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Constant static on base..

Ever wonder why "The Star Duster" required " at least 10'-0" of 1" thrd. pipe or the 1-3/16" dia. tubing to be below the attch. point of coax feed line with the coax symmetrically running through it ? Sure, you know the base was threaded or could be used with stub end piping, this was not just a "Cool Design" intended to sell their product, though it does resemble the Appllo Space Capsule. It's a very simple way to match and keep from resonating to the coax, just refer to Chapter 3, page 115, of The ARRL Antenna Book, Gerald L. Hall, K1TD. Detuning Sleeves.

This may be a simple inexpensive cure to the RFI coming back through the coax.
 
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Detuning sleeves? This is the first time I recall anyone mentioning them on any CB or Ham Radio antenna forums I frequent...

Just because there is a tube present in that location does not make it a detuning sleeve. I would have to get a close up look at a Starduster antenna to confirm or deny this. I am not saying that it is impossible, but at the same time I doubt it is the case. There is one in my neighborhood I will go have a look at sometime soon...

just refer to Chapter 3, page 115, of The ARRL Antenna Book, Gerald L. Hall, K1TD.

You have the 13'th edition of the ARRL Antenna Book. That is the only edition that this information is on that specific chapter and page. I would recommend using that instead of the "Hall edition" as multiple different editions of the ARRL Antenna Book were edited by Hall, through the 16'th edition (I'm not sure where he started as editor, at least as far back as the 13'th edition book that you have).


The DB
 
I built a heavy duty star duster, call it a Star Buster, scrap tubing, some stainless plate and pipe for the base of antenna to connect radials and antenna. Wouldn't get SWR down until I added at least quarter wave length or more (14'-9") below the base. Star D requires at least 10'-0". If the outer coax goes to ground the sleeve acts like a fourth ground plane radial. For what I have read, and the diagram in ARRL Ant. Book. It fits the bill. Acts like a balun. I tried to coil 8~10 with both 6" and 8" dia. would not tune. Put that 1-3/16" top rail under it with coax running through it. It works fer me.
 
"You have the 13'th edition of the ARRL Antenna Book. That is the only edition that this information is on that specific chapter and page. I would recommend using that instead of the "Hall edition" as multiple different editions of the ARRL Antenna Book were edited by Hall, through the 16'th edition (I'm not sure where he started as editor, at least as far back as the 13'th edition book that you have)."





Yup. That's the one. Had to look. Could not figure why it worked and stumbled on that little section. Just trying to help.
 
I've made similar antennas for several bands over the years, from 440MHz (just wires attached to a SO-239 connector) to 11 meters, although I tend to use four radials (instead of the three on the Starduster), and they all tuned right up after a little trimming. I'm not sure on the dimensions of yours offhand, but with the radials angled as they are you do have to make some adjustments to the antenna's electrical length as the radials will react with each other to an extent. There will also generally be CMC issues, although the cause is different than the CMC issues with most other antennas, which is likely why you had SWR issues to begin with, and also why this solution worked for you.

I'm glad this solution worked for you, although at the same time I wish I was there to see what else you did just to see what I would have come up with. I can pretty much guarantee that I would have solved your SWR problem using another method. That isn't saying that your method was wrong, its whatever works right?

When it comes to the actual antenna, just because this solution worked for you doesn't necessarily mean they are doing the same thing, that is all I am saying. I also have, with some time, the ability to confirm it, so if I am wrong and the antenna is using a detuning sleeve, I will return here and correct myself.


The DB
 
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Well today I checked ground from antenna to the mounting post. All good. Gave me a tone and then check ohms.. got a 0.06 on meter.. also thru ground wire I attached half way down post gave me the same 0.06 and good solid tone as well.

Now I just need a rod to ground too. Currently I just buried the end in the dirt a few inches down.. lol

I reset my SWR to be 1.1 or so ch 1 and flat on ch 40 when just the radio in place.. with TS350 I get 1.2 or so on both ends.. so I think that's good.

I noticed today static is not as bad and I talked on ch 19 to a driver about 20 miles away and heard him clearly over the 1-2 of hash on my end..

I also noticed it isn't constant.. so maybe it's a neighbor..

Still going to try snap on ferrite just outside shack wall and do ground rod.
 
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I've made similar antennas for several bands over the years, from 440MHz (just wires attached to a SO-239 connector) to 11 meters, although I tend to use four radials (instead of the three on the Starduster), and they all tuned right up after a little trimming. I'm not sure on the dimensions of yours offhand, but with the radials angled as they are you do have to make some adjustments to the antenna's electrical length as the radials will react with each other to an extent. There will also generally be CMC issues, although the cause is different than the CMC issues with most other antennas, which is likely why you had SWR issues to begin with, and also why this solution worked for you.

I'm glad this solution worked for you, although at the same time I wish I was there to see what else you did just to see what I would have come up with. I can pretty much guarantee that I would have solved your SWR problem using another method. That isn't saying that your method was wrong, its whatever works right?

When it comes to the actual antenna, just because this solution worked for you doesn't necessarily mean they are doing the same thing, that is all I am saying. I also have, with some time, the ability to confirm it, so if I am wrong and the antenna is using a detuning sleeve, I will return here and correct myself.


The DB

DB,
I have used scrap telescoping aluminum for this antenna built. It's of a larger dia. than the actual designed SD. It's radials are set @ approx. 22 deg. +/- . Held out with some fiberglass rods from Tractor Supply to hold the radials out. The start of this project antenna for 11 meter came from a friend finding a old SD in the trash bin at work. Actually, I was just given some of the parts, with the original lengths noted on the "Hub". It was originally used to communicate with the delivery trucks entering the plant and security back in the "bygone era" now pushed aside by cell phones, and tighter security measures. It was originally maintained by a couple of local hams.

Now the friend that brought it to me argued that I should replicate the exact dims. in order to get the "fine tune"......because "they were hams and only God was better". Unfortunately .......the dims. were set for a multi band, well, due to the fact the hams had set up their own unit so they could use it. So after I did the research to find the actual length needed, I found even the calculations were not able to register the desired freq. after trying to tune it. Guess the larger dia. tubing caused it. I don't know. So just pulled the pin and threw it in, set up and tested, and tested, and tuned until got close. Then high winds at 38' broke the "Hub". The original SD was built pretty flimsy. Fabricated my own hub out of scrap SS plate and 1-1/2" dia. pipe PUP. The 1-1/2" pipe was used to support the antenna with those chain link fencing "clamps".

After reading the original SD assembly directions, found the stated note that a 1-1/2" dia. thrd. pipe with lgth. of at least 10'-0" shall be used. I tried that and found that for some reason this worked better. Also found when added length to it the antenna SWR was getting better. Along with my RFI noise level dropping more as the length was added. Could not figure it out, Kav could not figure it either......."But it worked". He also argued I had built it wrong because it wasn't the recorded lengths "he" wrote on the original hub. So I must have broken a Cardinal rule and therefore I am banished to purgatory by him and evidently by you also. Mi Culpa, Mi Culpa, Mi Culpa........All the baluns I had turned with the coax would not allow me to tune well and my noise level was high. I admit to only trying something different.....even Kav admitted that for some reason it worked. He had overlooked the 10'-0" note, and it was not present at the finding in the scrap dumpster. He remembered seeing the antenna fixed to the building, but not how it was supported.

Now sir, to address the issue.....I merely am trying to suggest fixes to help someone based on my "Illegitimate Findings" and "Frankenstein methods" which for some unknown reason to me "Worked". Is this not what this site encourages? I encourage your ethics to help elaborate for the solution. I did not state this would fix PA770 problem, only brought up a confusing anomaly, to help remedy annoying noise levels.

Respectfully,

Redbeard
 
Redbeard, I am not criticizing you, and I didn't banish you to purgatory. Also, I do not think that your findings are illegitimate, nor are your methods frankenstein, and I never said or implied such things. I am the least picky person in the world when it comes to that. As I said above, I am glad your solution worked for you.

It is strange that you had to make the wider elements longer, typically the opposite is true. I'm not sure what the cause for that would be unless the original the dimensions were pulled from included the cap hat the the original m-400 has attached vertical element and yours didn't, or perhaps the different shaped hub... Like I said above, I would love to get my hands on it to play with it myself, its the things that don't go as I expect that draw my attention...


The DB
 
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Redbeard, I am not criticizing you, and I didn't banish you to purgatory. Also, I do not think that your findings are illegitimate, nor are your methods frankenstein, and I never said or implied such things. I am the least picky person in the world when it comes to that. As I said above, I am glad your solution worked for you.

It is strange that you had to make the wider elements longer, typically the opposite is true. I'm not sure what the cause for that would be unless the original the dimensions were pulled from included the cap hat the the original m-400 has attached vertical element and yours didn't, or perhaps the different shaped hub... Like I said above, I would love to get my hands on it to play with it myself, its the things that don't go as I expect that draw my attention...


The DB

No Cap Hat. Figured the larger dia. elements would reduce the size myself. The darn thing is a Frankenstein. Have wanted to take some pictures of it (bragging rights). Wanting to try a 102" whip with large spring for top element, but the current one is much longer. Would like to cut down on wind resistance. I can't figure out why it works being longer, but results running barefoot puts distance reached at approx. 25 miles with 4 watt output. Darn near to Victoria. 1.2/1 SWR, I'm happy.

We have a bad RF noise here. Two heavy trans lines at 130,000 run parallel on each side of us about 900~ 1200 feet away. One from Houston and another from Corpus to feed the many chem plants in area. When relative dew point is higher noise increases. Transformer feed to the house was replaced after Harvey with a smaller unit, which at time of install by VEC......to quote the power company........"We hope it's big enough supply to three houses, the barn and camper". Now it's a question weather the trans is burning out causing noise.

This Star Buster antenna doesn't rec. the noise. The receiver in the barn (about 60 feet away), running off of horz. beam picks it up really bad. It doesn't have the multiple grounding and the "controversial detuning sleeve" the vertical does. Have played with the gamma on the horz. beam till we were silly, and by then drunk enough just to leave it alone. Typically, a vert. will pick up the noise more than a horz. Have even done a voodoo ritual on it trying to relieve the static. All I can guess is the multiple grounding locations and the "sleeve" make a difference.
 
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