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Title: 80 Meter Driven Array Post by: W1IA on November 10, 2007, 09:48:04 AM It is up and has been a fun night! The intial testing for the antenna was great.
Info: 2 elements cut for 3800 kHz spaced at 55 feet up 65-70 feet. Fed each with 3 half waves into shack and 115 degree phase delay in one element. Over the pond was a typical 3-4 dB with an average of 15-20 dB front to back. The input impedance is around 18 ohms with an X = 16 @ 3800 kHz I used my trusty Johnson Matchbox to match the input impedance to use for 250 watts. Today I hope to finish the front/back switching etc.. Along with the phasing box to change delay line from 90 to 135 degrees. Brent W1IA ;D Title: Re: 80 Meter Driven Array Post by: K9ACT on November 10, 2007, 02:38:08 PM Guess I didn't make my question clear last night or condx garbled it but....
When pointed at us, you were nominally the same as the dipole. When pointed across the pond, you were barely readable and about 15 db below the dipole. I understand why getting rid of the backside noise is good but I do not understand why it is not 15 db above the dipole when pointed this way. Jack Title: Re: 80 Meter Driven Array Post by: Steve - WB3HUZ on November 10, 2007, 03:01:19 PM Quote 15 db above the dipole Because the array has nowhere near 15 dB of forward gain. You should see 3-5 dB over the dipole under perfect conditions. With fading, antenna placement, propagation modes, you may not be able to tell any difference. Congrats on getting the array up and working Brent. Hope to hear it on the air tonight. I'll have to work harder now to strap you in the DX Window, when working mobiles in Moscow with XYLs named Svetlana. Title: Re: 80 Meter Driven Array Post by: WA1GFZ on November 10, 2007, 05:33:02 PM very cool Brent.
The performance sounds the same as my set up worked. I was just out in the woods today looking at the tree that will not release my north element. I think I may saw it down and put the ant back up. Now consider this. Add another 42 feet of 50 ohm line to each run. This will raise the Z. Then do the splitter with with 70 ohm cable. I found an odd multiple of a quarter wave for the feed line worked better. Actually I tuned the length for best VSWR with series stubs. fc Title: Re: 80 Meter Driven Array Post by: N3DRB The Derb on November 10, 2007, 07:05:41 PM Jack,
thats a serious scope in your avatar. I have begun collecting small Japanese made refractors from the 50's and 60's for fun. Towas, Sears, etc. Derb Title: Re: 80 Meter Driven Array Post by: K9ACT on November 10, 2007, 08:01:03 PM Jack, thats a serious scope in your avatar. I have begun collecting small Japanese made refractors from the 50's and 60's for fun. Towas, Sears, etc. Derb You might get a honk out of the picture I took of The Great Globular Cluster in Hercules with a dept store Tasco http://schmidling.com/tasco.htm The point of this exercise was to demonstrate that one's money is far better spent on a good mechanical mount then on glitzy expensive telescopes. Having said that, a quality scope helps also http://schmidling.com/m13.htm js Title: Re: 80 Meter Driven Array Post by: Steve - WB3HUZ on November 10, 2007, 08:21:57 PM Quote The point of this exercise was to demonstrate that one's money is far better spent on a good mechanical mount then on glitzy expensive telescopes. Most especially when taking time lapse photos. The inexpensive CCDs have revolutionized amateur astronomy, although I see you used film in some of your shots. Cool. Title: Re: 80 Meter Driven Array Post by: Todd, KA1KAQ on November 10, 2007, 10:24:42 PM I have a 4.5" Newtonian Reflector, 450x. Haven't used it in years. Makes those moon craters look like swimming pools, but Jupiter and its moons are fuzzy due to marginal optics. Brent, condx were poor last night, but for what it's worth: when you were on the array I could barely tell you were in there. On the dipole, I could at least hear you and make out about 50% of what you were saying. So it would appear to be working? Title: Re: 80 Meter Driven Array Post by: K9ACT on November 10, 2007, 11:24:46 PM Quote Most especially when taking time lapse photos. The inexpensive CCDs have revolutionized amateur astronomy, although I see you used film in some of your shots. Cool. Actually, the inexpensive CCD's are just about useless for time exposures as the noise buildup precludes exposures longer than a few seconds. The CCD cameras used for astro imaging use Peltier devices to cool the chip and all sorts of other tricks to minimize noise. I started doing this long before they existed and film was all there was. Film is still the only option for large format but even that will soon be history as Kodak quit producing TechPan which was the only film really suited to astrophotography. Not only is electronic superior in every other respect but combined with computers and software, we (amateurs) routinely take hundreds of images, sort out the best, stack, average and process them for detail impossible to get with the largest professional scopes available only a few decades ago. CCD was clearly a revolution is astronomy. js Title: Re: 80 Meter Driven Array Post by: K9ACT on November 10, 2007, 11:38:41 PM I have a 4.5" Newtonian Reflector, 450x. Haven't used it in years. Makes those moon craters look like swimming pools, but Jupiter and its moons are fuzzy due to marginal optics. As a point of interest, under perfect conditions and with perfect optics, the maximum resolution possible with a telescope is 50 x the aperture in inches. This would be 225 for your 4.5" Newt. The 450x eyepiece is Madison Ave stuff. It is useless. In the real world, 25 x A is more realizable. There are two reasons why bigger is better in scope. One is this resolving power issue and the other is light gathering power which relates to what you get with a given exposure time or what is visually visible. js Title: Re: 80 Meter Driven Array Post by: Steve - WB3HUZ on November 10, 2007, 11:41:32 PM Quote Actually, the inexpensive CCD's are just about useless for time exposures as the noise buildup precludes exposures longer than a few seconds. The CCD cameras used for astro imaging use Peltier devices to cool the chip and all sorts of other tricks to minimize noise. For sure. When I say inexpensive, it's relative to the cost of prior generation electronic cameras and/or film. If amateur astronomers can afford something, it's inexpensive by definition. I've been doing the stacking and averaging of images since the early 80's. Title: Re: 80 Meter Driven Array Post by: K9ACT on November 11, 2007, 12:28:17 AM Quote Actually, the inexpensive CCD's are just about useless for time exposures as the noise buildup precludes exposures longer than a few seconds. The CCD cameras used for astro imaging use Peltier devices to cool the chip and all sorts of other tricks to minimize noise. I've been doing the stacking and averaging of images since the early 80's. People were doing that with film back then but that was over my pay grade or patience. What is really cool is that during the most recent Mars apparition, people were using $50 web cams to capture video streams and running this through automatic sorting programs which found the best of thousands then stacked and averaged them. They produced some very impressive pics. I evaluated this myself but concluded that I could do better with fewer better pics with a real camera. Check out my Mars pages. Unfortunately, aside from Mars then, Jupiter and the Moon, you quickly run out of light for web cams and are stuck with time exposures and back to cooled CCD's. js Title: Re: 80 Meter Driven Array Post by: K6JEK on November 11, 2007, 12:39:11 AM It is up and has been a fun night! The intial testing for the antenna was great. Brent, I would think you could get 6 dBd gain. I'm using something similar except, unfortunately much lower. Modeling showed 6dBd, if I recall correctly. I wrote this thing up for Electric Radio a couple of months ago. You'd think I could remember!@#Info: 2 elements cut for 3800 kHz spaced at 55 feet up 65-70 feet. Fed each with 3 half waves into shack and 115 degree phase delay in one element. Over the pond was a typical 3-4 dB with an average of 15-20 dB front to back. The input impedance is around 18 ohms with an X = 16 @ 3800 kHz I used my trusty Johnson Matchbox to match the input impedance to use for 250 watts. Today I hope to finish the front/back switching etc.. Along with the phasing box to change delay line from 90 to 135 degrees. Brent W1IA ;D I can find the modeling if you want it. I'm quite fond of the antenna. Title: Re: 80 Meter Driven Array Post by: Steve - WB3HUZ on November 11, 2007, 12:45:41 AM Quote People were doing that with film back then but that was over my pay grade or patience. Wow. I would imagine so. Sounds painful. What I was doing was electronic. Title: Re: 80 Meter Driven Array Post by: pe1mph on November 11, 2007, 01:37:31 AM Sent you the recording Brent!
Greetings, Henk ;) Title: Re: 80 Meter Driven Array Post by: W1IA on November 11, 2007, 03:23:12 AM It is up and has been a fun night! The intial testing for the antenna was great. Brent, I would think you could get 6 dBd gain. I'm using something similar except, unfortunately much lower. Modeling showed 6dBd, if I recall correctly. I wrote this thing up for Electric Radio a couple of months ago. You'd think I could remember!@#Info: 2 elements cut for 3800 kHz spaced at 55 feet up 65-70 feet. Fed each with 3 half waves into shack and 115 degree phase delay in one element. Over the pond was a typical 3-4 dB with an average of 15-20 dB front to back. The input impedance is around 18 ohms with an X = 16 @ 3800 kHz I used my trusty Johnson Matchbox to match the input impedance to use for 250 watts. Today I hope to finish the front/back switching etc.. Along with the phasing box to change delay line from 90 to 135 degrees. Brent W1IA ;D I can find the modeling if you want it. I'm quite fond of the antenna. You guys hijacked my thread HA! Brent W1IA Title: Re: 80 Meter Driven Array Post by: W1IA on November 11, 2007, 03:31:32 AM Sent you the recording Brent! Thanks Henk...very soon we will have a QSO Greetings, Henk ;) 73 Brent W1IA Title: Re: 80 Meter Driven Array Post by: K9ACT on November 11, 2007, 08:53:32 AM You guys hijacked my thread HA! Brent W1IA I forgot to ask at the end of my last.... "where is Brent?" but forgot. You also forgot to answer my original question which was something like.... why doesn't the forward gain mirror the backward loss? js Title: Re: 80 Meter Driven Array Post by: Steve - WB3HUZ on November 11, 2007, 09:33:55 AM That was answered early on.
http://amfone.net/Amforum/index.php?topic=12589.msg92741#msg92741 You guys hijacked my thread HA! Brent W1IA I forgot to ask at the end of my last.... "where is Brent?" but forgot. You also forgot to answer my original question which was something like.... why doesn't the forward gain mirror the backward loss? js Title: Re: 80 Meter Driven Array Post by: WU2D on November 11, 2007, 11:54:46 AM Brent - Verticals Rock for DX on 80.
I worked a few of the Czech CW stations in that OK contest last night on my wireless set 19 with 10 Watts out. Needless to say, that radio does not make the premium list! It all about the antenna. This was on my three element vertical (ground plane) Yagi. Since last year I added a third element and plane director. Mike WU2D Title: Re: 80 Meter Driven Array Post by: ve6pg on November 11, 2007, 06:35:03 PM ...tina.....rockin' into my qth....tim...sk..
Title: Re: 80 Meter Driven Array Post by: KA1ZGC on November 11, 2007, 08:12:10 PM Heard you talking with Don KYV and someone in 5-land last night when you were doing the A/B tests last night.
("...this is the shaded dipole, this is the wire array...") You were audibly stonger here on the array, but I was away from the meter. Congrats! --Thom King Abraham One Zebraham George Charlie Title: Re: 80 Meter Driven Array Post by: WA1GFZ on November 11, 2007, 09:43:26 PM Brent one thing I wanted to try but never got around to it was instead of making the feedline an odd quarter wave go even and make the last quarter wave 35 ohm coax rather than 50 ohm to get the low Z closer to 50 ohms for each antenna. I was going to make 35 ohm coax by putting two quater wave sections of 70 ohm in parallel. It would have taken 4 quarter wave sections to do both dipoles. Then I thought the best place to do this was right off the antenna to jace the Z to 50 ohms at the input of the feed line run.
Tom Vu built BB transformers at each feed point. That works also but you have to support the center when you have all that iron in the air. gfz Title: Re: 80 Meter Driven Array Post by: WU2D on November 11, 2007, 11:04:01 PM Don,
You were loud up here in NH late last night. I was playing with my homebrew Regen listening to some CW and I tuned up the band and bang - and you captured it- full phase lock. I did not have the minidisc hooked up or I would have some audio. Mike WU2D Title: Re: 80 Meter Driven Array Post by: W1IA on November 12, 2007, 08:52:53 AM Heard you talking with Don KYV and someone in 5-land last night when you were doing the A/B tests last night. Tom, ("...this is the shaded dipole, this is the wire array...") You were audibly stonger here on the array, but I was away from the meter. Congrats! --Thom King Abraham One Zebraham George Charlie I heard you in the back ground with the CW..HA! You should have fired up. Brent Title: Re: 80 Meter Driven Array Post by: WD8BIL on November 12, 2007, 10:27:22 AM You were loud at the cabin Brent !
My piss weaker was no match for the band this past week. Title: Re: 80 Meter Driven Array Post by: W1IA on November 12, 2007, 02:09:59 PM You were loud at the cabin Brent ! Bud I got the onions...I will be over for dinnnerMy piss weaker was no match for the band this past week. B p.s. have you had a chance to send the 0n4un book? Relay ? Title: Re: 80 Meter Driven Array Post by: WD8BIL on November 12, 2007, 03:30:25 PM Onions, taters and peppers with the backstraps tonite Tina !!
Drive fast, they won't last long !!! The book'll be in the mail tomorrow and I ain't found any 2P2T relays yet. Just 24 volt 1P1Ts. Still looking. Title: Re: 80 Meter Driven Array Post by: W1IA on November 12, 2007, 05:08:53 PM Recording from Henk PE3MPH in the Netherlands. I was in QSO with K4KYV and others.
Brent W1IA Title: Re: 80 Meter Driven Array Post by: ve6pg on November 12, 2007, 07:00:38 PM ...bud...where's "the cabin" ?....tim...sk..
Title: Re: 80 Meter Driven Array Post by: WA1GFZ on November 12, 2007, 07:21:17 PM Brent,
Do you have the phasing system working yet? Title: Re: 80 Meter Driven Array Post by: W1IA on November 12, 2007, 07:25:48 PM Brent, Do you have the phasing system working yet? Still building...maybe in a week. Have to manually switch the delay line for the time being. Brent Title: Re: 80 Meter Driven Array Post by: WA1GFZ on November 12, 2007, 07:50:56 PM I was lucky to buy a MIL motorized DPDT coax transfer relay from KW1I. It had connectors mounted on it so all I need to do is feed it power. It was new but not assembled correctly. Took about an hour to get it right. A couple sets of open frame 25 amp contacts would work just as well.
Title: Re: 80 Meter Driven Array Post by: KA1ZGC on November 12, 2007, 08:14:46 PM I heard you in the back ground with the CW..HA! You should have fired up. Okay, I'm confused... how can I send BBCW without firing up? Anyway, given your signal strength I wasn't sure how well you'd hear me. I wasn't hearing the guy in 5-land, mostly you and Don. I may fire up tonight for a bit, but I'm pretty beat. Don't know how long I'll last. I'll try to pay attention to the guess-meter next time I hear you. --Thom Kraft Advertisement One Zesty Grated Cheese Title: Re: 80 Meter Driven Array Post by: WD8BIL on November 13, 2007, 08:42:24 AM Quote bud...where's "the cabin" ?....tim...sk Hi Tim.... east central Ohio about 70 miles east of Columbus, Ohio. Just south of a li'l town named Newcomerstown. Newcomerstown, Ohio (http://maps.yahoo.com/;_ylc=X3oDMTExNmIycG51BF9TAzI3MTYxNDkEc2VjA2ZwLWJ1dHRvbgRzbGsDbGluaw--#mvt=m&trf=0&lon=-81.590137&lat=40.232364&mag=6) |