Author Topic: UHF/VHF SWR Meter....  (Read 9761 times)

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GreekMan

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UHF/VHF SWR Meter....
« on: March 07, 2013, 01:38:09 PM »
hi all!

I am considering a SWR meter for the V/U bands.
Could you educate me on them?

My cosndierations are:
- Is there any purpose for it (though I am doing some antenna experiments)
- since I will be using it with a HT will the adapter cable at the radio side mess results?
- Can cheap mean relatively good?

I need your suggestions on a budget model...
Buying from the US has become not afffordable with the letest increase in USPS postage rates

I am really considering this....
http://www.ebay.com/itm/Digital-VHF-UHF-Power-SWR-Meter-for-Two-Way-Radio-RED-DOT-1050A-100-500mhz-/251239713857?pt=UK_Mobile_Phones_Communication_Radio_Meters&hash=item3a7f0dcc41
or this
http://www.ebay.com/itm/Workman-104-SWR-Power-METER-VHF-UHF-Ham-Radio-120-500-MHz-No-Jumper-/121030607037?pt=LH_DefaultDomain_0&hash=item1c2dfc80bd

Thank you!

XJP5

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Re: UHF/VHF SWR Meter....
« Reply #1 on: March 07, 2013, 08:08:35 PM »
GM,

I've never seen anyone use an SWR meter with an HT, but they obviously make small portable units for that purpose. I searched and didn't find too many models available, but I would recommend one thing ... If you think there's any chance that you may eventually purchase a mobile VHF/UHF rig, you may want to spend a few dollars more and try to get some instrumentation with better quality.

I checked the eBay units you listed and I'm not familiar with either, but at that price-point I believe the accuracy and quality will be questionable. If I had to choose between the two you listed, the Red Dot 1050A would be my initial choice. For your application, I wouldn't recommend a high-dollar Bird meter certainly, but I did find this Comet CMX-400 that can be used on the VHF/UHF bands and is available in the UK, which may cut down on shipping costs for you. You'll have to inquire.

It does cost 79.95 GBP which converts to about $120.44 US. Might be worth saving a few extra dollars to buy this one. Now, you aren't going to be able to walk around with this meter attached, due to it's larger size, but for occasional SWR checks, it would work fine. It has 3 scales 30w, 60w, and 200w. It will also show forward and reflected power and PEP*. Min power for this meter is 6-watts, so it may not be sufficient to work with your handheld, since most are 5 watts max. 

The purpose for using a meter of this type is to measure your antenna's efficiency. An ideal transmission line would have an SWR of 1:1, with all the power reaching the destination and no reflected power. An infinite SWR represents complete reflection, with all the power reflected back down the cable. This can damage your transmitter. When experimenting with new antennas, always check at low power settings initially, in case the SWR is high. You can tune the antenna from there. The inline coax adapter should not alter SWR readings to any substantial degree.

I'm sure some of the other fine members here will chime in. I hope this helped you a bit.

* Peak Envelope Power (PEP) - means the average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope taken under normal operating conditions.
« Last Edit: March 07, 2013, 08:16:44 PM by XJP5 »

BTPost

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Re: UHF/VHF SWR Meter....
« Reply #2 on: March 07, 2013, 08:18:09 PM »
SWR Meters are fine for the average Ham, but the BigBoys will use a BIRD Wattmeter with the appropriate Slugs and Calculate the SWR in their Heads.... If you want quality Results, Use quality Equipment....
Bruce in alaska AL7AQ

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Re: UHF/VHF SWR Meter....
« Reply #3 on: March 08, 2013, 04:18:55 AM »
What BT said. But...something is better than nothing if you're going to play with antenna design. The decision to be made is this: If you are like most hams, you'll spend some money on bottom end equipment and then decide on better equipment later, so why not get the good stuff first. Took me a lot of initial expense to finally realize this fact.
"Preparedness is a lot more than just buying stuff"

XJP5

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Re: UHF/VHF SWR Meter....
« Reply #4 on: March 08, 2013, 07:09:58 AM »
What BT said. But...something is better than nothing if you're going to play with antenna design. The decision to be made is this: If you are like most hams, you'll spend some money on bottom end equipment and then decide on better equipment later, so why not get the good stuff first. Took me a lot of initial expense to finally realize this fact.

It's taking me a while to get my equipment put together, mainly because I'm saving for some better hardware, but I'd rather do it that way than to buy twice. Most of the time, you get what you pay for.

Earthbound

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Re: UHF/VHF SWR Meter....
« Reply #5 on: March 08, 2013, 05:24:22 PM »
I have a Workman SX-144/430 SWR meter.  Just under $40 new at a hamfest (avoided shipping).  Works good enough for me on 2m/440.  But...
 
An expensive meter wouldn't help me.  It's antenna construction that I need help with.  I have yet to make an antenna that has close to 1:1.  If we had an active local club I could probably find out what I'm doing wrong.  I need low SWR for HT to hit repeaters 50+ miles away.
Yaesu, meet Baofeng 8)

BTPost

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Re: UHF/VHF SWR Meter....
« Reply #6 on: March 09, 2013, 01:09:43 PM »
What you need is NOT a SWR Meter, but an Antenna Impedance Analyzer... They are expensive ($300+) for a cheap one... and much more for a unit like the BigBoys use.
I have a Cushman Comm Analyzer w/ Spectrum & Tracking Gen that I bought an Impedance Bridge for. It allows me to sweep an Antenna, and look at the Resonance Dip as a function of Frequency. Makes cutting Dipoles for HF a breeze. You cut it a bit long, and then stretch it up in the air, and measure where the Resonance Dip is, then calculate the difference between this, and where you want the final Antenna to be, and then calculate how much to trim off each end to move the Resonance Dip to the required Frequency. Trim to fit and raise for the last time, into place. Your Done.... Works for Trapped Antennas as well. Start at the Highest Frequency and adjust the Resonance to for the First Trap, and then the next, and the next, until you are finally at the lowest Frequency of the Antenna. then go back and recheck each, and your done.... RF Eyes are always better than No Eyes in these operations.... Just say'en...
Bruce in alaska AL7AQ

GreekMan

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Re: UHF/VHF SWR Meter....
« Reply #7 on: March 10, 2013, 08:25:45 AM »
indeed....this is what I really need but I cannot even find it at some radio gear shops' bench locally...
So my other way out is tinker with length and watch the performance on the SWR meter....after all it is not an issue of getting the most watts on the air (repeaters are very ckose together over here. With a long, base antenna you can reach half the country's worth off)
It is the health of my HT that i care.

Eathbound...very well phrased. i shoudl have said that fromt he start.