SWR new antenna

hi there
 is there someone out there that can help me out. I have just bought a sirio megawatt antenna and a magnet base and I am having problems setting it up to my radio. My radio is a Anytone 6666 and I cant get the swr no lower than 2 on 40 and 1.8 on 1. Now i am not sure if you have to turn the pwr down to its lowest point and then test it or does it not matter. Many thanks ct3036 73,s

Hi Bill.

Here's a handy guide.

https://www.rightchannelradios.com/blogs/troubleshooting-guides/18473439-high-swr-troubleshooting-guide#:~:text=One%20of%20the%20most%20common,if%20everything%20is%20installed%20perfectly.


You may have to cut a bit of antenna.
Some more experienced members will chip in and hopefully help sort you out.
Cheers.

Nige.

Many thanks. Sorry I am an old cber back in the 70,s when am was illegal. The good old days. 73,s my friend

bill53uk wrote:

Many thanks. Sorry I am an old cber back in the 70,s when am was illegal. The good old days. 73,s my friend

Good luck and hopefully you get sorted.
Your sig says down south in HH and seems a lot on down there.
So you should get plenty of contacts

Mind, you've been a member since 2019 so have you been on air that long and just changed rigs or are you just starting out again ?

At the moment Im just started up again from the 1970s. Met my misses on the rig and now we are married 36years. Thanks for the contact 73,s

Again, good luck Bill. Have a search on YouTube for "Fred in the shed"
Seems lots of activity down there and hopefully you get sorted.
Your swr is certainly ok recieving wise and shouldn't cause a problem transmitting.
Have you checked your coax for pinching or twists ?

checked the cable its brand new with a magnet at other end. When i turn down the power swr is ok but when I turn it up I get 2 on 40 and 1.5 to 1.8 on 1.

I take it you are going off the built in swr meter.
They can be wrong an external one is better.
Your swr is useable but obviously could be better.
Is the whip all the way down if so you could try cutting a 1cm off it and see how it goes.
Some of the Sirio mag-mounts had a doggy connection in the base but i don't think that is your problem.
Let us know how you get on with it (not the same as a dv-27 lol) ..

Hi there I am using a external swr meter and I have cut some off the bottom of antenna. When I turn the power down its between 1.5 to 20 but when I turn the power up the swr goes up. My rig is an Anytone 6666 and has 45 watts fm.

Is the higher reading after resetting the swr metre don't take that the wrong way but it should stay the same.

yes it stays the same. Ive tried other rigs but still the same. I just cant get it down low enough. I can if I turn the power down. The old days all rigs were set at 4 wqatts but now they can very from 4- 40 watts and that confuses me at times.

Hi Bill,

I don't know what SWR meter you have but the typical single meter window types requires you to set the meter in the 'FWD' position and then use the 'CAL' or 'ADJ' knob until you have a full meter reading. You then switch to 'REF' or reflected to read your actual SWR.

You have to do this in a constant carrier mode so no sideband, AM will work but depends on if you are clanking the mic around or talking into it so FM mode is the best option.

If you adjust the RF power at all then you have to recalibrate the meter again until you are reading full before once again setting to 'REF' or reflected otherwise your readings will be wrong. (The readings are a ratio of RF power going out versus RF power reflected.)

It is best to do this halfway through the frequencies you will using rather than trying to skip up and down the extreme ends of the channels in a weird sort of balancing act. (So for example if you intend to mostly use UK FM then set to channel 20.)


There's a good little demonstration video of one of these typical SWR meters below :-





Hopefully you get sorted.

I know it can be a pain if you've never done this before or haven't done this for a while and forgotten the basics but that's why it's handy to have such groups of helpful people such as here at Charlie Tango.


All the best,
Victor

If the SWR is higher on the higher channels and lower on the lower ones it is too long. You're running an Anytone 6666 and I bet if you were to go down to say 27.000 MHz you'd find it's almost near 1:1.

How good your RF ground is alters how long the antenna needs to be for a given frequency/channel - the better it is the shorter it needs to be, the worse it is the longer it needs to be. With mobile installs the manufacturer makes the antenna whip length for their mobile antennas assuming a piss poor install with a poor RF ground because most are. If you install it and you have a good RF ground you'll find there isn't enough adjustment to get the SWR down so it's out with a dremel and cutting it down. I don't use magmounts, I drill holes and use a fixed body mount and I do something called bonding too so the RF ground on my mobile installs are as good as it can be. As a result I typically find I have to cut a couple of inches off, three on the Sirio 5000 I currently use. 

When cutting do it a centimetre at a time, don't go overboard - you can't put it back on once you've cut it off.

Finally don't worry about getting perfect SWR. As long as it's below 1.6-1.8:1 on the channels you want to use that's fine.

my setup is as follows 1 nissan xtrail t31, 1 new mag mount, 1 anytone 6666 and a new sirio megawatt 4000and of course a crt swr meter if thats any help. When i do my test do i turn the power right down to the lowest watts or what. if i turn it down my swr is lower but as soon as i turn it up so does the swr.

Are you doing as Victor said.
Ie turn the power full up set the swr meter on cal an adjust then flick the switch to forward.
Should be the same as turning the power down then cal again then back to forward again.

Every power setting you will need to adjust the setting.
https://www.youtube.com/watch?v=IXgWQi2-_KI&ab_channel=ElectronsareFun

done as victor said and still no diffence. The power i am on about is on my radio that is 45 watts fm, not do i turn it down to the lowest wattage or does it not matter. as i said my swr is between 1.5 to 2.0 on channel 40. now if i turn the power up on my radio the 45 watts the swr goes up as well

Bill,

I don't get why you're turning the RF power up and down on your rig to check the SWR?

If you've adjusted the CAL/SET knob to read full scale on FWD then when you switch to REF you'll get your SWR reading. If you adjust the power after that then you'll need to adjust the FWD setting again.

If you don't obviously the reading will go up and down as you adjust your RF power as it's not longer 'calibrated' for a correct reading.


Let's hope we can get to the bottom of this to help you.

the thing i would like to know is do i turn the power down to test the swr.see how low i can get the swr and then all done.

bill53uk wrote:

the thing i would like to know is do i turn the power down to test the swr.see how low i can get the swr and then all done.

It's best to run low power as if there is an issue you won't damage finals or have the radio fold back power and mess with your readings.

However, what is CRITICAL, as other's have said, is you calibrate for the power you set, and keep it there for all the testing.

Without wishing to repeat what others have said, if the SWR is equally poor on low and high channels, then look to your groundplane first.  If it is OK on either low or high channels/frequency, but noticeably worse at the other end of the band, then it is an antenna length problem.

It could also be both, of course.

This might sound daft.
But any chance of you making a short video showing us your testing and post it on here.

bill53uk wrote:

the thing i would like to know is do i turn the power down to test the swr.see how low i can get the swr and then all done.

you keep the power full up to test swr because you will want to be running full power when you operate the radio ... as others have said you will probably need to trim the antenna to get the correct swr ...

I'd already made mention that SWR readings are a ratio reading of the power going out versus the power reflected back. (It's not actually a 'measurement' of anything with typical cheap SWR meters and doesn't have to be.)

If you push out 10 Watts of RF and have 0.4 Watts coming back then your SWR is 1.5.

If you push out 100 Watts of RF and have 4 Watts coming back then your SWR is ALSO 1.5.


Obviously it would be better to use the lower power in case something is amiss so that no damage can occur to the radio.


Setting up an antenna by SWR means should be the simplest method available but unfortunately there are so many misinterpretations to this method that it no longer seems simple.

been out today to try and get this swr done. I used my crt6900 and started off by turning the power down to zero.Once i got it to 1.1 all channels I then turned the power fully up to 12watt. With about 6 cuts of antenna I have managed to get it to 1.5 all channels.

Still thing something is wrong.
But your happy now i take it.