Antenna testing with results. 80 meter OWL doublet vs g5rv.

[ke7trp]

I decided to setup a portable station I could take with me camping/fishing.  I would also use this station for emergency use.

The radio was a surplus FT450 yaesu.  I decided on a few antennas and will be testing them out over the next few weeks. One of which is a simple G5RV. 

I setup the station in the back yard for testing. Here are the results as predicted:

Antenna one:  80 meter wire fed with 600 ohm open wire line to a KW match box balanced tuner and a home brew line coupled balanced tuner.  Antenna is 60 ft.

Antenna two:  G5RV using 450 ohm ladder line and 102 ft of coperweld antenna wire. Dentron Super super Tuner.  This antenna is 30 ft on a rope and pulley from tower.  The Feedline was existing half inch hardline that normaly feeds my 160 antenna.


20 meters:
G5RV winner.  5 stations report stronger signals from 100 to 2000 miles away.  Shocking, Its only 30 feet vs 60 for the doublet.  Mosely 4 element TROMPS both but that is expected.

40 meters.  Even.  6 stations said they cannot tell the difference in back to back instant switching.  This was suprising again.  I thought the G5RV was a POS antenna? Most of these stations where under 600 miles.

80 meters.  Doublet.  8 stations report NO signal difference AT ALL.  Exactly the same with instant switching.  These stations where under 600 miles.  Most under 300.  For a sky burner, Both off these antennas proved to be very close.  Sometimes one would beat the other for no real reason. But then, Moments later, The roles where reversed.

The Doublet did beat the G5RV in TWO stations.  Those two stations where east. AZ to Wisconsin on 80.  This man had a wire beam and said the doublet was a clear 8db! over the G5RV.  The other station was in kansas and he said the Doublet was 1S unit better than the G5RV.  For DX or longer haul, The Doublet at 60 ft is the clear winner.

Another thing I noticed is that the G5RV picks up more local man made noise.  I have a problem with a very high electical signal comming from a home in the next neighborhood over.  This shows a strong signal in 80KC pips across the 80 meter band.  The g5RV picks up this signal about 10 DB stronger that the doublet.  Confused as to why that is.  This hurts the g5RV if you are near one of those signals and trying to copy a weak station. 

In short,  I was very pleased with the G5RV at only 30 ft high.  You can certainly use the antenna and make many contacts with it.  I went into this thinking the G5RV would be like a dummy load.  The Doublet at 60 ft beats the G5RV for longer hauls and it should.  However, I wonder if I raised the G5RV up to 60 ft how much of that would difference would be leveled out. 

In all of the tests nobody knew what kind of antenna each one was.  They where simply 1 and 2.  Only after all testing was completed did I mention the types of antenna.

I am only going to use the antenna for emergency, field day and camping at 100 watts so I think it fits the bill.

Main G5RV drawback:  WONT tune 10, 15, 0R 17.  Frusterating.  I tried adjusting lengths. It works on 20, 40 and 80 only.  For this reason, I might alter it to another design that will work on those bands.  But for now, THis one just wont tune higher than 20.

[kb3ouk]

Actually, I don't find those results surprising. The G5RV, after all, was pretty much designed as a 20 meter antenna. The doublet is going to be directional off the ends of the wire at 20 meters. 40 meters isn't a hard band to put out a signal on, and 80 meters, in most cases the more power you have going straight up, the better. I've actually saw some information that makes it appear that as far as NVIS operation is concerned, the lower the antenna is, the higher the gain (in dBi) is.

[WB2EMS]

Main G5RV drawback:  WONT tune 10, 15, 0R 17.  Frusterating.  I tried adjusting lengths. It works on 20, 40 and 80 only.  For this reason, I might alter it to another design that will work on those bands.  But for now, THis one just wont tune higher than 20.

You might want to look at the ZS6BKW antenna. It's sort of an updated version of the G5RV done after computer modeling was available. I have one up at 30 feet and am very pleased with it out at my little cabin with QRP gear. It has some VSWR on 80 that can be easily matched out, and is flat on 40, 20, 10, and 6 meters. It works well on 17 with some SWR that my tuner takes out, but hates 30 and 15 meters, the autotuner in the 703 can't match it there. I think it matched up ok on 12 meters as well. The 40' feedline is enough to reach right to the rig in my case, I just use a BNC to binding post adapter. But if you attached 50 ohm coax at the end of the ladder line, it would be flat on even bands from 40-6 and would attenuate the reflected power on the others making the apparent match even easier for the tuner. This is where many of the G5RV's get some of their magic - the coax losses make the SWR look better than it really is.    Hey, as long as the transmitter is happy, right?

The dimensions I used worked out to be about 90.25 feet across the flat top, and 40' of 450 ohm feed line if I recall correctly.  

Here's some references to it.

http://www.nonstopsystems.com/radio/ZS6BKW.pdf  
some notes by the original designer.

http://www.w5ddl.org/files/Zs6bkw_vs_G5rv_20100221b.pdf
comparison of G5RV and ZS6BKW


http://www.wirelesswaffle.com/index.php?m=02&y=07&entry=entry070209-160601

I've been using it as a QRP antenna and working folks with 2.5 watts of carrier on 75 and 40 meter AM, as well as various modes on the higher bands. It always produces contacts for me, and surprisingly good signal levels at the far end.

I'd recommend checking it out. It's what I use instead of G5RV's these days.

[ke7trp]

Thanks for the replies fellas.  I agree for NVIS you just need some wire. They are soo close.  

I just did more testing on 40 and had a wild card.  A station in Tucson 150 miles south said the G5RV was S3 to 5.  On the 60 ft tall doublet he was reporting S9.  Maybe because the G5RV is broadside to him.  

Thanks for the information about the BKW antenna!  I have some 450 ohm line here. I might as well try this for fun.   It would take a few minutes to add the line and shorten the flat top.

I am using half inch hardline for the feed.  which I would never do in the field.  I might try to take the 450 out on the porch and run it soon to simulate field day. I am waiting for the power cord I ordered.  


C

[W2VW]

Sorry to have called B.S. once again Klarq. Please proceed as usual. It gives the internet reader a way to temper content. It's all good.

[KA0HCP]

It's a rare treat to be able to compare antennas directly on the air.  No real surprises.  The higher noise level on the G5RV is not surprising since it is an unbalanced antenna and more susceptible to common mode current.  Being lower it is going to perform better close in.

Thanks for the review!

[ke7trp]

It sure is!  Its nice to compare.  I have been testing back and forth all afternoon.  The testing pretty much follows the rules. Close in under 500 miles, They are the same or close.  Far out for DX The taller antenna is best.   Still suprised how well the low mounted G5RV works. 

I am going to convert it to the BKW today after work.

C

[Jim, W5JO]

Your tests are worthless unless each antenna is mounted exactly in the same manner, at the same height and the same orientation and field strenth is measured.  S meter readings at a distant location is arbitrary and not reliable.

Your equipment should be the same and each measurment should be at the same spot

[W2VW]

A couple wavelengths apart would be nice. Otherwise one wire may excite another. Not scientific but FB for advertisement.

[Steve - K4HX]

How do you figure the G5RV is an unbalanced antenna?

[ke7trp]

I got the 11 ft of ladder line added and removed (folded over) 7.3 ft of wire per side..  This moved the 20 meter dip to 13.5 mhz.   I removed a foot ladder and that got me to 13.7.  I just measured the top again and found I was to long.  Its now 1.1 at 13.9.  I did also notice that the other bands are falling inline now..

I will measure the ladder one more time.  I think its close..  10, 12, 17, 20 and 40 are all within .200mhz of where they need to be.  The match is also very low on all bands under 1.5.  80 is still a bit high at 5 to 1.  

This might really work out for a field day antenna.  Thanks again!

 

Main G5RV drawback:  WONT tune 10, 15, 0R 17.  Frusterating.  I tried adjusting lengths. It works on 20, 40 and 80 only.  For this reason, I might alter it to another design that will work on those bands.  But for now, THis one just wont tune higher than 20.

You might want to look at the ZS6BKW antenna. It's sort of an updated version of the G5RV done after computer modeling was available. I have one up at 30 feet and am very pleased with it out at my little cabin with QRP gear. It has some VSWR on 80 that can be easily matched out, and is flat on 40, 20, 10, and 6 meters. It works well on 17 with some SWR that my tuner takes out, but hates 30 and 15 meters, the autotuner in the 703 can't match it there. I think it matched up ok on 12 meters as well. The 40' feedline is enough to reach right to the rig in my case, I just use a BNC to binding post adapter. But if you attached 50 ohm coax at the end of the ladder line, it would be flat on even bands from 40-6 and would attenuate the reflected power on the others making the apparent match even easier for the tuner. This is where many of the G5RV's get some of their magic - the coax losses make the SWR look better than it really is.    Hey, as long as the transmitter is happy, right?

The dimensions I used worked out to be about 90.25 feet across the flat top, and 40' of 450 ohm feed line if I recall correctly.  

Here's some references to it.

http://www.nonstopsystems.com/radio/ZS6BKW.pdf  
some notes by the original designer.

http://www.w5ddl.org/files/Zs6bkw_vs_G5rv_20100221b.pdf
comparison of G5RV and ZS6BKW


http://www.wirelesswaffle.com/index.php?m=02&y=07&entry=entry070209-160601

I've been using it as a QRP antenna and working folks with 2.5 watts of carrier on 75 and 40 meter AM, as well as various modes on the higher bands. It always produces contacts for me, and surprisingly good signal levels at the far end.

I'd recommend checking it out. It's what I use instead of G5RV's these days.

[W2VW]

How do you figure the G5RV is an unbalanced antenna?

Balanced to unbalanced transition without common mode isolation. This would be in reference to crappy new G5RV appliance antenna and not original 3/2 length 20 meter design.

[Steve - K4HX]

That's the tradeoff of the BKW. It's shorter, so it won't work as well on 80 meters. But it will tune up mucher better on the higher bands than the G5RV.

[Steve - K4HX]

OK. Most of the commercially made G5RVs include a balun (not always a very good one but...)

How do you figure the G5RV is an unbalanced antenna?

Balanced to unbalanced transition without common mode isolation. This would be in reference to crappy new G5RV appliance antenna and not original 3/2 length 20 meter design.

[ke7trp]

That's the tradeoff of the BKW. It's shorter, so it won't work as well on 80 meters. But it will tune up mucher better on the higher bands than the G5RV.

Exactly.   You hit it right on the head.  I now have a reasonable match on 10, 12, 17, 20, and 40.   But 80 is 4 to 1 at 3.5 mhz.  So looks like I lost 80 in doing this.  But I gained all the higher bands.  Even 6 meters is very close.  Another few adjustments and i will have it.

On the G5RV and this BKW version, I am using a palomar BA-8 1 to 1 balun at the feed point.

I am thinking about making a PAR end fed style antenna for 80.  Then, I can use this antenna for higher bands and string out the 80 end fed at night.  Maybe this will work well enough with a tuner for 80 meters.  Most of the guys I talk to will be 200 miles or less on 80 meters. Wont be looking for DX. Just rg chew/ emergency use while having a beer at the campsite.

C

[W2VW]

A 102' flat top works almost as well as a 125' on 75m if one uses good engineering practice.

Compensate for lower radiation resistance, conjugate reactance, done. Not difficult with focus.

Post a watergate.

[ke7trp]

Wb2EMS  I cant thank you enough.  I got the ZS6BKW antenna setup now.  Its resonant on 6, 10, 12, 17, 20, 40 with NO tuner. Its very low across all of those bands.   I can cover 80 in a pinch. Its 3 to 1 on 3.55mhz.  3.8 is 6 to 1.  Any decent tuner can handle that for 100 watts of SSB or 25 AM.    I did not cut the flat top wire at all. I just folded it over so if I want 80 to work better, I simply unwrap it and extend it back out to 102.  Then its 2.5 to 1 on 80 in the phone band.

Now to compare to see if this thing works.  I am very pleased to have 10 and 17 meters.  I am missing only 15 but I dont use 15 much anyways and it wont matter for field day use.

So far on 40 meters, Its working great.   I am switching back and forth and they seem very very close.   Good enough for me!

[Mike/W8BAC]

Dose my heart good to know you will be the all band, nationwide  "Voice of Americe" when the big one hits. Heck, make that ZS65RV antenna your home setup! With spec's like that I can sell my amp and work you with my bed spring, roof gutter array. You can dispatch a rescue jump team to my location.

[WB2EMS]

I'm glad it was useful to you. Your results on 80 meters are similar to mine, some SWR, but the auto tuner in the 703 eats it up with no problem and the thing plays well on 75 for me.

I've been working 75 meters with the IC703 on AM from the cabin for about 3 years. The IC703 does 10 watts PEP, 2.5 watts carrier. A few weeks ago I had a 3 way QSO with KB1NFS in CT, a station near Rochester, and a third someplace in NY and was S9 or better with all of them. Clark couldn't believe I was running QRp. We carried on through sunset, for about 45 minutes or so with steady signals.

3 years ago I was on the AM transmitter rally from the same site with the same antenna and gear and easily worked half a dozen stations in Kerri's pileup from locals to NJ and beyond in a half an hour. Got good reports from all of them. Whenever I'm out there and try to join a QSO in the window, I get heard and usually pretty complimentary signal reports. So I'd say it works well on 75 meters, despite the mismatch. I'd prefer it to be flat on that band as well, but the G5RV isn't flat on most bands, somewhat masked by the RG58 attached to most versions of them. 

For me it's my go to portable antenna. I want to experiment with a 300 ohm twinlead version this summer for HF packing/SOTA  use. I've been wondering if there is a length of downlead that could be added in to adapt it for 30/15 meters. Those are good bands for some events, and switching in say 10 feet more of ladder line if it would make it match on those bands wouldn't be too hard to do in some situations.

Keep us posted with your results if you take it on the road. I will too.

[Steve - K4HX]

These might help.

http://www.w5dxp.com/goodbad.htm

http://www.w5dxp.com/notuner.htm

[ke7trp]

Operating portable today from backyard. Ft450at radio, john deer lawn tractor for power source and the zs6bkw antenna. Many contacts so far. Mainly 17 meters into east coast. Just worked florida. 80 degrees outside. Lots of fun.

[KB2WIG]

Nice cup holder.

Have you thought of operating JD MoBile?


klc

[W3RSW]

JD 's are green and yellow ..for .as long as I can remember. Off store rebrand?  Reprinted?

[KF1Z]

JD 's are green and yellow ..for .as long as I can remember. Off store rebrand?  Reprinted?

And some orange and red. ( home models .. Scotts )

some of the earliest JDs were red ( farm tractors)

The Iowa factory would custom paint farm equipment.


But, I think this is  a Scotts  (made by John Deere )

[W3RSW]

Oh, ok.  Looks like interesting stuff to research.