| Author |
Message |
    
Foxhunter
Intermediate Member
Username: Foxhunter
Post Number: 110
Registered: 4-2008
| | Posted on Friday, August 29, 2008 - 5:22 pm: | 
|
In the area of 11M/CB antennas: It's time to take down my 16-FT Shakespeare Big Stick. I got excellent reports on it and many people asked what I was using. I liked the antenna but had SWR fluctuations. I made all sorts of changes to correct this out-of-tune condition (height increase, relocation, changed coax, added 4-radial GPK etc etc) but to no avail.
So I have to choose from:
A Maco Alpha V 5/8, as well as an Imax 2000 and an Antron A99----plus two other green "A99 look-a-likes" (one with tuning rings and one without---they maybe be either a 3-piece Radio Shack "Crossbow or a Shakespeare Army Stick).
I've spent ALL afternoon reading the "Product Reviews" section on the Copper Forum trying to read what I could before posting. Among others Tech833 had an excellent article and posts.
I'm leaning towards the Maco Alpha V 5/8 but DO NOT like the small-sized wire going from the SO-239 to the ring/hoop of the Maco.
The wire looks way too tiny/small. Common sense would tell me (someone entirely new to home-stationing but still..) that an increase in the wire size would see increased power-handling & performance. Am I right?
Would changing this 14-AWG wire (I believe that's the size) to an 8-AWG wire cause any unforseen problems? Would it throw-off the impedence somehow or cause the tuning of the antenna to be off? Cause some sort of mismatch? Some problem?
I'm not real-familiar with antenna theory or antenna-alteration consequences. The antenna engineers who designed this antenna may've calculated the use of this small-sized wire into their equations for a reason. Or maybe it was just to save production costs----I don't know.
I believe I read an old post from PatZeroZero this afternoon that said that the difference between the Maco V 5/8 and the Maco V5000 was the size of this particular wire and that changing it would be the equivalent of being a V5000. Would that be right/correct?
The Maco V 5/8 I have I was told is 15-years old and bought from Copper Electronics. Before taking down the Shakespeare I will be changing all the screws/bolts & clamps as they didn't use stainless-steel originally and are all VERY rusted and will need to be taken off with a angle-grinder. So replacing the hardware will be one step for improving the antenna before placing it up (62-65FT to tip). However I really would like to change the wire size without doing an "improvement" that might have some hidden adverse effects. The antenna will be used at 1500W-2000W range at some point and want it to not fall short with power-handling capability. Can anyone familiar with this antenna address these questions please? |
Tech833
Moderator
Username: Tech833
Post Number: 1692
Registered: 8-2002
| | Posted on Friday, August 29, 2008 - 10:29 pm: |
|
Changing the size of that wire will not harm the antenna in any way, or affect the tuning. A larger size wire will increase the power handling ability somewhat, but STILL, the limiting factor is the connector. That wire will handle more power than the connector will. Unless you change the connector to a flange or something, I would leave the wire alone.
Changing the hardware is a great idea. Don't forget to clean up all the connections where the aluminum makes contact with other aluminum. That will make the antenna quiet, and last longer. |
Foxhunter
Intermediate Member
Username: Foxhunter
Post Number: 111
Registered: 4-2008
| | Posted on Friday, August 29, 2008 - 11:45 pm: |
|
Thank you Tech833 your advice is certainly welcomed and greatly appreciated. I will be upgrading the small wire/cable to atleast an 8-AWG fine-stranded cable of the same length.
The existing SO-239 is a "chasis-socket SO-239 with square flange"-type already, mounted to the hoop/ring bracket----but it is atleast 15-years old and of questionable quality/condition and only secured by two rivets.
Another Copper Member PatZero had advised me to upgrade this connector to a newer teflon/silver connector. I only have the nickel-plated material but will try and get the better silver-plate with Teflon insulator.
I'll be meticulous when it comes to cleaning this antenna into a like-new condition (inside overlapping/joining sections too as you pointed out). I am a firm-believer in "cleanliness is close to Godliness" when it comes to electrical/mechanical contact. I'll have a little trouble repalcing the rusted hoop/ring clamps that hold the rings to their brackets but I'll find something. All the rest of the hardware and additional hose-clamps will all be easily replaced with stainless-steel hardware.
May I ask an additional question or two about this antenna installation?
The previous owner had the coax wrapped tightly around the top portion of the 1.75-inch diameter heavy-walled aluminum pole/mast on which the antenna itself was mounted.
Should I duplicate what he was trying to do there with a "coax choke" of-sorts. Will that be effective? Good, bad or ineffective? I don't believe that the nine (or so) turns/wraps he made around the top of the mast was an actual "Balun" per-se, but was intended I believe to assist with stray RF or common-modes.
Would that be worth doing when I install the mast & antenna in the coming week? If so, given the 1.75-inch O.D. of the mast pipe, how many turns of the coax should I make (using RG-213)?
I was wanting to extend the length of the Maco's radials another 4-FT per radial. It is a 5/8 wave antenna and the 8-FT radials seem a little short. Increased wind-load is a concern, as well as additional weight/load with ice build-up in the winter and radial "snapping" but would their be a noticeable gain/improvement in doing this?
Any ideas, comments or suggetions by you or anyone would be greatly appreciated. Thanks---Fox |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1073
Registered: 5-2004
| | Posted on Tuesday, September 02, 2008 - 11:25 am: |
|
Foxhunter, I have a maco 5/8 and let me tell ya they are great. I got mine from copper in 2004 and it is going strong. You should not lenthen the ground plane as the antenna is designed to have radials that length.
You dont need to wrap the coax around the mast either, the manufacturer does not say anything obout that in the instructions and mine never needed it.
Get that baby rebuilt,up at least 36foot and enjoy, you will be very happy with it.
You can search the forum by typing in maco 5/8 and read lots of great info.
AP |
Foxhunter
Intermediate Member
Username: Foxhunter
Post Number: 112
Registered: 4-2008
| | Posted on Wednesday, September 03, 2008 - 12:09 am: |
|
Thank you---and I've done alot of reading on the Maco V 5/8 in Coppers Archives ALL AFTERNOON on Friday. I recently e-mailed someone my progress on this antenna and I'd like to cut & paste it here below:
*The Maco V 5/8-----I resurfaced the entire antenna using ScotchBrite pads. With some effort it came up beautiful and bright. 8-inches inside the sections and the complete outside surface. I did run into a bit of expense with all the replacement stainless-steel hardware. All: clamps / scews / bolts / nuts / lock & flat-washers are now stainless-steel. Low-quality material/hardware was a MAJOR fault from the antenna manufacturer. The degradation of the hardware I'm sure made poor mechanical AND electrical contact. If I were to buy a brand-new unit of ANY type such as this, replacing the hardware with stainless would be a priority and the very first thing I'd do.
One problem I did run into was for a "direct replacement part" for the clamp that goes around/onto the hoop-ring and is joined by that light gauge wire to the flanged SO239. The clamp was so rusted that it was extremely weak and thin. While buying the stainless-steel hardware at my local Sears Hardware, I purchased a pack of all-copper 1/2-inch plumbers pipe straps/clamps that, when folded over the hoop-ring-----are an exact match in size/length/width to the old rusted mild steel one previously on there. I doubled two of the copper pipe clamps together for added strength and thickness, tinned them both together and joined them to the hoop with a stainless machine screw. It was a definite upgrade. It looks way better than what was on there and should conduct far better---as this is a main power transfer point for the whole antenna. Once I adjust this clamp for antenna tuning I am considering soldering it to the aluminum hoop for assured electrical unity.
The only hold-up now is with the "panel-jack/flange mount" SO239 connector. The one on there really doesn't appear to be in bad shape (after running a wire-wheel over it to remove any grime/oxidation etc). The insulation appears to be of good color and intact. This is another area that needs upgrading----even if I were just buying the antenna new. The flange is only joined/fastened at only 2 of the 4 flange holes, with 2 small rivets. As I plan on seriously running 2000W+ or more through this antenna this SO239 will not be adequate I am afraid. I'll put an Amphenol silver-plated SO239 on there ATLEAST. I looked through my parts cases and only have the same nickel-plated ones, so I'll have to wait.
I wonder how the other Maco, the Maco V5000 is constructed? And what they've used for improved materials for comparison? What makes the V5000 a 5-KW gamma as opposed to the V 5/8's? I'll try and find out. I know I could've bought a new Maco but I've already become chin-high/deep with upgrading this antenna-----so I'm past "the point of no return". Like alot of projects they start out small and evolve. I'm just going to try and make this a "Super Maco" if I can.
Any suggestions or comments are still appreciated as I am still working on this Maco.
I just installed a nice Imax 2000 temporarily to replace the Shakespeare Big Stick I've had up the last 6 weeks. My antenna mounting location was relocated to the opposite corner of the house and the mast lengthened. The Imax's tip is at 64-FT. Boy that thing is scary the way it moves around. SWR is even across all channels at 1.2:1. It'll do for now 'til the Maco is done.
-----------------------------------------------
ALSO:
Although I'm going to post the following questions in new threads (and I've tried to read as much as possible first before doing so) I have two other issues I'm wondering about:
I need to find out what the best paint/sealer is to use on the aluminum Maco that can be bought **over-the-counter or off-the-shelf**. I'm really not crazy about some of the guys I've talked to on the air (or even read about on old posts) who say this does not matter much. I believe it does and commercial/professional systems companies say it is VERY important. The products they use however are specially made/commercial products not sold in small quantitites. Someone else considering doing the same might find the following of interest:
The most important qualities/characteristics of antenna paint are:
*NO METALLIC PARTICLES
*NO HIGH CARBON LEVELS
*NO CONDUCTIVE DYES
Also must be:
*RF "TRANSPARENT"
*UV RESISTANT
*DULL FINISHED/NON-REFLECTIVE
Has anyone found a good common product (readily available retail) that might fit the above description? I want to preserve the finish of the antenna and prevent future oxidation without any decrease in RX/TX or other RF interaction.
-----------------------------------------------
Also separately what I was referring to in my first posting at the start of this thread about "coiling coax" was the placement of an "RF choke" just below the antenna feedpoint. Known as (I've read) an "RF Choke" aka "Solenoid Current Balun" aka "Air-Wound Coil Choke".
I'm wanting to prevent the possiblity of common-mode currents travelling back down the shield of the coax. At higher powers, the slightest of problems (that one might not even notice at lower or mid-level power) will be greatly exaggerated/amplified/magnified. I want to not have any problems with this, as I have had in the past with this at one point. I'm trying to do what I can myself at lower-costs, as I can't just go out and buy what I need commercially right now. Improvising/Homebrewing is supposed to be part of the hobby to begin with too.
I've read some conflicting/confusing information a little on one or two points with making an RF Choke. I've read a technical sheet that says I can wrap 6-FT of coax TIGHTLY around THE MAST just below the antenna feedpoint. It goes on to say "purists" will insist on wrapping the coax EVENLY SPACED with a one coax-diameter space in-between each turn. Another technical article on RF Choke construction says not to use the mast, but to wrap the coax around a non-metallic PVC pipe section instead, and mount that at the antenna feedpoint.
I'd be thankful to anyone reading this who might be willing to share or comment.
I will re-post the above questions regarding *Antenna Paint and *RF Chokes on new threads as I know many members may not be reading this antenna thread. |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1074
Registered: 5-2004
| | Posted on Wednesday, September 03, 2008 - 7:07 am: |
|
I used clear laquer from my local hardware with pretty good results on aluminum but if I had to do it again I would not paint an aluminum antenna, I would just change all hardware to SS and use Noalox on all the joints and be done with it.
I used white laquer on my fiber glass elements on my PDL-2 after sanding lightly to get the splinters off and it worked out nice. My friend did same with an old Imax 2000 and it looks new with no change in SWRs or TX/RX. I will always paint fiber glass antennas for sure.
Like I said before I dont think you need a choke for this antenna but I could be wrong, try it first without one. I dont know of anyone needing one with a maco 5/8.
AP
I dont know if this helped but this is what I got |
Tech833
Moderator
Username: Tech833
Post Number: 1694
Registered: 8-2002
| | Posted on Wednesday, September 03, 2008 - 11:43 pm: |
|
Do not paint an aluminum antenna.
You only need to make a coax balun if your feedpoint SWR is bad. If the SWR is good, it is not needed on this antenna.
Do not lengthen the ground planes. They need to be 1/4 wave long. |
Foxhunter
Intermediate Member
Username: Foxhunter
Post Number: 118
Registered: 4-2008
| | Posted on Thursday, September 04, 2008 - 6:48 pm: |
|
Thanks I appreciate again the replies. I do not plan on painting the antenna. T
I've been considering the use of either Penetrox or Noalox at the various points where the the antenna sections join.
Would either of these products be better for this particular application than another? Would anyone advise against their use and why? They are not insulative materials but conductive. Would this be a benefit----or would there be a decrease (somewhat) in conductivity or power transfer? |
Tech833
Moderator
Username: Tech833
Post Number: 1700
Registered: 8-2002
| | Posted on Friday, September 05, 2008 - 9:19 am: |
|
See my answer in the other post. |
Foxhunter
Intermediate Member
Username: Foxhunter
Post Number: 126
Registered: 4-2008
| | Posted on Monday, September 08, 2008 - 2:00 pm: |
|
Yes I did see the other post and thank you. You're being a great help---not only to me but others as well who may be considering such an installation with this antenna currently---or in the future reading the "archived messages" on the Copper Forum.
Tech833---dispelling myths and misconceptions, constructive crticism and pointing out potential mistakes to those of us who are still learning is in the true spirit of "Elmering". I can promise you (and others who have shared good information as well) that your advice does not fall on deaf ears. The advice is invaluable and needed by those of us "lower down the food chain". Thanks---Foxhunter |
Tech833
Moderator
Username: Tech833
Post Number: 1704
Registered: 8-2002
| | Posted on Tuesday, September 09, 2008 - 9:52 am: |
|
Actually, I am 'lower in the food chain' than you guys. I learn a lot from all of you too. Now I know what a 'mall' is and a mud duck, etc. Thank you. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4388
Registered: 7-2004
| | Posted on Friday, September 12, 2008 - 7:16 pm: |
|
'maul'  ....now you REALLY know, paul.....as in 'paul the maul...with the BIG lowband signal'. |
Canal_digger
Junior Member
Username: Canal_digger
Post Number: 39
Registered: 1-2008
| | Posted on Wednesday, September 17, 2008 - 8:00 am: |
|
Finally! Got my hands on an old Super Penetrator in decent shape, has the usual wear and tear, but have an important question. Years back I remember buying a used alum from an old-timer who told me NOT to clean up/off the anodized aluminum off the antenna and keep it "gritty". He said it actually helped it perform better than a brand new smooth/clean one. Now that I have this one, aside from changing out a few parts for stability, should I take the ScotchBrite pads or scrubber to it or do I leave it alone? Thanks |
Tech833
Moderator
Username: Tech833
Post Number: 1706
Registered: 8-2002
| | Posted on Wednesday, September 17, 2008 - 5:16 pm: |
|
It doesn't really matter much. However, bare aluminum will skin over in very short order no matter what. So, removing material will only weaken it over time.
I suggest to clean up all metal-to-metal contact areas, and leave the rest alone. RF can't tell if it's shiny or not. |
Canal_digger
Junior Member
Username: Canal_digger
Post Number: 40
Registered: 1-2008
| | Posted on Friday, September 19, 2008 - 2:20 pm: |
|
Thank you and good advice- I will follow. On the model I stand corrected; not a Super Penetrator but actually the Radio Shack Crossbow .64 Wave antenna. Height from GPs is 22' 4", with 4 Nine foot GPs. Does not have the tuning "fork" on the exterior. I forgot how big these legendary performers were. Feel fortunate that I found one in great shape as I recall even when available in late 70s, were hard to get in stock. Looking forward to seeing how it compares with my Imax. |
