I visited many prospective QTH's in eastside Seattle with a radio/SA and
whip antenna to check for QRM. Perhaps the most significant learning
was that neighborhoods with buried power, including the ~13kv, were a
few to almost 10db quieter than older pole systems neighborhoods. How
much of that noise is from distribution problems vs created (conducted
then radiated) by residences with noisy SMPS is an interesting question.
The proximity to 250 to 325kv grid wasn't as significant, unless in the
immediate (<300ft) near field of the towers.
My QTH has a 325kv line 900ft WNW from my towers and there is little
extra noise from it (also the easy Asia path for me). Fortunately all
the new development to my N to E (EU/AF path) has all been underground
utilities. I still hear better than talking. Amazing how often with 5
over 5 on 20m aimed at EU stations heard on FT8 at -10 can't hear me at
QRO power. QRM and QRN at their end I guess.
I've also noticed that some distant SW noise sources (>1 mile) are
sensitive to weather. More so in the transitions wet > dry and vice
versa. Something to consider when testing for noise. The nearby grid
HV line goes thru a big swamp in that direction and I suspect that
maintenance on that section is not very good as I have never seen
helicopters working on it.
Some friends and I measured noise at a rural 20acre/parcel development
in the Cascades foothills with all underground power and it was about
6db quieter than my QTH even with a number of n*100kv lines about a mile
away. It would have been a great remote site, particularly on 160m.
At 0.6 mile away from my QTH, a pig pole had its grounding wire stolen
and the stub was radiating nicely on 40m. PSE was prompt in replacing
it when I filed a complaint about it as a shock hazard.
Grant KZ1W
Redmond, WA
On 10/20/2022 04:32, kq2m@kq2m.com wrote:
Before I bought the house at my present qth (which has HV lines cross my
driveway near the street ~ 550' from my house), I made a dipole and
brought my radio up to the qth and listened on the dipole as I tuned
around on 10-160. I heard low level noise that sounded like it could be
the HV lines and that repeated at regular freq. intervals but it was
minor and not likely to be a major problem except possibly on 80 and 160.
I bought the qth - that was 28 years ago. With bigger directional
antennas I hear the
noise louder but it is an inconvenience not a major factor and really
not audible on the high bands. The qth overall was worth the
inconvenient noise, primarily on 80 and 160.
You might want to consider doing what I did. Make a dipole and tune the
bands carefully with your radio ONSITE and see what you think. This
will either put your mind at ease or you will realize that it is not a
good idea to buy the house. Either way you you won't have to guess
anymore.
GL & 73
Bob, KQ2M
On 2022-10-19 19:56, Paul F. Merrill wrote:
We are looking at a house in the Northeast that abuts a utility easement
with High Voltage Transmission lines.
Should I pass on the property? The HF towers would be <500’ from the
wires. Given the 4 seasons, ice, humidity, etc. is this doomed to
failure
by its very proximity?
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|