Anyone? Exiter TX's tested 1w to 7w models Sinus /rev / driver board / pira / nrg pll pro III / zozo

[yellowbeard]

Everybody knows what I'm gonna say: England 1 - 2 Netherlands
https://www.amateurradioshop.nl/webshop ... broadcast/
https://dutchrfshop.nl/en/235-diy-kits-pcb-s
https://www.enigma-shop.com/kits-modules/ham-broadcast
Seems more difficult to find someone supplying a built up exciter, I don't know if its a legal issue or there's just no profit in it. Both Dutchrfshop and enigma supply built amplifiers as well as kits. With the Dutch fellas there probably will be VAT and import tax - I am in Ireland so it doesn't apply for me!

[Albert H]

NorthEast - you need to enlist the help of a friend who is used to working with electronics. Constructing a kit isn't difficult - you need to be able to correctly identify the parts (it'll never work properly if you mix them up) and you need to be able to solder neatly. You'll also need some basic tools and instruments - a multimeter is pretty essential - and (if you're building a 1 Watt exciter) you need a couple of 100Ω ½ Watt carbon resistors, wired in parallel to make a simple 1 Watt 50Ω dummy load for testing purposes....

[ronald001]

What about the latest RDVV touch screen model, and the model with rotary encoder?
Building the rotary with 1KW final right now, will post some picures later..
Both have SWR and temp protection, and can power down the amplifier

[LeeCavanagh]

Looks swanky that display , hot much extra does it add to the price?

Are you saying “rotary encoder” is for volume ? Power? Or tuning ? Having a rotary seems a bit counterintuitive to me, you don’t change it often so I don’t know what wrong with the touch screen (is it just like a fine tuning knob for all parameters ?)

[ronald001]

Both TX's have identical features - but the one with LCD screen can be controlled with the touch screen, and the one with 4x20 LCD with rotary encoder. Also the one with LCD screen has a deviation meter.

Functions:

- Temperature alarm and indicator
- Current alarm and indicator
- SWR alarm and indicator (still need to calibrate the SWR board)
- FWD REF power indicator
- Voltage indicator
- TX range 84-108 Mhz (In NL below 87.5 Mhz is used for WBDX)

The rotary is 95 euro, and LCD is around 120

(valid for 2 days)

[Zozo]

I tested the Zozo design it worked well.
I found it to have quite a strong 3rd harmonic into the aircraft and 2meter ham band.
If not aligned correctly with my spectrum analyser.
So it could do with better filtering around the doubler stage.
I found the final harmonic filter works OK above 180 mhz...
So If you don't own a spectrum or wave meter, I would avoid using this design and go for a NRG or Veronica kit.

Not sure of you're test bench equipment, but something must be way out of alignment or due a calibration at the very least, or have you mistaken these results with another board??

I setup the board this morning on 98MHz, with the analyser FC set for 145.5Mhz in the 2m band; as you can see there's absolutely nothing to be seen.

The 2nd harnonic is over 60dB down and the 3rd and subsequent harmonics are well and truly in the weeds.

FMTXMK3.png

[Albert H]

Stanley doesn't seem to understand harmonics. There are no harmonic products from that exciter that could end up in the aircraft band, even if the output filter was misaligned.!

[Zozo]

Stanley doesn't seem to understand harmonics. There are no harmonic products from that exciter that could end up in the aircraft band, even if the output filter was misaligned.!

I'm not sure how many boards I've personally built and sold, but all of them have had a very clean output in both the harmonic and audio domain. But obvisouly those constructed by others may be very different if they've not built it correctly?

I don't mind constructive criticism of a free open source project, if there honest and true!

A certain individial on a facebook group thingy had a very negative view of the SAA1057 and this board in general; apparenty they also use this forum so I'm told. I'm not interested in facebook, but I was sent a link here:

[Albert H]

Hi Zozo.
The SAA1057 is a fine choice for an exciter, as long as the resistor on pin 1 is increased from the datasheet value of 180Ω to 1kΩ. As we know, the IC was designed for the Philips digitally tuned portable receivers (I used to have one - it was excellent).

The IC was made in huge quantities, because Philips believed that it would be a big seller. Unfortunately, Philips failed entirely to make their controller IC available as they considered its code "proprietary", and the group at Eindhoven that designed it was disbanded. It was an ASIC with keyboard matrix reading, LCD drive for frequency display, I²C bus, and memories for each band for frequently used frequencies, and was a work of art! If they had made that IC available along with the '1057, it would have been the "go-to" tuning option for many other portable radio manufacturers.

The SAA1057s ended up being sold off for pennies, because the radio manufacturers developed their own solutions (or bought the Sharp chipset). This made it fair game for the pirates.

One of the nicer features of the '1057 is the split supplies - the Vcc3 input for example will work up to 33V, giving a big voltage swing for the varicaps. I've made use of this by developing 33V regulated by a zener on the board, using a simple voltage multiplier circuit, and giving the Vcc3 input that raised voltage. This allows the sensitivity of the varicap in the VCO to be made smaller, so that the modulation sensitivity is also reduced, making the modulator less prone to hum and noise issues, whilst allowing the VCO to tune right across the band without any adjustment.

The code that Jan Kolar made available on his "Pira" site works well enough. The only thing it lacks (because of the way the SAA1057 works) is a reliable "locked" detection output. The simplest and most practical solution for that is simply to delay the switch-on of the PA supply for several seconds after power-on. This is viable because of the reliability of the '1057 PLL - it tunes and locks wherever you've set the frequency to within a few seconds - every time!

I've used the IC to tune Band IV and Band V exciters and receivers by adding a prescaler IC and using the SW tuning range. This made for a very cheap solution, especially since I used the 12F609 PIC (62p in quantity!) to load data into the SAA1057. On the pirate gear I sold, I sanded the tops of the PIC, SAA1057 and prescaler to frustrate the copying solder-jockeys. The prescaler I used was the SAB6456, which Philips developed for TV tunerheads, and was another IC that was made in huge quantities and therefore cost next to nothing!

[rigmo]

you are bas ass boss

[rigmo]

QN8007 FM Transmitter - Stereo & RDS - 12W by ADSFMTX
https://www.youtube.com/@adsfmtx
https://web.facebook.com/ADSFMTX/

Integrated MPX/RDS Quintic QN8007 and output via RD15HVF1
RF output 50 ohm, UHF connector
Frequency and Power adjustment via front panel
Broadband. No RF adjustments needed
Adjustable power 1-12W

[Albert H]

That's a pretty board, but those "single IC exciters" are horrible - lots of in-band muck, plenty of harmonics, and nasty distorted pilot signals....

About 18 months ago, we tested every one of those "stereo sender" ICs that we could obtain. The best one we found was a Quintic part, but even that wasn't clean enough to be amplified. It was just about good enough for its original purpose - to provide a tiny flea-power stereo transmitter to make a stereo cordless connection from a portable CD player or MP3 player to your car radio.

If you're going to build a small stereo transmitter, it's best to do it with discrete parts - the proper way!

[radionortheast]

the zozo looks like you have to have the code for the frequency, think there are some specialised parts also like toko coil the ferrite you have to wind.

Does the dutch rf shop pay vat or is it something that has to paid afterwards, know someone posted some links above.

[radionortheast]

the 8066 is the best of a bad bunch when it comes to ics, all in one, 8027 is common in car transmitters puts out duplicate carrier if you have it on a lower frequency like 88.1 it will near 100mhz, the 8066 still puts out noise across fm but no duplicates, it is has good stereo sound a clipper if you set the audio too high, the rf can vary around on the 8027 they are often slightly off frequency too. I’ve tried to get the 8007 i’ve never been able to get hold of it, don't think its possible to find a chip that doesn't put out noise, I went every in car transmitter, similar type one.

[rigmo]

I’ve tried to get the 8007

i have few qn8007 someware brand new ICs

[radionortheast]

i have few qn8007 someware brand new ICs

Hi, the chip on its own would probably be no good to me, a lot of programming, surface mount soldering something I can't do, I was wondering if they produce noise across fm band? I do find that all chip transmitters do this, its a real problem if you try to amplify them won’t beable to hear other fm stations. With a better transmitter you just get a lowering of sensitiviy in radios, still alble to hear most if not all other radio stations.

I’ve been trying to make a transmitter using easyly availble parts, car transmitters, connecting to a 2.5w amplifier, readily available, lowered to 5/6dbm is needed for the amplifier, there would be a low pass filter on the output, simple. Its something i’ve given on, I now use signal generator pll max2870 module, it has its own problems, it was not intended for audio, op amp has to be used to pass the full bass to connect up my stereo encoder, the pll has to run off of a compleatly separate power supply, its become overly complex. The op amp dose increase the chance of picking more noise, from smps or rf, lot of ferrites had to used, it dosen’t interfere with other fm stations, it not as clean as a vco. The good thing is it outputs 5/6dbm it can connected up to the amplifier, delicate soldering is required to get audio in.

I do quite like the 8066, i’ve had a few kits 5/7w it is possible to correct some of the problems, rf locking the display using ferrites to the connecting ribbon cable to the display, a capacitor at the output can also prevent a mismatch, if you get a bit of a mismatch you can get spurs, so don't go connecting up your folded dipole . Its also possible to lower the volume if playing music from an sd card, connecting low value resistors to the left and right channels of the 3.5mm jack to ground. It is a shame, it will produce noise across the fm band it would be useable, smps/rf noise dosen’t seem to be a problem.