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Directional 75M DX Receiving Antenna




 
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Author Topic: Directional 75M DX Receiving Antenna  (Read 39347 times)
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WA1GFZ
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« Reply #50 on: March 01, 2009, 01:04:59 PM »

yes down at the noise floor could be unstable. I would think a low pass filter ahead of a rectifier would strip off some of the HF noise. I've never played with diversity except to use multiple receivers. I compare analog to SDR all the time and mercury is about eqiual. QSD, analog beats it every time. At least against the Racal AM detector.
Operating FM like the public service radios makes voting easier.
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Steve - WB3HUZ
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« Reply #51 on: March 01, 2009, 09:07:14 PM »

The two receiver system is superior because it uses signal from both antennas all of the time. The voting system uses only one system and thus can be throwing away useful signal at time.

Somewhere around here, I have a voting system design from the 30's. It was pretty simple and used latching relays, IIRC.

Here's another clip of the K9AY improving things on AM. Listen to the Tron on 160 meters, 26 February at about 10PM ET. The band is quite noisy and his signal isn't all that good on the dipole. Switching to the K9AY cleans it right up. On the clip, it's hard to hear when I switch the antennas (there is no audible click). Instead you will hear what sounds like Timmy fading and the static coming up. He wasn't fading. That was me switching to the dipole.

Tron is 600 miles from my location, but I saw similar results on stations as close as 250 miles.

* wa1hlr27feb090250z1885.mp3 (493.72 KB - downloaded 352 times.)
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K1JJ
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"Let's go kayaking, Tommy!" - Yaz


« Reply #52 on: March 01, 2009, 09:20:36 PM »

Yep, it's definately working well on those two tapes, Steve.   Reducing the static and noise is the name of the game.

Last night when we were working Europe, there were stations that I could not hear on my low dipole at all, but 100% on the Beverage.   You were able to give these same stations good reports, so I know your K9AY and new Bev are working well - especially you being another 400 miles farther southwest than me from Eu.

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
WA1GFZ
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« Reply #53 on: March 01, 2009, 09:28:05 PM »

very true Steve the brain is a lot smarter than a comparator
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Steve - WB3HUZ
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« Reply #54 on: March 01, 2009, 09:29:46 PM »

I know yours is. I'm not so sure about mine sometimes.   Grin

very true Steve the brain is a lot smarter than a comparator
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Steve - WB3HUZ
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« Reply #55 on: March 01, 2009, 09:45:59 PM »

You were making me work on some of them! A few I couldn't copy. I could tell they were in there and maybe get a word now and again, but nothing substantial. I remember when you, Brent and I got on and worked some DX back around 2004 or so. There were quite a few I couldn't copy or even hear that night, so things have gotten some better on this end. Gotta be able to hear those mud ducks, KAYMOAN!!


Yep, it's definately working well on those two tapes, Steve.   Reducing the static and noise is the name of the game.

Last night when we were working Europe, there were stations that I could not hear on my low dipole at all, but 100% on the Beverage.   You were able to give these same stations good reports, so I know your K9AY and new Bev are working well - especially you being another 400 miles farther southwest than me from Eu.

T
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ab3al
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« Reply #56 on: March 01, 2009, 10:04:27 PM »

Just buy a moonraker 6 and stop thinking so hard about all this. beverage is what you set next to the cb
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Steve - WB3HUZ
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« Reply #57 on: March 01, 2009, 11:39:16 PM »

Naw, just an Antron 99.   Tongue
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WU2D
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« Reply #58 on: March 02, 2009, 09:22:57 AM »

Frank,

Get out your shovel!

My two beverages, the 800 footer and the two beverage 40M array (278 feet each with 90 ft spacing) both are in those big old pine trees and they seem to have little effect. 

At MOT we had voting systems to fill in dead spots for UHF police handies used in urban situations. Tac was the older system and Spectra Tac was later (late 70's). At DTC we used a 5-way voting system for microwave video and it switched on the line retrace (fast). We tried a VHF system which used two verticals spaced 1/2 lambda. It worked to fill in dead spots but in an FM system, it gave little in the way of real improvement. FM systems have good limiting and this makes up for most fades. Yes these systems simply throw away the unused (and presumed to be bad) channels.

Mike WU2D
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Steve - WB3HUZ
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« Reply #59 on: March 02, 2009, 01:37:44 PM »

That's why you were able to hear the Euro AMers on 3705 kHz last winter!



My two beverages, the 800 footer and the two beverage 40M array (278 feet each with 90 ft spacing) both are in those big old pine trees and they seem to have little effect. 

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K1JJ
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« Reply #60 on: March 02, 2009, 01:47:59 PM »

Mike,

I remember last year we talked about your new phased Bevs for 40M.

How well has it been working compared to your reference dipole on 40M?   Is that a switchable, terminated pair for both USA and Eur? 

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
Steve - WB3HUZ
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« Reply #61 on: March 02, 2009, 07:18:07 PM »

Here's Mike working the Euros, as heard in the Netherlands.


That's why you were able to hear the Euro AMers on 3705 kHz last winter!



My two beverages, the 800 footer and the two beverage 40M array (278 feet each with 90 ft spacing) both are in those big old pine trees and they seem to have little effect. 


* WU2D WB3HUZ 3705 AM.MP3 (1951.14 KB - downloaded 336 times.)
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K8WBL
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« Reply #62 on: March 03, 2009, 10:35:22 PM »

Don't forget about the Pennant antenna, not so dependent on soil conditions and good nulls, can put it up in the air above ground and obstacles..

http://www.amatorradio.se/downloads/pennant.htm

73, Tim K8WBL
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WU2D
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« Reply #63 on: March 04, 2009, 07:00:14 AM »

Hi Steve,

Yes the 40M Bev has been a win.

Nice recordings - I did not have a chance to listen this year as I was travelling all of January. I did manage one project last month, a Paraset transceiver. This is something that I have wanted to build for a while, and yes it works on the Beverages too. It is a cute little spy rig. works like a champ with a two tube regen and a 6V6 oscillator at 6W out!

73's Mike WU2D


* ParasetContactWU2D.jpg (739.97 KB, 2109x1413 - viewed 620 times.)
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Steve - WB3HUZ
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« Reply #64 on: March 04, 2009, 08:49:06 PM »

That Paraset is too cool.

I hope we get quiet conditions this weekend. With the time change it might be the last good chance to work the Euro AM boys.

Some more from January 2007. Doesn't seem like it was that long ago!

* wb3huzwu2dw1iakykyv6jan073705.mp3 (1963.26 KB - downloaded 395 times.)
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K3ZS
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« Reply #65 on: March 05, 2009, 04:57:42 PM »

I google Paraset -  Looks like a lot of these have been reproduced.
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WU2D
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« Reply #66 on: March 05, 2009, 10:19:55 PM »

Yes the set has a following that started in Europe a few years ago and quite a few people have been making them and using them on the air.

The Italians got things started, then the Scandanavians and then the Brits and pretty soon hams all over were building them. Hey a three tube XCVR with historical significance, using common parts that really works is a good club project.

http://www.qsl.net/ik0moz/paraset_eng.htm

Mike WU2D


* WU2DParasetConstruction.jpg (686.84 KB, 2304x1728 - viewed 578 times.)

* parasetsch.gif (39.62 KB, 790x548 - viewed 587 times.)
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Steve - WB3HUZ
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« Reply #67 on: March 06, 2009, 11:25:53 PM »

Very nice. But I guess you can only use it in the deep woods or in an attic during the dead of night.   Wink
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K6JEK
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« Reply #68 on: March 07, 2009, 08:15:02 PM »

1) Anyone using 75 ohm flooded CATV cable to their receive antennas?  It's what DX Engineering is advocating these days. The RG-62A to my receive loop #1 is old and looking rough. I'm pondering this as replacement. The F connectors look clever too since I already have them and the tool but I would have to change my world.

2) Anyone using a small K9AY?  The one I find when I Google (I've lost the original article) is a 160/75.  For just 75 maybe I could shrink it.

3) Could you guys move?  I've been experimenting with phased small receive loops.  I point each at the local HNG (horrendous noise generator) to null that out then fool with the phasing to listen east.  I tune in one of you jokers, turn on the product detector, fiddle with phase and gain until your carrier is nulled then flip the phase.  S/N on your signal goes up but it's not dramatic. I'm beginning to think that all the darned noise on the band is over the US of A and that cutting out the noise from the Pacific isn't doing me much good.  So how about moving to Hawaii? The weather is better.
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WA1GFZ
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« Reply #69 on: March 07, 2009, 09:25:07 PM »

Ca is a weird place. Such a big state but people are packed in like chickens with tiny yards. It always reminded of a study done on rats confined to small spaces. Maybe you should move this side of the big hill.
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Steve - WB3HUZ
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« Reply #70 on: March 07, 2009, 10:57:24 PM »

Quote
1) Anyone using 75 ohm flooded CATV cable to their receive antennas?  It's what DX Engineering is advocating these days. The RG-62A to my receive loop #1 is old and looking rough. I'm pondering this as replacement. The F connectors look clever too since I already have them and the tool but I would have to change my world.


Yes, works great. I bury mine. Protects it from the lawn mower and reduces common mode current noise.
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K6JEK
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RF in the shack


« Reply #71 on: March 08, 2009, 12:33:50 PM »

Quote
1) Anyone using 75 ohm flooded CATV cable to their receive antennas?  It's what DX Engineering is advocating these days. The RG-62A to my receive loop #1 is old and looking rough. I'm pondering this as replacement. The F connectors look clever too since I already have them and the tool but I would have to change my world.


Yes, works great. I bury mine. Protects it from the lawn mower and reduces common mode current noise.
Steve,

I've never used the stuff.  Can you solder regular PL-259/UG176's to it or is it better to go with the F connectors and adapters where I have to?

Ca is a weird place. Such a big state but people are packed in like chickens with tiny yards. It always reminded of a study done on rats confined to small spaces. Maybe you should move this side of the big hill.
Indeed it is. We used to think of it as two states, north and south jammed together but it's really east/west.  The eastern part of the state is agricultural.  CA is the biggest ag state in the country.  The coast is crowded in different ways near SF and LA.

I have 1/3 acre acre in Silicon Valley which is huge by CA suburban standards but it's crummy from an antenna perspective, a triangle with a power line along the base.  The hypotenuse gets the dipole, the short side the receiving loops and the base gets nothing.  The redwood trees are in the wrong places too.

Instead of moving to your side of the hill, how about stopping right on top?  That seems interesting if cold.
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WU2D
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« Reply #72 on: March 08, 2009, 02:19:58 PM »

I have been using some nice Belden RG-6 for the Bevs that I scrounged - it is really low loss stuff.

Mike WU2D
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Steve - WB3HUZ
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« Reply #73 on: March 08, 2009, 08:46:24 PM »

Jon:

I never tried to put a PL-259 on the stuff. The snap F connectors were just too easy. I would imagine you could put any appropriately sized connector on that coax.

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KD6VXI
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« Reply #74 on: March 08, 2009, 09:11:11 PM »

Jon:

I never tried to put a PL-259 on the stuff. The snap F connectors were just too easy. I would imagine you could put any appropriately sized connector on that coax.



Mini-8 reducers (the numbers escape me ATM) work great.

--Shane
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