[RX320] RX-320D and the H-800 active antenna

[Frank Gentges]

Hi,

Its really not all that hard to build when you see our follow up 
material. Some of the follow up material makes it easier. My first 
full-up model is still up on my roof working just fine. Go to the AMRAD 
web site where we have this follow up material on this antenna and read 
the FAQ and parts lists.. See

http://www.amrad.org/projects/lf/actant/index.htm

If you are not buried in the midst of high power AM stations you can 
probably go with the J310 JFET and use 12 volts for the power. That 
eliminates the heat sink and the very special transistor. In addition, 
try a longer whip like 6 or 7 feet. The longer whip will improve the HF 
performance but may introduce too much signal in the AM BC band and 
cause intermodulation. At least it is worth a try.

We selected a Signal power transformer and they have since decided not 
to sell single units to experimenters. Another company stepped forward 
that is willing to do this and we have them in the parts list.

The Amidon cores are available from Bytemark at

http://www.bytemark.com/

Those are really high permeability cores and you really do need them for 
the low frequency coverage. Don't forget to get an extra core and you 
can modify your RX320 for LF and VLF. See

http://www.amrad.org/projects/lf/rx/RX320LFMod.pdf

We tested 3 modified RX320s and found the modification actually improved 
performance slightly at the 10-30 MHz end of the range. We dis not 
observe reduced performance as some have mentioned.

With all these changes the antenna all goes together about the same as 
the original article. With the modified RX320 you will have so much 
signal in the LF/VLF range that you will need a 10 or 20 dB attenuator 
in front of the RX320 to keep the AGC from pumping badly when you are 
tuned down there.

Frank K0BRA

Joe Strain wrote:

>It's not easy to build. Some parts (a coil or a
>transformer iirc) are expensive and hard to get. I
>have been accumulating parts for the da*n thing for
>years. i gave up and got the best commercial
>equivalent and found it an amzing antenna beating all
>my previous stealth and slinky antennas for apartment
>use
>
>http://www.northcountryradio.com/Published/actant_0896/page1.htm
>
>cost is less than $50.00 has been in service here for
>some time and it's a excellent product
>
>Yodar
>
>--- Tim Heasman <tim at sideswiper.plus.com> wrote:
>
>  
>
>>Hi all,
>>
>>I just found this file whilst looking up active
>>antennas.  It looked quite interesting.
>>
>>http://www.arrl.org/tis/info/pdf/0109031.pdf
>>
>>Happy New Year
>>
>>Tim
>>gm4lmh
>>
>>[Non-text portions of this message have been
>>removed]
>>
>>
>>    
>>
>
>
>
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