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Help Tuning Mobile Antenna to HT

K

kf4mnc

Member
Jan 2, 2011
19
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Hello,

Long time reader, rare poster. This question might fall into several areas, so I thought it was best suited for general discussion, Mods if you think it will fit somewhere else, please move it.

My problem is I have a Kenwood TH-D72 and I am trying to connect it up to my mobile antenna a Comet CA-2x4SR. I am using a Radioshack SWR meter model # 21-534, and my SWR is just pegging the meter at 3.0 +. I even tried another cheaply dual band antenna and the same results.

The only thing I can think of is that I am not calibrating the meter correctly, but I've read the directions a hundred times and I still get the same results.

I know the Radioshack meter isn't the best, but other have confirmed that it is fairly reliable.

Does anyone have any suggestions on how to get my SWR down to an acceptable range?

Thanks in advance for the help!

Chris
KF4MNC
 

That SWR/Watt meter is for 3-30Mhz only. You're in the 144Mhz range with that rig and antenna so it's not gonna work properly. You need a meter specific to that freq range. Hope this helps ya somewhat :cool:
73's.Chris.W8CDF
 
Slim said:
That SWR/Watt meter is for 3-30Mhz only. You're in the 144Mhz range with that rig and antenna so it's not gonna work properly. You need a meter specific to that freq range. Hope this helps ya somewhat :cool:
73's.Chris.W8CDF
Click to expand...


Agreed with Slim. You will never get anything near accurate with that meter on VHF/UHF. It was just not meant to be used on those frequencies but will work decent on HF. You need an SWR meter designed for those frequencies.
 
In general, that Comet CA-2x4SR antenna doesn't need to be 'tuned', it should be close as it is. At least, that's my experience with two of them. Still, it never hurts to check to see how it's behaving with an appropriate SWR meter.
- 'Doc
 
W5LZ said:
In general, that Comet CA-2x4SR antenna doesn't need to be 'tuned', it should be close as it is. At least, that's my experience with two of them. Still, it never hurts to check to see how it's behaving with an appropriate SWR meter.
- 'Doc
Click to expand...

Agreed. I own one as well. I just got caught up in the "WHY" and not so much the "WHY BOTHER". :D
 
Well I feel like a dummy! I should have read more closely. I was in a rush to get things set-up and made a mistake. :oops:

Thanks everyone for the help, I'll pick up a new one this week.
 
How does it work on receive? If you can hear well, it is an indication that there is not too much wrong with the antenna.

If you hear nothing, particularly on a local repeater or APRS frequency where you can hear signals on your rubber duck, then the antenna or coax may be toast.

For 2M/222/440 I have a MFJ-862 forward and reverse power meter that works very well.

I never liked the SWR meters where you adjust the response on forward and then masure on reverse. With the dual need watt meters you get a bit better indication. And just tune your antenna so the reverse (or reflected) meter doesn't move and you are set...

Dave, W6DPS
 
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Dave_W6DPS said:
How does it work on receive? If you can hear well, it is an indication that there is not too much wrong with the antenna.
Click to expand...

Even with an SWR of 5:1 it will still receive fine.

If you hear nothing, particularly on a local repeater or APRS frequency where you can hear signals on your rubber duck, then the antenna or coax may be toast.
Click to expand...

Agreed but which is it?



For 2M/222/440 I have a MFJ-862 forward and reverse power meter that works very well.

I never liked the SWR meters where you adjust the response on forward and then masure on reverse. With the dual need watt meters you get a bit better indication. And just tune your antenna so the reverse (or reflected) meter doesn't move and you are set...

Dave, W6DPS
Click to expand...


Cross needle meters are fine but regular SWR meters work just as well. There is just an extra step to calibrate it to the forward power that's all.
 
I dont have a SWR meter for VHF, so when I built my 1/4w antenna out of a mag mount cellular ant and 1/16" steel rod, I just measured it very carefully and started hitting repeaters I never could get with my rubber duck antenna.
Most HT's are built to handle more ref power than most mobiles.
 
towerdog said:
I dont have a SWR meter for VHF, so when I built my 1/4w antenna out of a mag mount cellular ant and 1/16" steel rod, I just measured it very carefully and started hitting repeaters I never could get with my rubber duck antenna.
Most HT's are built to handle more ref power than most mobiles.
Click to expand...


Oh yeah to that. The typical rubber duck antenna will exhibit an SWR of anywhere from 1:1 up to 3 or 4 :1 depending which way the radio is held.
 
That is because the tuner is acting like a bandpass filter and only allowing signals to pass that are centered on the frequency to which it is tuned. Completely different situation than having a high SWR simply because of an antenna out of tune without a tuner inline. Next time use an antenna for a different band and switch the tuner to bypass and see how much signal you get fed to the receiver.
 
Captain Kilowatt said:
That is because the tuner is acting like a bandpass filter and only allowing signals to pass that are centered on the frequency to which it is tuned. Completely different situation than having a high SWR simply because of an antenna out of tune without a tuner inline. Next time use an antenna for a different band and switch the tuner to bypass and see how much signal you get fed to the receiver.
Click to expand...

Okay.thanks bro.

The dev that made this thread get it sorted out ?

Sent from Outerspace, on the DarkSide of X.
 

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