SmartSDR v3.4.23 and the SmartSDR v3.4.23 Release Notes | SmartSDR v2.8.1 and the SmartSDR v2.8.1 Release Notes
SmartSDR v1.12.1 and the SmartSDR v1.12.1 Release Notes
Power Genius XL Utility v3.7.28 and the Power Genius XL Release Notes v3.7.28
Tuner Genius XL Utility v1.1.16 and the Tuner Genius XL Release Notes v1.1.16
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.
Significant difference between LP 700 and RF power of TG and PG
Your SWR will only be the same on all measurement devices if you are testing into a 50-ohm resistive load. You are testing on an inductive load that is showing a 1.4:1 SWR, and there is nothing wrong with that SWR Reading, although it will actually be higher if you read it at the antenna.
You can read about it in this document by the ARRL. https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf
SWR readings vary across the feedline and that is what you are seeing.
As for the power producing tuner? You can't cheat physics.
Mike va3mw es HNY1
Thanks, Mike..appreciate your thoughts. The 1.4 was at the antenna, at 55 feet, prior to attaching coax.. I understand the inductive--resistive issue. Root question remains---why the difference in power readings---which do I trust given the huge difference? Power producing tuner was an attempt at humor.....Regards, JIM0
Sorry I missed it. :). Sometimes you just never know.
With an SWR mismatch, your power will also be inaccurate. It is only accurate on a 50 ohm resistive load.
Thanks...will let you know if I ever figure it out. Mismatch is one thing but the entire set up is remarkably flat (for a change) Happy New Year JIM0
It is all about standing RF waves (waves that do not move in the feedline) and constructive and destructive interference.
I was trying to find a good article on it, but I am still looking.
In college, we built a test jig at 100Mhz that had jumpers in 1/4 wave increments. (ok, I built it and I feel like I soldered about 100 connectors on all the different cables we required). We then measure the RF power along the feedline on a 50 ohm load and on a 25 ohm load. I wish I still had the notes from it. :)0
Jim - Even with running into a 50 ohm RF load (Palstar DL5K) I see differences. My PG-XL and TG-XL (with latest updates) typically indicate power level indications which are fairly close (~ 30 watts difference @ 1kw), while my LP-700 shows 200-300 watts lower. ˉ\_(ツ)_/ˉ
Jim, I know you mentioned your system is relatively flat but couplers for LP 700 should be before amp and between amp and tuner.
Using Flex TUNE button, I see about a 5% difference in the PG XL, TG XL, and high power LP700 coupler with a 2000 watt 50 Ohm load on output of tuner and tuner in bypass.
The LP700 reads substantially higher PEP as it has much faster sampling rate for power sampling. Also the latest beta firmware for LP700 (not on their site) adds input power, output power and amp gain on the Trap/waveform screen.
Leave a Comment
- 19.8K All Categories
- 177 Community Topics
- 2K New Ideas
- 367 The Flea Market
- 6.6K Software
- 5.6K SmartSDR for Windows
- 107 SmartSDR for Maestro and M models
- 269 SmartSDR for Mac
- 210 SmartSDR for iOS
- 200 SmartSDR CAT
- 137 DAX
- 330 SmartSDR API
- 8.1K Radios and Accessories
- 6.6K FLEX-6000 Signature Series
- 673 Maestro
- 35 FlexControl
- 803 FLEX Series (Legacy) Radios
- 550 Genius Products
- 312 Power Genius XL Amplifier
- 200 Tuner Genius XL
- 38 Antenna Genius
- 160 Shack Infrastructure
- 105 Networking
- 277 Remote Operation (SmartLink)
- 108 Contesting
- 418 Peripherals & Station Integration
- 103 Amateur Radio Interests
- 697 Third-Party Software