Re: "active antenna preamplifiers" in ham radio May 1986
|
With my short E-field probes, I've never tried paralleling JFETS.? I need to try that someday with the J-310's.? I usually follow those with a simple emitter follower to establish 50-ohms for the coax.?
Dave - W?LEV
On Fri, Mar 14, 2025 at 8:19?PM Everett N4CY via <everettsharp= [email protected]> wrote:
If you want unbelievable nulls, that happen in about 5 seconds, buy a Perseus 22. You can also manually steer the signals with it to. If you are using verticals they need to be spaced about 200' apart. If you are using loops they need to be at least 55' apart.
?
I just finished building a Modified version of the AMRAD eProbe antenna which uses 4 2SK932 JFETs in parallel. I draws 50mA at 13.8VDC and works great. I am not able to hear WWBV much better than my loop and so far in testing it works well up to 30MHz. It is a lot more quiet then the loop on the VLF and LF frequencies.
?
Everett N4CY
In a message dated 3/14/2025 2:41:02 PM Central Daylight Time, martin_ehrenfried= [email protected] writes:
?
Although the basic concepts and principles are sound, things have moved on over the 40+ years that have passed since the articles were published.
?
Regards,
?
Martin
?
On Fri, Mar 14, 2025 at 07:30 PM, crabtreejr wrote:
Ralph Burhans wrote an excellent series of antenna articles in Radio Electronics in 1983:
|
