80M Preamp request

[David Douglass]

Hi All,

A little bit off topic I'm afraid, but I'm looking at utilising the RX
antenna socket on my K2/100..

I wonder if anyone can point me in the direction of a good 80m (or 80/160m)
preamp ?? I've seen the KD9SV web-site but wondered what else was available.
Something in kit form would be even better.

Many thanks

David, VK2NU


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[N2TK]

Still using an Ameco PLF-2. Haven't found anything better yet. Some preamps
don't have enough gain for ewes and pennants.  

The KD9SV 80/160M preamp looks interesting though. Would like to compare it
to the Ameco.

The Ameco nuvistor preamp worked well too.  Some Palomar preamps worked okay
and some didn't. Had to modify some.

N2TK, Tony  

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of David Douglass
Sent: Sunday, September 12, 2004 5:22 AM
To: [hidden email]
Subject: [Elecraft] 80M Preamp request

Hi All,

A little bit off topic I'm afraid, but I'm looking at utilising the RX
antenna socket on my K2/100..

I wonder if anyone can point me in the direction of a good 80m (or 80/160m)
preamp ?? I've seen the KD9SV web-site but wondered what else was available.
Something in kit form would be even better.

Many thanks

David, VK2NU


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[n6wg]

David
It depends on how much gain you feel you need.

There are a bunch of simple one-band preamps that are very easy to build.
Mine use a single 2N5109 transistor with a double-tuned input and
single-tuned output for 160m.  This is from Solid State Design for the Radio
Amateur, from ARRL.  Don't know if it is still available, and it's a bit
dated now.  But the info is still valid and works fine.

I also tried the emitter follower amp from the new Experimental Methods in
RF DESIGN by Wes Hayward, W7ZOI, Rick Campbell, KK7B, and Bob Larkin, W7PUA.
This is available through the ARRL bookstore.  I wonder if your Australian
ham organization might be reselling it?  Great book.  This little preamp
works very well also.

Anyway, my point is homebrewing a good preamp is pretty simple.  An Altoids
mint can makes a great container for the preamps.

Good luck and 73
Bob N6WG

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[G3VVT]

Preamps are handy to boost the performance of radios with poor front end  
sensitivity or for use with antennas with poor efficiency. However one has to be  
extremely careful that the addition of one does not actually degrade the  
performance of the radio.
 
The K2 with it's built in preamp switched on seems to on a par with the  best
radios at present available in the market on this score with an extremely  
sensitive RX front end. I would also have thought the ambient noise level  on 80
and 160m in a greater part of the world unless you intend moving to  
somewhere like Antactica would have largely negated the benefits of almost all  
preamps. Without being extremely careful with the gain and type of preamp you  are
adding could have an adverse effect on the performance of your K2.
 
The normal problem is how do sort out the wanted signals from the ever  
increasing layer of electronic smog that is emanating from modern  electrical and
electronic appliances, particularly on 80/160m?
 
Bob, G3VVT
K2 #4168
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[N2TK]

I hear you Bob. But I still need a preamp with my K2 on 160 and 80M when
using my receive antennas. I use pennants, ewes and flags, which are very
inefficient, but have decent directivity and help me over my transmit
antennas.

N2TK, Tony

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Sunday, September 12, 2004 12:48 PM
To: [hidden email]; [hidden email]
Subject: Re: [Elecraft] 80M Preamp request

Preamps are handy to boost the performance of radios with poor front end  
sensitivity or for use with antennas with poor efficiency. However one has
to be  
extremely careful that the addition of one does not actually degrade the  
performance of the radio.
 
The K2 with it's built in preamp switched on seems to on a par with the
best
radios at present available in the market on this score with an extremely  
sensitive RX front end. I would also have thought the ambient noise level
on 80
and 160m in a greater part of the world unless you intend moving to  
somewhere like Antactica would have largely negated the benefits of almost
all  
preamps. Without being extremely careful with the gain and type of preamp
you  are
adding could have an adverse effect on the performance of your K2.
 
The normal problem is how do sort out the wanted signals from the ever  
increasing layer of electronic smog that is emanating from modern
electrical and
electronic appliances, particularly on 80/160m?
 
Bob, G3VVT
K2 #4168
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