Ham Radio HF - The Small Garden Part 3 - G5RV
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- Опубликовано: 28 авг 2024
- Here we continue the series, looking at the G5RV and its basic design. To keep alerted for Part 4, please click SUBSCRIBE. There is one error on the video. The second line drawing should have shown the balanced line terminated into coax cable.
Great Video, thanks Peter. I heard and read plenty about the G5RV, good and bad. Your video puts it both ways without any side. I suppose that when the antenna was designed, HF Tx's being valved were much more forgiving to poor VSWR and you could adjust the output pi tank for 72 ohms output! I knew plenty of '101 owners who did just that.
Nice explanation of a handy antenna, thanks for posting.
Thanks Joel
I've always been a fan of the g5rv its a great antenna for what it was designed for. The last one that I had was in a flat dipole configuration at about 50 feet and it worked fantastic on 80, 40 and 20. They also work fine in inverted vee configuration just keep it as symmetrical as possible for ease of tuning and best performance.
Thanks for the input James
Great video with a great explanation....thanks....:)
Many thanks William
Thank you for the info and sharing, I have been following your video, I am new to HF and found information you given very useful. Always never late to receive a wisdom of knowledge, thanks again & 73.
Glad it was helpful! 73 Peter
Good explanation on the g5rv Peter, Louis described his reason for calling it an antenna system tuning unit, as it is tuning the combination of the antenna and feedline together to resonance, ARRL book and Walt Maxwells reflections goes into great detail in explaining this also.
Very nice explanation of one of the most popular antennas. Keep these videos coming ! 73's from Southwest Florida ...de W2CWL
Really well explained. Many thanks. De G5ROB
Glad it was helpful! 73 Peter
I’ve been trying various antennas for portable use in Raynet nvis inter UK tests and after maybe 8 different wire including some commercially made antennas I have come back to the G5RV for ease and speed of erection and predictable performance. With a good atu it works Very well even on the 5 mhz band.
It’s cheap to make and not too heavy. It’s now our go-to emcomm antenna.
Very proud that my Dad was one of the first Amateur Radio Enthusiasts - Pre WW2 ( G3HS)
Many thanks. There were quite a few 2-letter calls around when I first came on the air in 1960. Maybe I worked him. 73s Peter
I remember as a young boy spending time with my Dad whilst he took part in the" worked all Britain" competitions. He also had a set up in the family car ( G3HS Mobile ) which I found fascinating . His Wireless experience made him a prime candidate for the R.A.F. in which he served from 1940-1945 flying in Wellingtons from R.A.F.Harwell in Oxfordshire .
Nice to hear the G5RV talked up...
Many thanks
Hello Peter, My Old Kenwood TS820 Is happy with the G5RV, like you said simple antenna. works fine for my needs, looking forward to the next video
73 Paul de M0BSW
Hi Paul - nice to hear your results
Thank you so much. You answered my SWR questions. I can’t get it below 3 to 1 at best. I have not transmitted yet because I thought something was wrong with it. I have it up about 35 feet in horizontal configuration.
3:1 is fine. The ATU should match this. Check the Update Video and the link below it. You can then calculate the tiny loss on a typical length of coax. Press the PTT button and enjoy yourself.
Thank you sir for the information, I just purchased one from another ham and was able to install it in a horizontal plane in an L shape. So far I am impressed on 20 meters but my FT 710 is unable to tune on 80m. Did I hear you say adding more coax might help? Thanks WB9VVH
Looking forward to part 4
Many thanks
Peter, What an interesting story.. One of my old antennas when I lived in the UK, brought back quite a few memories! Still a popular antenna in North America after all these Years. At least now I can refer to your "history" of Mr Varney's antenna! (BTW - Would love to share a cuppa with you and reminisce one day.....( - ex-G4 now VE3)
Great to hear from yiu Terry. 73 Peter
Thx nice background story of the G5RV
Many thanks
Thanks for the video. 👍
You are welcome. 73s Peter
very good video Peter - I learnt a lot from this. I found that I had to add a choke balun of RG213 at the point where the ladder line joins the coax in order to stop rf coming back down the coax to the transceiver. I also found, as you said, that the length of coax affected the swr on certain bands. Maybe a 4 to 1 balun might work instead of the choke? For me 10 metres is the worst match... thanks again...
Nice to get your comments. 73s Peter
Great video. First of yours I have watched. I am considering a G5RV for my garden and I have decided to build one while following your suggestions. KN4VDG from across the pond. 73!
Thanks. 73s Peter
Absolutely Right
73s Peter
Again another enjoyable and informative video. Please can u do 1 on balanced and unbalanced atu, s how to tell the difference thank you. EI8HL 73s.
Hi there. Most ATUs now offer both. But you only need balanced if you are using balanced feeder rather than coax. Peter.
Surely having to use an ATU to match the antenna will incur losses which would cancel out any efficiency gained by using ladder line?
The point is the length of coax is short from ATU to the balun.
Loss per unit length may well be high, but however high a 3 meter coax run from the table to the window means inconsequential total loss. This is especially true if you use a 4:1 balun to do the ladder line to coax translation. That means the VSWR mismatch on the already short length of cable is only maybe 2:1 or 3:1.
Extremely informative for me. I will definitely be knocking one up next weekend now I understand a short length of coax into shack is acceptable 👍GW6BXU
Yes a short length of coax is fine. Check the update and the link below the Update video for coax loss calculation..
This was a recommended video, so I watched it. Very enjoyable talk. KC3BXZ Joe 73
Many thanks. 73s Peter
You are welcome. Peter.
It seems to be a doublet, optimised for 14MHz.
Hi. Check out the Update Video. 73s.
thx ! 73
I was wondering I have a G5rv i bought for $100 US I want to extend it 32 feet in the air and spread it out between two tree's I dunno if it is a 1/1 balun on it I think like you sid you can matech the antenna to about 1/1 but my question is can it withhold say 600 watts on 10 meters or 6 meters I like i said dunno about the balun on the end of it it was commercially made they say it can withstand about 1500 W But i do not need to catch the tree on fire i have a propain tank but it should be far enough away in the air say 60 or so feet up in a tree by rope and the insulators on each end I may have to find another place to stick it I wanted to place it in the back yard and run it N/S so the broad sides would be E/W I will not need more then 100 watts for CW and Digital modes I am a tech so i am restricted to freq based on my licence class How ever I would like to talk on 10 and 8 when i get the chance maybe 400 to 600 watts well tell me what you think. KG5CUO
Hi there. If the balun says 1.5kW I would believe what it says. You are not likely to reach that power level. The antenna is not critical as regards its position. The higher the better. I doubt the gas tank is a danger as these tanks would normally be well protected for domestic use. Peter.
@@watersstanton Yeah I am going to try something like LMR 400 about 75 foot it does not say it on the balun and you can't believe as advertised now days i think thay have 14 ga. wire that runs across at 52 feet on each side with a ladder line in the middle that goes down into a plug but i dunno if it is a balun or just a plug until i raise it and if it is just a plug i will prob replace with a 4/1 hooked up threw the ladder line . Is it critical on how it is hooked up on the ladder becase i dunno amutyjomh about this antenna other then its history as you have explained? KG5cuo I think it does not have a balun on it i may have to ad one..73
as long as i can keep it below 3/1 I can tun it :)
VE4JIM Thank you for this video...I am now subscribed... fought swr yesterday until dark...the only way I could reduce it below 3:1 was by adding about 250 ' of rg8/u I am sure the feedline was soaking up more rf than was going out of the ant...I was thinking of a balun but I was going to build 9:1 because of the 450 ohm ladder line ... would /should it be 4:1 or 9:1??
Many thanks Jim. Nice to hear from you
Thanks for that very good .
73s Peter.
Great explanation! 73
73 Peter
A very well presented video although I disagree with some aspects, the “make up” section should not radiate so I would regard it as close to being a matching section. It is NOT part of the antenna to my way of thinking. Semantics perhaps... The integral 4:1 baluns in most ATUs are in my mind a bad idea, firstly the Antenna is unlikely to be perfectly symmetrical and secondly the phase of the two balun windings is not exactly 180 degrees apart. Another objection is that most ATUs are more efficient dealing with high impedances than low, so I don’t believe the popular baluns are helpful. I think that a common mode choke suitably constructed is a better approach, it “forces” the current in each leg of the feeder to be equal. It is interesting to see the early illustration of the G5RV and to see that it is basically a doublet and was never intended to transition into a low Z feeder as is the norm now. It is somewhat ironic that doublet style aerials are tamed by avoiding resonance.
Hi there. Great to get your inout on the G5RV. Ironically it only seems to have become famous when the low Z was added! I agree it departs from the original idea. Take a look at the G5RV lecture to the NARC on You Tube.
@@watersstanton I will do, thanks for the reply.
watersstanton having now watched Louise Varney's lectures, he does not make many of the claims that people since have. He does mention the "make up" section, and specifically claims it is not a matching section. That section though clearly can move reactance etc around a Smith chart. Strangely enough some time ago I was looking at my 40m dipole and thinking of extending it to 3/4 wave. Sadly you can see where that is heading very nearly the same length. Controversially I think the aerial should be designed for the polar diagram primarily and then figure out how to drive it.
Hi Peter sorry this I nothing to do with RV ant, sorry if I have asked before, but don't Diamond make a 4 meter vertical antenna?, Sirio make them, their made in Italy and suffer from getting full of water and not working according to eham reviews, allthe same....Fred g4vvq.
Diamond don't seem to make any 4m antennas. Peter
The most innovate thing that could happen to antenna design is doing away with ft. Take a few steps back, think about how silly it is.
Put your argument to the US hams and see what response you get!
@@watersstanton lol, no doubt about it. Let's just keep talking meters, back to ft and cutting in metres.... for now we can talk about the 140ft and 3/32 band.
Agree and disagree. The coax length from the ladder line to the radio is VERY critical if you are using coax like rg8x, but if you use LMR-400 for example it wouldn't be critical like he said. The reactance of rg8 and similar coax is horrible at the higher frequencies. While RG8 and similar coax have low reactance at low frequencies, they have too high of reactance approaching 20 meters and starting to get overly horrible at 10 meters if the cable isn't at half wave length 'electrically', for the antenna he is talking about. I guess if you aren't wanting to do the math. I'd stay with high dollar coax, it wouldn't be a big deal or cost for less than 3 meters. Someone will have a scrap of coax like LMR-400 they just can't find a use for.
Coax loss can be worse than a poorly tuned antenna if the coax is cut at or near 1/4 or 3/4 wave length 'electrically'. So yes 3 meters(10 feet) could take a usable antenna system and make it unusable using cheaper coax. While coax like LMR-400 would act pretty much the same way, its reactance is far lower, especially at the 20 meter on up frequencies. So if one uses coax from a ladder line to the radio within a short distance; one should just spend a few dollars more.
er ....not sure you mean "reactance"
@@watersstanton
In electric and electronic systems, reactance is the opposition of a circuit element to the flow of current due to that element's inductance or capacitance.
The reactance of capacitance and inductance determines the "impedance" , impedance of course determines SWR(s). I see impedance as inductive, captive, and simply restive.
A coax is tuned by length. The manufacturers of coax places out technical sheets that can be used to tune(cut to length) coax for low loses,
It should be understood that the match of a load to the transmission line is different from the match of a source to the transmission line or the match of a source to the load seen through the transmission line. For instance, if there is a perfect match between the load impedance Zload and the source impedance Zsource=Z*load, that perfect match will remain if the source and load are connected through a transmission line with an 'electrical' length of >>>one half wavelength