Noisy 14 MHz delta loop - wire or propagation or what?

[AA7EJ]

This may be the stupidest question I have ever posted.
But I am at the end of my rope and looking for answers.

I have build 14 MHz delta loop using STRANDED RUBBER COATED WIRE from electrical extension cord. I think it is 14 or 12 gauge.

I am getting horrendous atmospheric noise ANYWHERE in FT857 receiver range.
At 15 MHz (WWVB) the S meter reads S9+ ( with AGC of course) , same on 10 MHz.
I build a comparison dipole from the same wire and have same noise problem.

This is my FIRST time I used the electrical cord and never had similar problem using smaller gauge stranded wire.

When I first used the delta ( in WPX contest) on 28 MHz there was zero noise.
It transmits just normal.

My next step is to replace the delta with 24 gauge solid insulated telephone jumper wire to see if the noise goes away.

Anything to do with static buildup? There is no static bleed path on the loop.

Am I barking at the wrong tree??

[AC0H]

Did this noise just show up or has it been constant since building the antenna.
The wire used in the antenna won't make a difference in the amount of noise picked up.
The fact that the dipole and delta both pick the nosie up on 20m means it's probably environmental.
Any new little electronic doo-dad added to the house lately?

[AA7EJ]

Did this noise just show up or has it been constant since building the antenna.
The wire used in the antenna won't make a difference in the amount of noise picked up.
The fact that the dipole and delta both pick the nosie up on 20m means it's probably environmental.
Any new little electronic doo-dad added to the house lately?

No new el gizmos added. But the noise showed up after the WPX contest, in force, mainly on 10 meters.
I keep hoping it is just propagation, but it has been that way since the contest.
I'll give it few more days.
What little real signals I hear are pretty normal strength.
But 10 meters is dead, I usually hear few beacons when it is open.
Nothing today.
Thanks for reply.
73 Vaclav

[K8JD]

How do you feed this antenna ?, using a 14 MHz loop on 28 makes me think its some kind of hi Z bal line.
I would try a quarterwave matching section of 75 ohm TV coax and then 50 ohm coax to the rig and skip the tuner and see what happens.
I have had several loops with this feed and all were very quiet antennas.
Single band antennas are more predictable in thier operation.

[AA7EJ]

It has a 2.25:1 trifilar toroid balun.
The noise level is same when fed without the balun.
I assume matching 100 ohms to 50 is close enough for government work. I am just playing around with it.
In theory it should work on even harmonics by itself and the balun should be wide enough to match it on 10 also.
I did some modeling but so far only on 14 MHz.
I am finding out that the the feed point impedance and corresponding resonance vary greatly with antenna height. The antenna is also sloped and I am trying to find out the effect of that also.

But the noise just started after the initial test, that is what is bugging me the most.

I have not decided if I like to keep it 14 /28 capable, but if it is going to be a single band, I am planning to try the matching section next. It seems mechanically more sound, and simpler HI HI HI.

[KF4OKF]

Loops are generally very low noise antennas for receiving. I have a 160m delta loop that I use multi - band here at my QTH in MD and it has very low noise on reception. Since you said you have the same problem with the dipole it sounds like the noise source may be local in nature. Are there any power transformers or power lines in the area? Have the neighbors added anything new recently that may be a noise source?

73,
Tory

[MI6KAK]

During a contest the bands are hot and heavy with very little space for noise. What I mean is you may not have noticed the noise until the contest was over then it was always there. I would agree with the rest of the posts it looks like a local noise problem and not the antenna. Have you used any other antenna before this?