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Old 04-22-2017, 3:40 PM
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Default ApexRadio RX antenna

Had an opportunity this afternoon to check out the ApexRadio 303WA-2 vertical antenna. The antenna itself stands about 6' tall. It was mounted about 8' above ground and fed with 60' of RG-58.

Here are the results of a side by side comparison of this antenna with a plain 50' wire antenna. Testing was done mid-afternoon when signals are generally steadiest. RX was Satellit 750.

On shortwave, the Apex antenna gave far better performance than did the 50' wire. Time signal stations WWV on 10000 and 15000 and CHU on 7850 were many S-units higher on the Apex vertical.

Dropping down to the AM broadcast band, the results were similar. WLW 700 and WGN 720 both had nice signals on the Apex. WTVN 610 Columbus 5kw and WEOL Elyria 1kw both in OH both had S9+ signals on the Apex. All signals were only S1 on the wire.

Heading down to the LW NDB band my expectations were not that great. However, what a surprise awaited me. Performance on the 50' wire was dismal as expected, but logged 35 NDBs, many out as far as 300 miles, on the Apex...wow! This was mid-afternoon, not exactly the best time for NDB hunting.

This unobtrusive relatively small ApexRadio 303WA-2 antenna is a real winner. This would be an especially useful antenna for someone who lives in an antenna restricted space.

Last edited by WA8ZTZ; 04-22-2017 at 3:53 PM..
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Old 04-22-2017, 4:29 PM
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The antenna can be seen here, via Universal Radio...

Apex Radio 303WA-2 Shortwave antenna. ApexRadio

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Old 04-23-2017, 10:09 AM
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If you don't mind my asking, please describe the 50' wire you're comparing this antenna to. I'm puzzled as to how a passive antenna so short can be so much better than a 50' piece of wire.

My best guess is that you're somehow reaping the benefit from 60' of coax on it's way up to the antenna. But I'd really like to know more.
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Old 04-23-2017, 12:46 PM
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Quote:
Originally Posted by ab3a View Post
I'm puzzled as to how a passive antenna so short can be so much better than a 50' piece of wire.
You aren't the only one... puzzles me too. Without dissecting the base section of the antenna to see what is going on inside limits me to guessing perhaps a ferrite arrangement of some sort. Would have to be very wide banded though, look at the antenna specs... 30 kHz to 30 mHz.

Anyway, the 50' wire antenna was just that. Nothing fancy, just an insulated 16awg 50' length of wire temporarily hung up about 8' and connected to the antenna input(s) of the Satellit 750 without any coax, matching device or tuner.

Your guess about the 60' coax got me thinking as to whether it was acting as an antenna so tried the ApexRadio antenna with just a 6' length of coax into my Tecsun PL600 on various SW sigs and then compared it to the 60' length of coax into the same radio, same sigs. If anything, there was a slight loss with the 60' coax.
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Old 04-28-2017, 6:42 AM
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ab3a,

Been giving this some more thought and figure that the ApexRadio antenna must have a very efficient impedance matching transformer device in order to couple the signal very effectively into the receiver. If so, it's amazing they got it so broad banded. This is just a guess on my part as there is no antenna analyzer in my shack and those of my friends only cover 160 meters at the lowest.
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Old 05-09-2018, 3:03 PM
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I just bought a used DXE NCC-1 phasing unit with plans to use it with a pair of DXE ARA3-1P active antennas when I finally have my house built. I've been fortunate to find a few acres surrounded by tomato fields in a sparsely populated rural area with absolutely no RFI. I think before I spend $300 each for the active antennas I'll try two Apex passive verticals for less than half the price of one active and see how it goes.
Man, I would love to hear from someone who has both the Apex and DXE for a comparison!
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Old 05-09-2018, 3:20 PM
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I missed this thread last year. WA8ZTZ, do you still use this vertical or has it given way to your recent SWL setup?
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Old 05-09-2018, 4:45 PM
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I tried the Apex 303WA-2. It is NOT an ordinary whip as you normally assume.

There is a total disconnect rf wise from the coax shield. This means that radials, should you try to use them, or incorporate the braid as a counterpoise is ineffective. This is on purpose.

It more or less emulates taking your portable receiver from inside your noisy indoor location, and walking out to the balcony or other area less noisy. They understood that for those who buy these things, they don't understand how to effectively choke/isolate an outdoor whip and are not really diy radio people who know what common-mode shield problems are with a transmission line indoors. It is basically just a fancy way of getting a small untuned whip outdoors.

So yes, getting a small whip outside surely helps! And so does the total disconnect from the common-mode of the coax running to it from indoors.

For those who don't know about common-mode issues or how to tame it, this is fantastic if 6 feet of antenna will work in your situation.

But for us, you can do the same by using 6 feet of wire, then totally isolating and choking your feedline, and then make no attempt to improve it with no radials/counterpoise either!

The Apex has it's purpose, mainly designed for easily-overloaded portables, but for most of us, it turned out to be just 6 feet of whip, totally choked from the coax shield, without any way to improve upon it. I wouldn't make it part of an extensive array.

Last edited by hertzian; 05-09-2018 at 4:54 PM..
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Old 05-09-2018, 4:59 PM
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Quote:
Originally Posted by WA8ZTZ View Post
Your guess about the 60' cox got me thinking as to whether it was acting as an antenna so tried the ApexRadio antenna with just a 6' length of coax into my Tecsun PL600 on various SW sigs and then compared it to the 60' length of coax into the same radio, same sigs. If anything, there was a slight loss with the 60' coax.
That's it! It makes no difference, other than simple line loss, since the coax shield is not used in the normal fashion with this antenna.
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Old 05-10-2018, 3:37 PM
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Quote:
Originally Posted by ridgescan View Post
I missed this thread last year. WA8ZTZ, do you still use this vertical or has it given way to your recent SWL setup?
Interesting that you should ask, just did an antenna shootout this afternoon between the Apex vertical, a homebrew box loop and a stock PAR EF-SWL connected to my Satellit 750 via a 3 way coax switch.. The loop was a disappointment as it apparently needs some kind of tuner or preamp to get it working. Otherwise, briefly summarizing... between the Apex and the PAR... the Apex had a slight edge over the PAR on LW. They both performed similarly on AM BCB. The PAR had the advantage on HF. The Apex continues to surprise me as to how well just a 6' whip performs. For someone with antenna restriction issues the Apex would be a nice choice.
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Old 05-10-2018, 8:41 PM
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Quote:
Originally Posted by WA8ZTZ View Post
Interesting that you should ask, just did an antenna shootout this afternoon between the Apex vertical, a homebrew box loop and a stock PAR EF-SWL connected to my Satellit 750 via a 3 way coax switch.. The loop was a disappointment as it apparently needs some kind of tuner or preamp to get it working. Otherwise, briefly summarizing... between the Apex and the PAR... the Apex had a slight edge over the PAR on LW. They both performed similarly on AM BCB. The PAR had the advantage on HF. The Apex continues to surprise me as to how well just a 6' whip performs. For someone with antenna restriction issues the Apex would be a nice choice.
Cool! You have a little antenna farm like I do choices are cool. Glad to learn about the Apex vertical and I think others ought to take heed that this is a serious limited space RX antenna! Which means, no excuse to not get it outside
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Old 05-10-2018, 9:33 PM
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Quote:
Originally Posted by hertzian View Post
I tried the Apex 303WA-2. It is NOT an ordinary whip as you normally assume.

There is a total disconnect rf wise from the coax shield. This means that radials, should you try to use them, or incorporate the braid as a counterpoise is ineffective. This is on purpose.

It more or less emulates taking your portable receiver from inside your noisy indoor location, and walking out to the balcony or other area less noisy. They understood that for those who buy these things, they don't understand how to effectively choke/isolate an outdoor whip and are not really diy radio people who know what common-mode shield problems are with a transmission line indoors. It is basically just a fancy way of getting a small untuned whip outdoors.

So yes, getting a small whip outside surely helps! And so does the total disconnect from the common-mode of the coax running to it from indoors.

For those who don't know about common-mode issues or how to tame it, this is fantastic if 6 feet of antenna will work in your situation.

But for us, you can do the same by using 6 feet of wire, then totally isolating and choking your feedline, and then make no attempt to improve it with no radials/counterpoise either!

The Apex has it's purpose, mainly designed for easily-overloaded portables, but for most of us, it turned out to be just 6 feet of whip, totally choked from the coax shield, without any way to improve upon it. I wouldn't make it part of an extensive array.

This makes sense, and its obvious that most of the cost of the $300 DXE ARAV3-1P is in the preamplifier and not the 8' whip.

I do want to test out a steerable phase array but the land right now is all trees and palmettos, almost no clear areas, so it'd be diffilcult to run anything like a couple of BOGs which is why I was thinking of the Apex vertical. Maybe hang up a pair of PAR EF-SWLs (I already have one, cheap enough to get another)...
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