So I have a 38 foot mast, standard military camo aluminum supports. It sits in a folding base I built. I have it guyed east / west with parachord. The wires for the inverted V dipoles also act as guy wires north / south. Am I correct is thinking the radiation patter is east / west? I have 3 antennas attached to it. The 2m is a diamond F22A 7/8 with ground radials. It sits at the top and the top of the antenna is at 48.5 feet. 1 f00tt below the radials I have a 40 m inverted V dipole I cut myself attached to an MFJ 1:1 current balun. SWR is less than 1.1:1 across the 40 meter band.

3 feet below that I have a Radiowaves 20 meter inverted V dipole. Before I put up the  40m dipole, the SWR on the 20m dipole was less than 1.1:1 across the 20m band. After I put up the 40m diploe, the SWR jumped to 2:1 across the band. The SWR from the low band to the high band climbs slightly. The ends are about the same distance from the 40m wire.

I have worked Morroco and France ( today ) on 20 meters, but would like to optimize the 20 m antenna.

Should I cut it to try to reduce the SWR. I do not yet have an antenna analyser, but the IC-7300 I have plots the SWR across the band. I am thinking of ordering a rigexpert AA-600 antenna analyser. Should I jst wait until I have that?

How far away from the 40 meter wire do I have to get to have the SWR on the 20 m antenna get back to less than1.1:1?

Any adice is appreciated.

As far away as you can get it.

They're going to interact with each other -- meaning you need to tune both -- if they're in each other's near fields, which on
the same mast they most certainly are. Every antenna installation is unique, so your main option here unfortunately is a
lot of experimentation, unless you want to create another support well far away (preferably a wavelength or more.)

Folks that make fan dipoles are pretty aware of how this works, and that might not be a half-bad option to try.

I can not get any further away on the same mast

I was thinking of taking down the 20 meter, and saving it for mobile use ( stationary mobile use ) and cutting some 20m wire and making a fan dipole.I will probably try that tomorrow.

I really don't want to create another support 20 meters away.

I did the same thing once, but with 10, 15 and 20 in a fan dipole. You can leave each where they are, you just have to adjust the length on each one a little at a time to get the best swr for each of them. Start with the 40, since its the longer one. Then adjust the 20. Then check the 40 again, and so on.

This. You're not going to be able to get them far enough apart to not interact, so save the feedline.

On the 20m "fan" elements, start out at least 8, better 12 inches longer on each side vs the regular published dipole lengths. The 40m might change a little but probably not much. Higher frequency bands in a fan typically need to be much longer than a single dipole length.

I've seen the IC7300 swr graphing and it's ponderous at best and of course only works in the amateur bands.

A good analyzer makes things sooooooo much easier. Cut the 20m elements long, analyze and find the SWR minimum, length*resonant freq/desired freq = corrected length.

As far as the pattern/directionality, an inverted V has vertically polarized radiation off the ends which helps fill in the nulls.

A 40m dipole with a 1.1:1 across the band sounds like a dummy load.

Guess I should read the OP more carefully. Yes the SWRs seem artificially low, especially on 40 where a dipole would have some variation in SWR across the band... maybe 1.4 or 1.5 at the edges at least. So I wonder what you are using for feedline, and if you have anything else that might be causing loss.

As said before, the 1.1:1 SWR across the 40 meter band indicates something is wrong. If cut to the center of the band, SWR should rise to something around 2:1 or more at the band edges.

The dipoles will interact, and both will require adjustment. Trim the 40 Meter one first, then the 20 Meter element. You may have to go back and forth a couple of times to get both down.

For your purposes, the radio's internal SWR meter will suffice. It's big limitation is not being able to measure outside the ham bands.

OTOH, the antenna is obviously working!

FWIW, I run a trap/fan dipole with the elements held apart by 1' lengths of 1/2" PVC pipe.

With an analyzer you will be able to tell if the 40M antenna is now too short or too long. Don't cut anything until this is known. Do the 40M antenna first and also check the 20M antenna at that point to see how it was affected.
73,
Rob

Well I am new at this ( 4 days with HF ) and the SWR 1:1 across the 40m  band was with the tuner on. lol. .

I took down the 20m and put up a fan for 40/20 and left a spot for 80, but havent cut the wire yet. 40m is tuned to 1:2 at 7.147 to 1.4 at 7.267 so I need to fold over some more of the end but not much. 20m s 2:1. So I will work on that next.

I got lazy and used the wire from the store bought 20m dipole so it is probably too short. I will replace that with my wire tomorrow and put that 20m wire back on store bought 20m dipole and save that for portable use.

Split-bolt connectors are worth their weight in gold it you're going to be doing a lot of adjusting. Most electrical supply houses carry them. Once the antenna is trimmed to where you're satisfied, wrap and solder the connections and save the connectors for your next project.

I have seen those in the local home depot. How are they used? Fold or twist the end of the wire and attach that to keep it secure?

Split-bolts come in different sizes. Get the size that fits your application. It's usually not recommended to fold wires inside the bolts but it can be done as a temporary measure. Home Depot also sells contact splitter blocks that can be used for the same purpose. I would not recommend to use split-bolts or contact blocks for permanent outdoor installations. Use some No-Ox grease and seal them from moisture, if you decide to use them anyway. Split-bolts must be tight to ensure proper connection.
Also,try to solder all outdoor connections, if it's practically possible. Try to avoid crimp-on connections for outdoor applications. I have seen multiple failures of crimp-on connections, especially on coax cables.