Output power on different bands
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- Posts: 4
- Joined: 02 Jun 2022, 12:42
Output power on different bands
Hi all,
I recently received mt (tr)uSDX, ordered from the AliExpress UpTech store.
I hooked it up to the audio interface of my laptop, using nothing but straight cables, and then used the tuning feature of JTDX to generate a signal. This was sent through an ATU-100 antenna tuning unit for power measurement, into a dummy load. The (tr)uSDX was powered with a 12V USB-C PD trigger module.
Here's the result of the measurement across the bands:
20m: 1.9W
30m: 3.0W
40m: 1.7W
60m: 2.0W
80m: 3.5W
My questions are: Are those typical values? Is especially the huge difference between power output on different bands to be expected? Would I see higher power outputs by supplying more voltage? Might my audio level be too low to achieve the theoretical 5W output, and is there something in the configuration I can tune?
73 de Andreas, DB8GK
I recently received mt (tr)uSDX, ordered from the AliExpress UpTech store.
I hooked it up to the audio interface of my laptop, using nothing but straight cables, and then used the tuning feature of JTDX to generate a signal. This was sent through an ATU-100 antenna tuning unit for power measurement, into a dummy load. The (tr)uSDX was powered with a 12V USB-C PD trigger module.
Here's the result of the measurement across the bands:
20m: 1.9W
30m: 3.0W
40m: 1.7W
60m: 2.0W
80m: 3.5W
My questions are: Are those typical values? Is especially the huge difference between power output on different bands to be expected? Would I see higher power outputs by supplying more voltage? Might my audio level be too low to achieve the theoretical 5W output, and is there something in the configuration I can tune?
73 de Andreas, DB8GK
- DH2LAB
- Posts: 51
- Joined: 08 Mar 2022, 01:39
- Location: Kiel
- Contact:
Re: Output power on different bands
The device is pre-assembled and not really adjusted.
Use this guide:
https://www.youtube.com/watch?v=qN7hHsvcNMM
viewtopic.php?p=1686#p1686
Normally you have 4-5 W at 12V if you tune the toroids properly.
Use this guide:
https://www.youtube.com/watch?v=qN7hHsvcNMM
viewtopic.php?p=1686#p1686
Normally you have 4-5 W at 12V if you tune the toroids properly.
73 de Matt, DH2LAB
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- Posts: 4
- Joined: 02 Jun 2022, 12:42
Re: Output power on different bands
Great information, thanks!
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- Posts: 123
- Joined: 16 Apr 2022, 13:02
Re: Output power on different bands
By following the coils spacing adjustment on the toroid you may get a benefit, but you may need to add or remove a coil.
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- Posts: 4
- Joined: 03 Jan 2022, 04:50
Re: Output power on different bands
how safe is it too unsolder the toroids ?
72
ON6UU
72
ON6UU
- DH2LAB
- Posts: 51
- Joined: 08 Mar 2022, 01:39
- Location: Kiel
- Contact:
Re: Output power on different bands
If it smells like fried finger, you should practice it first.
Good soldering skills should be available anyway.
And if you boil out the solder lugs, you've done something wrong.
73 de Matt, DH2LAB
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- Posts: 3
- Joined: 12 Jun 2022, 22:37
Re: Output power on different bands
Power input is very important. In my rig in 40m with 11.6V power is 4,5W and with 13,8V increese to 5,5W
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- Posts: 1
- Joined: 09 Sep 2022, 19:22
Re: Output power on different bands
Please tell me what is the maximum power input: Volts / mAh?
Thank you,
Boris
Thank you,
Boris
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- Posts: 31
- Joined: 29 Aug 2022, 16:43
- Location: Zurich, Switzerland
Re: Output power on different bands
Theoretically should still work with ~15V; I'd try not to put more than the standard 13.8V into it to keep within the safety margins available.
-- Cathal Ferris.
Paddler, pedaller, stargazer, nerd.
Wiggler of electrons both in silicon and in the ether.
Paddler, pedaller, stargazer, nerd.
Wiggler of electrons both in silicon and in the ether.
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- Posts: 9
- Joined: 20 Oct 2022, 21:36
Re: Output power on different bands
I too am seeing the same issue with a pre-built unit ordered from uellyqh (Sunny) on the eBay "official vendor" page. No criticism of this vendor - they have been incredibly helpful.
I'm using a power supply built with 8 AA cells. Currently measuring 12.12V on no load.
My power output on 40m is 3.2 to 3.4W and on 20m is 5.4 to 6W. A huge difference. SWR on the antenna is about 1.3
This is measured on the internal wattmeter and I have no idea how useful that is. I bought a used QRP wattmeter but it doesn't work! Wildly inaccurate!
I'm newly licensed and brand new to QRP. Any comments useful. I gather it may be a tuning issue on the RF board?
Tnx VA7RLX Ritchie in BC, Canada
I'm using a power supply built with 8 AA cells. Currently measuring 12.12V on no load.
My power output on 40m is 3.2 to 3.4W and on 20m is 5.4 to 6W. A huge difference. SWR on the antenna is about 1.3
This is measured on the internal wattmeter and I have no idea how useful that is. I bought a used QRP wattmeter but it doesn't work! Wildly inaccurate!
I'm newly licensed and brand new to QRP. Any comments useful. I gather it may be a tuning issue on the RF board?
Tnx VA7RLX Ritchie in BC, Canada
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