Portsdown 4 Update with LimeRFE and Wifi Control

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
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G8GKQ
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Portsdown 4 Update with LimeRFE and Wifi Control

Post by G8GKQ » Thu May 05, 2022 1:18 pm

I have just released an update to the Portsdown 4 software (202204240) with 2 major enhancements: Please report any bugs or suggested changes here.

Dave, G8GKQ

M0YDH
Posts: 264
Joined: Sat Dec 31, 2016 5:59 pm

Re: Portsdown 4 Update with LimeRFE and Wifi Control

Post by M0YDH » Sun May 08, 2022 6:24 pm

Hello Dave

I've been getting ready for the 4m and 2m activity weekend. Amps are all overhauled and tested with the ever-reliable Portsdown 2018. They're set up to put c.30mW into their Mitsubishi modules off 4mW from the Portsdown. I put the Portsdown 4 in the rack and connected everything up. No output power on 4m and 2m. 70cm working and nothing from the new 23cm amp.
This was with the 11 April release. I did some power measurements at the Pluto TX port.
0.07mW on 71MHz
0.67mW on 146 MHz
3.6mW on 437MHz
around 5mW on the spectrum analyser on 1255MHz
My other Pluto was the same. Pluto pwr is 0 all bands and both have correct firmware according menu 3.
I did the update to 24 April release and there was no change. Oh dear. My nice power meter with a Makis device has gone poorly so back to the Heathermeter.

Regards

David M0YDH
Attachments
2m
2m
PhotoPictureResizer_20220508_190651_copy_1008x567.jpg (139.3 KiB) Viewed 1942 times
4m
4m
PhotoPictureResizer_20220508_190548_copy_1008x567.jpg (134.33 KiB) Viewed 1942 times

G8GKQ
Site Admin
Posts: 2794
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Re: Portsdown 4 Update with LimeRFE and Wifi Control

Post by G8GKQ » Sun May 08, 2022 7:40 pm

Hi David

Not sure that these low power levels are due to any software changes. Remember that the Pluto is not specified to work below 325 MHz, and that the Pluto tends to give a lower output than the LimeSDR Mini.

With Pluto power set to 0, I get 0.5 mW at 71 MHz, 1.0 mW at 146 MHz, 1.8 mW at 437 MHz and 1.4 mW at 1255 MHz.

Have you ever measured these power levels in the past?

Dave

M0YDH
Posts: 264
Joined: Sat Dec 31, 2016 5:59 pm

Re: Portsdown 4 Update with LimeRFE and Wifi Control

Post by M0YDH » Tue May 31, 2022 6:08 pm

Thanks Dave. I didn't know or forgot about the low power out on the Pluto below 325MHz.
I've modified two of my PAs to have an extra input and a RF relay so I can connect either a microwatt Portsdown 4 or a milliwatt Portsdown 2020. Pluto power or attenuator values respectively have been adjusted to give c. 15W from the PA. The 70 microwatts on 71MHz is the last challenge in this saga. My thanks to Mike G0MJW for the relay pcb Gerbers. Very neat replacement for hard to get Minikits RF relays.

73
David M0YDH
Attachments
Two inputs and a relay to the PA
Two inputs and a relay to the PA
PhotoPictureResizer_20220529_095622_copy_567x1008.jpg (244.99 KiB) Viewed 1707 times

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