Will this compromised antenna work?

[Brian - K3ES]

Thank you Andrew! I had expected a stronger directional effect from the 2m whip, but your analysis lines up well with the QSO Map. The AX1 is not the best, but it is not a dummy load either. I guess even 5 watts of RF energy has to go somewhere.

Best 73 de Brian - K3ES

[Andrew (grayhat)]

Ok, added the car, the wireframe model is really raw, but it should give you a better idea and... yes, the car has an influence on the pattern, just look at the attached pic which shows the radiation pattern on the 20m band

download/file.php?id=179

brian02.jpg (72.11 KiB) Viewed 3395 times

HTH !

[KL7MJ]

I was uncertain, but the AX1 continues to amaze me. A compromised antenna is, first and foremost an antenna.

Brian,
Location is also important. I have a homebrew DS1-type antenna (6 foot whip and a coil at the base). I can make contacts here in the lower 48, but I couldn't even hear anything on it from Denali Park last month.

73,
Mike, KL7MJ

[Andrew (grayhat)]

Location is also important. I have a homebrew DS1-type antenna (6 foot whip and a coil at the base). I can make contacts here in the lower 48, but I couldn't even hear anything on it from Denali Park last month.

Mike, try this; open this mapping site

https://caltopo.com/map.html

center the map on your location, then right click the map and select "simulated view", that will allow you to see if there are "obstacles" toward a given direction

[Andrew (grayhat)]

Brian, if you're in the mood of experimenting a bit, here's an idea for you; we know that the AX-1 covers the 20, 17 and 15 meters bands, now... what about adding it 30/40 meters (or even more bands) coverage ?

Here's the idea

We start by building or buying a 9:1 (just an idea, other ratios may be considered) UnUn and connecting it between the AX-1 and the coax feedline

Next we extend the antenna but we leave the top "thinner" section recracted and then we find a way to clamp to the top of the antenna a piece of wire which we'll then layout as an "inverted L", hanging it to (say) a tree or whatever support, such a wire may run horizontally or sloping up or down, as the conditions allow (an up slope would be nice)

Now we adjust the wire length to find a decent match on the "extra" bands we want to cover, at this point we have the antenna ready and can pack everything and bring the stuff to whatever spot we want to use for our operations, once there, we setup the antenna, add the 9:1 and deploy the additional wire

The idea is that the antenna could then be used "as is" for the "standard" bands it covers and with the additional 9:1 and extension wire to allow covering additional bands, such a setup may be useful in case the higher frequencies are "closed" or, for example, willing to play NVIS on (say) 40m when we are in a valley surrounded by mountains

What do you think ?

[edit]

Judging from the result I obtained by checking a (very raw!) model, a wire of about 40ft and a 9:1, plus a 17ft counterpoise, should allow to "tune" all bands from 10 to 40 meters (and possibly 60m too) with NVIS radiation on the lower frequencies, by the way the additional wire length will need to be adjusted on the "real" antenna measuring the SWR on the various bands to find the "sweet spot"; an alternative may be using a 49:1 UnUn and cutting the wire to obtain an "inverted L" EFHW for the 40m band (if other "non resonant" frequencies aren't of interest)

[Brian - K3ES]

Thanks Andrew,

When I bought the AX1, I also bought an AE1 extension coil. When added to the coil for the AX1 and used with the longer 33 ft counterpoise wire, the AE1 permits tuning on the 30 and 40m bands. I have used the extension a few times. It will tune and make contacts, but requires more area.

Either configuration requires a wide range antenna tuner to get on the air, because of very narrow band width.

Best 73 de Brian - K3ES