Recommendation for an antenna

[Squad10]

Parelectronics.com states it's a ABS plastic housing, probably custom made but I'm not certain. polycase.com offers a wide range ABS enclosures/housings. Click on this link to LP Series:

Surface Mount LP Series

My Nylon-coated 7 X 19 stainless steel core rope HF antenna connects directly to my SW receiver. The only thing needed is a threaded bolt with washers and nuts to transition the stainless steel rope (receiver feed end) to copper coax so I could solder an RF connector onto the coax.

[prcguy]

Here is a link to an antenna similar to the PAR: http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf

Its rated 7 to 54MHz for transmitting but would probably work find for receive over the 2-30MHz range. You could Google a 9:1 balun for HF and probably find a better core material for the lower freqs or possibly add another winding to the one mentioned.
prcguy

Originally Posted by shortride

Is there anything special about the enclosure that houses the SO-239 other than the 9:1 transformer and having a ground terminal on it and having a way to anchor it? I probably could have one built cheaper than buy one.

Does anyone have a source for this type of enclosure? Can you buy transformers already made up? The wire and insulators aren't a problem.

[shortride]

I ordered a Par Electronics EF-SWL antenna. Hopefully I'll get it shortly before or after I receive my ICOM IC-R75 receiver.

[nickcarr]

Originally Posted by shortride

I ordered a Par Electronics EF-SWL antenna. Hopefully I'll get it shortly before or after I receive my ICOM IC-R75 receiver.

Good. I would also start reading the manual if you haven't already. I presume you also bought coax?

Download link:

Download Details

[shortride]

Originally Posted by nickcarr

Good. I would also start reading the manual if you haven't already. I presume you also bought coax?

Download link:

Download Details

I did buy coax.

[ka3jjz]

Originally Posted by shortride

When would one use the wire hook up on the back of the R75 receiver?

When you are just using a random length of wire to toss out into a tree - or, perhaps more commonly, where the feedline is part of the antenna. The classic inverted L does this (at least some of the sites out there won't mention using coax as part of the lead in, so both that and the antenna comprise the entire antenna).

On the most recent topic, you will need to buy some electrical tape and silicone sealant. Coax (more correctly the exposed joints where you connect to something) isn't waterproof. Wrap that PL259 and seal it up, otherwise eventually water will get into the coax and ruin it

Mike

[shortride]

Originally Posted by ka3jjz

When you are just using a random length of wire to toss out into a tree - or, perhaps more commonly, where the feedline is part of the antenna. The classic inverted L does this (at least some of the sites out there won't mention using coax as part of the lead in, so both that and the antenna comprise the entire antenna).

On the most recent topic, you will need to buy some electrical tape and silicone sealant. Coax (more correctly the exposed joints where you connect to something) isn't waterproof. Wrap that PL259 and seal it up, otherwise eventually water will get into the coax and ruin it

Mike

Thanks for the heads up on sealing the ends and connectors on the coax. I've got a roll of butyl tape that I used on my CB coax connectors to keep them sealed from the weather.

Ever use butyl tape? It works great.

[shortride]

Will an antenna tuner help with reception using the Par Electronics EF-SWL antenna?

[ka3jjz]

With antennas like this, generally no. Besides your R75 is plenty sensitive enough.

Remember you can put more wire on the transformer if you like. It's set up for, I think, 45 foot, but it doesn't mean you can't go longer if you wish...Mike

[shortride]

Originally Posted by ka3jjz

With antennas like this, generally no. Besides your R75 is plenty sensitive enough.

Remember you can put more wire on the transformer if you like. It's set up for, I think, 45 foot, but it doesn't mean you can't go longer if you wish...Mike

What will a longer wire do?

[Token]

Originally Posted by shortride

What will a longer wire do?

That is a loaded question And so many facets to it that any answer will be incomplete, but a few key points here. As a general statement a wire antennas length is related to its best performing frequency range. The longer the wire the lower the “best” performing freq range for that antenna. This pretty much goes for any antenna design for a specific mode of operation for that antenna. By mode I do not mean receiver modes such as AM, SSB, CW, etc, but rather the way the antenna works.

This is going to be a very simplistic description, with some inaccuracies of omission that would take lots of detail to fully explain and resolve. A Readers Digest version, as it were.

A longer wire will push the “best” frequencies of operation lower. It will make the antenna more efficient at lower frequencies. Now, that might sound bad, why do you want the freqs pushed down? But in general it is not a bad thing at all. The antenna, with 45’ of wire, will want to work best somewhere around 10 MHz, and on multiples of 10 MHz, such as 20 MHz and 30 MHz. It will work outside these freqs also, this is why the manual shows patterns at 15 and 25 MHz. It will also work below 10 MHz, but with decreasing efficiency the further you get from 10 MHz.

Any increase in wire length will decrease the “best” frequency, I am arbitrarily picking 90 feet of wire here. 90 feet of wire will push the “best” frequencies down to around 5 MHz and multiples of 5 MHz, such as 10, 15, 20, and 25 MHz, and some in between freqs also, normally falling half way between these points, such as 12.5, 17.5, and 22.5 MHz. You can see now that there are more “better” points of operation falling in the shortwave spectrum, and they are closer together. Also, while the efficiency will fall off below 5 MHz it will not fall of as rapidly as the shorter wire did, so that you get better performance below 5 MHz.

There is also the issue of capture area, or aperture. Bigger antennas tend to collect more signal, the disadvantage here can be the nature of that signal, such as some noise.

Another thing the longer wire does is introduce directionality. As the antenna gets longer, relative to frequency, directional lobes will be introduced tending towards the far end of the wire. The key is the relative to frequency part, so the same antenna, 45 foot, might be almost none directional at 10 MHz, but at 20 MHz the pattern has bent towards the far end a bit, and at 30 MHz it has bent even more towards the far end. The longer the antenna, relative to frequency, the more pronounced this will be, so that a longer wire will show more of this feature. By selecting the orientation of the wire on your property, if possible, you can use this directionality to your advantage. Put a desired target area (such as Europe from the US) in one of the lobes (high points in the pattern) and you will have improved reception from that area. Put a noise source in one of the nulls (low points in the pattern) and you can reduce noise in your receiver. Do not point the end of your wire directly at your desired target area, this will almost always result in less good signal levels from the target.

In general, use the longest wire you can get away with and you will have better performance. Orient the wire with some thought of where are your primary targets. Get the wire away from noise sources. And if one installation does not seem to work well for you try experimenting with different wire locations, orientations, and lengths, you may find something that works “best” for your specific situation.

T!

[shortride]

Token, that's a lot of information to taken in all at once. I appreciate the help and the information as well. Unfortunately it appears the direct of the end of the antenna will point to the south which is not the direction I wanted to list to. I would need a longer length of coax to reverse it and point it towards Europe.

I have two posts that are approximately 70 feet apart that are orientated north and south. One is 30 feet tall and the other 35 feet tall. The post on the north side is the one closest to the house and also where my D3000N antenna is already mounted. I had planned to run the coax for the Par Electronics EF-SWL antenna up that post over to the post on the south of my property. I would need at least 150 feet of coax to reverse the direction of the Par antenna.

[LtDoc]

Ain't harmonics fun?? Also a PITA, confusing, and whatever...
- 'Doc

[nickcarr]

Originally Posted by shortride

Unfortunately it appears the direct of the end of the antenna will point to the south which is not the direction I wanted to list to. I would need a longer length of coax to reverse it and point it towards Europe.

If you want to listen to Europe (and the rest of the USA) then you want the wire to lay along the N-S line. (The receiving lobes are 90 deg to that.)

[nickcarr]

Originally Posted by shortride

Token, that's a lot of information to taken in all at once.

This is why I didn't want to lay too much information in front of you to begin with. As you can tell, other members like to torture new guys.

The point is to try stuff yourself. Every antenna configuration is unique. It's best to start with something that works and then go from there. If you take notes of your listening experiences, then you'll eventually learn what works best for you.

If you enjoy the hobby then you can later invest in an active loop antenna, a bigger antenna and/or both! Certain antennas work best for certain situations.

Don't get caught up in too much technical crap for now... just get it up and start listening. Once you have a baseline then you can start planning for the future.

PS. If you want the technical information now, then start reading:

http://www.amazon.com/gp/product/087...pf_rd_i=507846

http://www.amazon.com/ARRL-Handbook-...=arrl+handbook

[majoco]

Apologies for being late. Here's a couple of charts which I printed out and keep in a plastic folder by the radios for quick reference....


...a quick and dirty guide to the BC bands, Aero, Amateur and Marine. Auckland HFDL is probably not a lot of use to you!

[zl2taw]

hey there Martin,
that was good timing I was looking for marine band plans
as I have been setting up band plans in HRD

I sir thank you

[shortride]

Originally Posted by nickcarr

If you want to listen to Europe (and the rest of the USA) then you want the wire to lay along the N-S line. (The receiving lobes are 90 deg to that.)

So it doesn't make any difference which end is North? That's great!

Originally Posted by nickcarr

This is why I didn't want to lay too much information in front of you to begin with. As you can tell, other members like to torture new guys.

The point is to try stuff yourself. Every antenna configuration is unique. It's best to start with something that works and then go from there. If you take notes of your listening experiences, then you'll eventually learn what works best for you.

If you enjoy the hobby then you can later invest in an active loop antenna, a bigger antenna and/or both! Certain antennas work best for certain situations.

Don't get caught up in too much technical crap for now... just get it up and start listening. Once you have a baseline then you can start planning for the future.

PS. If you want the technical information now, then start reading:

I've already got this antenna book. http://books.google.com/books/about/...d=HAMoAQAAMAAJ

I guess I need to get to it.

Thanks!

Originally Posted by majoco

Apologies for being late. Here's a couple of charts which I printed out and keep in a plastic folder by the radios for quick reference....


...a quick and dirty guide to the BC bands, Aero, Amateur and Marine. Auckland HFDL is probably not a lot of use to you!

Thank you as well Martin.

[nickcarr]

Originally Posted by shortride

So it doesn't make any difference which end is North? That's great! I've already got this antenna book.

Practical antenna handbook - Joseph J. Carr - Google Books

That is correct. The end makes no difference. Obviously, you'll want the coax end where it's convenient for your installation. The higher you can get the wire the better. Stick with the default length for now. If you have the space then definitely look at increasing to 90ft. As Token said that is a good SWL range.

I originally used a end-fed random wire (similar to the PAR) and over the years I went from 60ft to 300ft or more. Once I started "reading" about antennas, I quickly learned that I could have saved time and read the books first and saved myself some work -- but we all learn in different ways. Experimentation can be very enlightening.

Yeah the Carr books are decent and still valid. A tad dated but the principles are still the same. The ARRL books are nice to have and will teach you more specifics about electronics and why antennas do what they do.

[Token]

Originally Posted by nickcarr

If you want to listen to Europe (and the rest of the USA) then you want the wire to lay along the N-S line. (The receiving lobes are 90 deg to that.)

At the lower freq end this will be true, the higher in freq you go the less true it becomes with the lobes bending more and more towards the ends, but never actually on the ends of the wire.

From the OPs location the best layout (for Europe / North Africa) might be slightly skewed off the N/S line, say NW to SE. For the US dead N/S will be the answer. But it is not going to make a huge difference. Pretty much any layout that does not point the end directly at the desired target will be OK, with only moderate gains from having the wire layed out exactly correct, until the wire gets very long. The longer the wire the more critical the layout. With the stock 45 feet of the PAR the layout is very forgiving through the majority of the HF spectrum.

Try the most convenient layout first, if that works then that is all you need. Experiment as you gain knowledge and if you have the time/desire to.

T!