PreAmps

[KingCobra_CDX882]

Hey All...

A good thing about this forum is ability to get others views on things...
i will also post this in ametuer and VHF-UHF radios section for is related to there as well..

What are the best Pre Amps to use for say..
2 meters
1.25 meters
70CM band
23CM band

Not that it matters too much..
but using with
Icom 706 MKIIG
IC-7000
IC-910H (getting within 3 to 6 weeks)

with dual polarity 9 element beam for 2 meters on 17.5 ft boom
with 12 element horizontal beam for 1.25 meters on 12 ft boom
with 16 element horizontal beam for 70 cm band 12.5 ft boom
nothing yet for the 23 cm band but would be beams ofcourse

Later

 

[W5LZ]

KingCobra_CDX882,
I seriously doubt if a preamplifier would be needed with any of those radios, or any radio made in the last several years.
- 'Doc

 

[KingCobra_CDX882]

Doc..

That is where you are wrong
i talk further then i can hear..

so if i can not hear them..
how do i know to call them back..

i surly would agree...
if were talking about local contacts..

i am instead refering to catching more DX

 

[Beetle]

With all the gain in your antennas, any preamp is just going to raise your noise floor. As I said in another topic, with all the antenna gain, why would you want a preamp?

 

[Switch Kit]

20 years around this hobby and I have yet to understand the pre-amps on amplifiers ? , I will agree that it seems that I too have been able to talk farther then I sometimes can hear or at least hear the in coming signal loud and clear enough on many occasions. Lets say I was on the AM side of a basic CB radio ....I would hit the supposedly 20db gain pre-amp and all it would really do (or seem) is bring in all the static that was around me better and tend to make it even harder to hear my receiving target )-: .......I will say this much though ,the pre-amps over the years have seemed to work much better on SSB for reasons unknown to me ? .....I've basically been more so a AM'er over the years to it's counter part lower and upper side bands.....but I will say this much though ,SSB has always seemed like a much cleaner operation one way or the other.

 

[KingCobra_CDX882]

Ahh...

see i was asking about PreAmps..

i know preamps on a amp is already too late..

i was hoping someone would mention PreAmps mounted directly to the antenna..then coax goes from preamp and down to radio

Later

 

[351_bear]

pre amp

rm italy makes a decent pre amp but i think its out of your frequencies you were looking for its made for hf freqs

 

[Captain Kilowatt]

KingCobra: See my link in the amateur radio forum where you posted this EXACT question also. :roll:

I must say that first there are preamps on CB amps and then there are real preamps.The preamps in CB amps are,for the lack of a better word,garbage.They will make the S meter read higher but will also amplify the noise level.Some of the transistors used in those "preamps" actually have a higher noise floor than the radio they are connected to which means that given a quiet freq. and a very weak signal you may be able to hear better without the preamp despite the higher signal reading on the meter.A "real" preamp has a low noise transistor usually a GAsFET type.Some have bandpass filters built in to allow for a rejection of out of band signals that could swamp the rx.One common misconception is the use of a preamp to hear a station better over the noise or QRM.THAT DOES NOT WORK! :roll: A preamp is best used on a quiet freq. to bring a very weak signal up over the noise floor of the radio.Weak signal VHF/UHF is where they REALLY shine.I have a GAsFET preamp in my Mirage 2m amp and even though it is in the shack and not at the antenna it works wonders.The fact I use Andrews 1/2 inch heliax means that I am losing almost nothing before the preamp anyway. It's almost like having the preamp at the antenna anyway.KingCobra if you use that type of cable or better,and I believe you do,don't worry about where to put the preamp.Lightning can and will take them out fairly easily and one in the shack at the end of a GOOD cable can be protected by simply unhooking the cable,something you cannot do if it is mounted at the antenna. Here is something you can try.Point your antenna at the sun which is a huge emitter of wideband RF.If the noise increases then you have enough gain already.