HL2 - Low Power output on 28 MHz

[Ezio Insinna]

Hello dear friends of HL2,

Am I the only one to have this issue or are all HL2s giving a low HF output

on 28 MHz ?

I have two HL2s :

The first (one year old) gives 4.3 to 5W out betw. 80 and 12 meters, but on 10 meters only 1.3 W

The second I got last month i.e. last production batch, gives 4.3 to 6.5W betw. 80 and 12 meters but also only 1.3 W on 10 meters. Is this made on purpose ?

I have tried to increase the PA gain (see attached screen shot of the corresponding Thetis menu page) but it's not possible to set a value greater than 38.8 dB.

I asked myself if some HPF/LPF filter settings might be responsible for this but there is nothing I can set there too.

I have attached  two screenshots to show the situation.

Has anybody had this problem ?

Thanks for helping me out. 

 

73 to all

Ezio - K3EK / F5MWA

[Reid Campbell]

Hi Ezio ,

We need to see the OC Control page, as that controls the switching of the LPFs.

Cheers

Reid
Gi8TME/Mi0BOT

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[Ezio Insinna]

Hi Reid and Mike,

Here the OC page screenshot.

I hope you see what's wrong....

Thanks for helping

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[Reid Campbell]

Could you show us a screen shot during operation on 10 metres so we can see the console display.

[radi...@mail.com]

I have HL2 Build 9. I find that with N2ADR LPF in circuit, and correct band selected, I see maximum about 4.5W output and this comes on 20m band. On 160/80 about 4W. 10m band, about 3W. Certainly not as low as 1.3W.

Without LPF board selected, max power about 6W, again on 20m. 80m about 5W. 10m about 4.5W.

Software is SDR Console with full level two tone audio applied. 50 ohm dummy load.

I have the latest build also but not yet assembled so can't do test on that one yet. Will try and get it going tomorrow and report back.

73

Max

On Saturday, 1 April 2023 at 10:26:03 UTC+1 eziomi...@gmail.com wrote:

Hello dear friends of HL2,

Am I the only one to have this issue or are all HL2s giving a low HF output

on 28 MHz ?

[Steve Haynal]

Hi Ezio,

In addition to the other suggestions, can you also try measuring power output with no 10M filter (no filter selected with checkmark) during TX? Also, if you swap your two N2ADR filter boards, does the low power problem follow with the filter board? How are you measuring power output and are you certain it is accurate for 10M? Do you have the PA control set to the maximum drive for 10M? Do you see the same behavior with other software? What does the HL2 say the bias current and power output is on 10M into a dummy load with various software?

HL2s generate 5W on 10M, and this is checked at the factory. Bands which may be slightly below 5W (which is not much in terms of dB) are 40M and 12M.

73,

Steve

kf7o

[radi...@mail.com]

Hi Steve

Would you expect to see the power reduction on 40m and 12m as a result of the LPF tuning, or would you also see it with N2ADR board set to bypass? If the latter, what is the cause?

73

Max

On Saturday, 1 April 2023 at 22:42:04 UTC+1 softerh...@gmail.com wrote:

Hi Ezio,

[Ezio Insinna]

Hello Everybody,

Thanks for all the answers,

I first tried with and without the 10m filter activated, but the value only changed from 1.2 to 1.3W.

Then I thought to swap the N2ADR filters as suggested by Steve, but instead tried SDR Console and Spark. 

Well, both softwares allowed a steady CW output of more than 5W on 28.300 MHz ! 

When I went back to Thetis it started outputting 2.7W ! No idea why all of a sudden the output power had increased.

Measurements were made with a dummy load and a Bird wattmeter. The displayed values were the same on the Bird as well as on 

all softwares used.   

Strange things happen with Thetis, however only on 10 meters.  

Perhaps I should call for an exorcist.....

Has somebody seen any anomaly on my Thetis screenshot during operation ?  

Attached two screenshots, one with 1.4 and the other with 2.7W.

A pity for pure signal, but I think I'll have to use SDR Console which seems to work best for me 

(the spectrum display on Spark is really primitive).

Thanks again to all of you for your support

73

Ezio - K3EK / F5MWA 

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[Reid Campbell]

The usual Thetis response for this is to reset the database and reconfigure the software again. There must be a configuration mismatch somewhere and a reset is the quickest way to solve the problem.

You can find the reset button at the bottom of the setup pages.

Cheers

Reid
Gi8TME/Mi0BOT

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[Alan Hopper]

Hi Ezio,

sorry you find the spark display primitive, what about it don't you like?  To create a display like others would actually be simpler, I could create an option without the phosphor effect if there is a demand for it.

73 Alan M0NNB

[Ezio Insinna]

Hello,

Reid, thanks for the tip. I'll reset the Thetis database and see what happens.

Alan, sorry for treating the Spark spectrum display as "primitive". I like the simplicity of Spark very much, only the spectrum display is too small compared to other software

and the spectrum lines very dense (is this the phosphor effect?) .Sometimes it's difficult to distinguish adjacent stations  

Is there a means to have the display somewhat larger and the amplitude adjustable with a choice of color fillings ? In the style of Thetis, for example.

I'm not very young (77 windings on the coil of life) and I appreciate larger displays.

Or have I missed something in configuring the display options ?

Thanks to all for the kind assistance

73

Ezio - K3EK - F5MWA

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[radi...@mail.com]

Just a note to say I got my new HL2 up and running today. I'm seeing similar power output behaviour to my earlier post with my Build 9. As Steve says, slight dips where he mentioned (40m and 12m). 

What's interesting is that with N2ADR LPF board disabled, on 20m band into 50 ohm dummy load, I am seeing around 7.5W. Pretty impressive from the new PA transistor. I am down to just over 4.5W on 10m. Cannot claim any super accuracy but it gives a good idea. Power meter is Daiwa NS-660P

None of this make significant difference one I am driving my 600W LDMOS linear, which it does beautifully. As I'm in the UK I keep it under 400W of course (legal) and in fact I usually "coast" around 350W to keep a nice clean signal, which the HL2 does admirably.

Thanks once again Steve and all collaborators for a wonderful rig. I will now keep the new one for HF and reserve my Build 9 without PA enabled but with RF3 installed as my transverter driver for 6m/VHF/UHF.

Looking forward to buyable build of the new interface board.

73

Max

On Saturday, 1 April 2023 at 22:42:04 UTC+1 softerh...@gmail.com wrote:

Hi Ezio,

[Mike Lewis]

You can adjust the spectrum and waterfall display parameters with the sliders (3 dots). One of them will reduce the averaging to a single line draw effect you are likely looking for.

Sent from my T-Mobile 4G LTE Device
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From: herme...@googlegroups.com <herme...@googlegroups.com> on behalf of Ezio Insinna <eziomi...@gmail.com>
Sent: Sunday, April 2, 2023 8:45:05 AM
To: Alan Hopper <ahop...@googlemail.com>
Cc: Hermes-Lite <herme...@googlegroups.com>
Subject: Re: HL2 - Low Power output on 28 MHz

 

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[Ezio Insinna]

Hello

Mike: Thanks, I've tried all I could with the sliders but there is no way to adjust FFT averaging and decay. The lines are too dense and the FFT rate remains too fast.

Steve and Reid : Yes I solved the output power problem by resetting the data base. Something was not right. I now have 5W output on both HL2s at 28.300 MHz

Alan : More adjustment choices for the FFT management in Spark would be great. Also I cannot reduce the ratio Waterfall to Spectrum display. I'm used to have 2/3 spectrum and 1/3 Waterfall. 

Thank you all for your kind help and suggestions.

73

Ezio - K3EK / F5MWA

 

[Steve Haynal]

Hi Max,

Just over the years I've noticed the lowest output on 40M and 12M when measuring power into a dummy load with the N2ADR board in place. 

It really isn't a big deal if you see 4.8W on one band and 5.2W on another. That is a difference of 0.3dB, a difference so small that programs such as WSJTX don't bother to report to that precision.

73,

Steve

kf7o

["Christoph v. Wüllen"]

Hi all,

According to my measurements, the N2ADR in-line damping is up to 1 dB, so a small "jitter"
of 0.3 dB is just to be expected. On most bands, my HL2 makes almost 6W if the filters are
by-passed which reduces to the nominal 5W when the filter is engaged (between the PA and the
antenna).

> To view this discussion on the web visit https://groups.google.com/d/msgid/hermes-lite/2b7e9eec-bbf4-4d08-a1b2-3b91d96751f6n%40googlegroups.com.

[radi...@mail.com]

Yes, from my measurements I agree Steve. However, I do find on both units that with the LFP in place that the "worst" (lowest) output level is on 10M. Anyway, my Build 9 where this effect is most noticeable I am reserving for transverter driving from the RF1 low power output, and the new HL2 build is now my main HF station, and also in the smaller case (old unit is in the larger, original case) so it's also perfect for taking out on QRP expeditions too.

As you say, these results are of no real-world consequence. Observations, no more than that. believe me I am totally happy with both of my HL2s. I will tell you that the HL2 is pretty much the sole reason that prompted me to start up in ham radio after a very long break (38+ years). From reading some other stories on the internet I am not the only one either, so thanks for that. It has been (and continues to be) a blast!

73

Max