Amrad antenna
 

N9NEO wrote:
I am going to order some of the crystalonics Jfets for the Amrad
antenna. My friend recently built the antenna and he gives it two
thumbs up. The fets are priced at I think $14.75 for 2001 prices. I
have asked Crystalonics to hold this price and I am awaiting word
back. I will order a few extra so if anyone is interest in building
the antenna ask me for fet now. The reason I bring this up to group
its that the antenna is very good, and Crystalonics doesn't really
like selling one part at a time. If you have no idea what I'm talking
about then email me and I will send you pdf if you want.

regards
N9NEO
Just say NEO!

The AmRad design is based on Dallas Lankford's work.
You really need to look at The Dallas Files at http://
www.kongsfjord.no/
and check out "Some of My Favorite Small Antennas for MW and LW"
and "Low Noise Active Antenna AC/DC Power Supplies".

Dallas's solution to heatsinking the FET is much more stable then the
rigged
AmRad. I have built several of both designs and Dallas's is the clear
winner
in my RF hell hole. Dallas used a pricier version of a stock heatsink,
if you
are interested I will dig out the current part number.

The stock AmRad is a good antenna, but I found Dallas's worked much
better.
Even his simple JFET/Bipolar gives the AmRad a good run for the money.
$3 worth of parts and no heat to speak of, and the ability to operate
from a
standard 12V supply.

The AmRad DC supply uses a special Signal ? transformer that was very
pricy.
And it is very hard to build an AmRad with any other transformer. I
suspect,
but since I traded my remaining stock AmRad away, has greater then
normal
isolation from the mains, ie lower interwinding leakage capacitance.

For me the ability to operate from a stock 12V (or 13.67V in my case)
is a deal
maker. I want to be able to operate during extended utility power
outages.

The dipole version is very robust with IMD and is damn near bullet
proof.

Another very good antenna is his "15' Relay Switched Antenna", and if
you
are lucky enough to live in a very quiet RF location, adding one of
his "Ultralinear
2N5109 and 2N3053 Amplifiers" . The Kiwa Version 2 preamp is very
similar
and works nearly as well. The advantage of Dallas' amp is you can
customize
the gain etc.

Terry

Amrad antenna
 

On Jun 13, 7:38 pm, wrote:
N9NEO wrote:
I am going to order some of the crystalonics Jfets for the Amrad
antenna. My friend recently built the antenna and he gives it two
thumbs up. The fets are priced at I think $14.75 for 2001 prices. I
have asked Crystalonics to hold this price and I am awaiting word
back. I will order a few extra so if anyone is interest in building
the antenna ask me for fet now. The reason I bring this up to group
its that the antenna is very good, and Crystalonics doesn't really
like selling one part at a time. If you have no idea what I'm talking
about then email me and I will send you pdf if you want.

regards
N9NEO
Just say NEO!

The AmRad design is based on Dallas Lankford's work.
You really need to look at The Dallas Files at http://www.kongsfjord.no/
and check out "Some of My Favorite Small Antennas for MW and LW"
and "Low Noise Active Antenna AC/DC Power Supplies".

Dallas's solution to heatsinking the FET is much more stable then the
rigged
AmRad. I have built several of both designs and Dallas's is the clear
winner
in my RF hell hole. Dallas used a pricier version of a stock heatsink,
if you
are interested I will dig out the current part number.

The stock AmRad is a good antenna, but I found Dallas's worked much
better.
Even his simple JFET/Bipolar gives the AmRad a good run for the money.
$3 worth of parts and no heat to speak of, and the ability to operate
from a
standard 12V supply.

The AmRad DC supply uses a special Signal ? transformer that was very
pricy.
And it is very hard to build an AmRad with any other transformer. I
suspect,
but since I traded my remaining stock AmRad away, has greater then
normal
isolation from the mains, ie lower interwinding leakage capacitance.

For me the ability to operate from a stock 12V (or 13.67V in my case)
is a deal
maker. I want to be able to operate during extended utility power
outages.

The dipole version is very robust with IMD and is damn near bullet
proof.

Another very good antenna is his "15' Relay Switched Antenna", and if
you
are lucky enough to live in a very quiet RF location, adding one of
his "Ultralinear
2N5109 and 2N3053 Amplifiers" . The Kiwa Version 2 preamp is very
similar
and works nearly as well. The advantage of Dallas' amp is you can
customize
the gain etc.

Terry

Ok, thanks for the input Terry. Like I said my friend built one and
he likes it. I'[ll bet he didn't pay anything for the parts though.
That's one of the pleasures of working for a High Performance radio
manufacturer. I'll go price a transformer and see where that takes me
before I take another step. I've got the elliptic filter/precision
detector project underway and hope to finally send the board to fab at
the end of the month. (All boards spoken for.) LT has a new multi-pole
filter that you can set the passband frequency with a pot. I guess it
has a vco onboard. Gathering parts for my next project- the Amrad.
Thanks again for the input as always it's valued.

73
Bob