Different RF output

Hi I'm using a president teddy 1

And 30 watt set of boots.


On low channels I get only 10 watts to the antenna but 20 watts higher channels on UK Muppets.

And about 15 watts on channel 19
But on EU channels I get 20 watts

Boots are brand new.

Swr is 1.5 without boots and 2 with

Radio is output is 4 watts

Any idea what's going on?

Antenna is a MAAS YELLOW-STAR-27 CB Radio Silver Rod type Home-Base CB Radio Aerial Antenna

Thanks

Hi Bert,

On most radios you really don't know what your true wattage is as reported from the radio's meter (or external one) unless you're running into a good 50 ohm dummy load. Differences seen are to be expected when running 'real world' into an antenna.

(Although I'm surprised that my new Amateur Radio radio rig strives to adjust the output despite the load to the wattage you've set on screen....but then it did cost me enough money! )

Let me clarify what you're saying...

You mention that you get 10W on 'low channels' but 20W on the UKFM higher channels. Is that the 'low channels' in as far as the radio goes or the 'low' UKFM channels?

The reason I ask is that you then say you get 20W on the EU channels. (Which are lower in frequency than the UKFM band.)

I wouldn't be at all surprised if you get higher power on the EU channels as MAAS is a European manufacturer (German I believe) and might favour the SWR curve to the EU channels rather than the UKFM band.

If what you are saying is correct then it looks like there may be a 'hump' in the SWR curve around the mid frequency response of the antenna compared to the specified bandwidth. Without seeing a measured SWR curve of this antenna I wouldn't be able to tell you exactly and trawling the web turned up nothing as regards further information.

These antennas are advertised as 'pre-tuned' and looks like the elements are screwed together for ease of use but is there anyway to adjust the length at the tip at all? Only because I was going to suggest that you could maybe adjust the antenna to suit for yourself.

You don't mention what 'boots' you are using but often there is confusion with model numbers rather than specified Watts and of course advertising blurb that exaggerates true power outputs.


I think what you are experiencing is pretty typical and I wouldn't worry too much about it all but of course there will always be other suggestions such as ....use 'better' coax, adjust the antenna height, keep the antenna away from other objects let alone the 1:1 SWR stories that abound.

Unless you're going to delve into the realms of Vector Network Analysis (NanoVNA's are pretty cheap but you have to know what you're actually measuring) to understand your antenna systems better I'd be happy with what you've got.

Up to you but if you're running the cheapest coax you could get online and the length is very long then maybe the coax suggestions might have some footing. Same goes if you've plonked the antenna on the ground against a wall when it'd be better up as high as you can get.

I wish you well with it all, hope you get to your own operational satisfaction and I wouldn't sweat the small stuff unless things are really awry. 

It's funny how often radio enthusiasts treat each other as if the other party doesn't have a clue....if you're new it's all about learning and even old hands can make simple mistakes. The fun of radio can often be with the operational idiosyncrasies as well as making radio contacts.  


All the best,
Victor

I'm using 30 meters of Nevada mini 8, on my  zetagi dummy load 20 watts on the meter. On most, I'm was talking about low end of the Muppets band,

I update what boots they are asap

If you're reading 20W straight into a dummy load it might just well be that your 'boots' are at that output level.

30m of coax is a long run though with over 1dB loss at CB frequencies so that 20W could be as low as 15W actually reaching the antenna. I always try to run as short a length of coax as possible but I know that isn't always feasible for everyone.

You can check coax losses with the handy calculator linked below :-

https://www.qsl.net/co8tw/Coax_Calculator.htm


Even with those losses though the receiving station will hardly see the difference on your signal between 15W & 20W unless you are at or near their noise floor. Similarly you will have differences in your reception abilities and you can't work them if you can't hear them. You can run more power to 'get-out' allowing for the coax losses on the outgoing signal but it's hard to overcome losses on your received signals.


Again I wish you the best with it Bert and above all enjoy yourself.  

73,
Victor

The
Boots are Dirland dl 25

30 watts 26 to 30 mhz

Yeah I know them Bert, similar to the old President LA-25 except they marked theirs as 25W 26-30MHz.

They came in various guises but all looked the same commonly with just a single epitaxial transistor which although usually capable of at least 30 Watts never succeeded in doing so with the simple circuitry used. (No proper adjustable input/output matching and mass produced circuitry.)

Like I said, don't sweat the small stuff but with the 1dB loss mentioned on the coax earlier it might be worth seeing if you can mount the antenna for a smaller run.

73,
Victor