Proton P99

[kiser sosay]

Maybe it's been covered already, but i'll get striaght to it here. I've just returned to the hobby after some time away. My setup is as follow's. Proton p99 antenna 15' up to base (no ground radials). 50' Astatic RG8x with 7 turns stacked 5" diamter coils 1 ' under the antenna connection. this is to stop any common mode if that's correct. forgive me, im learning all over again. The rig is a Galaxy DX98VHP. This is powed by an Astron RS 35m. With a swr of 1:2. My question is this.

The proton 99 antenna is my current base. Very similar to the A99 in many aspects. The proton is 18.5 feet 1/2 wave, and 4 sections instead of the A99's three piece constuction. The p99 being 4 piece, puts each section at roughly 4.625' long. I want to remove the top section and replace it with a 102" s.s. whip I have. This will put the antenna at 22.275' roughly 5/8 wave correct?

I want to know if this is safe to do? Also what kind if any performance increase over stock it may have. Will adding my own g.p. radials consiting of 4 102" s.s. whip's make a big difference?

iIt just seems like my mobile setup. Uniden pc76xlw peaked tuned upgraded final, wilson 4' superflex on the top of the silverado cab. With swr at 1:2. Seem's to hear better than my base at time's. Or at least with less static. When I use the Uniden on the base antenna. The weather broadcast is very static filled. They are 15 -20 mies from my house. When its in the mobile its crystal clear parked in my driveway 20 feet from the base antenna. Could the rf choke coils be affecting this?

 

[Robb]

Wecome to the forum!
The biggest problem I've had/have with static/noise on my base -I believe- is the proximity to the power lines/poles. It gives me 3 S-units of noise -or more- during the day an drops down to 1-2 at night. A friend of mine 2 miles away has almost 20 S-units of noise sometimes. That's is the way it is in modern suburbia - I guess.

As far as the 102 inch whip on top of the p99; I would say 'try it if you have one' and see what happens. The worst thing that could happen is that it will have an unusable SWR and you will have to take it down again. I've heard of guys doing this trick to IMAX 2000's - but I like my IMAX the way it is. It wouldn't hurt to put your antenna up a bit higher if you could - maybe 35 ft to the base of the antenna would be great!

Great radio - that Galaxy of yours! I have a Galaxy 95t2 that I have yet to put in my mobile.

 

[kiser sosay]

Thanks for the welcome, and the reply Rob.

As for the the hieght of the antenna. I do plan on getting it up to 25'-30' as soon as possible. I just wanted to chat it over with some of the nieghbors who have to look at it. Not that it isn't very visible right now, roof mounted on a metal vent pipe ranch style home.

Above ground power lines do split the property line at the backyard. maybe 50' - 60' to the main lines from antenna. And 30' from the lines running from mains to house.

I really did'nt think the 102" s.s. whip would hurt much. I'll be sure to let everyone know how that work's or dosent.

I'm also curious as to how much a elevated radial system would perform on this. I don't want to purchase a g.p. kit that is made up of 4 6' fiberglass radials. I've heard mixed reviews on some of thease kits similar to the ones that go on the A99 witch will also work on my proton p99. I was thinking of constucting my own set. It would be basically a steel ring big enough to slip over the Base. It would be drilled and tapped in the four opposing directions. I would then use 4 x 102" s.s. whip's for the radials. I dont' see a problem with this either, but some one please correct me if I am wrong.

 

[hookedon6]

... I want to remove the top section and replace it with a 102" s.s. whip...

this was fairly common a "few" years ago on the bleed stick,... err,... big stick antennas.

you may want to use a FRANCIS whip, they are 1/4 wave (physical) long, but 3/4 electrically.

 

[packrat]

Dont change the top section. If you do it will change the operating frequency and it wont work on 11m. Yes, it was a popular swap on bigsticks, but the top section was already 102" long, so it only changed the material.( BTW, Another popular swap for the bigstick was to replace the top section with a K40 antenna. ) Also, your antenna is a vertical dipole of sorts, and dipoles dont use ground radials. Dont waste your money. IMHO> Also, dont try to compare one setup to another, as you will go nuts. EVERY setup has some performance differences. Even side by side setups. Just get the ones you have optimized for their location and have fun.

PR

 

[W5LZ]

Not being familiar with that antenna I 'googled' it to see what it was. Seems it is a replacement for the 'Imaxx 99' which has been discontinued. The only apparent difference being the name and the 'P99' has something like 1 dB more gain. And considering the name, that '99' part, it appears to be a 'knock-off' of the Solarcon 'A99'. That's speculation, so take it for what it's worth. It makes me tend to believe the 'P99' should behave/operate like the 'A99' though. If that's true, then I think it's safe to say that something isn't 'right' with your base set up, especially if a mobile antenna 'beat's it.
There are a couple of things I can say that are going to be true no matter who made that antenna and what it is. One of things is that if you change the length for whatever reason you've changed how the antenna is tuned and designed to work. That change is almost always for the worse, doesn't matter what your've "heard". You can't thange the length from a 1/2 wave to a 5/8 wave without changing the antenna's matching system/device. The input impedance for those two electrical lengths are no where close to being the same. Ain't gonna work. (Nothing new there, that's already been said.) Mechanically I'll bet the weight of the thing is changed and it would be 'top heavy'. Hope the rest of the thing is strong enough to handle that.

Adding radials or a 'groundplane' typically isn't going to increase the performance of a 1/2 wave antenna. That antenna does have something it's using as a 'groundplane' already, the feed line is acting as the 'counterpoise'/'groundplane'. Is that the 'best' way of doing that sort of thing? No, but it certainly works! If changing that makes a big difference (and it would have to be a fairly big difference if you can hear it) then something was wrong with how it was set up to start with. Blame that on yourself or the manufacturer, it really doesn't matter, something wasn't 'right' for whatever reason.

I tend to be wrong when I have to guess as to what is meant by a non-standard way of writing SWR readings. Does that "1:2" mean 'two to one', '1.2 to one', or something else? A '2 to 1' SWR isn't going to make as much difference in what you hear as what you've said. That might be part of the problem, but certainly not the cause of it. If it's a 1.2 to one, leave it alone, nothing wrong with that. The only real problem is that I don't know what you meant.

And just for grins, have you tried using that base radio with the mobile antenna? Not sure that would tell you much, other than to confirm that there's something wrong with the base antenna. It would be interesting though.

Not much help, sorry. Good luck.
- 'Doc

 

[kiser sosay]

Thanks Doc,
Sorry for the confusion on the swr aspect. Im doing my posting here from this extremely small keyboard on my phone.

But back to it. As far as the swr it is 1.2 on 1 and 40. And 1.0 on channel 20. As i'm getting back into this, i'm not sure exactly how write that in the proper way.

I wasent sure on how the matching system on the antenna would effect what I was wanting to do here.

Now as far as the antenna using the feedline as a counterpoise. I have maybe 8" of striaght coax under the feedpoint. it then begins its coils for the rf choke / air balun. then maybe another 8" of coax before entering the attic of the house. so maybe 8' total of coax exposed outside. With about 6' of the 8' bieng the coils. Should I remove the coils and let the coax hang striaght down under the feedpoint for more of a counterpoise?

Thanks again for the welcomes, and the replies you have given me.

Jay-

 

[packrat]

Try to think of a peice of coax, now strip the cover off of 8" or so and roll the shield back over the remaining cover. this leaves one 8' section of center conducter, and one 8' section of shield. the center conducter is one half of the antenna and the shield is the other half. Hope you understand what I am trying to say.

PR

 

[BOOTY MONSTER]

Thanks for the welcome, and the reply Rob.

As for the the hieght of the antenna. I do plan on getting it up to 25'-30' as soon as possible. I just wanted to chat it over with some of the nieghbors who have to look at it. Not that it isn't very visible right now, roof mounted on a metal vent pipe ranch style home.

Above ground power lines do split the property line at the backyard. maybe 50' - 60' to the main lines from antenna. And 30' from the lines running from mains to house.

I really did'nt think the 102" s.s. whip would hurt much. I'll be sure to let everyone know how that work's or dosent.

I'm also curious as to how much a elevated radial system would perform on this. I don't want to purchase a g.p. kit that is made up of 4 6' fiberglass radials. I've heard mixed reviews on some of thease kits similar to the ones that go on the A99 witch will also work on my proton p99. I was thinking of constucting my own set. It would be basically a steel ring big enough to slip over the Base. It would be drilled and tapped in the four opposing directions. I would then use 4 x 102" s.s. whip's for the radials. I dont' see a problem with this either, but some one please correct me if I am wrong.

heres a very simple homebrew ground plane i made for my 1/4wgp and im currently using it on my homey 5/8 wave . its just 4 108 inch 12 gauge speaker wires and four 5 foot peices of 3/4 pvc pipe with a 4-way . works suprisingly well . you can do this very cheaply and then know if investing the time and money into something better looking will improve your antennas performance .

 

[W5LZ]

kiser sosay,
As I said (or maybe didn't say well enough) the SWR thingy is just me not understanding
how you said it. From your explanation, it seems to not be a factor anyway, which is good.
If I'm not totally confused, yes, you can 'tune' that antenna, make it's input impedance
match the feed line and radio, by adjusting the position of those 'rings'. That's what they
are there for, impedance matching, making the antenna 50 ohms like the rest of the
antenna system.
And before I make it too confusing, I think I'll quit right there. I will say that an
SWR meter is not a very easy thing to correctly tune an antenna with. It really doesn't
tell you enough. It'll work though.
- 'Doc

 

[kiser sosay]

Thank's again to eveyone .

Doc, I knew the function of those tuning rings to an extent. Thank u for giving me the in and out of it.

So if im understanding all of this correctly. The coax is acting as a counterpoise or ground of sorts. Is this correct? If so, then would the coils in the coax, just below the feed point be hindering the antennas performance? If so should I take out the coils completly? Or should I move it to the radio end?

 

[W5LZ]

I can't honestly say about those coils in the feed line (called a choke). they do help with some forms of interference so I'd maybe move them down about 8 or 9 feet from the antenna. That would allow the 8 or 9 feet to be used as a counterpoise and still stop some of the CMC type stuff on the outside of the feed line. If that doesn't at least make some difference, then moving them down doesn't sound like an answer. You've then got the choice of removing those coils completely, or just forget about them. If it were me, I think I'd try moving them away from the antenna a ways (8-9 feet). If no help, beat the @#$ thing to death with a hammer! No help, but satisfying as #$!!.
- 'Doc

 

[packrat]

No, the coax does nothing except carry the signal between the antenna and the radio. The antenna is a self contained item. At least that is the way it should be. Just forget about the coax. If it conducts the signal, it is fine. Try not to get into the overcomplicated antenna syndrome. Someone much smarter than us figured out all there is to know a long time ago. Benefit from thier knowledge.

PR