Retevis HS4: Can it PASS the Spectral Purity Test?

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Күн бұрын

Пікірлер: 31

@mikesradiorepair Ай бұрын

One suggestion when doing radios like this, what I call black box CB radios. They usually measure fine for harmonics. The problem that I have seen before is close in mixing products being emitted. Set your span to .5 or 1 MHz. I have seen radios that had extremely high unwanted emissions that were fairly close to the carrier frequency. It's all but impossible to see with a very wide span because the spurs are so close to the fundamental, there are to few data points stretched out over a huge span and limited resolution. They can be a couple kHz away or even 10's to hundreds of kHz away from the fundamental. All depends on the frequency synthesis mixing scheme of the specific radio. I tested one once (not this make/model) that when modified and used on the CB band had huge spurs dead center in the Tech SSB portion of 10 Meters. When using a spectrum analyzer think of the resolution bandwidth and span kind of like the focus / zoom of a pair of binoculars or a telescope. When zoomed out you can see a huge amount but you can't make out fine details. Basically impossible to see a single tree at a large distance. When you zoom in those far away fuzzy objects become clear and that one tree all of the sudden becomes 3 or 4 very close together trees. Same basic effect with spectrum analyzers.

@TheSmokinApe Ай бұрын

Thanks for the insight and suggestion Mike 👍

@KK6USYHamRadioAdventures Ай бұрын

Nice review Ape!

@TheSmokinApe Ай бұрын

Thanks Chuck 👍

@robertmeyer4744 Ай бұрын

Love to see clean radios. Nice 40 DB attenuator ! I got a 25 watt N one. My 40 DB slug for bird rated 10 KW . My biggest dummy load is 2.5 KW . Think I am good for full legal power testing. I did back to back 4:1 UNUN testing for power test and was decoding FT8 on 10 meters without antenna. Just UNUN into dummy load on bench. Bad was wide open. Even CB 6 blasting in without antenna. 9 or 10 turn of 2 sets MAG wire on T200-2 RED core was best for power. and 100 watt FT8 into dummy load calling CQ for almost 2 hours and core was room temp. The FT 240-43 at 4:1 tested 500 watt FT8 about 30 min and started getting warm. with same core wound 49:1 it got hot in 15 min . FT 240-61 tested bast for power on 10 meters. with 49:1 . did not test 4:1 with type 61 yet. I only have a few toroids . That 10 meter radio should do a POTA just fine at 40 watts. End Fed half wave . work great . Poseidon with a ATU . The 27.555 MHZ was a big pile up past few days. I could not tell were DX coming from. The UK CB band herd in NY in morning. 10/11/12/15 meters wide open . 17 and 20 as well. 7200 was crazy ! 73

@TheSmokinApe Ай бұрын

Hey Robert, I have a tapped slug around here that you are making me want to dig up

@robertmeyer4744 Ай бұрын

@@TheSmokinApe So far that the only slug I have. LOL😀

@TheSmokinApe Ай бұрын

@ I have a few floating around, I suppose I should do a video

@KS0JD Ай бұрын

Nice clean little unit! My question is just how clean is a whistle? The one my old football coach used dirtier than the gym floor. Thanks for the video Ape! 73

@TheSmokinApe Ай бұрын

I never thought about the football whistle 🤔

@Siskiyous6 Ай бұрын

Thank you Mr Ape, those spurious emissions are how they get ya

@TheSmokinApe Ай бұрын

@@Siskiyous6 it sure is LC 🍻

@richysradioroom Ай бұрын

Nice.

@TheSmokinApe Ай бұрын

Thanks Richy 👍

@hazer72 Ай бұрын

big ass > little ass > little coax > tiny SA makes sense!

@TheSmokinApe Ай бұрын

Right 👍

@bassangler73 Ай бұрын

Anytone, seems to get lumped into the junk chinese radio crowd..I have an 878UVii+ and i love it.. Thanks Ape!

@TheSmokinApe Ай бұрын

Anytone is OK in my book 👍

@WECB640 Ай бұрын

Once we clip D34 and install the "super modulation" kit, it ain't gonna look nearly as nice on that fancy splay. LOL "All knobs to the right!"

@TheSmokinApe Ай бұрын

Haha, once it gets peak’d!

@johnnorth9355 Ай бұрын

Oh for a proper vfo !

@TheSmokinApe Ай бұрын

Right

@LarryAllenTonar Ай бұрын

At 4:45 we can tell that your videos are not scripted."-40 dB + -50 dB equals-80 dB"? "Or thereabouts" You're still in the top 3 of reviewers I trust, with a big gap to the untrustworthy rest.

@TheSmokinApe Ай бұрын

@@LarryAllenTonar lol, not scripted at all…. I do fix that later in the video. Thanks for watching Larry, glad you like them 👍