nrgkits.nz wrote: ↑Wed Jun 17, 2020 12:34 am Albert H posted a 5W exciter schematic a few years back, it’s on the forums under a thread labeled “cheap 1w exciters”. Use the output matching from this schematic, not only does it match from around 12R up to 50R it also acts as a band pass filter from 87.5 to 108 - this should help cut back any 1/2 freq and 1 1/2 freq from getting to the output.

Do you mean the output matching after the oscillator in the schematic or the output matching on the final ?Also when I changed the coil that feeds the transistors with 5v for a ferrite bead with 5 turns it got rid of all the 1/2F and 1 1/2F, it’s in the grass.The only problem is 2f which is only
A couple db down from the carrier but this should help sort that.

Yes I was referring to the output after the final, but it sounds like you’ve already solved the problem with the 1/2 and 1 1/2. The 2F you’re getting will be the harmonic content, a low pass filter on the output will fix that. In my designs, harmonics are -65dBc below the main fundamental.

nrgkits.nz wrote: ↑Wed Jun 17, 2020 11:27 am Yes I was referring to the output after the final, but it sounds like you’ve already solved the problem with the 1/2 and 1 1/2. The 2F you’re getting will be the harmonic content, a low pass filter on the output will fix that. In my designs, harmonics are -65dBc below the main fundamental.

I don't know if its a problem with the circuit though because there is nearly the same amount of 2F coming out of the oscillator as 1F?

Also there are a lot of spurs next to the carrier so maybe there are some low frequency oscillations?

Is your power supply clean? have you got sufficient RF bypassing from the supply rail to ground? If you're using a voltage regulator IC, have you put RF bypass capacitors on the pins to ground?

I don’t know How clean my power supply is it’s an old maplin 12v linear supply.My regulators are bypassed it includes them in the schematic.Maybe the problem is that the piece of wire going from my oscillator into the analyser is becoming apart of the oscillator?When I put my head near the wire the super and harmonics change and flare up.Maybe it needs a buffer?

On time... Did you solve the problem ? Is there any capacitor connected at the output ? (it is absent on schematic). Do you have photos of mounted TX - would be nice to see In attachment schematic of version with no tune 1 - 2 W PA and SAA1057 based PLL (open pic and zoom it to make it sharp).

1608cc wrote: ↑Sat Sep 26, 2020 5:56 pm On time... Did you solve the problem ? Is there any capacitor connected at the output ? (it is absent on schematic). Do you have photos of mounted TX - would be nice to see In attachment schematic of version with no tune 1 - 2 W PA and SAA1057 based PLL (open pic and zoom it to make it sharp).

Hi 1608cc,
No I didn't in the end. I really made a dog's dinner of it when I was constructing it. Maybe I'll revisit it sometime.

I changed tac' and gone with a dual-gate fet oscillator, with a TSA5511 PLL and a 1 watt stage instead. I've nearly finished Ironing out all the problems with the prototype. After I've got some boards made I'll make a post about it!

Hi , I'm Zeal from South Africa and can I inbox you sir @NRGkitz

[R post_id=25830 time=1571898380 user_id=1487]
bb105 x 2 facing cathode ,bb204 any vhf varicap will suite .
[/quote]

I'm looking for this but I'm from South Africa

you have to try as well.maybe add a fixed one and squeeze the coils .

Hi Zeal
You can buy them communica.co.za in Pretoria or Cape Town.

Many modern DSP radio receivers are going to be much less forgiving with slightly off-channel relatively stable VFOs compared with the older receivers people used in the past.
A signal just 20kHz (0.02MHz) or so off-channel causes "soft-mute" (significant volume reduction) to kick-in on a XHData D808 receiver I tried.
Slight drift around this threshold would therefore have the annoying effect of significant jumps in volume.
so take note the non-PLL design, may be troublesome on modern DSP radios

Thank you sir

How to remove the antenna n put the coaxial cable Bnc head?

Zealmclazy wrote: ↑Sat Apr 20, 2024 7:05 pm How to remove the antenna n put the coaxial cable Bnc head?

You need to put a decoupling capacitor on the antenna output.

A 102 disc capacitor should do the job.