Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Please help a new ham tune his radio

Turbo T

Turbo T

Certified CB Rambo
Feb 2, 2011
963
141
53
I recently acquired my tech license. Today my Yaesu FT 7900 R came in the mail.

I took my new Tram 1180 dual band antenna (bought at ham fest - hams recommended it) and hooked it to my SWR3 meter. I sat the antenna dead center of the roof, hook it up, and set the radio to the 144-145 mHz area.

My SWR's are like 2.5 and they get worse the higher you go in frequency.

I tried raising the antenna but no dice. The antenna consists of two metal whips with a load coil in the middle.

Anyways I'm a bit stumped. What should I do? I want to get on the air and start talking.

Thanks in advance.
 

pappy.gif
I agree with Beetle. I searched the net and didn't find anyone with a SWR problem only a warning not to exceed 50 watts. Hopefully, your SWR Meter is at fault (also, make sure all your connections are clean and tight).
 
The SWR 3 meter that I just looked at was for the HF bands... 1.8 to 30 MHZ ...if that is the meter that you have it will not be accurate at VHF/UHF frequencies..

Chances are you will still have to tune the antenna to the radio when you locate a proper meter ...but a proper meter is going to be a must have deal in order for an accurate reading


Also when tuning an antenna remember the LOWER in freqnency the longer the antenna,the HIGHER in frequency the shorter the antenna
 
The meter I have, in the instructions, says it works on frequencies 1.7 mHz to 150 mHz.

I did make sure the connections were clean and tight. I also had the radio's power on low. (5 watts) when i took the measurements.

I did stumble across this though, where someone claiming a CB SWR meter hooked backwards, would almost give you an accurate reading, but heck is there really any truth to it? No VHF SWR Meter? No Problem. -KB6NU's Ham Radio Blog
 
Dual band 2 meter 440 antennas are most often plug and play are they not. At least the Diamond mobile antennas I used were.

It is prob your meter that is wrong perhaps.

Look for a hAM IN YOUR AREA, They might have a meter for you frequency or an mfj anilizer.

AP
 
I think I'd be very careful with that advice of a CB SWR meter working backwards thingy. I don't know anything about KB6NU, but without a lot more explaining about it, I would have to say he's mistaken. That "almost an accurate reading" means you might have an "almost broken" radio, sort of.
I have used a watt meter hooked up backwards to measure 'reflected' power, but I also wouldn't take that ability for granted and certainly wouldn't swear to the accuracy of it (I also rechecked it later with a 'proper' meter).
No pre-tuned antenna is ever going to be as 'tuned' as you think it is, all of them can use some adjustment.
Know anyone with a VHF/UHF capable meter??
- 'Doc


(I don't know anything about your meter, so don't take anything I've posted for 'gospel'.)
 
airplane1 said:
Dual band 2 meter 440 antennas are most often plug and play are they not. At least the Diamond mobile antennas I used were.

It is prob your meter that is wrong perhaps.

Look for a hAM IN YOUR AREA, They might have a meter for you frequency or an mfj anilizer.

AP
Click to expand...

Thanks I'll try this. I was under the assumption though all antennas require tuning, and not just plug n play.

W5LZ said:
I think I'd be very careful with that advice of a CB SWR meter working backwards thingy. I don't know anything about KB6NU, but without a lot more explaining about it, I would have to say he's mistaken. That "almost an accurate reading" means you might have an "almost broken" radio, sort of.
I have used a watt meter hooked up backwards to measure 'reflected' power, but I also wouldn't take that ability for granted and certainly wouldn't swear to the accuracy of it (I also rechecked it later with a 'proper' meter).
No pre-tuned antenna is ever going to be as 'tuned' as you think it is, all of them can use some adjustment.
Know anyone with a VHF/UHF capable meter??
- 'Doc


(I don't know anything about your meter, so don't take anything I've posted for 'gospel'.)
Click to expand...

Doc, not off hand do i know of anyone with a meter, well there is a ham club in the next town 10 miles over, but I do not know any of them, but i suppose it's never too late to make friends?

Moleculo said:
Is this antenna on a mag mount or did you drill the hole in the roof and use a permanent mount?
Click to expand...

The antenna is a magnet mount.

Robb said:
Try another jumper coax.
Check your coax on the antenna for faults.
Check your PL connectors and solder joints.
THEN recheck your SWR.

Don't take anything for granted.
Click to expand...

Thanks Robb, I know the coax is good b/c I use it all the time when checking SWR's on my CB antennas. I didn't see any issues on the antenna's coax or on the coax connectors.

I suppose it could be my meter. I only paid $25 for it at the ham fest, and that was brand new. The guy who sold me the meter said it works on CB and 2 meter ham. The instructions say it's good for 1.7 mHz to 150 mHz. When this meter is used on my CB radio and then bumped against what my Radio Shack SWR meter shows, the SWR-3 shows a higher SWR, like maybe .50 to .75 higher than my Rat Shack meter.
 
could be bad antenna or base, water in coax, etc. I was once given a mag mount antenna, took it apart and it was full of water with the connections inside corroded almost to nothing. A 50 ohm load rated to 5 or more watts is always a good thing to have around too. Hopefully its a bad meter but if its not you could end up with a bad radio.
 
One easy way of checking the accuracy of that meter is by using a dummy load (if you have one). You should do that sort of checking with anything 'used', or 'new', it simplifies things. Any antenna can be 'tweeked' a bit, some need it more than others.
From there the 'problem' could be almost anything, so start eliminating possibilities...
- 'Doc
 
Just about every dual-band VHF/UHF antenna I've ever used has been good to go as soon as it was mounted. I generally see maybe 1.4:1 on 2M and around the same on 70cm, which is not at all bad. I suppose I could have adjusted it, but what difference would it have made? Absolutely none. The problem with this type of antenna is that what affects one band will affect the other one as well, and I'd be chasing my tail and getting frustrated while I could be on the air having fun.

I still suspect your meter. If you can find someone with an MFJ-259B, you can analyze 2M with that. An MFJ-269 will cover UHF as well.

Personally, I use a 259B for up to VHF, and a 219 for 70cm.
 
Thanks I will look into the meter.

Is a dummy load considered a mandatory thing when dealing with antennas? I've never used one, but have considered buying one.

I also wonder about the antenna. I bought it new. But the antenna, so I was told, is a dual band antenna. It actually consists of two whips with a loading coil in the middle. I've wondered if maybe the antenna was crap. It's 36 inches tall when used with the loading coil.

I was sort of leery about it but everyone there swore up and down it was a great antenna for dual band use. I've read 49" is what is required for 2 meter for 5/8 wave. Wonder what it is for 70 cm?
 
I agree most of these 2 meter and 70cm antennas and or dual band antennas are factory set hookup and go type products. If you know for a fact you have a good radio ground then Ide say get that meter out of line. I own several meters but for the 2 meter band I use a DAIWA CN-101L 1.8-150 Mhz dual cross needle meter and its a nice meter for just an accurate (SWR) and (average power) reading on HF-2 meters.

NEW!! Top of the Line SWR Power Meter Daiwa CN-101L | eBay
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ BJ radionut:
  • @ BJ radionut:
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?


      Top Bottom
      Back