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| To Pre-amp or not to pre-amp http://www.interceptradio.com/bbs/viewtopic.php?f=1&t=5599 |
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| Author: | kc6pqe [ Sun Sep 04, 2011 4:01 pm ] |
| Post subject: | To Pre-amp or not to pre-amp |
This weak VHF reception even with my outdoor discone has got me down. I'm thinking of adding a pre-amp...Does the group have a favorite? Or maybe not to waste money chasing gooses? |
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| Author: | Rich [ Sun Sep 04, 2011 8:28 pm ] |
| Post subject: | Re: To Pre-amp or not to pre-amp |
Pre-amps are only useful if you have a deaf receiver or a lot of feedline/splitting loss. Keep in mind they amplify both the signal and noise. Not only that, they add additional noise (this is why the noise figure of the amp is important). If you decide to use one then make sure to get a mast-mount amp, as its better to amplify and "push" a good signal down from the antenna end of the feedline as compared to trying to amplify a degraded signal at the radio end of the feedline. If your issue is feedline loss then you are better off investing in better coax. If its signal level then buy some mast and get the antenna a little higher. 10 more feet at VHF can be a world of difference. |
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| Author: | kb7dqh [ Sun Sep 04, 2011 9:04 pm ] |
| Post subject: | Re: To Pre-amp or not to pre-amp |
I use a 5 dB GAIN omni, and 1-1/4" hardline... but the 6db per port loss on the splitter is a killer :shock: :mrgreen: Commercially built preamps (that are worth buying anyway) cost as much as a really goood antenna and coax. Discones have NO gain... Bandwidth??? Gobs... but only necessary if you listen to stuff from DC to daylight :mrgreen: Getting a good low-noise preamp with the same bandwidth as the discone gets into some $$$$! Having friends in the two-way radio biz helps here as surplus "stationmasters" and hardline may from time-to-time become available for the cost of "making it go away". If most of your listening is on a single band and largely in the same direction from where you are to where it's at, consider a Yagi antenna cut for the band of interest.... and aimed at the target transmitter :mrgreen: Stuff to think about... Eric KB7DQH |
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| Author: | nickcarr [ Thu Sep 08, 2011 1:37 pm ] |
| Post subject: | Re: To Pre-amp or not to pre-amp |
kb7dqh wrote: If most of your listening is on a single band and largely in the same direction from where you are to where it's at, consider a Yagi antenna cut for the band of interest.... and aimed at the target transmitter This is your best bet. DPD Productions has a 118-1000 Mhz scanner beam that you may like -- and it's a good price. http://www.dpdproductions.com/page_scan ... #scannerlp |
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| Author: | Mark [ Thu Sep 08, 2011 6:57 pm ] |
| Post subject: | Re: To Pre-amp or not to pre-amp |
Got it, love it. Jim put it together for me... |
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