Yesterday, one of my recent Tech class students emailed me, asking me how he could measure the SWR of a 2m antenna that he had:
I happen to have an older magnetic mount mobile antenna with a UHF connector attached. I was thinking of trying out this antenna with my Baofeng HT. The only issue is that I don’t have a SWR meter. I believe you said you do. Do you have any recommendation? I did a search on eBay, and got more than 1,200 hits, with costs from $4 to $600+.
So, I did a little Googling, then replied:
The one I have is an Opek SWR-6 Unfortunately, they don’t make this model anymore. I think I paid about $60 for it. It works well for a cheap meter.
Opek now sells SWR-8L. On Amazon, it costs $110. A similar meter is the Daiwa CN-501V. It will set you back $100. MFJ sells a bunch of SWR meters that purport to measure SWR on the 2m band, but because my experience with MFJ equipment has been less than satisfactory, I do not recommend MFJ.
Having said all that, you may not really need a VHF SWR meter. You can usually guess the SWR from the output power reading. If it’s lower than full scale, then the SWR is high. :) You’re not going to damage the radio because even the Baofeng has high-SWR protection circuits. You could also use an inexpensive HF SWR meter to make this measurement.
If you really want to spend some money, consider purchasing an antenna analyzer that covers the 2m band. You’ll have to spend more, but you’ll get more, too. For example, the RigExpert AA-170 costs $334, but you can also analyze HF and 6m antennas as well.
So, what do you all think? Did I steer my Elmeree in the right direction? It doesn’t seem to make sense to me to spend $100 for a VHF SWR meter when you could purchase an antenna analyzer for not too much more. Are there any other VHF/UHF SWR meters or antenna analyzers that you would recommend?
Dave K7RPM says
My advice: Since you will be spending more money on the meter than you did on your HT, look at the meter as a long-term purchase. In other words, buy a good one. Buy one that will do everything you want for the rest of your life. Buy Once, Cry Once.
Yohei, N8YQX says
Baofeng HTs are cheap. I think the possibility of damaging an HT with high SWR is low, but if it does get damaged, just buy another HT.
David Ryeburn, VE7EZM and AF7BZ says
Why not build a Wheatstone bridge SWR sensor? At this power level you can use small resistors. They’re cheap. A diode and a capacitor are cheap. You probably already have something that can measure DC voltage. Short leads and use of non-inductive resistors will insure that SWR readings are accurate enough. You ought to be able to do this for a fraction of the cost of that cheap Baofeng HT, and learn something while doing it.
Brent KF5THB says
Did I miss the reason why loaning to or assisting him with your meter wasn’t practical? In that he was testing and adjusting an antenna he found rather than setting off to build one (versus several) it seems like a one-time use situation. just saying. ..
Dan KB6NU says
Good point. I guess I just got the impression that he wanted one of his own. He is, of course, welcome to use mine, if he likes.
Milton says
Hola , deberían analizar más la situación de roe y sobre los analizadores de antenas, HC4Z 73
Bob K0NR says
“You can usually guess the SWR from the output power reading.”
Most FM rigs don’t provide an accurate display of output power when transmitting, so I don’t think this works.
Dave New, N8SBE says
I still have and use my old Daiwa meter, that coveres 160-2m and has a switchable full-scale power level of 200-2kw.
For low-power applications, I have a surplus Bird wattmeter, found at a local swap, with a couple of slugs, one that covers VHF/UHF at about 25W full scale.
Also, an MFJ-259 analyzer is real handy, and covers through VHF. The slightly more costly MJF-269 covers the UHF band, as well. I have the 259, and so far have been too cheap to buy the 269 just for the extra band. If someone was starting out, I’d say go for the 269, instead.
Finally, I have a MinVNA Pro, with the 2.5 GHz extender. The annoyance with this is that you have to have it tethered either via USB or Bluetooth to a laptop or your cellphone (they have a neat Android app, not sure if they have one for iOS) to get a displayed output, so I don’t break it out too often. Also, you have to attach the extender to cover UHF, which means you can’t get a continuous plot of a VHF/UHF antenna (most analyzers that quit at 170 MHz use the same Analog Devices front end ADC chip). It does give you a lot of information though, including the sign of the reactance, which the MFJ analyzer doesn’t.
I do agree that for someone starting out, it’s best to not get a really cheap meter. I’ve gone through a couple of those, and found their shielding to be rather poor, and susceptible to changing readings depending on the power level used. Unless there is something wrong with the feedline or antenna (such as shorting or arcing over at high power levels) there is no reason that the SWR should change when you change the power level. The little Heathkit SWR meter is a case in point (not the larger one with the remote sensor). If you find one in a swap, avoid it like the plague. Heathkit had a really bad habit of spraying krinkle-coat paint on the INTERIOR of their cabinets, making it all but impossible to get an RF-tight seal. The HW-101 transceiver is another case in point. It is a (lack of) shielding nightmare.
If you are Elmering someone, do them a favor and loan them or help them use a decent meter you may have in your collection. I recently helped a new ham install a quad band (10, 6, 2m, 70cm) antenna on his vehicle, and I used a variety of meters/analyzers to check the SWR on the bands that had no adjustment (they were OK), and to set the SWR on 10m. At the same time, you can explain the use of the various meters/analyzers, and they can see for themselves which ones they might wish to own in the future for their own test bench.