC. This forms an external feedback circuit which maintains a steady signal level into the FM IC. Two transistors, one FET and one Dual Gate MosFET are the only active components in the front end.
The 148 uses the most complicated receiver front end of any manufacturer. It does the same job as above but with more components ie. Three transistors, three FET's and one Dual Gate MosFET as mixer. Again AGC is sensed before the signal enters the FM IC.
Let me know if you need more info'.
Like an insurance policy, the more you pay the greater the benefits.
Explanation is for PPM receivers.
Both the 138 and 148 use the same circuit components after the RF input side of the receiver.
The 138 uses AGC sensed from the output of a Dual Gate MosFET 1st mixer, before it enters its main FM demodulator IC. This forms an external feedback circuit which maintains a steady signal level into the FM IC. Two transistors, one FET and one Dual Gate MosFET are the only active components in the front end.
The 148 uses the most complicated receiver front end of any manufacturer. It does the same job as above but with more components ie. Three transistors, three FET's and one Dual Gate MosFET as mixer. Again AGC is sensed before the signal enters the FM IC.
Let me know if you need more info'.
Like an insurance policy, the more you pay the greater the benefits.
02-11-2003, 11:57 PM
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138DP vs 148DP
Roger,
For PCM receivers all of the above stands.
Both the 138 and 148 use the same Comparator IC and Processor chip for PCM output.
The only difference is the 148 uses two voltage regulators as opposed to one voltage regulator used by the 138.
For PCM receivers all of the above stands.
Both the 138 and 148 use the same Comparator IC and Processor chip for PCM output.
The only difference is the 148 uses two voltage regulators as opposed to one voltage regulator used by the 138.
