#150 RF Sampler RF Tap 3 in 1 Home Build

looks good,,do you think the mini switch will do 100 watts? will atch the test , then i will make oen,i do have samplers but like you all in one

Hi Tony,
Nice stuff !!
could you tell us what the make/model value of that resistor in the bottom is ?
and maybe what size toroid coil that is ?
thanks,
kevin rea
lancaster, calif usa
k6rea

Do I see thermal labels there? I'm curious how long these will remain readable if you use the dummy load :-)

I love this design! I have been wondering how to do this very sort of thing for HF and VHF ham. For UHF and higher, I'd just use a directional coupler, but that isn't going to work well for VHF and lower. I watched your functional test, too. Would you mind doing a frequency response test of this roughly for the ham bands, say 2 MHz through 150 MHz? Curious about reflections/loss on the through line and the output levels on sample. It seems to function perfectly at 11 meters. I'm curious if the metal film resistors will go inductive in the VHF range, and I'm curious how linear or even usable the torroid output will be over such a broad range (6+ octaves). Love the idea of a mini-antenna bnc port for sampling. Thank you for sharing this!

Thanks for sharing! Dank je wel Tony ik ga hem ook maken. Heb je nog een schema van het design zoals je hem uiteindelijk hebt gemaakt? mvg Leo PA1Ldb

Perfectly.
Had to be inserted relay for swich remote.
What's material ferrite coil ???

This is just what I was looking for. Thank you for the step by step build of this sampler box, as soon as I get a good VR I'm building my own.

What's the toroid number and what size wire for it, did you use?

Thanks. I want to make a switchable attenuator

wat zijn de waardes van de potmeter, je zegt 47 ohm maar je vermeld 470 ohm verwarrend

Please what is the part number or ohms you used for the variable pot

Using the short length of wire is what we, in the US, called a "gimmick", which acted somewhat like a capacitor. They were used in some PA neutralization circuits.

Since all die-cast aluminium boxes are actually trapezoidal viewed from the sides, I always think they look much better with the lid as the bottom, and labelled that way up! BTW, I wouldn't put 100W into that tabbed 50ohm resistor for too long, they need a LOT more heat-sinking than that metal box alone can dissipate after some minutes of operation. A big finned heatsink thermally pasted and bolted to the top surface would really help there. The little switch could also be bigger as it may not like the SWR if the dummy load fails or it is accidentally flipped at 100W. Those switches are usually rated 250V at 50Hz, not at HF radio frequencies.

Why not add this sampler circuit to the inside of an antenna tuner (such as the MFJ Versatuner)? As a matter of fact, I've done that already. By positioning the torroid core around the wire lead to the input to the tuner from the transmitter, the remaining circuitry fits nicely into the Versatuner box. There is plenty of space to mount the pot and sampling jack on the rear of the box. Then, no matter which output is chosen for the Versatuner (dummy load, antenna 1, antenna 2, etc.) an adjustable sampling signal is always available at the sampling jack without siphoning off any of the signal through resistor dividers.

Would like to built the part with the core only but for power till 1.5KW, which core size and type (43 I suppose) would you recommend. Regards.

Fantastic video.

nice work

You continue to impress…
Thank you !

When I was much younger and with minimal training, I bought a spectrum analyzer to tune several duplexers for a public safety organization I belonged to. It was roughly the same price, as it would have cost to send them out for professional tuning.

I was a total IDIOT and connected the output of a Motorola 110 watt UHF (70cm + up to T-Band) P25/analog repeater DIRECTLY to the input of the Rigol 7nit. POOF and even a bit of smoke…🤣
10+ years later, I’m still clueless, but a bit more experienced. 🙂

I have a Telewave 44 watt meter that does not require “slugs”. It has a non-adjustable RF sampling port built in.
They claim The attenuation is variable, but there’s no external adjustment, so I’ve been way to chicken to connect it up.
This project seems ideal.

sorry maar ik vind het niet zo'n goeie video!
werkt het? ik heb het niet kunnen zien?

Nice job!

I have a 100W 6GHz dummy load. I want to get a proportional sample into the TinySA from the transmission line to get an accurate power measurement. Any tips?

I think you should make some electronics tutorials, you are an EXPERT and we could definitely benefit from your experience :)