Tuesday, June 02, 2009


THE G5RV; What it is, What it ain’t!
A Real World Comparison.
Bob Raynor N4JTE




During the last 5 or 6 years I have built 38 homebrew antennas, both wire and verticals from 160 thru 2 meters. Most of these were monoband gain arrays. I have never tried a G5RV so a few weeks ago I set out on this experiment.
The G5RV has been well represented on the bands and well disparaged in other venues of opinion. I figured why not build one and compare it to some other antennas in equivalent directions and find out for myself !
This article is aimed at a new ham considering a multiband coax fed wire antenna that is easy to build and costs less than a commercial single dipole. I would hope that my observations will be of use to a beginner and perhaps also to some of my crusty contemporaries.
As designed by Varney, the G5RV, is in essence, a slightly long, extended double zepp on 20 meters with an ½ wl tuned stub. The basic EDZ will ordinarily be fed with an 1/8 wl tuned stub in the monoband configuration.
The classic G5RV is a center fed 102ft. long wire fed either with 300 twin or 450 ohm ladderline, 31 ft. or so long, depending on the choice. It is non resonant within the ham bands but is actually close enough to tune out the resultant swr and work well with the internal tuners prevalent in the newer transceivers.
CAVEAT: Stick with the original design and lengths and flat top if possible. This antenna has a bunch of well thought out compromises and Varney knew what he was doing. I attempted to optimize 20 meters by trying 10 different tap points on the 450 line and found that the 31ft. was the best, but I had to try, hi. Also, http://www.w8ji.com/ , Tom has a good swr scan at 100 ft. high ,mine at 38 ft was pretty close so check his out if interested.

COMPARISON ANTENNAS;

1; My G5RV was built in the classic design and was flat top at 38ft. with a center support and two available trees. Due to their location the actual horizontal angle was about 165 degrees as opposed to the preferred 180.
Antenna was fed thru 100ft. of RG 213 to a MFJ-986 differential tuner.

2; 40 meter double extended zepp, 165ft long at 60 ft high. Ladderline fed direct to ATR-30 tuner. Both antennas favor the E/W direction and were about 80ft. apart.

3; 2 pairs of 40 meter phased verticals covering NE/SW/SE/NW, switchable.

4; 20 meter diamond shaped quad loop at 40 ft. in E/W favor.

5; 17 meter monoband vertical at 35ft. high with 4 sloping ground plane radials at 22ft high, 45 degree slope.

ON AIR TESTS:
The testing was done during May of this year (2009), over a 4 week period with the usual zero sunspot activity with an occasional short duration small cycle 24 sunspot showing up. All tests were A-B-C, instantaneous and no antennas were identified until later discussions at the end of the qso’s.

75 METERS.
Antennas; G5RV and 40 meter zepp/doublet.
1900 utc to 0500 utc
Stations contacted; 124 Stateside
12 DX
The overall consensus was that 95% of the stations worked could not discern any significant difference between the 165ft. long zepp and the G5RV. What was truly astounding was that I tried the same test on a few of the same contacts and told them which antenna I was now on. Amazingly, somehow the G5RV was now getting a 1 S unit lower report than before being named.
Go figure, hi.
The G5RV is only about 20 ft. short as a dipole on 75 so I was not totally surprised that it held up well against, in this case, a 165 ft. long doublet. I had expected a little more advantage for the doublet being longer and higher but the result speaks for itself. I did run into some RF into the laptop on the first night of testing but a 1 to 1 balun at the ladderline /coax connection took care of the problem and remained connected for all testing.

40 METERS;
Antennas; G5RV
40 meter 4 square
40 meter EDZ
1500 utc to 0500 utc
Stations contacted; 186 Stateside
22 DX
I really put the G5RV to the test on this band as I have multiple gain/direction antennas well proven on this band for stateside and dx contacts.
During local daylight the G5RV held it’s own, and them some, with many stateside contacts and rag chews. When working multiple states at the same time the G5RV was the antenna of choice with all stations receiving and being heard well. The G5RV filled in the missing South and North lobes on the zepp and made for a more comfortable roundtable between MI, SC, VA, ME and NY. Both gain antennas showed a couple of S units gain when pointed at their locations but the G5RV saved a lot of time switching around and served very well in this capacity.
So; during daylight the G5RV on 40 meters was a delight to this beam/array operator as it had no problem being heard as well when put up against 3 dbd gain directional arrays. I could not see, nor document, any particular lulls on receive or transmit that would indicate any pronounced directionality with the G5RV. The G5RV has become my 40 meter daylight antenna of choice.
Nighttime testing on all paths was very enlightening in that again the G5RV was competing against two antennas designed for distance and gain.
The best example exhibited was during a test between HI and a G4 along with 56 stateside checkins on my http://www.omiss.net/ one night.
To Hawaii, the G5RV was given 5/7, the Zepp was given was given a 5/9 and the phased verticals were given 5/9 plus,(better aimed, hi). To the G4 the G5RV was 5/7, the zepp was 5/9 plus a roomful and the phased verticals had a similar report. There were many other dx contacts made during the testing period but I notated this one for the fact that both HI and England were available for testing at the exact same time. Is the G5RV a pile up breaker on DX, No. Will it be heard and worked on 40 meters when the beams/ arrays are done calling and are chasing someone else, Yes !
I was very happy with the G5RV on 40 meters as it compared well with some tough competition over 4 weeks, day and night. Bottom line is that I was impressed enough to take down the 4 square on 40 for the summer and rely on the zepp and the G5RV on this band. To be honest, I also need to put in an above ground pool. But if the G5RV did not work as well as it does the pool idea would be history.

20 METERS;
Antennas; G5RV
40 meter zepp/ doublet
Quad loop at 40ft.
1700 utc to 2200 utc.
Stations contacted; 53 Stateside, 9 Dx.

All contacts were made from here in N.Y. during midday. A test I really wanted to try was a simple dipole at the same height vs the G5RV, but I could not find a way to build them in the same direction without encountering mutual coupling, I tried, but no way! So I put up a diamond shaped single quad loop at 40 ft. coax fed, with a resultant 1.7 to 1 swr favoring E/W for extra comparisons.
The band propagation on 20 meters was pretty crappy during the 3 week period I had the time to test things but at least the playing field was level for all 3 antennas.
The only pronounced plus difference (3 S units), was shown by the G5RV when working Mexico and the Azores as compared to the doublet and the loop.
All the stateside contacts reported non discernable differences between the doublet and the G5RV, the quad loop was always a distant 3rd in all comparisons. Not having a clue what the lobes really look like on the 40 EDZ, I’m guessing that the G5RV has a small gain in it’s favored directions over the zepp and the quad loop.
The G5RV proved itself as a basic, competitive wire antenna on 20 meters with perhaps some gain over a dipole and full sized vertical loop in the same direction.

17 METERS;
Antennas; G5RV
17 meter monoband Ground plane vertical at 33ft.
Daytime
Contacts; 11 Stateside, 2 DX

Another band with hit and miss propagation, but enough to give some real world results. It has been said by some that the G5RV will not work on 17 meters, well, I will leave others to define “work”. The swr on the G5RV was around 9 to 1, but it loaded up easily on 18.165 on the MFJ versatuner. The 40 meter zepp/doublet will not load up on this band so I built a 17 meter monoband vertical at 35ft tall with 4 raised radials sloping off at 45 degrees around 22ft. off the ground. SWR was 1.2 to 1 and direct coax fed.
As I said, the propagation was hit and miss but when the band was open both antennas worked exactly the same with a 5/9 here and a 2/2 there, across the country, Cuba, and the occasional South American contact.
Whether both antennas stink the same or work, will only be up for conjecture till we get some real sunspots. At least the G5RV will at least let you know when the band is open so you can aim your 6 element monobander in the right direction.

FINAL COMMENTS;

I did not try any tests on 15 or 10 meters because the band is abysmal up here in NY when I can get near it, but for information purposes, the G5RV loaded up easily on both bands and on 10 meter FM, it actually opened some repeaters in NY and MA.
OVERALL, I feel that the G5RV, after 220 plus contacts, is an excellent trapless, multiband coax fed antenna well suited for a beginner to build. As detailed during the article, it compared extremely well with a ladderline doublet and various other configurations in real time comparisons.
I hope some of the observations and comments provided here will give the antenna experimenters out there some real world, non biased, on the air comparisons to think about while perhaps practicing on their modeling programs.

Thank you Mr. Varney; G5RV, you left us a good one!

Tnx for reading.
Bob N4JTE

5 Comments:

Blogger Alan said...

Wow, thought this would be a quicker read! I've got you bookmarked. Your site DEFINITELY requires a quiet room and rapt attention. I'll be back often. Thanks for posting this on QRZ. de....Rynn

7:45 PM  
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1:19 AM  
Blogger Kumar said...

Hi Robert_N4JTE,

I run broadside roughly North to South, a 102' G5RV, and a 160-10 ('modified 170' with a trap') OCF dipole. A 75m dipole in a semi-sloper NW orientation is the third antenna. All homemade. I've found, that the G5RV is superior to the OCF on short to medium skip, but the OCF excels long skip. Hawaii and Japan at least 2/3 S units over the G5RV.

Thanks for the blog,

Kumar_J88CF

10:10 PM  
Blogger Alan Vega said...

Great testing. Thanks to Google you answered my question perfectly.
WA6MOW

7:54 AM  
Blogger Alan Vega said...

Nice jjob. Thanks for the test.

7:54 AM  

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