bobbyc
06-17-2003, 03:16 PM
Hi,
I'm trying to figure out what kind of attenuator I need, or whether I should just go with a less gain sector. We need to put up a new amped tower at 36dB output, and have 115' of lmr-600. The amp is a full power (500mw) YDI mast mounted amp. The radio is a hermes (15mw). The sector antenna is either going to be a 13dB or 16dB radiowaves sector.
From what I understand, the YDI amps are linear, meaning that you add the power from the radio card (minus cable/connector loss) to the transmit gain of the amp (14dB?)
So, my math is as follows:
LMR-600 loss: 5dB
(2) connector loss: 1dB
1 12" lucent radio pigtail: 1dB
total loss: 7dB
15dB -7dB=8dB to amp.
8dB plus the 14dB transmit gain from amp=22dB.
36-22=14
So, I think it would make sense to use the 13dB radiowaves sector, right?
Or I could use the 16dB sector, and then get an additional 2 dB of loss by making a 15' lmr400 jumper cable with 2 connectors... and putting it between the dc injector and the 12" radio pigtail.
What do ya think? I've been unable to get ahold of YDI to confirm that their amps amplify transmit gain at 14dB all the time, or whether it depends on the amount of signal coming into it.
Thanks,
Bob C
I'm trying to figure out what kind of attenuator I need, or whether I should just go with a less gain sector. We need to put up a new amped tower at 36dB output, and have 115' of lmr-600. The amp is a full power (500mw) YDI mast mounted amp. The radio is a hermes (15mw). The sector antenna is either going to be a 13dB or 16dB radiowaves sector.
From what I understand, the YDI amps are linear, meaning that you add the power from the radio card (minus cable/connector loss) to the transmit gain of the amp (14dB?)
So, my math is as follows:
LMR-600 loss: 5dB
(2) connector loss: 1dB
1 12" lucent radio pigtail: 1dB
total loss: 7dB
15dB -7dB=8dB to amp.
8dB plus the 14dB transmit gain from amp=22dB.
36-22=14
So, I think it would make sense to use the 13dB radiowaves sector, right?
Or I could use the 16dB sector, and then get an additional 2 dB of loss by making a 15' lmr400 jumper cable with 2 connectors... and putting it between the dc injector and the 12" radio pigtail.
What do ya think? I've been unable to get ahold of YDI to confirm that their amps amplify transmit gain at 14dB all the time, or whether it depends on the amount of signal coming into it.
Thanks,
Bob C