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Post by tube radio on Tue Apr 14, 2009 7:32 pm

Does anyone know how to construct a dummy load for my Knight T150A transmitter.


The instructions say not to use a light bulb.

I would appreciate any information.

Thanks .

Lee

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Post by Tony V on Tue Apr 14, 2009 9:16 pm

Lee...please make sure you convey that your interested in building a dummy load for your transmitter instead of buying something to do the job. Its seems that point wasnt made clear when you posted this on the other forum. It might be helpful to post some spec's of your transmitter also for those who might have made one for their transmitter but may not be familiar with your particular model. Since you mentioned you have some instructions related to this, it might be helpful to post those also so the guys get a better idea of what your trying to accomplish. I wish i could help but have no knowledge of these but the more specific you can be will hopefully help you from getting frustrated like you did on the other site. I understood your frustration as i've had that happen when the topic went off course on a couple questions i've had in the past. Hopefully the more information you can post about your set and what you intend or want to do might help this from happening on here. Good luck buddy!
-Tony
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Post by tube radio on Tue Apr 14, 2009 9:36 pm

Thanks Tony.
I am trying to restore the Knight T150A which was my first transmitter and I wanted to use a dummy load to try it out after changing some bad componets.

I did not get frustrated because it went off my topic.

I did not like the comment he said about me being a new ham and having a vanity call when he did not know anything about me.


Lee

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Post by tube radio on Tue Apr 14, 2009 10:16 pm

Thanks to all,
I have Jonnnysan one of the ARF membere giving me a resistor that I can use as a dummy load.

Thanks to all.

I appreciate you all I have gotten a lot of good help here. Very Happy Very Happy Very Happy Very Happy Very Happy

Lee

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Post by Tony V on Wed Apr 15, 2009 3:13 am

Lee,
I'm glad it worked out for you. Let us know how your transmitter turns out.
-Tony
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Post by tube radio on Wed Apr 15, 2009 8:26 am

Thanks Tony

Lee

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Post by Timaaay! on Wed Apr 15, 2009 2:20 pm

Hi Lee,
Glad your on the right track. I understand that some transmitters don't like a light bulb as the resistance changes as power does. Also incandescent bulbs have a lot of inductance. That being said, the resistor should work well for you as long as it's not a wire-wound type (That's almost the same as a light bulb filament). I've used 50 ohm resistors with good luck but obviously you'll want to be mindful of the wattage.
I have a 25 watt, 52 ohm resistor that I've used. I was able to fit a hear sink from a large CPU on it. It gets pretty darn hot with a long key-down!
You'll want to keep the leads as short as possible (I'm using a piece of RG8 with the resistor on the end) and it doesn't seem to have any problem handling 100 watts intermittently.
Let us know how you make out, Lee. Good luck!

PS- I'd love to hear you on the air with that Knight T150A as soon as you get her straightened out!
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Post by tube radio on Wed Apr 15, 2009 11:11 pm

Thanks Timaay for the information the resistor he is sending me is a power resistor that is 50 watts at 50 ohms, and I have a lot of cpu heat sinks that I can use.

I will let everyone know how it works out, and I would love to have you hear me when I get it working. Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy

Thanks again,

Lee

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Post by Timaaay! on Thu Apr 16, 2009 3:13 am

My G5RV Senior didn't survive an ice storm this winter but I still had my 160 meter dipole. Several weeks ago we had a really bad wind storm here with gusts over 60MPH. I very big pine tree fell and took out one leg of my 160 meter dipole Crying or Very sad
It still works, with very low SWR on 80 meters. I guess its an end fed Zep for 80 now.
Unfortunately, a serious auto accident last year has ended any hope of my ever climbing trees again. I'm still looking for someone who can climb for me. I have 10 ga. copper clad steel wire (it may sound like overkill, but I want this one to last as long as I do.) and all the other materials needed.
I gave a local ham a 2 meter commercial beam, a six meter beam, and a Heathkit Mohawk (receiver) as trade. He was supposed to put the antenna up for me. I've never heard from him again and he hasn't returned any phone calls. Live and learn, I guess.
Anyway, I'd love to chat with you on 80 meters sometime.
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Post by tube radio on Thu Apr 16, 2009 9:03 pm

Timaay How well does the G5RV work I am thinking about buying one.

Sorry to hear about your accident, wish I was closer to help you, I don't clime trees but i throw a rope tied around some object up in the tree and pull the wire up.

Also you can use a slingshot tied to the line of a fishing reel with a sinker on it.

There is an article in the March QST about a spudgun that you can make from PVC tubing and pump it up and use it to shoot the line up into the tree.

Lee

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Post by Timaaay! on Fri Apr 17, 2009 7:08 pm

Hi Lee,
I have tried several antennas and the G5RV worked great! I originally had a Carolina Windom (off-center fed dipole) and put up G5RV. I was able to do A-B tests when both antennas were up. They were both up around the same height. The G5RV won hands down! Not only was it much better for local rag chews, it was usually better for DX as well. For some reason, the G5RV doesn't get the respect that it deserves. I think it was the best all-around antenna I've ever used. I've had random wires, an inverted L, a Bazooka, and a delta loop- the G5RV, as an all-around antenna was definitely the best, in my opinion. I had the 204 ft. one because I like 160 meters, but a few friend of mine have the 102 foot version and it works just as well (but not on 160 of course)
I tried a slingshot but didn't have any luck. I'm not sure if it's the sling shot itself (I got it at Wal Mart) or that I wasn't using it properly. I tried several different things and different weight objects, but could only get it about 15 feet high!
The other problem I have here is that it's like a forest! I mean the trees are all very close to each other. Anything I shoot up there, will never fall back down without getting caught in other branches. Almost all of the trees branches touch each other. There are almost no clear areas. I have plenty of room as I'm on over 3 acres, but the only clearing is where the house is.
To get my 160 meter dipole up, I'll bet I had to climb at least a dozen trees, with a chain saw, to cut limbs off and untangle wire. I also cut down three big trees to make room for it. It quite a project Very Happy
That spudgun sounds very interesting. I'm going to look and see if I can find the article online somewhere. I just may be able to do something with that. If it's fairly strong, I may be able to tie something heavier that would fall through the branches. Thanks for the heads-up, Lee.
I'll let you know how I make out! The race may be on- My new G5RV or your Knight. Who will be first? LOL
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Post by tube radio on Fri Apr 17, 2009 9:32 pm

Hi Timaay,

I got the knight working on the resistor dummy load now all I need is an antenna to use it on the air.

I think I will get the 102 ft G5RV and see how it will work.

I checked and the spudgun is not on the QST website
if you want a copy of the article I can scan it for you.

Lee

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Post by kb4yrc on Sun Apr 19, 2009 1:11 am

Have you concidered a bow & arrow, or a cross bow ? A lot of hams have used this method of puttin' up antennas. I live in the building of a radio station, and am loading one of the tower guy wires as a sloper. .... Gregg ...... edit.. Or the ol' rod & reel trick ......

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Post by Timaaay! on Sat May 02, 2009 12:55 am

The race is still on Lee Very Happy
I haven't been able to get the antenna up. If you could scan that, I would be very grateful.
I tried the fishing poll, bow and arrow, and am ready to give up. The BIG problem is that there are just so many trees, anything I toss up there, just gets tangled in branches and never falls back down. Mad
Imagine trying to do this in dense forest; that's exactly what it's like here. I think I may be able to use more weight with the spudgun. Thanks
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Post by tube radio on Fri Jun 12, 2009 10:23 am

Timaaay

Did you ever get the chance to build the spudgun?

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Post by tube radio on Wed Jul 08, 2009 8:02 pm

Timaay did you get your antenna up yet?
Lee

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Post by TonyC on Thu Jul 16, 2009 3:13 pm

I'm curious as to why the manual says not to use a light bulb. I always did and it never caused any problems. Maybe they are worried that the bulb will blow out and leave the transmitter with no load? I like the bulb because it gives you a visual feedback as you make adjustments.
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Post by tube radio on Thu Jul 16, 2009 4:29 pm

I will read the instructions again and let you know what it says.

Lee

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