173,213,216 or 465 MHZ which one is best?

[Falconry Equipment International]

Hi guys in the Uk , which frequency do you use & consider is best?
personally I use 173 Mhz for these reasons: I am told that a) it is the only legal frequency in the UK, b) as the frequency gets higher the wavelenght gets smaller, the smaller yaggi/ antenna on trx (used to be big + on higher frequency systems but with RT+ & power max this has resolved that issue) but you also get a more defined signal, ie ieither a bleep or no bleep, no greay area and therefor if your hawk is in a gully etc on a kil you have a lot less chance off picking up a signal of some sort. sure there are other reasons, but can't rem,ember at present. Probably got things muddled but no doubt there are telem/ radio guys on here to put us right

[OutFlying]

the lower the frequency the better the signal will transmit (diffraction ?) in hillier areas, but also it needs a larger aerial and yagi. 465mhz is useless round here to many hills.

[Falconry Equipment International]

Hi Outflying, sounds like thats what I was trying to explain. as for JPJ a few years ago thinking 465 was brilliant, I doubt if she's sver had to track a hawk on a kill, but stand to be corrected :wink:

[OutFlying]

a friend had a system from Hungary on 400 Mhz (Digicom) - looked the business, small fitted in your pocket, worked well until your bird went over the hill. No signal until you climb the hill. Same goes for Finntracker, you'd be better off tieing two tin cans to your bird :D

[Hodgesargh]

I'd always go for 173. It's legal, it works well and it's the frequency that all my mates use so if any of us mislays a bird, everyone can keep their electronic ears open. (we keep notes of settings for each other's transmitters on our own receivers - useful in a panic!)

[IAmTheWeasel]

In the US, 216 is the most popular as many folks use this so they can help track a lost bird for someone else. In California, I heard that quite a few falconers have switched to 218 as there is alot of electrical interference from power poles on the 216 freq. At least this is what a Cali falconer told me.

[OutFlying]

SJ, Diffration diagram.

[Falconry Equipment International]

OutFlying
downloaded your file, unfortunately it is a PC doc & I can only open pdfs as I run apllemacs sorry SJ

[Slink]

Screamin Jay,

I converted the attachment to a .jpg, if that's any use to you?

Now a bit of techie stuff...

The wavelengths are quite significantly different. 465MHz has a length of approx 0.65M, 216MHz is 1.39M, 213MHz is 1.41M, and 173MHz is 1.73M. The 148MHz which also seems to come up in some countries is nearer 2.03M in wavelength.

What this means is twofold - firstly equipment size. The driven element of a yagi (the actual aerial - the passive elements help to increase the signal) is approximately 1/2 wavelength long, so the lower the frequency, the longer and wider the antenna. Secondly attenuation. You imagine a video sender (so you can watch TV upstairs) which uses around 12cms for a wavelength (2.6GHz, or 2600MHz), and has no size or power restrictions. If this reaches the mews at the end of the garden, I'd be suprised. If, however, you drop to 2MHz (150M wavelength), you can talk to yourself by going all the way around the world. Part of this is due to the diffraction shown in the diagram, and also reflection - from structures, hills etc, but also the sky. So the trick is to pick a frequency which is low enough to give an adequate range without being absorbed by the first hedge it comes to, but high enough that it is not reflected by everything, or your df would swing aimlessly around in circles! The frequencies in use have been arrived at by trial and error, and also regulatory pressure. A system in the Uk using around 440MHz would possibly not be much use, as a large amount of ISM equipment (Industrial, Scientific, Medical) uses this band, all of which would have higher power than a telemetry transmitter. Likewise for bands around commercial radio, taxis, TV and so on - all to be avoided for telemetry purposes. So, we get a compromise, as with everything else, and it is here that the manufacturers use their expertise to produce a system more sensitive, but less prone to bleedover or breakthrough, than their rivals. In general terms, this means more money!

Steve

PS, I have approximated! I have used 300000000 metres per second as the speed of a radio wave to do the wavelength calculations - 299792458 is the accepted speed, but the numbers come out nasty! If you're desperate, the wavelength in metres=the speed of light in metres per second (or a radio wave, same thing) divided by the frequency in hertz.

[Falconry Equipment International]

Steve that is really helpfull and wqas exactly what in my clumsy way I was trying to put across
SJ

[The Late Lord Lucan]

Whoa, very technical slink, I'm glad you added the diagram for numbty's like me......

Screaming Jay wrote....snip......
I am told that a) it is the only legal frequency in the UK

There are several legally used frequencies for telemetry for birds, I did paste up a link for 'Ofcom' who control this type of thing. If you do a search you will find it somewhere.

Outflying wrote worked well until your bird went over the hill. No signal until you climb the hill. Same goes for Finntracker, you'd be better off tieing two tin cans to your bird

The Finntracker is a bit better than people give it credit for, although it does take a lot more practice to use well than some of the others.
I have used one for about 5 or 6 years now. It wasn't my first choice, but as I had it given to me for free........
For short/broad wings, this has to be a very good choice. very small and compact, It's a little bit 'lairy' on a big falcon, although I get away with it because where I live is very flat and not many trees.
Having said that, I disagree with your comment about the hills, outflying.
Mine has been used in hilly areas and wooded areas, even in very heavily built up towns, and I've never had a major issue with it.
I have hung my transmitter in a tree, next to a marshall RT, and had a signal over a greater distance than the marshall.....
Before anyone starts up about any comparison between the two, I'm not comparing, I'm just saying what happened on a particular day.
Mine has been used with several big falcons, Goshawks, & numerous other birds, none have been lost or hard to find due to the inefficiency of Finntracker telemetry.

Regards,
Lucky.

[Falconry Equipment International]

Whoa, very technical slink, I'm glad you added the diagram for numbty's like me......

Screaming Jay wrote....snip......
I am told that a) it is the only legal frequency in the UK

There are several legally used frequencies for telemetry for birds, I did paste up a link for 'Ofcom' who control this type of thing. If you do a search you will find it somewhere.


Mine has been used with several big falcons, Goshawks, & numerous other birds, none have been lost or hard to find due to the inefficiency of Finntracker telemetry.

Regards,
Lucky.
LLL
As I have litrtle understanding of radio technology this was my reason fro wording , what you quoted in such a way. I had a suspicion that there were sevral but have not a clue what they are. Do you? if so would any of them be ven better from this diffraction point of view, ie as steves eloquent response and diagram showed, how about 151 mhz or even 100 . presumably much smaller than this and the yaggis whoul;d start to get outrageous?
SJ

[OutFlying]

SJ, that was the diagram I put up for you. 151 mhz - I think picks up interference from power lines etc. Also the transmitter aerial is longer.

LLL, If your receiver is not tuned precisely for the transmitter it can affect performance greatly. Many people do not check and finely adjust the tuning to get the best signal. The diagram seems to back up what I say regarding 433mhz performance in hilly terrain. Usually if a product is good, it will sell well - the finntracker in this country isn't and hasn't been on most peoples wishlist.

[Falconry Equipment International]

Oh Ok OPutflying, interstingly somketimes I have had interference from power lines etc. in damp conditions with 173 ( both marshall and MN10

[OutFlying]

yes you will whenever near power lines whatever frequency. But I think power lines actually interfere more with 151mhz and not just when your near them.

[Slink]

Just a quick note - it's not my diagram! It's the one that OutFlying posted as an attachment, I just converted it to a .jpg so you Mac users could see it :D
As far as regulation is concerned in the UK, I don't know - the radio stuff comes from my background in aviation, so although the theory is the same, the regulations aren't - I shall be doing some research on that in the next few months before buying telemetry myself!
Steve.

[OutFlying]

It wasn't mind either, I borrowed it from the Marshall's handbook.

[The Late Lord Lucan]

I had a suspicion that there were sevral but have not a clue what they are. Do you?

This lists the legal frequencies that can be used in the UK.

http://www.ofcom.org.uk/static/archive/ra/publication/interface/word-pdf/ir2030v1-2.doc

Regards,
LLL.

[Falconry Equipment International]

I had a suspicion that there were sevral but have not a clue what they are. Do you?

This lists the legal frequencies that can be used in the UK.

http://www.ofcom.org.uk/static/archive/ra/publication/interface/word-pdf/ir2030v1-2.doc

Regards,
LLL.
bloody ell LLL now I'm really confused
SJ :rolleyes: :yawinkle:

[Slink]

LLL, thanks! Trying to decipher that document is a barrel of laughs :?
I think the table required is 2.2, which contains the frequencies and the power limits below.

<SNIP!> Table removed - see later post from The Late Lord Lucan:The relevant table is 2.5

This is part of the text that I received in an email from OFCOM.

"There are some licence exempt frequency allocations for this type of use (falconry). Please refer to UK Interface Requirement IR 2030 for details (Table 2.5) for the technical details."

It also appears that generally 10mW would be the maximum power that can be used by such devices. To put that into some form of context, CB radio uses a maximum of 4W - 400 times more power than a telemetry transmitter, and amateur radio which shares the 430-440MHz band can use 400W, which is why it is easy for a low power transmitter on a hawk to "vanish" under a lot of other radio noise from other users.

Regards,
Steve

[OutFlying]

I might be mistaken (most likely) but I thought 173mhz was a reserved frequency for falconry. And that if you can across somebody transmitting on this frequency it was possible to contact the agency and report it.

[OutFlying]

found this link, read both pages

http://www.ibr.org.uk/dirv3/page177.html

[Tim Laycock]

I was at the NEFC AGM last night, Eddie Alum of Falcon Electronics gave a very informative talk about telemetry.
One of the interesting facts I picked up on was that the higher the frequency used- The smaller the yagi needs to be. Did not know that!!!

Falcon Electronics will have a stand at the F-Fair this year so go and have a look.
I dont use Eddies gear myself but by all accounts its second to none!

[The Late Lord Lucan]

The relevant table is 2.5

This is part of the text that I received in an email from OFCOM.

"There are some licence exempt frequency allocations for this type of use (falconry). Please refer to UK Interface Requirement IR 2030 for details (Table 2.5) for the technical details."

http://www.ofcom.org.uk/static/archive/ra/publication/interface/word-pdf/ir2030v1-2.doc

Here is a link to a previous discussion.....
http://www.falconryforum.co.uk/viewtopic.php?t=987&start=0

Regards,
LLL.

[Slink]

LLL, thanks - that will teach me for not reading it correctly! I shall edit my previous post accordingly!

So, we have 2 bands available, with 2 different channel spacing in each, namely 173.7 - 174MHz at 10mW with 12.5kHz or 25kHz spacing, and 458.9625 - 459.1000MHz at 10mW, also with 12.5kHz or 25kHz spacing, but according to that table, they are shared, not exclusive - the comment (f) In categories ii, iii, vi and viii, these bands may also be used in an airborne application for the tracking of birds - seems to indicate this, anyway!

Blackbird, have a look at page 1 of this thread - I have included some examples of lengths for frequencies.

Regards,
Steve.

[The Late Lord Lucan]

I might be mistaken (most likely) but I thought 173mhz was a reserved frequency for falconry. And that if you can across somebody transmitting on this frequency it was possible to contact the agency and report it.

but according to that table, they are shared, not exclusive - the comment
Quote:(f) In categories ii, iii, vi and viii, these bands may also be used in an airborne application for the tracking of birds
- seems to indicate this, anyway!

They are shared frequencies. And the amount of different things that are on these frequencies, it is amazing that our telemetry works at all!

Regards,
LLL.