The AM Forum

Well, I ordered 2 mini 75m antennas from MFJ. They only handle 250 W PEP so this is not an indoor transmitting solution, but hopefully will at least be a receiving solution.

The full length 75m whips I have are just too long when put together as a dipole. They are practically bent in half to fit in front of the window and go from  wall to wall. Even standing straight up as a single antenna they go from floor to ceiling and bend at the top.

Hopefully these mini antennas will fit in the window as a dipole and at least provide some receive. They should according to the site and MFJ support they are only 36" (sounds impossible but we'll see) and the front window is 6' so they should fit OK even assembled.

I may not be able to hear the world but hopefully something. The window faces southeast so hopefully I will get to hear some activity. Perhaps even some from my friends in the Mid Atlantic. My inspiration for getting on AM in the first place!

Have you tried 25ft of hookup wire draped around the room?  It doesn't take fancy or expensive antennas for reception.

Yeah, I tried that. It increased the noise floor on 75 a bit but that's about it. The walls in this building are concrete so it's likely there is metal mesh in the walls to give the concrete something to bond to. The walls aren't magnetic, so that rules out steel but doesn't rule out aluminum.

Even VHF/UHF signals are degraded drastically when in an internal room without windows or far from a window in the bouilding. For example the local repeater is full strap with the HT sitting in front of the window. In the center of the room the signal is noisy. I can even null out the signal just by turning the HT at random angles. So something is up with that.

In any event it's likely that I'm living in a Faraday cage.

If you have vinyl windows, you can try stringing up enameled magnet wire thru the widow and under the eaves of your house. It works fine as a receive antenna, and in fine gauges is darn near invisible. Shutting the window is possible and with care won't damage the wire.

I use a version of the beverage antenna for receiving. After a year of using it I would be unwilling to use the same antenna for rx and tx. Noise level is next to non existent. In fact when I first built it there was no signal on the air on 80m and I told myself it was crap because there was no hiss when I connected it. About a year later after hanging a long wire for transmit I decided to try it once more. It was however during the active time of day and was astounded at its performance. Mine isn't fancy either. In fact it is so simple most would never try it. Every once and a while I do a quick comparison of the two receive antennas I have in the shack. Today was a prime example. Noise level on the regular was terrible today. A switch to the beverage style was almost a shock. Almost no noise, and good signals. Really digs them out. I wasn't convinced so when I built it I fudged it a bit. I bought two lengths of insulated or plastic coated binding wire from Lowes. The green stuff. I joined them together and ran them along the rail fence beside the house. They are about 3 feet off the ground right on the old cedar rails. I didnt terminate although I can since there just happens to be an old steel power pole strain take where the wire ended. I figured just to try it and see first. Anyway that was a while go now. The antenna cost me I think something like $17. If you have worked me I used it to hear you. It works very well to say the least. It is nice to just flip the standby switch and not bother with the antenna switching. I know. Most beverages are more complicated than that. I cant help it. It works and works very well.
What would one have to lose trying one of these like this? At worst $17. As for me after over 30 years in the hobby not to mention many years as a SWL I know this is the best antenna I have ever listened on. I have no need of more. I can hear long after the others have thrown in the towel. Its ability to hear is one thing and nothing to be sneezed at. The lack of the usual background noise is almost spooky.  
I wish there was some way to help others understand how well these work but there isn't. I have done my best .
Don  
I have forgotten but I think it is about 60ft total length.  Not 600 or 300 etc etc .     


 

Don ..I have always said any beverage is better than no beverage.....I have found that you should Make them as long and low as you can ...The longer they get, the more directional they become...The lower they are, the better the signal to noise ratio...Terminate a long beverage and it becomes unidirectional...I have never had one over 600ft...I have had great results (Like you are having) with short low wires..Low noise  ..These are my observations......I've converted a few of my ham friends...

Beverages are usually excellent receive antennas. I have several set up for my station. I don't they are an option for N3LRX, unless he can get one out a window or place one on the grounds of the building with with a stealth coax feed to his  apartment.

Yea, I live in a 3rd floor apartment with 4 floors above me and one apt. on either side of me. My front yard consists of concrete and asphalt, no fences or trees.  If I lived in the back of the building on the northwest side I could throw wire out my window and utilize all kinds of trees but that's not currently an option.

I've build a receive loop for 160 and 80.. actually tunable from 1350 kHz to 5 Mhz
It works remarkable well and could be an indoor solution :
http://youtu.be/7Kn-0UxYlRo
(sorry for the low audio on the video)
The one in use now , has a double varicap and remote tuning via a 9V DC injection

More info in the pdf
www.n6rk.com/loopantennas/pacificon.pdf‎

73 Frits W1FVB

well, my mini-tennas are on their way. UPS has possession of them and they should be here Friday. We'll see how mini they are.

Mini-tennas arrived they are actually 48" long but still fit reasonably well in their position. The noise floor on 75 went up a bit compared to the random wire I had hooked up. I guess the test will come tonight when the sun goes down. It still puzzles me why I don't hear anything. No slopbuackets no nothing. Usually there is always someone on the band somewhere. I hope this wasn't another waste of money, I've got 4 antennas now 2 that are way too long and the two I just bought.

Oh well, we'll see.

Well, I'm beginning to think my Faraday theory is accurate. I gotten nothing all day just dead air. No voices, slopbucket or otherwise, and no CW anywhere on the band(s). Much like a microwave oven is a Faraday cage for cell fones this apartment is for HF. :'( I've even tried other bands and just get noise on 2 receivers. Both just get an S4 hiss.

On the brighter side of things I did upgrade my tuner today. I put in an LED for the meter lamp and it's nice! It illuminates the entire meter instead of a yellowy blob of light in the middle of the meter. It also doesn't induce any noise in the receiver like the incandescent bulb did.

Well, that's the bad news and the good news of the day.

What two receivers are you using?

Actually, 3 receivers now. a  DX-200 and 2 DX-300s I'm listening now on global receivers to a group on 3880 and they are strapping in NC. I hear nothing on my receivers. Just noise not even a hint of audio or carrier. Not even a single waa waa slopbucket! Or even the atmospheric noise I hear on the NC receiver. Just a buzzing kinda static. The only familiar voice I hear on the NC receiver is the Chuckmiester. K1KW.

I'm really depressed.. :'(

My bad they are on 3875. They are so clear both sides of center.

Oh, now I'm really insulted. A slinky in Lexington, KY. on globaltuners is doing better at receiving than me. This is bad..