The AM Forum

I am setting up my first dedicated AM station for 75m and 40m.  I have a Viking 500 almost ready to go live and also buying a SuperSenior 80-40.  For SSB/CW I have a 2kW-ICAS EFHW that has worked very well but would not handle the Viking or SuperSenior.  I do have several 80-90' Black Locust trees near the shack but little room for ground radials.  Any advice would be very much appreciated.

Jerry NY2Kw

You already have ready made masts there, how about Inverted V's.

73's
Mickey KF4NU

An 80/40 fan dipole is what I use. Works perfect. I run a pair of 813s modded by a pair of 813s. Handles the juice just fine. Cut for the AM portion of both bands.

Thinking outside the box, a steerable tuned loop would magnify your ERP a bit...

73DG

I’m similar to John on this with an 80-40-20 fan dipole, hung very slightly inverted V style. The ends are 5’ down. I run the RCA into it with no issues.  That’s a kilowatt plus of carrier converted broadcast transmitter, so, yeah, wire antennas can handle the gas…

Ed

Some loop antenna information - https://kk5jy.net/magloop/

Full wave loop has worked well for me.  I run open wire into a Kilowatt Matchbox.  Held up by trees.

For my AM set-up I use an MFJ 80/40 meter dipole. Total length is under 90 feet as a flat dipole. SWR is great for all of 40. Under 2:1 on 80 for about 100 khz, under 3:1 for over 150 khz.

If MFJ still has any in stock the 800 watt version runs under $100.

Inexpensive and easy to set up.

Rich

This may work for K1JOS with all those tall trees.

80-10 loop.

I recently downloaded the latest (free) version of EZNEC (https://eznec.com/) & have been modeling an 80-10 horizontal loop for my NW Michigan cabin. I have 5 acres & lots of tall trees but no tower. I’ll be heading up soon for an extended stay & wanted a simple multi band wire antenna.

After many tries I finally arrived on an isosceles triangular shaped loop that should cover 80-10 with 50 ohm coax feed (with 4:1 balun @ feed point).   

The loop is 274’ in circumference. The base is 80’ & each side is 92’.  Height is 40’.
The SWR 200 is below 2:1 on 40, 20, 15, 12 & 10. It is below 3:1 from 3.6 – 3.8 and 3.3:1 @ 18.1 MHZ.
A 4:1 balun @ the feedpoint should make modern rigs with internal atu’s happy.

Hopefully it actually works as well as EZNEC predicts. I’ll find out next week.

Does the circle on the plot denote the feedpoint?

Yes.

I tried to attach the EZNEC file but that file type is prohibited.

125' flat top, balanced feedline w/ link coupled transmatch.