Antenna mod

[Rob Thomson]

I swapped my stock antenna for an rp-sma socket.

Much more useful

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[Kilrah]

I'll have to do it one day... should take a whole 5 minutes.

[jhsa]

video it and time it, cos I doubt it

[Rob Thomson]

Hardest part is getting the SMA install neat.

That being said...

A few days back I did 1820 meters on a stock antenna. No warnings - so view an could have gone further!

Rob

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[G550Ted]

Very nice looking job Rob! Did you take any pictures? Care to share details and any lessons learned (learnt ) Did you actually us an RP-SMA setup or just install the mating (female) connector for a SMA antenna?

Ted

[Rob Thomson]

Really nothing to it!

Just unsoldered the old cable. Soldered on the pigtail - and then secured the sma to the case.

Securing the SMA was the hard part.

What I did was.

Sourced a washer that the sma bulkhead connector attached too. Then pushed this into the old hole, by heating it with the tip of a soldering iron. This gave a good and secure metal base for the antenna.

On then inside of then case, I then infilled the hole with some sugru to provide additional purchase for the connector.

Finally, I capped the top off with another washer that was painted black.

Done!

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[Rob Thomson]

Did you actually us an RP-SMA setup or just install the mating (female) connector for a SMA antenna?

Ted

Good point. It may well be am sma pigtail I used. It matches my antennas - so that's what matters!

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[G550Ted]

Really nothing to it!

Just unsoldered the old cable. Soldered on the pigtail - and then secured the sma to the case.

Securing the SMA was the hard part.

What I did was.

Sourced a washer that the sma bulkhead connector attached too. Then pushed this into the old hole, by heating it with the tip of a soldering iron. This gave a good and secure metal base for the antenna.

On then inside of then case, I then infilled the hole with some sugru to provide additional purchase for the connector.

Finally, I capped the top off with another washer that was painted black.

Done!

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Thanx for the description Rob.

Merry Christmas.

Ted

[LTMNO]

Great work. Need to do the same.


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[Tr3TopFlyer]

Rob after installing the connector what antenna did you use? Did you do this to allow for better range?

[Rob Thomson]

Just about flexibility.

It gives the option of using a 5dbi omni, or a 7dbi patch.

To be fair - the stock antenna goes a long way if you set your receiver up right

[Tr3TopFlyer]

Rob the reason I'm asking is because I was experiencing some range issues when using the X series Rx's with 1.3GHz VTx. I am using a low pass filter to help eliminate the harmonic but still wasn't able to achieve a proper range test until I lowered the output power of the VTx from 400mW to 200mW and move the Rx several inches farther from the VTx. At that point I was able to get about 70 meters distance, in range test mode, before getting a loss of signal at the Rx. I just want to optimize everything I can to avoid any issues. Any suggestions are very welcome.

[Rob Thomson]

Not really sure you will get the answer here - much better suited to ask on fpvlab?

It sounds to me like you have some sort of frequency interplay - I guess thats why with fpv its all about 'separation' to avoid problems!

[Flaps 30]

It gives the option of using a 5dbi omni, or a 7dbi patch.

I wonder what the transmitter output power is, and if it can be changed or is changed to the different regions. Using the patch antenna in the UK would probably take you above the legal limit of 100mW ERP....

To be fair - the stock antenna goes a long way if you set your receiver up right

On the original D8 receivers the 'whisker' was/is set to 33mm which is about 3mm too long, which would lead to a shorter range. Has this been corrected with the new RX's or the PCB aerials?

I am waiting on the delivery (hopefully on Friday) of a nice little unit which will make answering the above questions a simple process, along with helping me construct/modify aerials with some confidence. ----> http://www.rigexpert.com/index?s=it24

[Tr3TopFlyer]

How is that different from an RC Explorer?

[Flaps 30]

The Rigexpert IT24 arrived today. So some quick tests made.. The 'normal' aerial (2dB) was checked, in fact three of them from Frsky were checked and found to have an SWR of 2.2:1 and it dipped lower at a higher frequency. Adding a bit to the 'whisker' to make the overall length of it to be 25.7mm dropped the SWR down to 1.09:1 along with centring it to 2440/30 Mhz which seems to be the centre of the band that the Frsky TX module seems to use. The aerial cover makes a substantial difference to the SWR and the 'whisker was cut to allow for this. Without the cover, the 'whisker' would be nearer to 29mm to achieve the same result.

All of the above has a bearing on the way that the receiver aerials are constructed and the fact that the 33mm 'whisker' on some of the Frsky receivers are way off from what they should be, which is another topic for another thread in the pub at a future date I reckon.

The Frsky 5dB aerial was pretty good as its SWR at 2430 Mhz was 1.7:1 and the Frsky 7dB patch was even better at 1.45:1. Both aerials were roughly central for the frequency range we use as to the lowest SWR.

I wonder what the transmitter output power is, and if it can be changed or is changed to the different regions. Using the patch antenna in the UK would probably take you above the legal limit of 100mW ERP.

Taking the Rigexpert as being fairly accurate as I have no other means of checking its power calibration. The Frsky DJT module power output was measured at 25 mW which is lower than what I would have expected. So the use of the 5dB or the 7dB patch antenna would be a good idea in the UK.

I would love to know how the Taranis stacks up with regard to power output. Maybe we should meet up with your TX and my Rigexpert in hand Rob.

[Rob Thomson]

Can do - I have two radios.

1 with stock antenna, and one with my mods.

Your only an hour or so from my place.

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[Spainman]

I am waiting on the delivery (hopefully on Friday) of a nice little unit which will make answering the above questions a simple process, along with helping me construct/modify aerials with some confidence. ----> http://www.rigexpert.com/index?s=it24

This might be interesting for you - I got myself an It-24 and spend today some time checking the measurement results against a professional spectrum analyzer. See attachment. Everything looks good (considering it's low price tag). As long as the SWR is low it's quite precise. Peak power measurements also seem to make sense. It's build on top of the CC2500 + CC2591 btw, just like the Frsky stuff.
The +5dB gain setting in the spectrum analyser mode is broken btw, make sure you don't use it when graphing or you will see nothing but noise. The graphs looked strange and I asked the manufacturer - gain setting will disappear in the next fw-version.

[Flaps 30]

Nice work there Spainman

It certainly was of interest. Some of what you have done is also verified this end, although I didn't check out the +6dB setting so I will not use it. Seems like that chipset is getting around a lot.