Date   
Re: U3s alternate pa transistor

Nik
 

Perhaps an alternate approach would be to tune the existing PA circuit to be more efficient at higher frequencies in the hope that the efficiency drop at lower frequencies flattens out the output curve.  As long as there would be sufficient drive for the 5W amplifier to give a Watt or two output........

Re: 2m under threat for Thales

Lex PH2LB
 

A much better attitude is the guy in this video : 

https://youtu.be/lf14OSTzLNQ 

Re: 2m under threat for Thales

Lex PH2LB
 

https://www.youtube.com/watch?v=R_c4zmlD1UI

Indeed, not the best attitude. 

IRF510 Substitution

Vernon Matheson
 

Thanks all for your input.

 

I did find them at Kits and Parts and ended up buying a few other things as well. Shipping from there is $11 versus $20+ from some of the others.

 

You have to remember that if I buy from Digikey Canada I pay in CDN $ and shipping is $8. The $8 gives me guaranteed 2 day delivery.

 

To buy in USD I have to pay as of today $1.315 CDN for $1 USD

 

Thanks again.

 

Vernon

Re: U3s alternate pa transistor

ajparent1/KB1GMX
 

>>> BS170 drops down as frequency increases because of it's input capacitance.

And you will not find a part that will do more with the available drive.
The problems is you will need more drive with any FET...  IF you have
the money and the ability to mount beam lead device EGaN MOSfets
would be the ticket...  However mouniting a face down beam lead
device in a package that is 1004 size is a surgical experience on a
specially laid out board.  I know I have done it.

I know of another device that might be better but they are about
16-22$ each and scarce.

THe BS170 can produce more power on 10M but the output circuit
has to be for 10M, same for 15M  that reauires optimization for
the waveform to get decent class E performance.  Even Class C
the same applies.  Wide band switching amplifiers are not easy.

Allison

Re: IRF510 Substitution

ajparent1/KB1GMX
 

NO, just plain no.  The input capacitance alone is 10X higher!
Its like substituting a 5 ton truck for for a Smart car as your daily city driver.
Karlis YL3JG, was right.

If you want to use RFD15HVF1 you will pay 6$ (likely shipping too) for one,
and IRF510s are under 1$.  IF capcitance were the only parameter it might
be a option save for its a VHF MOSFET  and if it oscillates its on you. 
Personally I've used them at 2M they are good at HF, Not impressed.

Allison

Re: Incorrect Local Date Day #clock

Roger N5RWK
 

Alan, you are indeed correct, my issue looks like the same issue that was reported last October with #ND.

Hope Hans is able to fix it soon, it's probably just a minor logic error.

73,

Roger N5RWK

Re: Incorrect Local Date Day #clock

Alan de G1FXB
 

I believe this has being reported before, Hans has placed it on a to-do list.

https://groups.io/g/QRPLabs/message/27844

perhaps read the whole thread to confirm it's like your findings?


Alan

On 03/07/2019 21:01, rwklein@... wrote:
Just got my clock assembled with a 4x20 display, and am programming it.?? I ran across an apparent bug with the #ND (local date day) tag.

I have line 2 of my display set to alternate between UTC date and local date as follows:
#DD #DM 20#DY [] #ND #NM 20#NY

Local Offset is set to -300, as I am on UTC-5 hours, Central time here in the U.S.

What gets displayed for UTC day is 03 JUL 2019, but the Local day shows 02 JUL 2019!

BTW, local time here is 14:57 central, 19:57 UTC.?? In other words, the day should be the same.

Is this a bug, or maybe a highly localized distortion in the space-time continuum? :-)

73,

Roger N5RWK

Re: Incorrect Local Date Day #clock

Roger N5RWK
 

Forgot to mention the firmware is C1.02a.

Incorrect Local Date Day #clock

Roger N5RWK
 

Just got my clock assembled with a 4x20 display, and am programming it.  I ran across an apparent bug with the #ND (local date day) tag.

I have line 2 of my display set to alternate between UTC date and local date as follows:
#DD #DM 20#DY [] #ND #NM 20#NY

Local Offset is set to -300, as I am on UTC-5 hours, Central time here in the U.S.

What gets displayed for UTC day is 03 JUL 2019, but the Local day shows 02 JUL 2019!

BTW, local time here is 14:57 central, 19:57 UTC.  In other words, the day should be the same.

Is this a bug, or maybe a highly localized distortion in the space-time continuum? :-)

73,

Roger N5RWK

Re: 2m under threat for Thales

Lawrence
 

Out of curiosity if 2m is not being used in the U.K. what frequencies do you use for public service and emergency response support networks and local chatter?

Here in BC Canada, 2m is used locally for nets, our club as 2 each week, a check-in net and a technical net.  BCFMCA has a daily check-in net that draws 100+ hams on a good day and there are many others.  I don’t know about the rest of the world but here there are something like 6 2m repeaters in the city area and a dozen or more in the regional area.  With the advent of DMR,  D-Star, Fusion and other digital systems we are linked world wide on 2m.  I don’t hear a lot of local chatter or QSO’ing etc but they all have regular nets and are in integral part of the amateur public service and radio emergency response networks.  We use 2m for communications at public service events like marathon, fireworks nights etc.

73 Lawrence Harris VA7EDU

On Jul 3, 2019, at 12:07, Stephen Farthing G0XAR JO92ON97 <squirrox@...> wrote:

Guys,

I can only speak for what I’ve experienced in the U.K. Two meters, apart from the FM repeater section, is not used much apart from contests. Turn on your radio and tune around if you don’t believe me. Or better still try for some CW or SSB contacts. Good luck! There is an old saying “use it or loose it” and in my experience Amateurs in the U.K. haven’t been using it much for a long time. So I’m not surprised that commercial companies have their eyes on this mostly unused spectrum. I read somewhere that (though I don’t know the truth) that the Thales proposal is to allocate more spectrum for Aircraft to use. Commercial aviation has expanded rapidly especially in the budget airline area. I guess we’ve all benefited from this. So it’s possible that they need more spectrum and Thales are leading the way. 

Now I’m not saying that we should give up without a fight but I can’t see how we can win if we don’t start using 2 meters far more than we do now. 

Regards,

Steve G0XAR





Re: 2m under threat for Thales

Braden Glett
 

In Ohio (USA) it's the same - turn on your 2m radio and there is nothing. That doesn't mean no one is using it, but few are, most of the time. I tried 2m for a while but it didn't appeal to me at all. I do feel sorry for those who do use it (and might lose it) but I'm not sure what could be done to make 2m interesting to people so that they use it as they once did.

Re: 2m under threat for Thales

Stephen Farthing G0XAR JO92ON97
 

Guys,

I can only speak for what I’ve experienced in the U.K. Two meters, apart from the FM repeater section, is not used much apart from contests. Turn on your radio and tune around if you don’t believe me. Or better still try for some CW or SSB contacts. Good luck! There is an old saying “use it or loose it” and in my experience Amateurs in the U.K. haven’t been using it much for a long time. So I’m not surprised that commercial companies have their eyes on this mostly unused spectrum. I read somewhere that (though I don’t know the truth) that the Thales proposal is to allocate more spectrum for Aircraft to use. Commercial aviation has expanded rapidly especially in the budget airline area. I guess we’ve all benefited from this. So it’s possible that they need more spectrum and Thales are leading the way. 

Now I’m not saying that we should give up without a fight but I can’t see how we can win if we don’t start using 2 meters far more than we do now. 

Regards,

Steve G0XAR




Re: IRF510 Substitution

Jim W7EED
 

Mouser (http://www.mouser.com) has 7,000 pieces of the IRF510PBF in stock at $0.91 in single unit quantities.  Their shipping charges are comparable to DigiKey's.
--
73,
Jim W7EED

Re: U3s alternate pa transistor

m0bmn
 

Hi

Ok I understand what you want to do but to be honest I think you will need to adjust the bias on each band when you change bands if you want the same power output, also  I believe that the power output will  change due to the changing impedance of the antenna at different freqs, its not going to be easy to have say 2 watts on each band  without manual adjustment, I could be wrong and I’m sure others will join in  with their own ideas.

Good luck ,

73

Paul M0BMN

 

Sent from Mail for Windows 10

 

From: nik@...
Sent: 03 July 2019 15:43
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] U3s alternate pa transistor

 

Hi Paul.

I’d like to have a more constant output across the HF bands, so I could drive the 5W PA and achieve a consistant output of around 2W from 40 to 15 metres. 

 


Virus-free. www.avast.com

Re: IRF510 Substitution

Alan G4ZFQ
 

RD15HVF1 RF Mosfets are designed for RF, have low input capacitance
Kees,

That does seem to remind me, I guess it has been discussed before. Looks like that could do the job if the Si5351 has sufficient drive. Yes, but this post does not show a level response but maybe more level? https://groups.io/g/QRPLabs/message/16014?p=,,,20,0,0,0::Created,,RD15HVF1,20,2,0,5995175 .

73 Alan G4ZFQ

Re: U3s alternate pa transistor

Alan G4ZFQ
 

I’d like to have a more constant output across the HF bands, so I could drive the 5W PA and achieve a consistant output of around 2W from 40 to 15 metres.
I think this will need a more complex design. The simple switched BS170 drops down as frequency increases because of it's input capacitance. A bigger device will probably have more capacitance. More drive or a completely different design required.
Personally I do not think it matters, LF requires more power than HF when it's open. On 10m few days ago my U3S with 50mW to the antenna made it to FY5KE, 6900Km.

73 Alan G4ZFQ

Re: IRF510 Substitution

Kees T
 

RD15HVF1 RF Mosfets are designed for RF, have low input capacitance and are ~$5 at RF Parts.

73 Kees K5BCQ

Re: U3s alternate pa transistor

Nik
 

Hi Paul.

I’d like to have a more constant output across the HF bands, so I could drive the 5W PA and achieve a consistant output of around 2W from 40 to 15 metres. 

Re: 2m under threat for Thales

Braden Glett
 

Lex, thanks. It was nice to read a reasoned rebuttal to this proposal, at a time when so many hams are saying really emotional, ranting things about it. Only yesterday I heard a very stupid man on YouTube (unfortunately with a lot of ham subscribers) advocating that if this passes he is going to go pirate, in reaction. Not exactly the way to influence public policy.
Brady KD8ZM