Clifton Labs Active Antenna

[N4LTA]

Thanks to everyone who helped convince me to get this antenna. I just got it all installed and tested and I am, to say the least, excited about it.

We have a 2 1/2 acre pond in the neighborhood and it is down a bit so I put a piece of 1" rigid conduit in a hole 3' deep with concrete and mounted the antenna about 7 feet high and fully extended the whip. I also drove a 1/2" copper pipe ground next to the  mast which is right at the pond edge. The ground should be excellent. I ran quad shielded filled RG6 about 25 feet to another pipe and another driven ground.  A common mode choke as described by Clifton Labs was mounted on the pipe about 18" from ground level and the conduit shield grounded before the choke. From there about 250 ' of RG6 was run to the shack and run through another common mode choke of the same type.

Tonight I receieved France, Britain and Iceland on LF strong enough to demodulate the AM and very audibly hear the station. Before, with a 80 meter dipole and choke the best I could do was just detect a signal sometimes. The chokes reduce noise on either antenna at least 3 S units.

Would have never believed I could do this well with such a simple antenna stystem.


Pat
N4LTA

[WA1GFZ]

Glad to hear your story since I bought 4 kits to build a 4 square. I was planning a spot out back near the stream.

[Steve - K4HX]

What sort of chokes? Excellent results.

[N4LTA]

Go to his site and it is described and the manual is shown with excellent photos.

The common mode choke is for receiving only for LF through HF.


http://www.cliftonlaboratories.com/Documents/Z5100A%20Manual%2001.pdf


They cost about $40 or so to make. It involves 26 feet of RG174 run through 4 ferrite cores (actally 5 as one coil has two cores). They all fit in a 4 x 4 x 2" plastic junction box. These things work very well - it dropped the noise on my 80 meter dipole at least a couple of S units on 75 meters.

I have become a real beliver in common mode chokes for the power and RFs feed in the shack.


Pat
N4LTA

[Steve - K4HX]

Thanks for the link Pat. I have chokes on my Beverages and K9AY but they aren't designed for LF. I can still hear pretty well down there with the K9AY. I logged about 20 NDBs a few weeks back but I didn't hear any European BC stations.

[N4LTA]

That is about what I had been receiving with my 80 meter dipole and a common mode choke.

When I first heard the LF commercial stations, I though it was intermod from local BCB stations until I looked at the frequency and switched to AM. I could  clearly hear the french language. Then I looked around and could hear two other European stations.

Pat

[N6YW]

I assume you're referring to the model Z1501 antenna? I wonder if this application would work for me here at home. I have a 30' X 90' lot and only room for a Vertical, which is what I use. A DX Engineering 43 ft. non resonant model with a tuned counterpoise. My question is, are you using it strictly for BC listening or do you use it as a receive antenna for Ham Band use too?
 I can access the entire Venice Canals here where I live (Venice Ca.) and bond the grounding easily. This would mean I would easily have 10's of thousands of square feet of water to use, and it's salt water fed by the grand canal from Marina Del Rey.
The performance you are suggesting would be wildly welcomed here because I run several nets every week on the Left Coast, and very useful in grabbing otherwise unreadable weak signals. I will read up further on his website. Thanks for posting this.
73 de Billy N6YW

[N4LTA]

I gave the antenna a good test this afternoon and I am even more impressed.

Yes - it works on all HF bands -  I monitored 3885 with my K3 and it did an excellent job and was quiet. My K3 has a receive antenna connection so I will likely use this antenna on 80 and 160.

This afternoon in about an hours time, I copied about 40 NDBs  - many were over 300 miles away. The main thing is that I copied many closer ones that were covered up in noise on my other antennas. In the time that I was monitoring, I probably copied 20 NDBs that I have never copied before. The longest path was a NDB in coastal Va probably close to 500 miles away.

Tonite, with tons of QRN crashing, I copied the French LF station loud enough to listen to the music and voice.

Also copied Algeria good enough to hear the music and voice on AM.

Worst problem is that I am using a R75 with a good lowpass filter - but several close in NDBs rip up the R75 front end. I am working on a good stable up converter to use with the K3.

Pat
N4LTA

[N6YW]

That sounds excellent.
Forgive my ignorance, but what is an NDB? I am pounding my brain trying to decode the abbreviation.

[N4LTA]

Non Directional Beacon - used for aircraft navigation   they are loacted from 200 Khz to about 530 Khz and there are hundreds of them in the US and thousands in the world.

Pat

[VK7ZL]

I have been using an active antenna designed by PA0RDT (details of the antenna are on the web) primarily for NDB's and Navtex on 518Khz and have logged stations at distances of over 12,000Km using an Icom R75 receiver.

Check my web site for details of the loggings shown on Google Earth maps.
http://www.users.on.net/~bobw/vk7zl/

It would be interesting to compare the two antennas side by side.

Bob

[N4LTA]

I built one of those but have not given it a good test as the Clifton antenna came in and I put my attention on it. It is hanging in a tree about 100 feet from the house.

Last night was a very pleasant learning experience for me. In about 45 minutes I logged 20 or so new NDBs including two Canadian NDBs, one in the Bahamas, three in Ohio, and one in NY. NDBs were everywhere and Argo really helped get them out of the qrm caused by local NDBs. Also heard a 500 Khz QSO between two 500kc.com stations and three 500 kc.com beacons plus another sttion transmitting Opera. Later the European LF station were S7 and full copy.

The R75 crapped out with IMD caused by several close NDBs and I need to get my K3 and an upconverter going.
The local ND about 13 miles away is 30 over and it wipes out 20 Khz or more of prime bandwidth (FRT 248 Khz) in the R75.

I sure would like to see that 500 Khz ham band approved - even with a 1 watt erp power limit would get some good local distance and dx at night. It would be lots of fun building a 100 watt transmitter (class D or E) to a short vertical.

Pat
N4LTA

[VK7ZL]

Pat

It would be good if you could compare the two antennas. With the PA0RDT antenna it is important to ground the shield of the coax at a couple of points before entering the shack.

I don't have a problem with front end overload the problem I have is that every beacon is North of me so it is difficult to seperate them out at times. I am going to build an 8' loop this Winter which will allow me to null out the Northern beacons and hopefully catch a few more in the Pacific area.

Navtex on 518Khz often produces some interesting and unexpected results.

New Zealand already has 600M priveleges and we did a trial here in Australia in 2010. There were some CW stations on 507Khz (very easy to copy) and digital signals on 508Khz with typically 1W ERP.
ZL1EE was reasonable copy here most of the time using Spectrum Lab to decode the signals. The VK1 and VK2 stations were more difficult as they were only running about 500mW.


The big problem with 600M is an efficient transmit antenna. This is the ideal setup:

http://lnx.arimi.it/?page_id=788


Bob

[Iz2jgb]

Hello Bob and all The amfone group.

I'm new to The forum , this is my first post.

Our club station (IQ2MI) has been granted
A temp permit to operate on 600mt
So we have build that Marconi antenna
That performs very well in tx. With
An ERP of 25 mW we have been heard
Around The europe , up to 2000km!

For any interested in that antenna
I can be reached by email : iz2jgb@arimi.it


73

Giorgio

[KA0HCP]

Welcome, Giorgio!