If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
You are fast!!
That could work for us if you hold the aerial near the amp. I think .And it's cheap.
Any idea on the VHF amp that work from a 1mW input?
I found the local supplier for Mini Circuits here in South Africa. They do ask double the price but that is ok as Mini Circuits do not ship here for cheap and this way I know I will get it.
I still want to try the components on a pc board.
The POS-200+ and the POS-1000W+. They are much cheaper and how difficult could it be to make a pc board for it.
Mounting on PC boards is a very difficult job, the design is not the same as for none RF electronics, Not advised
Mini Circuits does give some guideline for pcb layout on plug in VCO models and I will also contact their technical advisers for help, But I think they will suggest the same as you did. http://www.minicircuits.com/pages/pdfs/vco15-19.pdf
Any of the below sourced parts not the right ones for the job?
Only the ones with an * in front are the ones I'm concerned about
if there are special considerations.
Need to find a more easily available replacement for: Toshiba S-AV10L amp
Now if someone could post a complete schematic tying them all together,
this took enough time for today. I saw the different amp circuits, etc...,
but if someone could put them all together in one solid schematic, that
would be helpful to everyone.
@10mw input it will give around 8.5watts on the output @ a frequency of 136mhz. The voltage divider resistance will have to be changed for the output drive, minor detail, the rest is the same
Originally posted by Michael John NunnerleyView Post
The S-AV10L should be available, I have seen it in some places on the web.
10mw is plenty to drive these amps and others to 10-15w.
The frequency is linear with the control input voltage, you can use the table supplied by Mini Circuits on the data sheat and put a volt meter on the control line, its that simple.
We are now talking 135mhz and 810mhz so the sizes I gave for the antennas have now changed, I will recalculate and give you them at a later date.
If I can find a site with the toshiba amp I will post it.
Mike
Looking at the datasheet it looks like the S-AV10L needs 200mW as input.
Will it even work with a 10mW input
With a 12.5V supply it gives only 2W with a 40mW input. I really cannot see that it will work without a pre-amp.
I cannot find a supplier for the Hitachi PFO 310A
Looking at the datasheet it looks like the S-AV10L needs 200mW as input.
Will it even work with a 10mW input
With a 12.5V supply it gives only 2W with a 40mW input. I really cannot see that it will work without a pre-amp.
I cannot find a supplier for the Hitachi PFO 310A
Yes the S-AV10L does need a pre amp using a BFR93, but is a very simple circuit which will give around 150mw into the amp.
I have not looked at suppliers for the PFO 310A, only looked at data sheats, as a possibility
Michael, can you put all the information in a single document with a step by step instructions os it is easy to replicate?
Thanks.
Hi Bugler –I’m afraid it’s going to be a bit difficult for Mike or anyone else at this stage to put any sort of comprehensive total plan together, I guess if you read back through the threads you’ll see that this was originally done in the late 80s.
The components available and cost have changed out of all recognition.
Just as an example I worked in a minor way with UHF at the start of the 80s amongst the equipment was a racal frequency counter it cost thousands, I’ve just ordered a counter off eBay (admittedly not a Racal) for less than £10.
Mike is obviously a very skilled RF engineer (a black art in its self) so if you bear in mind what he’s trying to which is…
a/ share this technology with us
b/ explain as best he can to us why it works
c/ adapt the construct so that as many people as possible can “have at it”
In practice Bugler certain components of the construct are “disappearing” off the market as soon as they are posted here luckily the basic components are in everyday use and manufacture and have to be, But In practice we have to change brand. Toshiba, Motorola, siemens, Pye yasu It really doesn’t matter which we use just a few slight component changes are needed however It does make putting all the Information together difficult I guess you could say we are forced to work “on the hoof”
You will also see that there is a terrific amount of injection and Idea’s flowing into this project from the forum members which are being assimilated and either incorporated or rejected In other words the forum is interacting debating and progressing. It’s doing its job! For Instance the frequencies have been moved slightly for various reasons; this means the magnetic loops will have different dimensions yet to be worked out. Or perhaps something like this could be incorporated VHF Magnetic Loop by dxzone.com and maybe this70cm Magnetic loop I don’t know its still work in progress.
However the rate of change is a bit frantic at the moment, Mike is an award winning designer in his own right and I assure you are watching the real deal unfold right here.
So please don’t loose patience, in practice (and I know because I’ve worked at UHF) you can build two identical units and they will both react very differently. It’s very difficult to design the fluctuations out. That’s why Mike advised Nvisser to think twice before attempting a PC board.
We will each in the end have to make our own unit as best we can, Dr Stiffer pointed out that it was in the end pretty much inevitable because of the nature of RF.Component and cable differences ect
But fear not Bugler a plan is rapidly coming together... stick with it
Comment