Michael,
At 01:59 PM 5/9/2007, Michael Wolthuis wrote:
Well, now that it is summer in MI I finally am installing a full new satellite setup, but the preamps have always confused me and I am looking for help to get it right once and for all.
Well spring is just starting here and the frost is not out of the ground but starting to see a little green. Leaves should be out in a couple weeks.
All the latest conversation shows I should get ARR or SSB preamps. My question is two-fold:
- Which models of each for UHF/VHF? (do I need the mast mount type
so I can put them outside, or can I put them inside a small weatherproof enclosure)?
Actually, your choice. Wx proof cost more. buying a sandwich box to use is cheaper.
More importantly: 2)I am confused by Bias T's, Power Injectors, vs just running 12volts of a power supply up to the small tripod and connecting it to the preamps.
I prefer running power separate from the coax. Cheaper, simpler, more fool-proof.
From what I can tell I need preamps that sense transmit and receive since I will be likely transmitting and receiving on such things as PCSAT on the same freq. So it needs to pick that up remotely on the coax? So, with that said I would imagine that is the RF Switched version of the ARR preamps. Then, I am just down to how do I power them? It seems to me that putting both the UHF and VHF preamp in a waterproof enclosure and then running 12volt power to them makes sense, but if I could power them via Coax that would be easier to do in the setup.
I believe you can buy an RF-sensing preamp with either power up the coax or with external power and T/R control line. I do not like using RF sensing T/R switching since in CW or SSB the relays are constantly switching back an forth. Relays will fail faster this way.
One can buy a plain preamp, run four-wire cable and use a coax relay to switch between Tx line and preamp. I prefer to run separate Tx and Rx coax lines to the shack, but you can add another coax relay between the preamp and your TS-2000 to use a common coax.
Probably cheaper to buy the preamp with internal switching. Beware that some models only rated to 25w power.
The radio is a TS-2000x if that helps.
I have a FT-847 so not enough familiar to advise on the TS-2000; both can power preamps thru the coax.
Whatever your choice, mount the preamp at the antenna for best low-noise performance. At 144 MHz you might get away with the preamp in the shack; at 432 MHz you will sacrifice several dB of noise factor; at 2400 MHz you will hear little to nothing with a preamp and converter in the shack.
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================