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Old 13th Sep 2019, 9:06 pm   #41
James Duncan
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Default Re: Antenna recommendation for 40 and 80M bands

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Originally Posted by budkor22 View Post
Last night, cut the wire, and put up an antenna. I had to just go by with the garden limitation. I thought the garden was 20m x 20m, but it wa actually about 16-17m at max. And due to trees and hedges, it could only accommodate maximum 15m stretch of wire, and hung on the tree and bent L shaped for another 5m. And that is the centre element to 50 ohms coax.

And 5m of wire was connected to the coax outer braid, and then to the outside water tap, which is connected to the copper pipe of the mains water under the kitchen sink.

And it tunes 15, 20, 40 and 80m band with almost 1.1:1 SWR.

I worked a station in ST. Albans on 80M band CW at late night. I got 569, and he was 569-599 QSB. I was using about 40W pep.

The receiving on all bands has got really quiet (I mean much much less band noise but received signals were same or better), and I heard a 9K and VEs and K9s on 20M in early evening.

I will keep on experimenting with the LF band antenna getting more parts such as baluns, open wire feeders and wire for radials in the future. But will see how this antenna will perform for a while, and if it is no good, then will move on to maybe the Doublet or Loop or GP. Balanced dipole seems a challenge for this QTH due to the house building being at the side of the garden, and making feeder very long.

Here is rough sketch of my LF band antenna I put up last night. I don't know what it should be called. But I decided to make use of the outside tap as part of the earthing, and it seems working OK for tuning at least.

And the PSU doesn't make buzzing noise when tuning the 80M band either. Before it was quite bad with the buzz from the PSU. So some improvements are showing with the HF antenna now being outside.
That is good well done, you have made a Off Centre fed dipole, your 5 metre wire to the water tap is part of the antenna which will tune easily with a old type tuner, no balun, Just see the site I sent you and you will see your antenna, not sure why you are so concerned about earths, your rig has an earth connection and that is your protection, if you mess with an rf earth do not have it connected to the mains earth, radials cut for bands in use enhance these OFC antennas and all vertical designs a lot
an RF earth is not the same as an electrical earth,
Hope to work you on the bands
cheers
MM0HDW
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Old 14th Sep 2019, 12:59 am   #42
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Question Re: Antenna recommendation for 40 and 80M bands

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Originally Posted by James Duncan View Post
Extract:
. . . your rig has an earth connection and that is your protection. If you mess with an rf earth, do not have it connected to the mains earth . . .
Presumably, the part sentence "your rig has an earth connection and that is your protection" refers to a connection to the a.c. mains earth.
So if the rf earth is not to be connected to the mains earth, how do you suggest that is to be achieved, since that 'rf earth' will be joined to the metalwork of the rig . . . which will be at 'mains earth'?

I did make a suggestion in my post 23 to solve that conundrum, but, judging by its responses, it seems that it was not a good idea.

Perhaps I've misunderstood you, or that I've missed something obvious (not unusual )

Al.
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Old 14th Sep 2019, 2:39 am   #43
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Default Re: Antenna recommendation for 40 and 80M bands

If your house is powered via what used to be called a PME connection, then bringing any unbonded earth into it is verboten. Rather a lot of 1960s houses onwards have one conductor a combined neutral and earth. A fault in the supply wiring, interrupting this conductor to one or more houses can cause all the earthed stuff to go live (via whatever loads are on in all the homes affected, combined) The voltage can approach the full 240, and the available current will be the total load current of all the homes affected. There are no fuses in neutral and earth connections!

The 'fix' for this unlikely, but nasty risk is for the wiring regulations to require ALL touchable metalwork in such houses to be bonded together. All water and heating pipes, gas pipes, metal sinks etc. No separate external earths may be brought in. They would create a shock hazard, so local earths are required to be bonded to the provided 'earth'. Someone standing outside must not be able to reach in and touch anything bonded to PME.

There is an RSGB booklet on how to handle these systems. If you are doing anything with earths entering your house, you need to find out what system you have in order to know what regulations affect you.

It's easy to say 'who will know' but in the low probability event of trouble, you can find yourself in a fatal accident enquiry, or with your house insurance ruled void just when you need it. Much as you may want, you can't nip back in a tme machine and change it. The probability of it happening is low, but the consequences can make up for that in nastiness.

Note that the wiring regs have no concern over RF noise and interference. Trying to fix that and staying legal is quite a puzzle. But, other people have had to deal with it already, hence the RSGB booklet.

The vast majority of people are unaware of this issue and don't even know there are different systems let alone know which one they have. Ignorance of laws is not an acceptable defence should anything go wrong.

On a course, I was told that there had been cases of fatal shocks received by people outside touching brass taps for hosepipes.... with a copper pipe to the bonded water system. PME earths aren't allowed to be exported outside. I suspect my house may be the only one on the estate with a deliberate plastic pipe to the outside tap.

Earthing is a minefield, and some of the rules are seriously counter-intuitive.

There often is no labelling telling you what sort of system you have, yet you are required to do different things.

You thought aerials were difficult?

David
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Old 14th Sep 2019, 7:53 am   #44
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Default Re: Antenna recommendation for 40 and 80M bands

The antenna is changing the lowest tuned SWR time to time as well. Sometimes, it goes up, and sometimes it is down. Checked all the connections and seems fine, it looks like more ATU issue?

But 1:1 balun was ordered about 2 - 3 weeks ago. At the time, I thought that would make things simpler for antenna. Just attach some wires at the end, and coax feeder, and it will work. But now I learned that it is not that simple.
But 1:1 balun - would it not reduce the band and EMS noise and also prevent common RF current on the coax feeder at least? Also was hoping it would reduce SWR on the feeder.

I read on the internet - not to get voltage baluns, but get current baluns, and don't get 4:1, but get 1:1. There are a few videos explaining why on youtube, but haven't watched till the end. Was too long video.

Yesterday, HF band condition was poorest I have seen. There was nothing on all bands, and even 7 Mhz was dead all day. The only band active was 80M with many nets. I worked one special event station near London in the early evening on 3.750 Mhz. He struggled copying my calls, but persisted trying, and we made contact. It was good.

I tried again late at night, as someone was calling CQ on 3.740 Mhz, but he couldn't hear me saying my audio was too rough.

I think my HF rig has TX distorted audio issues - not sure if it is mic or the rig itself.

Last edited by ORAWA01; 14th Sep 2019 at 8:03 am.
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Old 14th Sep 2019, 8:01 am   #45
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Default Re: Antenna recommendation for 40 and 80M bands

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Originally Posted by James Duncan View Post
That is good well done, you have made a Off Centre fed dipole, your 5 metre wire to the water tap is part of the antenna which will tune easily with a old type tuner, no balun, Just see the site I sent you and you will see your antenna, not sure why you are so concerned about earths, your rig has an earth connection and that is your protection, if you mess with an rf earth do not have it connected to the mains earth, radials cut for bands in use enhance these OFC antennas and all vertical designs a lot
an RF earth is not the same as an electrical earth,
Hope to work you on the bands
cheers
MM0HDW
Yes, the antenna is matching very well on all bands from 7Mhz and up wards. On 3.5 - 3.790 Mhz, it is 1.5:1 - 3:1 SWR with ATU.

Sure. I will try to be on 80M today between 3.700 - 3.710 Mhz from about 2:00 pm, and 4pm. And in the evening from 8:00pm. And tomorrow, Sunday as well. If you are around, please give us a shout please.

If anyone is around that time on 80m, please give us a shout for giving us audio report and chat tnx.

Call sign is GM0MOP.

73 Jay

Last edited by ORAWA01; 14th Sep 2019 at 8:07 am.
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Old 14th Sep 2019, 8:30 am   #46
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Default Re: Antenna recommendation for 40 and 80M bands

Matching is easy. An effective ATU can even give a good match into a wrong-value dummy load resistor.

Don't concentrate too much on matching. An antenna has to also be a transducer between electrical signals and electromagnetic waves. Otherwise a dummy load would look like a good antenna.

The signal strengths you get from various places matter, but then so does the background noise. on transmit the proportion of the power radiated in a wanted direction compared to that wasted heating things up is the figure of merit.

Matching needs to be close enough for the transmitter to give its rated wellie.

Audio distortion could be RF getting into the microphone connection, if your shack is runninng RF-hot.

David GM4ZNX

running a station for the scouts today. I'll listen around if I'm on at that time.
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Old 14th Sep 2019, 8:49 am   #47
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Default Re: Antenna recommendation for 40 and 80M bands

I feel the audio distortion is very likely to be due to the POWER Mic supplied with the old TS-130SE.

I don't have any other Kenwood/Trio mic, so I am stuck with this mysterious power mic for the time being. The supplier promised to send me Trio mic, but it is not arriving for over 10 days since the promise.

But yes, I used to think low SWR is absolute must for TX antenna, but that is not the case, I learned. That is good to know.

Yeah, please gives us a shout if you are around.
I think we might have worked before on 2M band many years ago. GM4ZNX sounds familiar call to me.

Hope to hear you on the band. 73
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Old 14th Sep 2019, 12:46 pm   #48
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Question Re: Antenna recommendation for 40 and 80M bands

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Originally Posted by Radio Wrangler View Post
If your house is powered via what used to be called a PME connection, then bringing any unbonded earth into it is verboten.
And if the house uses the TT system - which this one does - how does that change things?

Al.
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Old 14th Sep 2019, 1:13 pm   #49
ORAWA01
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Default Re: Antenna recommendation for 40 and 80M bands

Not sure what Earth system this house uses for the mains power, but it is definitely not connected to the water pipes. Checked a few mains wall sockets earth with the water pipes under the sink with DMM. No connections.
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Old 14th Sep 2019, 2:02 pm   #50
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Question Re: Antenna recommendation for 40 and 80M bands

Your plumbing may use plastic pipes in certain places. How old is your house?

Al.
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Old 14th Sep 2019, 2:35 pm   #51
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Default Re: Antenna recommendation for 40 and 80M bands

Yes you could be right. Because I checked conductivity on the drain pipes from the gutter, and it was not conducting. I looked at it closely, and there were some plastic joins between the pipes.

Mains water pipes seem all made of copper downstairs at least. Upstairs bathroom, yes I see plastic pipes.

I think this house had been built in 1950s.
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Old 14th Sep 2019, 5:45 pm   #52
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Question Re: Antenna recommendation for 40 and 80M bands

If your house was built during the 1950s, originally it would not have had plastic pipes. Since yours has - even if simple plastic unions - that suggests some modifications to the plumbing have occurred since then. Many 1950s-built houses had the bathroom downstairs: that might explain it.

You say: "I checked conductivity on the drain pipes from the gutter, and it was not conducting". I would not have thought that the guttering and its associated downpipe(s) would be connected to the mains earth connection: I've never known that & cannot think of any reason why it should be so connected. Plus, if there is high electrical resistance between the gutter and downpipe, that is normal: the joints in such - if they are metal, typically cast iron - are usually made by a type of non-conducting mortar / mastic, W-H-Y.

One further Q.: is the incoming electricity fed to your house by a pair of overhead lines?

Al.
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Old 14th Sep 2019, 6:12 pm   #53
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Default Re: Antenna recommendation for 40 and 80M bands

No, it is not.

The mains cables are passing along one side of the garden. I don't know where they go to. I see a few thick cables about 10 meters high from the ground, and disappearing into the large tree at the corner, and across the hedges of our garden there are blocks of old houses too. I would imagine it goes there. But our electricity must be coming via under the ground. I can't see any power lines above the ground coming into our building at all.


But the drain pipes connected to the gutter = originally I was thinking of using them as stealth HF antenna. So I went out with DMM, and did some investigation, and that's how I found about them. But because of that. I was thinking maybe that type of piping and plumbing is something to do with 1950s houses, even if the mains water and drainage pipes? Just as something for inference I wasn't saying water pipes and gutter drain pipes are connected

But even if part of the water pipes are joined by plastic, it still would be good earth better than nothing, because the pipes gets filled with water often, and will be damp, which might give some sort of connectivity to the rest of the pipes. I am no sure 100% if they are all copper ipes or there are some plastic joins in them.


Anyhow, good thing is that the mains electricity is not connected to the water pipes.

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Old 14th Sep 2019, 6:18 pm   #54
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Default Re: Antenna recommendation for 40 and 80M bands

What's the water supply incomer, metal or plastic?

Lawrence.
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Old 14th Sep 2019, 6:20 pm   #55
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Default Re: Antenna recommendation for 40 and 80M bands

It is metal. Rusty looking.
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Old 14th Sep 2019, 6:25 pm   #56
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Default Re: Antenna recommendation for 40 and 80M bands

I take it that it, or at least any metal pipe connected to it inside the building is bonded to the MET?

Lawrence.
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Old 14th Sep 2019, 6:56 pm   #57
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Default Re: Antenna recommendation for 40 and 80M bands

What is MET?

I am not sure. Only thing that I checked and confirmed is that there is no connectivity between the water pipes and mains electricity here.
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Old 14th Sep 2019, 7:10 pm   #58
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Default Re: Antenna recommendation for 40 and 80M bands

MET is the Main Earthing Terminal in your supply installation.

Lawrence.
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Old 14th Sep 2019, 7:10 pm   #59
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Default Re: Antenna recommendation for 40 and 80M bands

Ah... MET. If it is connected to the water pipe, then there would be connectivity between the wall socket's earth point and the water pipes.

But there is NO connectivity. I have checked a few wall sockets on the walls. No connection.


Today during the day, 80M was not good. There were high level of static noise on the band. Not sure if it is just the band condition during the day, or it is due to some electric devices near by being switched on.

I did call some CQ, but heard nobody on 3.700Mhz.

So I QSYed to 40M band, and worked a very strong EI station. He was copying me well, and gave me 59+. I was usng about 50-60 W into the wire antenna.

He was 59+10, and he was using a 10 meter high above ground vertical antenna.
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Old 14th Sep 2019, 8:18 pm   #60
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Default Re: Antenna recommendation for 40 and 80M bands

The RSGB document referred to by Wrangler is well worth a look. There are two versions of it, the better one being the "Advanced" version http://rsgb.org/main/files/2012/11/U...g_Rev1.3a-.pdf.

If I read it correctly, then it raises interesting questions for anyone who has a vertical aerial with a good ground radial system. It actually suggests that a radio amateur might consider having his house re-wired with a TT mains supply arrangement, though I thought that was against the trend and that safety considerations and the modern regs were pushing people away from TT. That's exactly what I was planning to do; have a new consumer unit installed and go from TT to PME, which the supply people confirm I can do.

Mmm, aerials, aerial tuners, and earthing systems. Stamp collecting would be easier.

B
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