We have NULLS!

Status
Not open for further replies.

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Got the new Wellbrook ALA 1530S+ up and installed in its set location. It's about 40ft from the house and right in-between other backyards -- so it should be fairly quiet. I'm using a RCA (Channel Master OEM) rotator. Delivery time for the loop was 8 days -- which is great from the UK.

The coax is RG-213. I just can't bring myself to use RG-58. :lol:

I'm using 10ft 1.25" EMT conduit for the mast. The loop mast is 5ft 1" white PVC that has been painted matte black with bumper spray. I'm using an 8" gray, threaded nipple and slip-on thread adapter to mate the loop. The Wellbrook has a .748" aluminum mast that is about 6" and it fits with the 3/4 nipple very tight. There's zero movement there. Just to be safe I wrapped that end with a few turns of electrical tape.

The PVC mast, coax and loop was heavier than I thought when it was finally raised -- but the rotator seems fine and there's no struggle. Total height is about 15 ft to the center of the loop.

Everything is working great so far!

Pictures:

ala1530splus1.jpg

ala1530splus2.jpg
 
Last edited:

brandon

Member
Database Admin
Joined
Dec 19, 2002
Messages
3,511
Location
SoCal
hey nick the loop turned out great!
thanks for sharing the photos
 

majoco

Stirrer
Joined
Dec 25, 2008
Messages
4,278
Location
New Zealand
Nice job! I'm sure it will work out well for you.

Not to be a killjoy now that you have it erected, but I would have secured the coax cable with a few more tyraps down the conduit and left a loop of cable where it emerges from the bottom of the antenna, just to take the strain off the joint.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Yeah actually it started out that way. I then pulled on the coax thinking it was "too fluttery." I'll have to get up on my ladder to fix that. Easy fix though. :wink:
 

nanZor

Active Member
Joined
May 28, 2009
Messages
2,807
Be sure to rotate it through 180 degrees to compare the nulls on each side. Ideally they should be the same, but a small amount of real-world imbalance may get you a deeper null on one side as compared to the other.

On my first runs with a small loop, I even go 360 degrees at least once to see if there are any major issues with balance.

I've got a feeling the Wellbrook is much better than my homebrew versions!

Nulls are nice to "hear" - I know the feeling! Congrats - nice install too.
 
Last edited by a moderator:

Turbo68

Member
Joined
Dec 12, 2005
Messages
878
Location
East Devonport,Tasmania,Australia
Looks Good used the RG-58 coax wasnt happy with it changed to Belden-9913 cable worked good too hard to put down the walls then decided to use RG-213 had the 1530 on a rotator for a while last year excellent results sold the rotator got myself a Yaesu-G250 will be up by the end of the year might even put all my loops on rotators.

Regards Lino.

HF ANTENNAS:WELLBROOK-ALA1530,1530L,330S.
 
C

comsec1

Guest
antenna works!

I purchased the 1530 about 1.5 years ago and finally got it set up with a rotator. For anyone interested they do help nulling out local noise. My set up is similar to yours nick, I have about 120' of rg-8 and the same rotator. Mine is only 4' off the ground as I have it hid behind a pine tree and about 50' behind my house. I have mine connected to the AUX REC antenna on a ten-tec omni 7 . I don't have any sophisticated test equipment other than my ear and thats what counts but it sure helps in a high noise enviroment. I have heard others say that the S-LEVEL readings are much lower which seems true for a comparison between my B&W end fed V and my hustler 5btv but without the noise(interference) the signals are easier to copy and makes HF more enjoyable. I would recommend this type of magnetic loop to anyone who has a an interest in HF monitoring. I have noticed that most of the times for the desired signal the direction does not matter, the trick is to null out the local interference.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
I don't have any sophisticated test equipment other than my ear and thats what counts but it sure helps in a high noise enviroment. I have heard others say that the S-LEVEL readings are much lower which seems true for a comparison between my B&W end fed V and my hustler 5btv but without the noise(interference) the signals are easier to copy and makes HF more enjoyable. I would recommend this type of magnetic loop to anyone who has a an interest in HF monitoring. I have noticed that most of the times for the desired signal the direction does not matter, the trick is to null out the local interference.

I would agree completely. I have a very high quality vertical ham antenna that is 36ft and brings in all kinds of signals -- but it also brings in noise. The 1530 is quite a bit smaller and does an impressive job bringing in HF signals.

I believe height may play a part in some directivity. Also, I've noticed that the directivity stops around 12 Mhz.

If you have any interesting in the LW/MW bands then the loop is all but required for quality listening. For 160/80m ham bands it can really help as well.

Like you said, the key is to make the listening enjoyable. I am going to move my vertical to my Icom 7600 and keep the loop on the Perseus.
 

E-Man

Completely Banned for the Greater Good
Banned
Joined
Mar 1, 2004
Messages
841
Location
Global
From everything that I have read for optimal performance you got it. Rotor, 15' height, 50 ohm feed line. And the PVC will insure isolation from ground. Good Job!
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Update

So, I just wanted to update a few things about my loop installation -- an effort to share some "lessons learned" (usually the hard way.)


1. RG-213 is too heavy for the loop. If used with a rotator, then I highly suggest LMR-240. This stuff is very nice. It's my new, favorite coax. It's very thin stuff (probably 1/3rd size of RG-213 or LMR400.) The attenuation properties are virtually identical to RG-213.

2. Do NOT use BNC-SO239 adapters! These things suck -- at least for loops. I purchased LMR-240 with BNC male connectors.

3. When using coax-seal make sure the BNC female connector is part of the equation. When I wrapped up my connectors, it went on perfectly, but I didn't check the wrap around the mating portion to the loop. This time, I used coax-seal around the entire connection and pushed it around the female connector as well to make sure it had a proper seal. I then wrapped it in high quality 3M electrical tape to be extra sure.

4. Leave plenty of slack for the rotating loop.

5. Check #3 again

6. Check rotator and loop alignment. In my hurry to get things raised up, I failed in aligning it properly to the correct compass directions. (I thought I had but ended up off slightly.)
 

ridgescan

Member
Joined
Apr 1, 2008
Messages
4,778
Location
San Francisco, Ca.
Hell Nick I raved about the lmr240 when I replaced both my scanner and HF runs with it. Nobody said a thing. I love it so much I even built my patchchords with it. Far as I know you and I are the only ones in RR running it.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Ridge, that's an excellent idea. I have a local source that provides RG8x for patch cables but the LMR240 might be a better option.

I take it you like working with it -- soldering your own connectors, etc? I need to buy the proper soldering iron. I also need to pick up a heat shrink gun and material so that I can give my cables that professional look. :cool:

This will make it very easy to work with:

Coax Cable Stripper for RG-8X
 

nanZor

Active Member
Joined
May 28, 2009
Messages
2,807
Yep - it is the signal-to-noise ratio that really makes small loops shine, rather than banging the s-meter.

You'll probably find like I did that when copying 80/75m nets, YOU can hear nearly everyone cleanly even at S1/S2 levels, whereas the net participants are running huge antennas, huge power, and have their RF-gain turned way down so that only S9+ signals on their end make it through - and even then they miss some stations that you have no trouble at all with just a tiny loop.

For some fun, do a psychological test and cover up your S-meter and run that way for awhile. Pull off the cover on the dx you hear, and you'll be amazed. :)

Don't get too excited about getting the loop too high as it will make the elevation angle rise. Getting it high will clear obstacles that may affect your loop nulls, or get it further away from localized noise that no null can take out. Raising it high can also be useful for ground-wave or direct local contacts, but for the most part I found that extreme height was not necessary for sky-wave signals, and detrimental at some point to the elevation angle. And of course if you have a common-mode problem, you end up with a "lollipop vertical" with weak nulls. :)

For the most part, I found that unless I had a need for direct-wave local reception, or I needed height to get extra clearance away from very close localized noise, having the loop just about one half to one whole loop diameter above ground worked just fine.

Even though the look angle isn't as low as a true vertical, the signal-to-noise ratio can help make up for that when you are able to do "armchair copy" on S1 signals. Long live the small loop!
 
Last edited by a moderator:

ridgescan

Member
Joined
Apr 1, 2008
Messages
4,778
Location
San Francisco, Ca.
Nick I build my own ends:) I like it because you can just make the patch exactly the length you need. The 240 stays put in the position you place it in once utilized, being it's hardline.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Updated Pictures

These are pictures as of today. I included a close-up of the rotator. It's a great rotator for the money. It's held up perfectly thru the rain, hail, snow and gusty winds.

1530a.jpg


1530b.jpg


rotator.jpg
 
Status
Not open for further replies.
Top