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Message |
    
Coyote
Intermediate Member
Username: Coyote
Post Number: 480
Registered: 11-2004
| | Posted on Tuesday, October 25, 2005 - 8:57 am: | 
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Well, I am temporarily off the air on the base. Turned the radio on last nite for the first time in about a week. When I keyed up, the SWR was through the roof. I started checking jumpers and all were ok. Checked the main line in and there it was, center pin to outter connector shorted. I removed the PL259 and checked with just bare center wire and braid, still shorted. No $$ right now and no one to help bring down the antenna to replace the coax if I had it.
CEF443
Middle TN Coyote
10-7  |
Marconi
Intermediate Member
Username: Marconi
Post Number: 454
Registered: 11-2001
| | Posted on Tuesday, October 25, 2005 - 1:06 pm: |
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That does not necessarily mean that the coax is bad. Some antennas show a short via the matching network.
What kind of antenna do you have? |
Coyote
Intermediate Member
Username: Coyote
Post Number: 481
Registered: 11-2004
| | Posted on Tuesday, October 25, 2005 - 3:09 pm: |
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Marconi, well, I suppose it could be the antenna. Its an Archer (RS) 5/8 aluminum ground plane I've had for about 30 years. None the less, no $$ to replace either, nor is anyone available to help bring the antenna down any time soon to check it. Thinking of building a dipole to use until I can find a volunteer or two to help bring the old antenna down.
73
CEF-443 |
Marconi
Intermediate Member
Username: Marconi
Post Number: 457
Registered: 11-2001
| | Posted on Tuesday, October 25, 2005 - 3:50 pm: |
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Now a dipole that you build or buy should show and open when checked with an OHM's meter.
I don't know anything about the Archer 5/8, but most of the others out there that fed via a coil of some type also show a short. |
Coyote
Intermediate Member
Username: Coyote
Post Number: 482
Registered: 11-2004
| | Posted on Tuesday, October 25, 2005 - 4:22 pm: |
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Maybe someone else has an idea. I wont know for sure till I can bring down the antenna and check it. All I know is something is def. a miss. My SWR has never been pegged before.
The dipole will be just a temp. fix till I can fix or replace whatever has gone wrong with the other one. And who knows, the dipole may out perform the old antenna and then I wont have to worry with it.
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Nobodyknows
Intermediate Member
Username: Nobodyknows
Post Number: 120
Registered: 4-2005
| | Posted on Tuesday, October 25, 2005 - 9:06 pm: |
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Are you sure that it's the antenna? I have a CLR-2, 1/2 wave ground plane that shows ohms between the center and ground connector and swrs were good. Theirs a cap or something in the base of it that connects the vertical to the ground planes isn't there? So you get an ohm reading that may appear to be a short. |
Moonraker
Junior Member
Username: Moonraker
Post Number: 48
Registered: 3-2005
| | Posted on Tuesday, October 25, 2005 - 9:15 pm: |
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On the A99 and the Imax2000, the center conductor and the outer shield show a direct short on an ohm meter. When I bought my Imax a few years ago, I called tech support about this and he said it was normal. Coyote, I don't know if your antenna is the same way or who you to call to find out, but I hope you get it fixed. |
Coyote
Intermediate Member
Username: Coyote
Post Number: 484
Registered: 11-2004
| | Posted on Wednesday, October 26, 2005 - 8:55 am: |
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Moonraker, I wouldnt know who to call either, this antenna is over 30 years old. I never checked it with an ohm meter before so I wouldnt know if it should show a reading or not, BUT, I did a bit of checking last nite and I did find what may be the real problem. It seems my amp may have a slight problem, with the amp turned off, I get a reading on the ohm meter between both input and output center connections to ground on the SO259's. I will post all the info in the amp section soon, maybe someone can tell me what needs to be replaced? The amp is a Kris Boomer 70w max.
I am going to redo the PL259 on my coax and see if the antenna shows good SWR without the amp in line. Im betting it will.
Thanks for yal's input. 73
CEF-443 |
Marconi
Intermediate Member
Username: Marconi
Post Number: 459
Registered: 11-2001
| | Posted on Wednesday, October 26, 2005 - 12:15 pm: |
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Hey Coyote, hold up before you change the PL-259 and removing the amp from the line at the same time. That is no way to check something out. You will be making two possible changes at the same time. Remove the amp first and check. Then, if necessary, redo the fitting if when removing the amp it still shows bad.
Personaly, I would not use the reading you got at the ports on your amp as an indication that the amp is bad either. I have never seen an amp that did not show some reading when checked that way. |
Narf_edwards
Junior Member
Username: Narf_edwards
Post Number: 15
Registered: 3-2005
| | Posted on Wednesday, October 26, 2005 - 1:12 pm: |
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Would any know how to rewind the loading coil in the base of my old archer 1/2 wave fiberglass.I am restoring mine and the ferrite was broken.I need to know the number of turns primary and secondary.I can reuse the cap but I lost the original ferrite with the windings so I cannot just copy it.I have looked high and low on the web but to use a winding calculator I need to know inductance and capacitance etc. which I am unable to obtain values for.This probably sounds like a waste of time to most,but I cannot afford a new antenna and thus I am trying to repair this one.The other option I suppose is to eliminate the coil all together and just use it with a tuner and feed thru a coax balun.Any help would be appreciated.I have already re-laminated the fiberglass and mounted a heavy copper plate at the top bracket which now holds 4 4.5 foot copper radials.Maybe the radials will bring the feedline impedance down enough so there will be no need for the coil.Or maybe the shunt coil and cap is mandatory to get this thing to go.I don't know.
Thanx
Narf |
Coyote
Intermediate Member
Username: Coyote
Post Number: 486
Registered: 11-2004
| | Posted on Wednesday, October 26, 2005 - 3:18 pm: |
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Marconi, I already removed the PL259 when I first started checking. So either way, I'll have to put another one back on. If the reading stays the same, then I'll hook it all back up the way it was to start with. If the SWR is still through the roof, I'll remove the amp from the line and see what the SWR goes to then.
Oh, btw, the dipole I made last night has a 1.5:1 SWR across the entire band. When I first got it up, I had the amp in line and the SWR was still pegging. I removed the amp from the line and the SWR dropped to the 1.5:1. I've only talked to one person since I put it up and they said it sounded good. Right now its only about 20 foot off the ground at the feed point. I made it using some left over coax from when I put the other antenna up and ran it out the window by the radio and put it up on the side of the house in a inverted V. Its good for talking local at the moment, and since DX has been pretty much none, I figured thats good enough for now.
Anyhow, thats where I'm at now, using a dipole and no amp and have a 1.5:1 SWR across the entire band.
73 |
Narf_edwards
Junior Member
Username: Narf_edwards
Post Number: 17
Registered: 3-2005
| | Posted on Wednesday, October 26, 2005 - 5:14 pm: |
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Sorry I started a new topic for above post
My apologies
Narf |
Chad
Advanced Member
Username: Chad
Post Number: 531
Registered: 11-2004
| | Posted on Wednesday, October 26, 2005 - 7:02 pm: |
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Woah, was the original antenna OK without the amp?
Does your house have celotex under the siding? |
Kid_vicious
Advanced Member
Username: Kid_vicious
Post Number: 737
Registered: 9-2004
| | Posted on Wednesday, October 26, 2005 - 7:44 pm: |
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coyote, im betting that the amp is the culprit.
that amp is quite old and if it hasnt had new transistors put in, then they are suspect.
do you have a wattmeter on that SWR meter so you can see the power out with the amp on and off?
this is the exact reason to make a dummy load.
if you had one, you could hook it up to the output of the amp and if the SWR was still sky high, you would know it was the amp's fault.
do a search on this forum for "dummy load" i have a thread on how to make your own. for the power handling that you need though, it may be cheaper to buy one.
you may find that the transistors on your amp are quite inexpensive and can just replace them.
good luck,
matt |
Chad
Advanced Member
Username: Chad
Post Number: 533
Registered: 11-2004
| | Posted on Wednesday, October 26, 2005 - 9:39 pm: |
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KV is right it would help greatly to have a load but remember, many loads are VERY broad banded.
If something were wrong in the output filtering of the amp causing it to make harmonics the load would still show a good SWR. Since an antenna has a more narrow bandwidth the harmonics would show up as increased SWR. Because, that's what's happening, the antenna is rejecting the harmonics.
Loads are good. I need a good one. I have enough to tune a radio
Chad |
Coyote
Intermediate Member
Username: Coyote
Post Number: 488
Registered: 11-2004
| | Posted on Thursday, October 27, 2005 - 9:41 am: |
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KV, I put the amp back in-line last nite with the meter on the output side. With the amp off, the SWR is a little over 1.5:1, this is with the dipole being used, with amp on, the SWR only goes up to about 2:1 putting out 60w. It was pegging the meter before. So the amp seems to working properly. I think the problem was in the antenna switch i was use'n. I hooked up the radio straight to the amp, put the meter after the amp hooked the dipole straight to the meter and all seems acceptable. Put the switch back in line and the SWR went nuts again. Guess where that switch is now?  It's not being used, thats for sure.
I haven't hooked the ground plane back up yet. Never went and got a new end for the coax yesterday. Just ordered new ends from Copper this morning since RS wants like $5.29 for just one and Copper has a package of 10 for $6.50.  I can live with the dipole for a few more days. Kinda have'n fun experimenting with it right now. 
Chad, My house is made of stone and built into the side of a hill. The other antenna is probably just fine. SWR before it all started was just a little over 1.5:1 without the amp on and about 2:1 with it on putting out 70w.
Thanks for everyones help and input. |
Chad
Advanced Member
Username: Chad
Post Number: 536
Registered: 11-2004
| | Posted on Thursday, October 27, 2005 - 9:59 am: |
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OOOH yeah I remember now. I'm getting old, well, my brain is |
Coyote
Intermediate Member
Username: Coyote
Post Number: 497
Registered: 11-2004
| | Posted on Monday, October 31, 2005 - 12:41 pm: |
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Well, I don't have a final verdict on the ground plane yet. Been having to much fun experimenting with the dipole. Still waiting on the new connectors to arrive from Copper, they will probably come in today.
I first put the dipole on the side of the house and had acceptable SWR, BUT, the RF it was putting into the TV's and speakers was tremendous. So, I moved it to the top of the house which wound up being about 35' high. The RF into the house increased even more, SWR about the same. Did manage to make an AM DX on ch. 26 to Rattle Snake in Up State NY though and it had real good RX.
These arrangements were all in the inverted "V" configuration. SO, I moved it again, this time I decided to get it away from the house as far as possible with the lead I had available.
I ran it to the nearest tree I could reach and climb without killing myself, or risk serious injury. Could only get it about 15' up and in a configuration like this -------< (a sideways Y) with one half of the Y going to the highest limb i could reach and the other half of the Y below it goin to about 6 or 7 feet off the ground. I really didn't think this would work all that good but I decided to give a try. SWR went to 1:1 across the entire CB band and then some with the amp on. The ends of the "Y" are pointing north/northeast. If you have read the CEF Net connections or the DX connections section you will see how this arrangement worked. SO, now I'm thinking, is this thing acting like a beam or something? It's really a bit low to be a good beam if it is. I realize with it being as low to the ground as it is, that the angle of radiation is probably pretty high, which might account for the contact's I made with it.
Which will bring me to my next "experiment".
Two 1/4 wave dipoles, with the horizontal Y's pointing away from each other and maybe put it on some type of beam/frame and get it up higher on a mast. It would look something like this;
>----|----<
The feed point would be in the middle with the center conductor and sheild being feed to both sides. A dual dipole thats horizontal.
Anyone have any thoughts on how this might work? I'm willing to try it for fun if it hasn't been attempted before. If anyone has heard of it, let me know your thoughts or how it worked. I'm curious.
CEF-443
Middle TN Coyote |
Coyote
Advanced Member
Username: Coyote
Post Number: 502
Registered: 11-2004
| | Posted on Tuesday, November 01, 2005 - 8:44 am: |
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Humm... I guess I can see why this got moved.. but in a way, it kinda covers two topics... but it did start out about coax.. so I can see the reasoning for the move...
CEF-443 |
