Thanks for the comment, so am I. I was thinking there maybe some problem with the GS-35B type valve as I read they're not particularly linear... and no-one has posted any video of a GS-35B amplifier output on a scope for reference.
@@vk6cs456 They are linear enough,especially if you have higher idling current,,around 150ma minimum....try to directly connect coax cable between bird signal sampler 4273 and scope ,and terminate input on scope with 50 ohm,if scope do not have 50 ohm port...if you use hi impedance probe,as you do results can be funny...that is proper way to measure rf signals...
Very good video, I am just about to build a dual gs35b amp by converting an old henry 2k into this setup. Upgraded HV transformer and vacuum variables. Should be alot of fun. Will be mono-band on 11M. will see what type of power we can extract from it.
season greetings Steve, now get a dipole at 20m high and call cq on 3.793 Mhz like Robin used to do before he went of air, worked him just about every evening here in South Africa.
Don't kick it up and down the street. That would be tough on your foot ! Tie it to the back bumper of your truck with a nice long rope and go for a drive in the Outback. ;-) Happy New Year Steve Bob K6TR
Hey Steve, nice vid on the line year (hi hi). It's a good feeling isn't it, to know that the amp is working properly after all. So is your other scope a Tektronix? I didn't see the model of it. Looks like a good scope, maybe just needs a bit of work. Probably not quite ready for the garbage yet. ;-) de KD5MHQ
Hi Bob. It's a Hitachi I bought way back in the mid 80s. The peculiar thing is, if the amp is switched off the 100W of drive going through to the dummy load is shown as a nice sinewave.
Issues on the Hitachi due to old cap's and oxidated contacts? I still have one as spare for if the digital fails. Maybe it needs some attention after so many years of service, I recommend don't throw it on the street, this can be a very reliable scoop for spare.
Are you sure that the newer scope hasn't got a lower bandwidth and therefore acting as a low pass harmonic filter? Sorry if I'm stating the bleedin' obvious......... Tim M6TYH
Hi Tim, no apology necessary, all suggestions welcome. The old scope is 35MHz and the new one 40MHz. The old scope shows the 100W drive radio output waveform as a nice sinewave... that's the same frequency but a smaller amplitude so I think it's just RF getting into the scope.
No, I mean find out what's wrong by isolation testing the scope before you throw it away. Compartmentalise and test each part of the scope and find out what's wrong with it. The fix will be simple for sure. Don't just bin it because you think it's rat-arse;
![Electronic Circuitry Diagnosis And Fault Finding! [Repair]](http://i.ytimg.com/vi/LC7OjuYAOQE/mqdefault.jpg)
Thanks for sharing, Steve. Glad the amp is working properly.
Thanks for the comment, so am I. I was thinking there maybe some problem with the GS-35B type valve as I read they're not particularly linear... and no-one has posted any video of a GS-35B amplifier output on a scope for reference.
@@vk6cs456 They are linear enough,especially if you have higher idling current,,around 150ma minimum....try to directly connect coax cable between bird signal sampler 4273 and scope ,and terminate input on scope with 50 ohm,if scope do not have 50 ohm port...if you use hi impedance probe,as you do results can be funny...that is proper way to measure rf signals...
Very good video, I am just about to build a dual gs35b amp by converting an old henry 2k into this setup. Upgraded HV transformer and vacuum variables. Should be alot of fun. Will be mono-band on 11M. will see what type of power we can extract from it.
season greetings Steve, now get a dipole at 20m high and call cq on 3.793 Mhz like Robin used to do before he went of air, worked him just about every evening here in South Africa.
Cheers Johan. I'll carry out some tests to make sure there's no TVI before using the amplifier (at 400W) in the evenings.
Don't kick it up and down the street. That would be tough on your foot ! Tie it to the back bumper of your truck with a nice long rope and go for a drive in the Outback. ;-) Happy New Year Steve Bob K6TR
Thank Bob, and all the best for 2018. Maybe I'll do as you suggested.
Hey Steve, nice vid on the line year (hi hi). It's a good feeling isn't it, to know that the amp is working properly after all. So is your other scope a Tektronix? I didn't see the model of it. Looks like a good scope, maybe just needs a bit of work. Probably not quite ready for the garbage yet. ;-) de KD5MHQ
Hi Bob. It's a Hitachi I bought way back in the mid 80s. The peculiar thing is, if the amp is switched off the 100W of drive going through to the dummy load is shown as a nice sinewave.
you can kick it over to vk4 Steve. 😂
nice output mate.
Thanks Daz, I'll give it a poke with a stick before I bin it.
Issues on the Hitachi due to old cap's and oxidated contacts? I still have one as spare for if the digital fails. Maybe it needs some attention after so many years of service, I recommend don't throw it on the street, this can be a very reliable scoop for spare.
The peculiar thing is it shows the 100W from the drive radio as a nice sinewave.
Are you sure that the newer scope hasn't got a lower bandwidth and therefore acting as a low pass harmonic filter? Sorry if I'm stating the bleedin' obvious.........
Tim M6TYH
Hi Tim, no apology necessary, all suggestions welcome. The old scope is 35MHz and the new one 40MHz. The old scope shows the 100W drive radio output waveform as a nice sinewave... that's the same frequency but a smaller amplitude so I think it's just RF getting into the scope.
Isolate and retry before kicking up street.
From the mains supply? I don't have an isolation transformer.
No, I mean find out what's wrong by isolation testing the scope before you throw it away.
Compartmentalise and test each part of the scope and find out what's wrong with it.
The fix will be simple for sure. Don't just bin it because you think it's rat-arse;