Which Portable Antenna Would Work Best?

Started by gil, June 29, 2016, 07:56:41 AM

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gil

Hello,

Between the following, what do you guys think would work best:

1. A 10 to 11ft whip with UNUN at the base, using a tuner.

2. An 8-9 ft whip with an adjustable coil 2ft from the botton. No tuner.

Both antennas would use a counterpoise.

Opinions? Thanks.

Gil

kk4zvd

Hi Gil,

This might not be the choices you provided but it is close. I can honestly say this Antenna is incredible, I have used it to my jeep when stationary. They up the antenna and made contact with a station in Austria from Virginia using a yaesu ft-857. I have also attached the antenna to a picnic table and made contacts on 5watts using the yaesu ft-817. This antenna is very easy to deal with and packs up in seconds. Right now through MFJ the antenna is $99

MFJ-2286

PORTABLE, VERTICAL ,MFJ BIG STICK ANTENNA ,7-55MHZ, 1KW, W/17FT STAINLESS STEEL WHIP
WITH COIL TUNER.


gil

Thanks Terry. I knew about the 17ft whip but not this whole kit with the coil..

Gil

cockpitbob

#3
I home-brewed something similar to the MFJ-2286.  I made my own coil and put it between 5' of aluminum tent poles and an MFJ 8' telescoping whip.  I only use 2 radial wires.  It will tune 40-10 with no tuner needed if I adjust the length of the radials along with where I tap the coil with the clip lead.  MFJ's manual for the 2289 says just lay down four 12' radials and moving the coil tap will get you SWR < 2:1.  I find that hard to swallow.

During last year's QRP Skeeter Hunt I set it up along with my 63' EFHW 40/20 antenna which was up high enough to be a sloper.  The EFHW did noticeably better than the vertical, but that makes sense since it is 63' long instead of 14' long and is way up high. The end fed is the orange wire on the left.

Still, the vertical is real handy for when there's no trees.  And it collapses down to about 2' long and weighs about 1.5 pounds.
If I had it to do over again, I wouldn't.  I probably have 10hrs total into making it.  There were more pieces to make than you would think, and I probably have $35 invested in it.  For $100 you get one that's longer (17' vs 14') and it's plug and play.

gil

Here is an update...

I would buy a Chameleon Hybrid Micro and whip for my sumer camping trip, but I doubt I will have the money before I leave. Too bad, I would have liked to review it... Chameleon, pretty please? ;)

So, I need a self standing portable end-fed antenna... Options are the MFJ 17ft. telescopic whip or as Ray suggested, a fiberglass pole. The question is, as always, how to feed it? My tuners are mostly made for longer wires, 9:1 transformers. If I want to use a shorter wire, then a different solution is needed.

Enters the Ruthroff 4:1 UNUN. All credits go to G8JNJ:
http://www.g8jnj.net/cometcha250b.htm
See PDF attached as well, end of the article.

I still have a couple FT-140-61 toroids... I am having a hard time finding a 3/8-24 antenna base that won't cost me a fortune in shipping.. I'd need a small one to screw on a Hammond watertight cast aluminum case. The 4:1 Ruthroff UNUN works with wires shorter than 1/4 wavelength and is very easy to make.

Gil.

gil

Martin, G8JNJ suggested that I try 12 bifilar turns on the FT-140-61 for a 4:1 Ruthroff UNUN.

Gil.

cockpitbob

Quote from: gil on July 10, 2016, 02:21:51 PM
Martin, G8JNJ suggested that I try 12 bifilar turns on the FT-140-61 for a 4:1 Ruthroff UNUN.

Gil.
For fun I ran the numbers on that.  It looks good down to 1.8MHz at 100W.  Nice UNUN.  It should be good for several hundred watts over a broad frequency range.  What frequency range does G8JNJ say it is good for?

gil

QuoteWhat frequency range does G8JNJ say it is good for?

He did not say but I did specify I was going to use it from 40 to 15m. He has a few articles online, check him out... I asked him if I should use the T130-2 or FT-140-61. He said both would work but he would prefer the 61 material.

Unlike the EARCHI 9:1, the Ruthroff 4:1 has to be used with wires shorter than 1/4 wave.

Gil.

gil

#8
New development... I will be reviewing the Chameleon MPAS portable antenna system! It includes the CHA Micro UNUN and the MIL whip. Not sure if the extension will be included. Packet is in the mail, stay tuned...

I will still make the Ruthroff UNUN. I saw a great idea in a video about sticking copper tape inside the elements of a telescopic fiberglass pole. This avoids having to use a wire. It can be used with either a half wave tuner, depending on the length of the pole, like on 20m for a 10m pole, the EARCHI UNUN for multi band use, or the Ruthroff UNUN for shorter poles or 80m.

Gil

Rescue9

After 10 years of testing & reviewing backpacking and hiking gear, I'd love to get a chance to review the Chameleon system. Nice gig Gil. Have fun!

gil

QuoteNice gig Gil. Have fun!

Thanks, I plan a hike in the Pyrenee mountains on the French-Spanish border. It is a section of the GR10 trail starting from Lourdes going East. Those mountains, from what I have seen on videos about the GR10 have few trees, so a self standing antenna is a must. My budget is quite insufficient, but hell, I've done worse than starting a trip with no money ::)

I will be taking my KX2 and Weber MTR as a backup or for when batteries are low. I wish I could review the KX2 with more options like the ATU, microphone and battery/charger. Wayne, pretty please? Those reviews will be great for the Radio Preppers YouTube channel I want to start. I also need a lighter key than my Kent and a solar panel. Leaning towards the CHEOTECH 19W. I will make a video of all the gear I'll take with me.

Gil.

Lamewolf

#11
Quote from: gil on June 29, 2016, 07:56:41 AM
Hello,

Between the following, what do you guys think would work best:

1. A 10 to 11ft whip with UNUN at the base, using a tuner.

2. An 8-9 ft whip with an adjustable coil 2ft from the botton. No tuner.

Both antennas would use a counterpoise.

Opinions? Thanks.

Gil

Without a doubt, the one that uses no tuner and adjust to resonance.  With the unun/tuner combo there will be much more loss in most cases !  Then there is feedline loss if the swr is high on the coax due to the tuner being inline near the radio end.  With the resonant antenna, feedline losses are nil.

gil

Thanks Lamewolf, I thought as much after thinking about it a bit more..

Gil

cockpitbob

Lamewolf's comments on losses are true.  However, given that one S-unit is a 4:1 power change, even if your losses are crazy and you are loosing 75% of your power in losses, that's only 1 S-unit.  To me, operational convenience becomes a big issue.  Adjust a coil to resonance or adjust a tuner, or have an auto-tuner and push a button?  Those options may be a big deal to you.  Personally, I like resonant antennas and having the fewest pieces in my set-up.  In other words, I don't like tuners.  However, it's really nice to have a tuner that can make that antenna your bitch and force a tune on any band you want to work.  Apples and oranges, but it's all good fruit.

Lamewolf

Quote from: cockpitbob on July 10, 2016, 07:39:36 PM
Quote from: gil on July 10, 2016, 02:21:51 PM
Martin, G8JNJ suggested that I try 12 bifilar turns on the FT-140-61 for a 4:1 Ruthroff UNUN.

Gil.
For fun I ran the numbers on that.  It looks good down to 1.8MHz at 100W.  Nice UNUN.  It should be good for several hundred watts over a broad frequency range.  What frequency range does G8JNJ say it is good for?

Should be good 160 thru 6 meters and  possible work on 2 meters also.  If you have an analyzer, hang a 200 ohm non inductive resistor on it and sweep it, should be flat on the bands I mentioned.