Two-Meter Antennas [Archive] - 4WDTrips.net Forums

YukonBob

09-02-2003, 06:11AM

The decision about which radio to buy was pretty straight forward.

The decison about the antenna caused me lots of searching.

I was hoping that the process would be pretty simple because I decided to drive the 60 miles to the Ham Radio Outlet to let them sell me what I needed. When they told me that the antenna, mount, and cable would cost more than the radio ($140) , I balked. Time to do more research. I figured I was getting the Best Buy treatment. Sell the product at a really low price, but make up for it on the accessories.

I started from scratch on antennas because the forum was down. My antenna theory tells me that the ground plane is important and having the antenna mounted in the center of the ground plane and high on the metal is important. High output power makes up for bad placement to some extent but if you want the best you can get you need to consider the placement of the antenna. The theory with CB antennas is the center of the roof is the best place and the center of the hood is the second best place. I think it's the same with two-meter.

My initial thought was to mount the antenna in the right hood channel. That would give me an easy path though the firewall for the antenna. This was the $150 antenna the HRO wanted to sell me. My objective was to leave the radio and antenna mounted full time. Unfortunately, a single band 5/8 wave antenna and my Yukon are too tall for my garage.

I looked at small antennas and dual band antennas but after reading the reviews at eham.com, I was scared away from them. They seem to be pretty fragile. When driving single track roads in all parts of the US and Mexico, I seem to hit a lot of bushes on both sides of the road. I do not have the confidence that any of the antennas will hold up to the punishment.

I had asked a few people about the performance of their antennas. I heard that ona recent Mojave trip the antenna that worked best for receiving was a mag mount antenna mounted on the roof. It seemed to confirm everything that I had learned.

The problem with two-meter mag mount antennas is they seem to be a little under magnet. I see ads that say they are tested up top 70 miles an hour. That scares me. I'm use to the power and quality of a Wilson 1000 for my CB. It's really tough to knock the antenna off with bushes, trees or wind. You can look at Uwe's pictures of our Baja trip when the wind plus our speed down the highway was well in excess of 100 miles an hour. The Wilsons stayed on the rood.

It didn't appear that I was going to find a quick solution to a permanent mount for the two-meter. So I went with what I knew best, I bought at Wilson two-meter mag mount antenna from ALF for $30 plus $6 shipping. It is not a permanent installation butI know it work really nice until Ifind one.

Post Edited (YukonBob) : 9/3/2003 3:32:37 AM GMT

JackSilb

09-04-2003, 06:06AM

What radio did you get? How much? Rational for the radio?

If your 2m Wilson has the same mag mount as the Wilson CB you are all set.
I missed the post that you were a HAM.
Did you play with the setup yet?

The $140.00 at HRO was ridiculous!
I got a made in Japan, good stuff, 2m antenna there for $30.00 or so.

-JACK
</div>

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Tread Lightly! empowers generations to enjoy the outdoors responsibly...

YukonBob

09-05-2003, 04:44AM

Yaseu FT-2800M is the radio. The rational was Uwe and Jack liked it. I got it at HRO for $140. </div>
Probably one of the best things is that I bought the radio without an antenna. I've been using it in my office with a CB antenna hooked up to it to try and learn about it. No transmissions, just receptions. I have a 14 Volt power supply from my model radio cars days. I think it's much easier here than hanging out in the cab of my Yukon. </div>

JackSilb

09-05-2003, 09:31PM

> I think it's much easier here than hanging out in the cab of my Yukon.

I see but you can't talk to us this way.
Now I remember the brand of the antenna I got. It is Diamond. Very well built. If yours go bad, try this brand.
Nice on the Yaesu. I liked it even more after I saw Uwe's radio. No fan to go bad, large display ...

-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...

BajaTaco

09-09-2003, 02:53AM

I have heard or read repeated times that SWR on a 2m antenna is not as critical as on a CB antenna. So, I wasn't too worried about getting mine checked, and I certainly didn't want to dish out more $$ to buy a good SWR meter.

About a week and a half ago, a friend of mine brought over his SWR meter. He is a ham, and so I guess this was a pretty good one. It showed my SWR was really bad!! I think it was reading up around "10" on the meter. Not good for the radio I guess. We got the antenna tuned, and now it is at about "1.25" (very good) so I should be able to transmit much better. So I recommend you guys get your antennas tuned - I had no idea mine was so bad.

I was also interested to find out that the actual power output on my transmission was different than the specs on my radio suggest. It was higher according to the meter. I wrote it down somewhere... I'll have to look for it.

http://www.bajataco.com
Vibram or BFG - getting there on rubber and seeing it all!

JackSilb

09-11-2003, 05:16AM

Baja,

Did he use a SWR meter that covered the band you were using? Or it was an approximation?

-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...

BajaTaco

09-11-2003, 04:56PM

I dunno. Since my first post regarding this, I am learning a little bit more. I guess I shouldhave saidit was a wattmeter, not an "SWR meter". It was bird wattmeter that looked like this...

http://www.radiodan.com/bird/images/db50wloadmeterf.jpg

He had a "slug" in it that was a 50w slug I think. So, we were measuring the watts going out from the radio, and the watts being reflected back at the radio. So my statement of an SWR reading of "10" was actually 10 watts. So, translated to SWR, I think it was probably about 2.38 maybe. (Here (http://www.tl.infi.net/~allenk/vswr.html) is an SWR calculator). We got my antenna tuned so that I was only getting about 1.2 watts reflected back to the radio during transmission.

http://www.bajataco.com
Vibram or BFG - getting there on rubber and seeing it all!

JackSilb

09-11-2003, 10:58PM

I need to get back to my notes. I believe that meter has to cover the frequency range to be able to work good. Something to do with resonance and response to frequency.
I know that the SWR meter that cover HF, VHF, and UHF is expensive.

Wasn't a question in the exam pool about SWR meter in VHF?

Can anybody comment on using an HF meter in VHF? Error?

Thanks,
-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...

w5wi

09-24-2003, 03:17AM

To get accurate readings you have to measure transmitted and reflected power. The higher reflected the higher swr.

You have to have an swr meter that is calibrated to the band your testing. A 2m and 440 swr meter is not too expensive. A multi band tester or a Bird wattmeter with appropriate slugs is expensive.

Whether your using HF, VHF or UHF to get the best performance you must have low swr. 1 to 1 is best. 1 to 1.5 is acceptable but with a low power radio you are losing radiated power back down the antenna with anything over 1 to 1.

dale de w5wi

BajaTaco

09-24-2003, 04:47PM

Thanks for the info Dale. We had my antenna adjusted all the way to get the final reading, so I guess maybe I should try a different antenna at some point. I would think that 1.2 watts reflected back is acceptable if I am on anything higher than the lowest power setting.

http://www.bajataco.com
Vibram or BFG - getting there on rubber and seeing it all!

w5wi

09-26-2003, 03:23AM

Baja,

Check the SWR at the lower and upper end of the 2m band. You will get two different readings. You should set the antenna where it is a balance between each end of the spectrum. This is especially important if your using repeaters which are all over the band with the TX and RX frequencies. Of course, the SWR is only affected by your transmissions, not RX.

dale

BajaTaco

09-26-2003, 02:44PM

Thanks Dale, but it's too late. The bird is gone, so I can't use it. But my friend seemed to know what he was doing and I think he accounted for that.

http://www.bajataco.com
Vibram or BFG - getting there on rubber and seeing it all!

WhiteThaiGer

01-11-2004, 06:47AM

Went to the HRO with Jack today to borrow their antenna analyzer.Best SWR reading we could get was close to 2. Advice from the Ham guys: cut a whole in your roof and put the antenna up there.</div>
Questions remains: Why does Baja get much better TX/RX results than me with same antenna & cable setup and very similar radios??? http://www.4wdtrips.net/forum/emoticons/notme.gif </div>

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BajaTaco

01-11-2004, 04:57PM

http://www.4wdtrips.net/forum/emoticons/headscratch.gifhttp://www.4wdtrips.net/forum/emoticons/notme.gif
What was it when you first tried it before any adjustments? Did you have to cut the antenna? Maybe the 2.0 will work better than what you had.</div>

http://www.bajataco.com

WhiteThaiGer

01-11-2004, 05:03PM

BajaTaco said...
http://www.4wdtrips.net/forum/emoticons/headscratch.gifhttp://www.4wdtrips.net/forum/emoticons/notme.gif
What was it when you first tried it before any adjustments? Did you have to cut the antenna? Maybe the 2.0 will work better than what you had.
</div>Now its a little below 2, before it was a little over 2. Not much change. We'll see on the next trip.

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BajaTaco

01-11-2004, 05:07PM

Well, that should help. The bad thing about having it up on the roof is when you go on a trail with low overhanging trees - like when we went to thearcheo site through that ranch in Baja - that antenna is gonna get completely laid flat on a more regular basis. Maybe it won't matter though, I dunno. That antenna is super flexy.

http://www.bajataco.com

JackSilb

01-13-2004, 05:52AM

Uwe,

Your current antenna setup will not work well on the roof hole scheme. You will need another type of antenna / connector. Like Al's, Bob's, or Jack's.

Still making this work is a nice exercise and you will learn. Or just leave the current cable and antenna connector for the CB and make the nice ground plane install for 2m.

-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

WhiteThaiGer

01-22-2004, 05:28AM

Antenna woes continue http://www.4wdtrips.net/forum/emoticons/cry.gif </div>
Last weekend I had Steve http://www.4wdtrips.net/forum/emoticons/shocked.gif (yep, the one who had theworst transmissions of everyone in the group before his new radio) complain about how hard it was to hear me.... </div>
So I took the multimeter to the car and checked:</div>

if the antenna cable plug is making electrical contact with car's body. It does
if the centerpin of the connector is connected to the antenna. It is not
Maybe I don't know http://www.4wdtrips.net/forum/emoticons/notme.gifhow these antennas work, but I had thought that the center pin should have direct, electrical contact to the antenna rod. Is there somekind of inductive connectionhttp://www.4wdtrips.net/forum/emoticons/headscratch.gif? </div>
Chris, you have the same antenna, how is it with yours? I have contact up to the bottom segment of the SF-2 antenna (just below the white shrink-wrap). There is no contact from the bolt at the bottom to the rod. Maybe you can check it when you have a chance.</div>

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MrS

01-22-2004, 09:17PM

WhiteThaiGer said...

if the centerpin of the connector is connected to the antenna. It is notThat dosen't sound right.

How did you check it? Volts, ohms, ?????

Where from? The radio connector to the mast?

I can check mine to and we can compair notes.

Sounds like you may have something here.

I'd think a cable problem would have showen on the SWR.

KF6YSB

MrS

01-22-2004, 09:21PM

WhiteThaiGer said...

Last weekend I had Steve http://www.4wdtrips.net/forum/emoticons/shocked.gif (yep, the one who had theworst transmissions of everyone in the group before his new radio) complain about how hard it was to hear me....
Boy that Steve guy sounds like a nice guy. He must not be the kind to let his past, hinder his helping friends. I hear he has acool truck (andcamp lighting) to boot, I can't wait to meet him. His wife must be a lucky woman.

http://www.4wdtrips.net/forum/emoticons/baja_rofl.gif

KF6YSB

WhiteThaiGer

01-22-2004, 09:49PM

That dosen't sound right.

That's what I thought.

How did you check it? Volts, ohms, ?????

With a multimeter. Volts??? I thought I'd rather check resistancehttp://www.4wdtrips.net/forum/emoticons/wink.gifThanks for making sure Steve.

Where from? The radio connector to the mast?

Center pin of cable at connector that plugs into radio to the mast (rod, whip, whatever). When that didn't show anything I took the mount appart and made sure the cable from the radio to the mount is ok. No recistance their, just a fraction of an Ohm. Then I investigated the mount and noticed that the bottom is connected, but there is a disconnect between the bottom of the mount and the top (where the rod is inserted). That's what's puzzeling me. Is it a bad unit or can any of you Radio experts explain please?

I can check mine to and we can compair notes.

Sounds good. I checked my cheapo CB antenna, it has connection. I did this just to see if there is something systematic that I dont' know about.
Maybe Baja can check his, cause it's the exact same setup and then I could go down to the HRO on Saturday.

Sounds like you may have something here.

I'd think a cable problem would have showen on the SWR.

That's what I thought and I'd think it would have a hard time transmitting this way.I can go back an check. I should have done these test when we were at the HRO, but I thought the Ham guy and Radio Jack would suggest all the necessary tests....
Now where is Radio Jack anywaywhen you need him??
</div>

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alanh

01-23-2004, 05:09AM

If I've got my messages straight, this is a Hustler SF-2 right? I didn't find much info with a quick search, but it seems like it ought to have continuity from the center pin of the antenna to the metal whip, unlessit was one of those thru-the-window-glass antennas. I get the impression it has a wire coil at the base toadd more length electrically without a longer physical antenna length. Perhaps there is a problem there unless there is an insulating coating or something like that on the antenna preventing good contact with your meter probe.

If it is indeed a Hustler antenna, you might try sending them an e-mail or calling. http://www.new-tronics.com/main/index.html

Alan
PS: RF can act pretty strange at times, so it might appear to work halfway decent according to the meter. Not quite the same, butquite a fewyears ago I was troubleshooting a computer memory card at work. The digital signals were not real high speed at that time, but fast enough that they had some characteristics of radio frequencies. We had a test program that sometimes passed, sometimes didn't. Turned out that one or more of the address or data lines (don't remember anymore)had breaks in them, but somehow it managed to partially work, even for memory chips beyond the break. Not really a good troubleshooting technique, but you could wave your hand around near the back or touch it and change the way it worked or didn't.</div>

Alan

Post Edited (Alan H.) : 1/23/2004 5:18:00 AM GMT

WhiteThaiGer

01-23-2004, 02:50PM

Alan H. said...
If I've got my messages straight, this is a Hustler SF-2 right? I didn't find much info with a quick search, but it seems like it ought to have continuity from the center pin of the antenna to the metal whip, unlessit was one of those thru-the-window-glass antennas. I get the impression it has a wire coil at the base toadd more length electrically without a longer physical antenna length. Perhaps there is a problem there unless there is an insulating coating or something like that on the antenna preventing good contact with your meter probe.

If it is indeed a Hustler antenna, you might try sending them an e-mail or calling. http://www.new-tronics.com/main/index.html

Alan
PS: RF can act pretty strange at times, so it might appear to work halfway decent according to the meter. Not quite the same, butquite a fewyears ago I was troubleshooting a computer memory card at work. The digital signals were not real high speed at that time, but fast enough that they had some characteristics of radio frequencies. We had a test program that sometimes passed, sometimes didn't. Turned out that one or more of the address or data lines (don't remember anymore)had breaks in them, but somehow it managed to partially work, even for memory chips beyond the break. Not really a good troubleshooting technique, but you could wave your hand around near the back or touch it and change the way it worked or didn't.
</div>Thanks Alan, you got the right antenna. No coating, no window stuff. I actually sent an email to the company after my post here a couple of nights ago. No answer yet.

Nice story about the memory!

Here is the antenna mount assembly. The rod inserts at the top. the bottom is attached to the hood mount. I have continuity from the radio to the red line on the pic below. There is no continuity from the red to the blue line or anywhere above the blue line, including the rod when inserted. Mysterious things must be happening behind the black rubber...
http://www.rxtx.com:8085/4wdtrips/photogallery/data/media/46/SF-2-1.jpg

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MrS

01-23-2004, 03:28PM

resistance would be the first check. Since your antenna is base loaded and mine isn't, baja may be the guy you need to help you.

I'll call tomorrow (sat). I have got plumbers out for a major repipe, not sure how the free-time thing will play-out.

You radio still works better than a CB, so don't break anything. :-)

KF6YSB

JackSilb

01-24-2004, 07:19AM

Sorry, I could not get here earlier. Too much work. My wife told me today that I did not need to come home. The kids were used to that. Anyway...

UWE, this is great news!
All makes sense now. You have a bad connection.
You should see almost 0 ohms connection between your middle pin on the connector (using the multimeter in OHMS) the the top of the antenna. The same thing from the outside of the connector to the base of the antenna (ground). AND should have an open circuit from the center pin to the outside of the connector. The 50 ohms coax cable should show 50 ohms just for RF not for your multimeter.

Hey, remember I asking you if you have tested the connector?
The guy at HRO said, forget it. If the connector was bad you would not have a good SWR ...

Solutions. Cut your current connector and measure the resistance between the central conductor from the coax to the top part of your antenna. Just above the coil is fine. It should read VERY close to 0 ohms. maybe 0.3 max. Then measure to the base of the antenna where you have the ground.It should read OPEN (~infinite resistance).
Then measure from the outside part of the coax (the shield part) to the base (ground) of you antenna. It also should have a almost 0 resistance. Base here means the part that connects to the car using your antenna support.

If there is a problem. Then you need a new cable. Now we see the light at the end of the tunnel. And it is not a train coming.

-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

WhiteThaiGer

01-24-2004, 04:21PM

Sorry, I could not get here earlier. Too much work. My wife told me today that I did not need to come home. The kids were used to that. Anyway...

Okay, I believe you, I won't complain. Spent time with the family....like showing them how to diagnose antenna problems, they'll love it http://www.4wdtrips.net/forum/emoticons/joker1.gif

UWE, this is great news!
All makes sense now. You have a bad connection.
You should see almost 0 ohms connection between your middle pin on the connector (using the multimeter in OHMS) the the top of the antenna. The same thing from the outside of the connector to the base of the antenna (ground). AND should have an open circuit from the center pin to the outside of the connector. The 50 ohms coax cable should show 50 ohms just for RF not for your multimeter.

Everything expect center pin to top of antenna checks out.

Hey, remember I asking you if you have tested the connector?

No http://www.4wdtrips.net/forum/emoticons/wink.gif You did talk about ground and that is fine

The guy at HRO said, forget it. If the connector was bad you would not have a good SWR ...

That's true! He was too focused on his ground plane, 'Put it on the roof' was what he kept saying. Trust no one!http://www.4wdtrips.net/forum/emoticons/nono.gif

Solutions. Cut your current connector and measure the resistance between the central conductor from the coax to the top part of your antenna. Just above the coil is fine. It should read VERY close to 0 ohms. maybe 0.3 max. Then measure to the base of the antenna where you have the ground.It should read OPEN (~infinite resistance).
Then measure from the outside part of the coax (the shield part) to the base (ground) of you antenna. It also should have a almost 0 resistance. Base here means the part that connects to the car using your antenna support.

If there is a problem. Then you need a new cable. Now we see the light at the end of the tunnel. And it is not a train coming.

In my previous posts I tried to explain, that the connections from the plug that goes into the radio to the base are ok. This includes the shield/base and the signal wire (center pin). I've already narrowed it down the base assembly shown in the post above. I can't disassemble that without destroying it.
Note that the cable is not permanently connected to the base, it connects with a bolt. The bold is not the problem, since I have continuity all the way to the base assembly (see picture & post).
The antenna company says I can send it in for evaluationunder warrenty if I find my receipthttp://www.4wdtrips.net/forum/emoticons/headscratch.gif . Well otherwise it's ~$15. I may just do this. No trips scheduled for the next couple of weeks...

</div>

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JackSilb

01-24-2004, 07:33PM

Oops, I missed the part you tested the cable.
Lets stop by HRO one more time. Get one of their antennas for test.
This time, lets make sure Jose is there. He will work on it until we get it done. I have been giving them good money.

-JACK

So much to see, so little time. Try using your 4WD tosee and do more.
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BajaTaco

01-26-2004, 01:21AM

Sorry Uwe, but I just now had a chance to reply to this. I will check the resistance on mine tomorrow when I have some daylight, for a comparison. In the meantime, have you seen this regarding testing continuity (http://www.firestik.com/Tech_Docs/Testing_Continuity.htm) on the FireRing coax? It sounds like you sort of already did this, but you might want to check using the metal disc that is imbedded into the connector as shown, just for good measure.

http://www.bajataco.com

BajaTaco

01-27-2004, 02:14AM

I was finally able to check my antenna. I do indeed have continuity from the bottom part of the antenna to the rod. One thing that is kind of odd, is that if you look at the picture...

http://www.rxtx.com:8085/4wdtrips/photogallery/data/media/46/SF-2-1.jpg

...you can see a very thin ring of exposed metal where the top of the black coating meets the metal part. When I touch the probe to this thin ring, and put the other probe on the rod, I do get some weird ohms readings that seem unsettled, but overall are pretty low. If I touch the probe to the area just above the thin ring (the part that tapers up where the blue line is shown) the resistance returns to a 0.0 reading, or very close to it. So I guess that confirms the theory that the coiled part (between the blue and red lines in the pic) has a defect.

Just for the heck of it - I will mention this - did you make sure that you are not resting your arms/elbows on the hood of the truck while you are holding the probes and getting a reading?

</div>

http://www.bajataco.com

WhiteThaiGer

01-27-2004, 03:39AM

Thanks Baja! That settles it I got to get a new antenna.</div>
I don't see the thin ring you have and that shows on the picture on my antenna.</div>
The weird ohms you see could also be related to bad contact.I notice a thin film of dirt/sfuff on my antenna in places when I was not getting continuity and started to wonder if the metal is coated.</div>
I now took the part in the picture out and tested it separatly again. Still bad.</div>
I don't understand how resting arms on the hood would cause me to read a dis-continuity?</div>

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BajaTaco

01-27-2004, 03:26PM

I replied to this last night, but like others, the one time that I don't copy my text to the clip board, I lost it http://www.4wdtrips.net/forum/emoticons/cry.gif

Anyway, glad I could help. Regarding restingyour arms on the truck - try it. Find two locations for your probes that give you a zero reading for ohms, and then holding the probes in the same locations, rest your arms on the metal body of the truck.

http://www.bajataco.com

WhiteThaiGer

01-27-2004, 03:38PM

BajaTaco said...
I replied to this last night, but like others, the one time that I don't copy my text to the clip board, I lost it http://www.4wdtrips.net/forum/emoticons/cry.gif

Anyway, glad I could help. Regarding restingyour arms on the truck - try it. Find two locations for your probes that give you a zero reading for ohms, and then holding the probes in the same locations, rest your arms on the metal body of the truck.
</div>Yeah, the forum has problems these days http://www.4wdtrips.net/forum/emoticons/cry.gif

I realize that your body can kind of complete a circuit and you get some MOhm readings, I didn't understand who it could give me a false 0 Ohm reading. BTW, I did the little arm test you suggest, just out of curiousity, it does not give me a reading. Probes are probably too well insulated.

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