VK Logger Ham Radio Forum Archive

Tnx Alan.... unfortunately the 22" Samsung monitors I have dont have the VESA mounts [CRYING FACE]

Leaving me with one 19" monitor VESA mountable - the HF/6m WSJT/digital mode screen. (VHF and up digital is on another monitor and laptop)

In buying my son his new dual 24" monitors, I proudly took ownership of the 'hand me down' monitors only to realise I may have not won out in the deal!



Sent from my SM-G900I using Tapatalk

Greetings to all!

Just recently I've been working on a 'low powered' transmitting amplifier for use at 3.4 GHz. The TOSHIBA ones deliver more power than I want, and they are VERY power-hungry, so I opted for use of a couple of modules obtained on UK eBay (seller = sbx55), modules that use superseded but still available Filtronic FETs - FDP2000AS and FDP4000AF.

Here is a picture of the completed amplifier: A great amount of fun and satisfaction was had in each of the metal work stage, the RF assembly stage and in testing and "snow flaking" this project. Connected as you see one after the other, these two amplifier 'modules' deliver 4 Watts output from 25 mW drive power. Saturated output is 4.5 watts. And the current drain at +10V is just on one Amp.

Happy constructing!

--Doug Friend, VK4OE.

I like it!

What's that all-metal module on the right hand end, Doug? [ Asked on the principle that the only stupid question is the one not asked ]

looks like a circulator to me...

Yes, Roger, it's a circulator connected as an isolator with 'port 3' terminated.
Cheers and 73,
--Doug, '4OE.

Avery good article on circulators and isolators in Rad-Com RSGB magazine this month

Nearly there, 6m, 9cm, 6cm and 3cm, getting ready for the next field outing.

Oh-oh I feel the constructers shield slipping between my fingers!
Neat Pete

Great job, Peter.

Are you able to lift it by yourself?

Anyone got any hf amplifier ideas?

On the bench at work today. 2.6GHz 1kw solid state amplifier

I started building a four band AM/SSB rig using some of the new Mini-Kits M1 Kits.
Front panel design.
Drilling some holes.
Mock up.
Pretty lights.


Ben

Have been working with the Si5351 as a crystal replacement for use in the Pic-a-Star rigs.
It's not confined to that rig, can used anywhere to replace a crystal. Pcb is 20 x 30mm in size, all smd components.
That Si5351 can really hurt the eyes when soldering it in, especially without a decent mag lamp.
More info here http://www.vk5tm.com/starlo.php

Has any one got a circuit for one of these. I believe it out of a Codan 9105.

MMIC based LNA for SOT-86 devices from RF Bay: http://www.ebay.com.au/itm/160567119632

This is what's in the kit:




0603 parts make 0805 parts look big, and the SOT-223 voltage regulator ginormus!
I'm not using the supplied 78M08 DPAK, but fitted a 78M05 in a SOT-223 instead (middle leg broken off - not needed, as the rear is also GND).




Completed LNA, using an NLB-310 MMIC @ 50mA:



It provides 11dB gain @ 2450 MHz and 9 dB gain at 5760 MHz.
NF not measured - who cares - it is what it is.

Having an Altronics store in town now is really handy for buying 0603 and 0805 parts.
Not the cheapest way to buy SMD, but very convenient for QTY=10 of this and that.

http://www.altronics.com.au/search/capacitors/?sr=smd
http://www.altronics.com.au/search/carb ... rs/?sr=smd

Adam, you could have bought your SMD caps from 'RFExtra' in your same purchase order. I have been buying my microwave caps from him for years, 100 at a time. They (the SMD caps) are in all of my transverters.

And when I drop one on the floor, and it is gone 'forever more', I have spares!

73 Bruce VK2EM

DDS Synthesiser for the old Codan rock radios.

Extract all the channel xtals and inject the DDS output into the radio.
Flop the injection to the either side of the IF and it switches sidebands.

The actual on-air performance is pretty good because the codan channel filters are 200-300khz wide and tend to keep the crud out.

Peak the radio on (say) 7150 and it covers the whole 40m band pretty well. 30m is a doddle, on 80m it struggles to cover the DX window without a re tune.

Most of these sets have some switching arrangement that includes adapting the PA filter. Did you do anything about that?

VK3ALB wrote:Most of these sets have some switching arrangement that includes adapting the PA filter. Did you do anything about that?

Yes Lou you are correct, the PA filter switching may need adjusting, but in this radio the existing PA filter matched the relevant amateur band, so nothing needed to be done. The original channels were only a few tens of kHz outside the ham bands.

Richard

Thanks Richard,

That makes perfect sense. I imagine if someone wanted to make it multi-band they could use the crystal select wafer on the channel switch to change the LO injection. Nice project.