Base New Imax wont tune 11m....this sucks

[Big Kahuna]

Yes a 1.3-1.4 still falls within the specs they’ve advertised. SWR in the CB band will be slightly higher now than it was previously due to the length change but the antenna is still completely usable in the CB band.

I think it’s important to point out that while this has long been a popular antenna with the CB crowd it’s marketed as a CB/Ham antenna and even before the length changed it was more resonant above the CB band. As far as I’m aware this antenna never was centered in the CB band, it’s always been a broad banded antenna.

I’ll post up more after some additional testing.

 

[lonestarbandit]

I am unable to get mine below 1.4 to 1.
The Solarcon Imax2000 I had 15 years ago could do a 1.2 so there may be something to this "they shortened the max2000" (no I).

 

[lonestarbandit]

NightThumper may have the cure and I am trying it myself.

FS: Texas Star DX500V

 

[Big Kahuna]

I am unable to get mine below 1.4 to 1.
The Solarcon Imax2000 I had 15 years ago could do a 1.2 so there may be something to this "they shortened the max2000" (no I).

Yes you will likely not be able to get a 1.2 SWR anymore as compared to the old one. In testing it looks like lowest SWR is around 1.38-1.4 across the CB band which would make sense with it being slightly shorter than the old version. The nice thing is it's usable up into 10 meters without a tuner as it's lowest SWR/resonant frequency is around 28 MHz.

I've found for the antenna to be optimally centered in the CB band with a 1.05 SWR or below you'd actually need to add 12" to it right now - which is why I think you can assume even when it used to be 4" longer it was not centered in the CB band and that's why this antenna has been advertised as a CB/Ham antenna and many ham radio users liked it. That's also why we hear stories of people putting a 102" whip in the top of it and saying that they see a better SWR.

So the antenna is still usable at 1.4 for CB - 4 watts input would see 3.892W out and 0.108W reflected but many people think it's a CB band centered antenna and want to see that low SWR and I think that's where a lot of the issue is coming up, especially since the SWR previously was lower. Also many people try to install these antennas in a way that even if the SWR was a 1.1 in theory, they might see a 1.5 or higher due to reflect. You give them a 1.4 SWR antenna and they put it next to a house and now they're seeing a 2.0 SWR. (Same type of thing when someone mounts a 3' firestick behind the cab of their truck and wonders why they have a high SWR).

We get hung up on low SWR but this antenna with a 1.4 SWR would still likely outperform a A99 with a 1.2 SWR in the same install

So going forward users should expect that this antenna will give them a 1.3-1.4 SWR.

 

[NightThumper]

With a 10 inch riser on the Max-2000 here are my results. Antenna is at 36 feet. Read the display on the right-hand side. The first display is showing input SWR into my AL-82 amplifier…500 plus watts output

 

[lonestarbandit]

I am against the house however on 20 foot of pole so decently above it. I have a new base box coming soon and I don't like to be that close to 1.5 - 1. If NightThumpers trick works for me I'll be a happy man. I realise that 1.5 is quite usable I just dont like seeing it all day long on the meter and some boxes may be less tolerant than a radio regarding SWR depending on tuning.

 

[Big Kahuna]

I am against the house however on 20 foot of pole so decently above it. I have a new base box coming soon and I don't like to be that close to 1.5 - 1. If NightThumpers trick works for me I'll be a happy man. I realise that 1.5 is quite usable I just dont like seeing it all day long on the meter and some boxes may be less tolerant than a radio regarding SWR depending on tuning.

In my trial I just stuck some wire into the end so it was touching and then taped it in place for the quick test. I then did a Nano VNA sweep and saw a 1.042 SWR at 27.3.

I'm going to try a 102" SS whip next and see what results I see. If CB users are going to be more inclined to buy the antenna with a lower SWR the manufacturer might consider adding or selling an optional 14"-16" length section that could be added at the end. They could make it adjustable for SWR just like a wilson/skipshooter tip.

For 10 meters leave the tip off, for 11 meters, add the tip.

 

[Big Kahuna]

With a 10 inch riser on the Max-2000 here are my results. Antenna is at 36 feet. Read the display on the right-hand side. The first display is showing input SWR into my AL-82 amplifier…500 plus watts output

Can you post a picture of your riser?

 

[NightThumper]

This is what I purchased off Amazon. Need to use a coupling nut as well. Can’t see it very well but here’s a couple of pictures of it up in the air.

Pro Trucker Replacement 10" Stainless Steel Shaft for Wilson T2000/T5000 Series

The Hillman Group 4375 3/8-24 Coupling Nut Fine Thread (5-Pack)

 

[Big Kahuna]

This is what I purchased off Amazon. Need to use a coupling nut as well. Can’t see it very well but here’s a couple of pictures of it up in the air.

Pro Trucker Replacement 10" Stainless Steel Shaft for Wilson T2000/T5000 Series

The Hillman Group 4375 3/8-24 Coupling Nut Fine Thread (5-Pack)

Very cool!

 

[NightThumper]

After I got it up we had 40-50 mph winds come through. No problems whatsoever.

 

[NightThumper]

Okay so here’s the Max-2000 on 28.100

 

[Big Kahuna]

I tested the antenna with a 102" whip as the top section today

It added 9" to the length (over the stock top section) but I actually saw worse SWR in the CB band and the resonant frequency was still up at 28.000MHz.

Ch 1 - 1.78
Ch 40 - 1.46

The lowest SWR with the factory top section was 1.385 at CH 40 so with this current version adding a 102" whip did not do anything of value. This is could be due to the diameter of the 102" being much larger than the internal copper wire.

It's interesting that adding the 102" whip making the antenna 9" longer did worse than NightThumper's experiment of adding 10" with the spacer between the top and middle sections or my experiment of adding 12" of copper wire to the factory top section.

 

[lonestarbandit]

That is interesting. I had read somewhere they said DONT do the 102 whip as it doesnt work but they didn't say why. This will be interesting. When my parts get here I will see if thumpers results can be repeated on a disimilar system (Other than Max2000)

 

[lonestarbandit]

Gentlemen the parts and the results are in.
NightThumpers fix took a best of 1.45 and a worst of 1.6 on the Max2000 to now:

Channel 1 = 1.10
Channel 40 = 1.13

Rings are 3/4 way down.

I could probably adjust more but pain of death from the spouse helping if I continued.
I am beyond happy for those numbers and feel confident to hook my new box up when it arrives next week.