Found a cheap batch of the BLK-89-S+ DC Block from #minicircuits - wondered if they were usable at near-VLF frequencies (they’re specified from 100kHz-8Ghz).
They turned out quite acceptable 👍🏼🙂🙂
I don’t need that many, at all 😂, but it was a bargain and I’ll likely sell some of them once I’m done with the tests.
Amazing you can make an almost flat frequency response that wide 😳 They’re NOS from 2013, but they don’t seem to age, shelf life is ‘eternal’ on these devices ☺️

#hamradio #rfengineer #vlf

Some learning.
Some failure.
Some broken stuff.
Reworked some stuff.
Signals are still jacked.
Gonna need to rethink.

#SoftwareDefinedRadio #SDR #RTLSDR #TrunkRadio #Scanner #OpenSourceSignals #Intel #NUC #MiniCircuits #LotusSys #LowNoiseAmplifiers #LNA #DisconeAntenna #Antennas

I picked up the little 3-band Mountain Topper at the Danish #hamradio fair - first test: does it transmit? It sure does 😃 Nice and clean signal, about 4W output with 10V supply.

It’ll be fun to try it out in the wild, I might bring it on a #SOTA mission 🙂

My test setup uses 20dB coupler with another 30dB attenuation added to protect my spectrum analyzer. The load is a 30dB attenuator which can handle 10W, more than enough 👍🏼

More to come! 🙂

#hamradio #hamradioportable #qrp #cwops #siglent #rohdeschwarz #minicircuits #testandmeasurement #rfengineer #rfengineering #lnr #mountaintopper

A debate came up at work: what happens to the wanted signal when an interferer pushes the LNA into compression? Let’s try it! 🙂

Using A LOT of attenuation, I merged a 7MHz carrier (my wanted signal) with a stronger 25MHz interfering carrier. Stepping up the amplitude on the 25MHz signal, finally pushes the amplifier into compression: it’s gain drops and it becomes highly unlinear. Mixed products of the two carriers appears, as well as the 2nd harmonic of the interferer.

The 7Mhz carrier is still there, but since the amplifier now has less gain, it drops in amplitude.

Any #hamradio operator has experienced this on a crowded 40m band at night, in fact even worse, because numerous powerful stations mix and creates a lot of spurious noise on transceivers with low intermodulation performance.

#rfengineering #rfengineer #hamradio #hamr #electronics #electronicsengineering #testandmeasurement #siglent #minicircuits

It’s Friday and it’s #mailbag night 😃

FLUKE 52ii thermocouple thermometer, 10MHz OCXO and distribution amplifier, a #minicircuits 7GHz mixer, a #brymen 789 multimeter and a carry pouch for my BM235 multimeter. Everyone should have a travel multimeter, right? 😛😂

Have a great weekend out there,

#electronicsengineering #hamr #hamradio #testandmeasurement #

Worked on the antenna combiner and the mini amps needed.

Significant loss on the antenna combiner and RF amplification to the radios help eliminate that loss.

Initial test with basic antennas seems to be very solid. Need to bolt everything down and get it back into the car. #WiFi #WarDrive #LotusSys #MiniCircuits #RF #IntelNUC #ZimaBoard #Hak5WiFiCoconut #CollectAllTheWiFi