| Author |
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Don
| | Posted on Tuesday, December 18, 2001 - 2:26 pm: | 
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If I wanted to use the a99 for 10 meters and not cut the top section, were should the tuning ring be set at? I read somewhere that it was not good to cut the top section.
Thanks
Don |
Marconi
| | Posted on Tuesday, December 18, 2001 - 4:03 pm: |
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Don, when I put the rings all the way to the bottom of one of my A99's it tuned in with the lowest SWR's at 26.900. I guess that with the rings all the way up you should be able to get closer to 28.000. The antenna is somewhat broadbanded so you should be good to go with an SWR of less than 2:1 somewhere in the low 28.000's.
I did notice the bandwidth curve was not smooth when the rings were all the way down. Don't know what you will get with them all the way up though.
Marconi |
Don
| | Posted on Tuesday, December 18, 2001 - 10:22 pm: |
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Is it in fact, bad to cut the top section of the antron99 ? Does anyone have any information on this? |
Tech181
| | Posted on Wednesday, December 19, 2001 - 12:00 am: |
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Don,
The enclosed instructions with the A-99 give you the exact measurements as to how much to cut off the top section to allow operation on higher freqs. I don't have it handy but they are included with the antenna. I would imagine you could remove the yellow cap from the top of the antenna, lop off what you need, and replace the cap. I have never done it, but if the manufacturer includes the instructions...Well?
Steve
Tech181
Tech181@copperelectronics.com |
Marconi
| | Posted on Wednesday, December 19, 2001 - 6:37 am: |
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Don, it is OK to trim the A99 for higher frequencies, just protect the exposed cut area.
If you do not have the frequency instructions that 181 mentions, let us know.
Marconi |
SSB2103
| | Posted on Wednesday, December 19, 2001 - 8:47 am: |
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Unless you know how to grow fiberglass I suggest you get a matching device |
Vernonott
| | Posted on Wednesday, December 19, 2001 - 1:58 pm: |
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SSB2103:ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,Thanks I needed a good laugh today. |
Rightwing
| | Posted on Monday, December 24, 2001 - 8:28 pm: |
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i feel the same way, if you can get away with using a matcher, use it. just dont buy junk. get one like the hams use. i own a mfj949-c.why butcher up a perfectly good antenna? |
Doug
| | Posted on Wednesday, December 26, 2001 - 12:49 am: |
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Tuners are no good ! You are only fooling yourself and your antenna. Strive for a low swr and forget about the tuner. |
AntennaMan
| | Posted on Wednesday, December 26, 2001 - 9:28 am: |
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Antrons99s will work on 10,11,12,15,and 17 meter with out a tuner usually. Especially with a goundplane kit. |
Taz
| | Posted on Wednesday, December 26, 2001 - 12:24 pm: |
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antenna man works for eei |
Marconi
| | Posted on Wednesday, December 26, 2001 - 1:44 pm: |
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AntennaMan may be right about the range of the A99 with a GPK increasing the effective bandwidth, but I don't think it is quite good enough to work the full range he describes. I have not work mine in those areas so I cannot be for sure. I do know that my A99 did not hear well when going that low in frequency. I am not sure if the GPK will have any effect on this quality or not either.
Doug, you are getting a bit categorical in your position. Nothing is that definitive. A no-good tuner will be no good, but good tuner will work just fine for this purpose. There is probably not a good item in a CB line that will do this adequately however.
A tuner is all about allowing one to work a large band of frequencies with an antenna that is either not cut for the area worked or if you wish to work a non-resonant antenna. As long as the line at the transmitter sees near 50 ohms the antenna just don't care what signal it gets. The antenna will radiate what ever arrives there. Now you may find some line losses out beyond the tuner due the tuners transformation, and these losses can be real losses. But, that is simply due to the characteristics of the line and nothing else.
Of course in our CB world the ideal setup is to be able to operate with a fully resonant antenna. That is just not always possible. If you have to work around 10,11, and 12 meters, you probably can get buy without a tuner, if the antenna is very well matched near the middle of this range and it really shows to be broad banded. I have made a few 11-meter dipoles out of RG-8 coax, and this makes them light enough and thick enough to do just what you are asking here. If you install then with a little inverted V angle in the setup, it will also add some to the workable bandwidth. The problem is they don't hold up real well, they tend to stretch, and they do not take a lot of power because of the dielectric inside, but that aside, they work great.
Marconi |
Doug
| | Posted on Wednesday, December 26, 2001 - 6:28 pm: |
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20+ years experience in cb radio only. Do a side by side test and you will find that a tuner bites. To the best of my knowledge , Hams use them beacause of the use of one antenna only. Correct me if I am wrong. Better yet tell me about a good wideband antenna that sells like hotcakes... |
Marconi
| | Posted on Wednesday, December 26, 2001 - 11:53 pm: |
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Doug, maybe you could give me some details about the side by side test you mention or know about that causes you to claim, "...that a tuner bites." I will then give you some comments about my own experiences using tuners.
I have no idea what antenna you are suggesting that is, "...wideband antenna that sells like hot cakes..." I also fail to see what this statement has to do with your conclusions about tuners. But in response, I believe that in the CB area the Imax 2000 has the reputation of being widebanded. Tell me what you have in mind, and I will tell you what I think.
Marconi |
Doug
| | Posted on Thursday, December 27, 2001 - 12:49 am: |
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I am done with this thread.
This is like trying to convince someone that there are better antenna's on a mobile than a 102 steel whip.
By the way I run a wilson 1000 only because I feel it looks better on my truck. |
bruce
| | Posted on Thursday, December 27, 2001 - 7:12 am: |
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Guys i use a mfj tuner on both my dypole and mfj vert. antenna. Tunners don't bite they do what needs to be done to trick the radio into thinking it is looking at a matching ant not some 3 foot wire at 3.92 mhz. The rule is simple antennas work at only 2 frequencys resenance and the 3rd harmonic any other is a crap shoot. |
Vernonott
| | Posted on Thursday, December 27, 2001 - 11:06 am: |
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Come on Doug,hang in there.What if after going into 300 caves the special forces said we are done with this job let the old fart go.You are not suppose to be convincing anybody,just giving your honest opinion.Why some young whipper snapper told me on the forum the other day I was negative and senile both of which he spelled incorrectly but that's not enough to make me be done with the thread or the forum.73 |
bruce
| | Posted on Thursday, December 27, 2001 - 12:03 pm: |
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Vernonott your old, negative, senile... and i'm only kidding. As for spelling i never make a mistakee. |
Taz
| | Posted on Thursday, December 27, 2001 - 2:24 pm: |
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right bruce |
Vernonott
| | Posted on Thursday, December 27, 2001 - 3:06 pm: |
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Bruce : If you had attended school in Miami Beach your spelling would be A+.The teachers there all wear string bikinis and give you a big hug every time you get it right.73 |
bruce
| | Posted on Thursday, December 27, 2001 - 7:21 pm: |
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Vernonott... O MY WHERE DID I SCREW UP? I went to school in new york city both tech school and college... I could have had profesers in strings... insted of a bunch of old men. Hell i would't have learned anything but damn it would have been much more fun. |
BRONCO 129
| | Posted on Friday, December 28, 2001 - 8:40 am: |
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WHERE SHOULD THE TURNING RINGS APPOX BE SET FOR AM BAND CB.I'M JUST GETTING STARTED AND HAVE AN A99 BUT DO NOT HAVE IT INSTALLED YET. |
Vernonott
| | Posted on Friday, December 28, 2001 - 11:28 am: |
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Bronco129:I have installed eleven A99's and not one of them needed any tuning.They normally come ready to stroke.73 |
Scrapiron63
| | Posted on Friday, December 28, 2001 - 2:32 pm: |
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Vernonott, that's the same I have found with the 99 and Imax, I check them before sticking'em up, but they were all good, so why mess with them. I've seen people start screwing with the rings and turn a 30 minute job into an all day cussin'.
scrapiron |
LARRYBONNER
| | Posted on Friday, December 28, 2001 - 2:38 pm: |
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THANKS VERNONOTT! |
dimstar
| | Posted on Friday, December 28, 2001 - 4:19 pm: |
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I have an A99, and all I had to do is stick it to the mast. Ive got a 1.2 to 1.5 swr. Dont touch the rings. Im putting up my brothers Imax99 tomorrow. Ill let you know how it turns out. |
Antennaman
| | Posted on Friday, December 28, 2001 - 11:25 pm: |
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Did not mean to cause a stur. The only thing you loose by using a tuner is antenna gain. Plus, if you use a calculator, you will find that 1/2 wave at 11 meter(around 220 inches) you will find that at that legnth, you are close to full wave at 52mhz, little less than Half wave at 24 mhz, Pretty close to 1/4 wave at 21 mhz, and almost 3/8 wave at 14 mhz. That is close enough to get at least unity gain with a tuner. I am just rustling numbers off the top of my head, but do the math. You will find that except for 20 meters, with a little adjustment, you could get a decent match in all the bands I mentioned. With a tuner, even better. Now, if you were talking about an IMAX 2000, which is 5/8 wave. Totally differnt circumstance. I know this from putting a meter on it. I dont work for EEI what ever that is.
Antennaman |
Tech833
| | Posted on Saturday, December 29, 2001 - 11:23 am: |
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Antennaman,
Your calculations would be correct if the Antron 99 were direct fed. However, since it is capacitively coupled, your calculations and assumtions on frequencies lower than 20 MHz. are incorrect. The resistance of the A99 goes up considerably as you go lower in frequency regardless of the multiplier.
If you used a direct fed 1/2 wave like a 'Ringo', then you would be right on. |
Bigbob
| | Posted on Tuesday, January 01, 2002 - 11:02 pm: |
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Doug,if you have but one antenna you are right.Most ham antennas are narrow banded except verticles like MFJ's& antron's which have LC matching stubs.The purpose of the matcher is to fool the finals by presenting a 50 ohm load which improves tube or transistor life.A 50 ohm load translates into a 1 to 1 swr. |
Marconi
| | Posted on Wednesday, January 02, 2002 - 7:48 am: |
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833, my Autek meter shows that the resistance of an A99 drops considerably as you go lower in frequency.
I guess these meters are not all they are cracked up to be.
Marconi |
Scrapiron63
| | Posted on Wednesday, January 02, 2002 - 1:03 pm: |
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Marconi, just from memory, I believe on the mfj 259 analyzer, when I checked A99's, the resistance would go down as you went down frequency to a point, then start back up. SWR would come up some also going down freq, but not as fast as going up freq, with the resistance getting higher. Quite a bit higher on freq, there would be a short curve down on resistance and SWR. That was not checking at the antenna, but at the end of the 102 feet of Coax I have running from tower to my shop. I run Belden 8214, RG 8 coax, which was the best shielded I could get at that time without going solid shield. The 8214 has the larger center conducter also, it will not fit in regular PL 259s. We could probably get another argument about lengths of coax, the MFJ directions with the analyzer says length of coax does not matter, as long as its 50 ohms, antenna 50 ohms, everything will match. I have a friend that has built and installed antennas longer than the 30+ years I have, and he bets on multipliables of 3 feet for coax, base or mobile. I've used that also, and found it to work. When I set a base antenna, I try to get the lowest SWR reading, while keeping the resistance at 50 ohms, on the frequence where I talk mostly, I don't generally go over 20 channels above or below regular 40, so most antennas will take that spread, and stay good on SWR and decent on resistance. Of course you have to use a jumper, even setting it up at the antenna, and it has to be long enough so you can raise the antenna some of the ground. I use a 36 ft jumper for testing, then when connected to the 102' feed to the shop, it doesn't change. I run Wilson mobile antennas, and use the coax that comes with them, they always match good for me. On whips, I use 12, 15, 18 feet, whatever they need for the mounting distance, jumpers the same, 3-6-9 ft, whatever matches and is required. I remember some beam, maybe the PDL2's, gave instructions for 4 ft multipliables in coax lengths. Right or wrong, the way i've done has worked for me, and lots of others i've helped over the years. Maybe this rambling will make sense. Scrapiron |
RCI 2990
| | Posted on Wednesday, January 02, 2002 - 9:35 pm: |
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I could have gotten a MFJ 949 antenna anylyser(SP?) for $100.00 gently used but passed it by.. ARRGGH!! :-( another deal passed up.... |
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