Hello Dr. William, as docment says: "The recommended 10 trifilar turns on transformer T1 are suitable for the whole of HF but perhaps not optimum at the extremes. It would be worth experimenting with fewer turns at the upper frequency turns and perhaps more turns at MF/LF e.g. the 600m band.".

I don't know if I should change its turns, maybe fewer or more turns for 3.5 mhz / 50 mhz ?

Here goes my latest compiled 'best results' achieved, using PSU at 13.8v, trying not to get the irradiator too warm, watching "quality of signal" (fewer harmonics and shape) in SDR receptor, using the RD06HVF1 transistor (rated for 6 watts); I evaluated JT65, JT9, WSPR and CW at 40 wpm (readed using Cw Skimmer) emissions;

07 mhz: PA Bias 3.00v ; U3S Bias 1.70v ; 2~4 watts ; high warming

10 mhz: PA Bias 3.33v ; U3S Bias 2.00v ; 4.5~5 watts ; no warming

14 mhz: PA Bias 3.33v ; U3S Bias 2.00v ; 3.5~6 watts ; no warming

18 mhz: PA Bias 3.33v ; U3S Bias 2.00v ; 1~1.4 watts ; no warming

21 mhz: PA Bias 3.25v ; U3S Bias 2.00v ; 3~3.7 watts ; medium warming

24 mhz: PA Bias 3.25v ; U3S Bias 2.00v ; 2~4 watts ; no warming

28 mhz: PA Bias 3.25v ; U3S Bias 2.00v ; 0.5~1.9 watts ; medium warming

50 mhz: PA Bias 3.33v ; U3S Bias 2.00v ; 0.2~1.7 watts (maybe more) ; no warming

In all tests the current varied from 300 to 950 mA; in idle mode it was 105 mA.

Next step is to test the RD16HHF (rated for 16 watts), I will add 3.5 mhz band, in few weeks to come.

I accept (and need) tricks, tips and advices about the best practices.

Thanks,

73 de PY1ZB

Roney Monte

On Mon, Feb 20, 2017 at 4:50 PM, K9HZ <bill@...> wrote:

“I think that RD06HVF1 have warmed more on 7mhz because its is not in optimum transistor performance range.”

Optimum performance range?  The RDxx series transistors are true RF transistors and should perform perfectly from DC to UHF…, in fact much better than the IRF510 which were designed as motor and power supply switches.  Nothing wrong with the IRF devices but the RDxx series will have better RF characteristics like lower capacitance, higher frequency response, and a better IO mapping (linearity). 

I have not investigated my PA kit yet (probably because I have one of my own design working). While Hans is a pretty good engineer and designed this kit to work for most conditions… my guess would be that T1, C1, C2, C3, C6 are not optimal for the RDxx device over the entire 1-50 MHz range.  In fact, I would be very surprised if they were.   My back of the envelope calculations say that the capacitors should all be 0.01 and T1 needs 3 fewer turns than at 7 MHz… but those are only my estimates. 

Make sure you built T1 correctly!!!  From your output results, I ‘d say that is a good place to check.

 

 

 

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email:  bill@...

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Roney Monte
Sent: Monday, February 20, 2017 9:38 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] RD15HVF1 x RD06HVF1 (not the IRF510)

 

I'm testing the PA 5w Kit with the following scenarios, using just a monoband U3S, each time with a specific LPF and antenna tuned for low SWR. (The transistor normal limit is 6 watts)

I have a receiver/workstation (SDR) 2 km away, with remote access in order to watch the spectrum of each test.

 

50 mhz -> got only 0.2w*, but very strong signal, no propagation here (not warming)

28 mhz -> got 1.5, signal being listened in world JTs/WSPR (medium warming)

24 mhz -> got 4w, bad propagation (not warming)

21 mhz -> got 2.5w, signal being listened in world JTs/WSPR (medium warming)

7 mhz -> got 2w, signal being listened in world JTs/WSPR (warming so much)

 

* (Maybe my MFJ870 is not working well in 50 mhz ?)

 

I think that RD06HVF1 have warmed more on 7mhz because its is not in optimum transistor performance range.

On 10M/15M/40M I have been listened for more than 10.000 km.

I'm continuing with my tests. After all band tested, I will post the detailed results.

73 de PY1ZB

Roney

 

On Mon, Feb 20, 2017 at 10:50 AM, <ajp166@...> wrote:

I've used both and they work very well from DC to UHF.  The data given is limited to those ranges as 

your dealing with vendor intended use not usability.  I've used both at 40M, 10M, and 6M.

input and output matching is the area of attention and you may have to extrapolate for

outside the available data range.

 

For a 5W amp that is robust [ can withstand shorts opens and bad SWR] I go for the RD15

as it will stand more abuse.

 

Allison/kb1gmx