k9rzz
Member
This week I bought a broadband preamp that I plan on using with my big satellite dish, but since it was raining all day, I did some experiments indoors and I thought I'd pass along what I learned. Maybe it will help some of you guys who are trying to hear some of the distant 800 mhz stuff in your area.
This is the amp I got (and the guy I got it from):
http://cgi.ebay.com/25dB-UHF-VHF-FM...59977387QQihZ020QQcategoryZ4693QQcmdZViewItem
Hey! I paid $9.99 and now it's on sale for $7.99 !
As you see, you just plug it into the wall, so that's easy enough. The manual says that it will give you 20db of gain at 970mhz so I gave it a go on 956mhz which what I think I'm hearing is Muzak (2 channels). With a UHF ground plane on the first floor I can _just_ hear them, S0, just above the noise with the antenna peaked at the best spot. What I did here is haul my radio up the the attic, hooked up the preamp, and put in a 1/4 wave piece of wire right into the input (about 3" long).
Wow ... S5 !
That's the best I've ever heard them.
Next I hooked up 70 feet of RG6 in line, which is how much I would need to run down to my shack in the basement ... S3. Hmmmm. Just for kicks, I hooked up my 2m 5/8 wave vertical, mag mounted to a sheet of aluminum ... S0. Yuck!
Next I took the setup to the second floor. No RG6. S3 again. So I lost 2 S units going from the attic to the second floor. Next I went to the first floor, same setup, no RG6, S3 but with the antenna in very specific, hard to hold it there, places. Otherwise about S2. Still much better than I can do with no preamp and a decent UHF vertical. So a $10 dollar investment improved my signal from noisy to pretty good. Putting forth the effort of mounting the antenna in the attic, and running 70 ft of RG6 would give me 1 more S unit, to S3. If I ran 70 ft to the attic without a preamp .... I might gain 3 S units from the height, but I'd loose 2 from the coax. Is is worth it? I dunno.
BTW, this preamp does have a FM notch filter and it works. It takes it down about 20 db. I hooked it up to my FM beam on the roof and the preamp just gets overloaded here in the city. For my FM DXing, a preamp is not useful at all. At 154 mhz, the back ground noise jumps up to S5 from zero and I really don't hear anything more than without. I suppose if I was really out in the boonies it would help, but in the city, it doesn't. Now if I can find some cheap bandpass filters, like for aircraft or 154 mhz, then I'll try those in line with the preamp. That may work well.
This week I will be searching for satellite sigs with my 7 ft dish and this preamp ... so stay tuned ... it will be fun!
This is the amp I got (and the guy I got it from):
http://cgi.ebay.com/25dB-UHF-VHF-FM...59977387QQihZ020QQcategoryZ4693QQcmdZViewItem
Hey! I paid $9.99 and now it's on sale for $7.99 !
As you see, you just plug it into the wall, so that's easy enough. The manual says that it will give you 20db of gain at 970mhz so I gave it a go on 956mhz which what I think I'm hearing is Muzak (2 channels). With a UHF ground plane on the first floor I can _just_ hear them, S0, just above the noise with the antenna peaked at the best spot. What I did here is haul my radio up the the attic, hooked up the preamp, and put in a 1/4 wave piece of wire right into the input (about 3" long).
Wow ... S5 !
That's the best I've ever heard them.
Next I hooked up 70 feet of RG6 in line, which is how much I would need to run down to my shack in the basement ... S3. Hmmmm. Just for kicks, I hooked up my 2m 5/8 wave vertical, mag mounted to a sheet of aluminum ... S0. Yuck!
Next I took the setup to the second floor. No RG6. S3 again. So I lost 2 S units going from the attic to the second floor. Next I went to the first floor, same setup, no RG6, S3 but with the antenna in very specific, hard to hold it there, places. Otherwise about S2. Still much better than I can do with no preamp and a decent UHF vertical. So a $10 dollar investment improved my signal from noisy to pretty good. Putting forth the effort of mounting the antenna in the attic, and running 70 ft of RG6 would give me 1 more S unit, to S3. If I ran 70 ft to the attic without a preamp .... I might gain 3 S units from the height, but I'd loose 2 from the coax. Is is worth it? I dunno.
BTW, this preamp does have a FM notch filter and it works. It takes it down about 20 db. I hooked it up to my FM beam on the roof and the preamp just gets overloaded here in the city. For my FM DXing, a preamp is not useful at all. At 154 mhz, the back ground noise jumps up to S5 from zero and I really don't hear anything more than without. I suppose if I was really out in the boonies it would help, but in the city, it doesn't. Now if I can find some cheap bandpass filters, like for aircraft or 154 mhz, then I'll try those in line with the preamp. That may work well.
This week I will be searching for satellite sigs with my 7 ft dish and this preamp ... so stay tuned ... it will be fun!
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