Re: East, West, and in between on 160m


Matthew King - AK4MK
 

Hmmm.... at 30ft, that antenna is about 0.07~ above the ground on 160m. That's the equivalent of a 20m dipole about FOUR FEET off the ground. I think we all have an idea of how well that'd work for anything other than very close-in communications.

An end-fed antenna really likes to be right at 1/2~ long at the lowest frequency of interest, so that'd be about 255' on 160. A true "long wire" antenna is a full wavelength or longer at the lowest frequency of interest, or just over 500 feet.

As Carr says  in the Practical Antenna Handbook regarding an end-fed antenna (an inherently unbalanced antenna), " ...the user must realize the most important thing he or she can do to improve the antenna is to make sure there is an excellent RF ground system attached to the chassis of the ATU (tuner) or transmitter where the wire connects."  The emphasis is mine, and is meant to indicate that a piece of #6 wire to an 8 foot ground rod isn't an effective RF ground. That's a safety ground. An effective RF ground is a counterpoise or radial field. 

Right now, with no counterpoise, your feedline is being forced to be the counterpoise, or at least it would be without the isolator on it. I'm of the opinion that you're much better off WITH the isolator so that you're not bringing RF into the shack on the feedline, but I'm also of the opinion that you NEED a counterpoise, especially with the isolator on the feedline. No matter how productive the antenna may have been to this point, an effective counterpoise would make it much more so, especially on 160 where it's already very low and very short.  There's not going to be a whole lot of efficiency there either way, but the counterpoise should help quite a bit.

In effect, you have three things you can do to improve your antenna:

Get it higher
Make it longer
Give it an effective counterpoise system

Several radials (8-16) just as long as you can make them and fanned out equally (as obstacles allow) hooked to the ground post on your matchbox should make a real difference in the performance of your antenna on all bands. More radials are better, if you can do it, up to a point of diminishing returns of about 40 radials. If the isolator is currently at the feedpoint, you could move it to the shack entry point instead and that'd make your feedline radiate and be a very minimalist counterpoise. It may well bring common mode current close enough to your shack to make weird things happen to speakers, computers, monitors, TV's, etc... as well, though.  If absolutely NOTHING else can be done, at least do a short piece of #6 wire to a fully driven ground rod with a well-biting clamp on it.  That might make some difference, but nothing approaching that of a real counterpoise.  

Good luck with it, friend Jim - I'll be out spreading more radials myself in the spring!

73

Matt
AK4MK

On Thu, Feb 1, 2018 at 2:11 PM, Jim K5SP <jinnis@...> wrote:

No counter poise.  Am using the 88 foot QSO-King by NU0R.  It's up about 30 foot. Has a line isolator in the feed coax.


Jim


On 2/1/2018 12:34 PM, Matthew King - AK4MK wrote:
Hey, Jim - what sort of counterpoise are you using on your end-fed wire?  How high is it? How long is it?

Inquiring minds wanna know more!

73

Matt
AK4MK

Virus-free. www.avast.com

On Thu, Feb 1, 2018 at 1:11 PM, Jim K5SP <jinnis@...> wrote:
Using an end-fed wire. Oriented kind of NW-SE. And running about 50 watts.  Crank it up to 80 watts at times on this band, but any higher start getting ALC.  SWR is about 1.4 on the wire.

My contact the other evening was with KX4WB who is in TN, so think I am getting out East.

Have a Gap Titan DX vertical, but it doesn't want to load on 160, even using an external tuner instead of the rigs internal tuner.

On the top band, I am starting to feel like Barry does on all bands.  hihi

Jim K5SP


On 2/1/2018 8:10 AM, Rick - N7WE wrote:
Jim-

You may have said earlier and I missed it, but what are you using for an antenna on 160?  If it is a wire, how is it oriented?  How much power are you using?

Rick - N7WE


On 2/1/2018 08:34, Jim K5SP wrote:

And I am curious about it also. The other evening I could see 4-5 stations, with great copy on KX4WB and some copy on the others.  But the only one that I could QSO with was KX4WB, nobody else would respond. It seems that in my location, since I can see/hear some of the east coast stations, I should also be able to see Barry, but no luck there.

Can we get some midwest stations on?

Jim K5SP








--
Jim,  K5SP #483
Member Services Director






--
Jim,  K5SP #483
Member Services Director


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