290 mk 1 mutek board fitting
steve barrett
mutek f/end board
that I could have.
cheers
steve
Shaun Scannell
it seems to do is degrade the receiver performance. I am pretty close to
our County Police HQ here along with any number of Paging transmitters, and
probably a load of other crud in the 135 - 180 Mhz range.
The receiver is really quite good without it, but appalling with it. If you
want to run the 290 portable on it's whip then possibly it may help.
However on any reasonable antenna, it is a) not necessary, and b) a positive
nuisance.
The receiver is pretty good, and although the S meter doesn't bounce around
too much it certainly ain't deaf. If you are trying to use the FT290 with a
big amplifier and want the receiver to reciprocate, then I believe you are
using the wrong rig in the first place.
I don't have the instructions any more though, but I stress again that you
will almost certainly be better off without, unless you live in the back end
of nowhere with absolutely no local signals in the 10's of millivolt range
close by.
steve barrett wrote in message <822pbt$nf9$1...@news7.svr.pol.co.uk>...
@rl.ac.uk Mike
you
> want to run the 290 portable on it's whip then possibly it may help
Well that is a little strong ! It certainly helped my early model FT290R
quite a bit, the pin switching being bypassed and the gain not excessive. It
soon became apparent that 2.5W was not enough for mobile work, but at least
I was not an alligator with it. With a mobile 25W PA it became quite a
capable mobile rig for the early 1980s. No problems with pagers - unlike my
IC2E, probably because of the added mutek filtering. It did suffer badly
from in-band strong signals. This is no longer a concern on 2m in Southern
England.
However, if you are going to use a good solid state linear with a built in
pre-amp, (e.g. BNOS LPM3-50) there is no need to fit the mutek board.
steve barrett
with the occasional portable operation.
I have the mutek board but no fitting instructions so still require those.
I can then decide if to leave the board in or take it out again if I get
problems like those that
shaun mentioned.
steve
Mike > wrote in message <827urf$16...@newton.cc.rl.ac.uk>...
John Robertson
mark one in 1986 when I got my ticket and the difference was
marked.. Mine was just the opposite to Shaun's experience.
Pretty poor without the board but hot with it. If I remember correctly
setting the gain on the pre amp was critical to performance.
I have used it mostly for ssb work on the satellites but cant say
I've noticed to much breakthrough on FM. I can force it by pointing
my 10 ele X'd yagi at the local pager xmitter and switching the masthead
and linear pre amps on...
Steve if you haven't had any joy with obtaining the instructions
from someone yet drop me an e-mail and I'll see if I can find them
Shaun Scannell wrote:
>
> My fitting instructions are don't. I had one of these in my FT290Mk1. All
> it seems to do is degrade the receiver performance. I am pretty close to
> our County Police HQ here along with any number of Paging transmitters, and
> probably a load of other crud in the 135 - 180 Mhz range.
>
> The receiver is really quite good without it, but appalling with it. If you
David Wrigley
<st...@barrett1959.freeserve.co.uk> wrote:
>The main purpose for the 290r is to drive a 10ghz transverter
>with the occasional portable operation.
>I have the mutek board but no fitting instructions so still require those.
>I can then decide if to leave the board in or take it out again if I get
>problems like those that
>shaun mentioned.
>
Hi Steve
I wouldn't fit a pre-amp in what is after all the IF stage of your
10GHz system. There wouldn't be any advantage to do so. In fact if
you fit a low noise front end on the 10Ghz transverter you will find
the overall gain more than adequate without it.
Use your Mutek for the talk back receiver where it can be of use.
I have a Mutek in my talk back receiver and if you get some info on it
please let me know - I bought my rig second hand and never received
the info.
73 David G6GXK
@rl.ac.uk Mike
> I wouldn't fit a pre-amp in what is after all the IF stage of your
> 10GHz system. There wouldn't be any advantage to do so. In fact if
> you fit a low noise front end on the 10Ghz transverter you will find
> the overall gain more than adequate without it.
I have deliberate excess gain stage in my 10 GHz transverter receiver
section. This is promptly used up in a 20dB attenuator. The OVERALL gain is
then about 13 dB.
Why ? Before the attenuator, I blew up several mixers and IF amplifiers by
not switching the PTT and also when one of the PIN diodes went short
circuit. The 20 dB pad reduces the 3W drive to a safe level so damage can't
happen. The loss in overall noise performance is not significant enough to
worry me with only 1W transmitter power.
g3...@qsl.nospam.net
>On Fri, 3 Dec 1999 18:00:15 -0000, "steve barrett"
><st...@barrett1959.freeserve.co.uk> wrote:
>
>>The main purpose for the 290r is to drive a 10ghz transverter
>>with the occasional portable operation.
I cant think of worse piece of gear to drive a 10GHz transverter!
@rl.ac.uk Mike
>
On the contrary, they work quite well Peter. The old model is much better
than the new one as you can switch from SSB to CW without going via FM and
changing frequency. A worse unit might be a Liner 2, an FT706, a 19set. Of
course there are better options.
Mike
steve barrett
I would be interested to know why peter thinks the 290r mk 1 is a poor
performer.......
anyway thats what I have at present along with an FT847 so I can do tests to
see what is best !!!
2m tx / rx to drive a 200mw DB6NT transverter. Anyone fancy a sked??????
qth here is S.E.Essex JO01HO.
still want 290r mutek board fitting instructions if anyone has them..
Steve G4HTZ
g3...@qsl.nospam.net
<st...@barrett1959.freeserve.co.uk> wrote:
>I would be interested to know why peter thinks the 290r mk 1 is a poor
>performer.......
Many years ago I checked the noise figures of over half a dozen of
them at our local club. None was better than 5dB and a few were as bad
as 7dB! IC202s were also checked and fared much better... one around
2dB and the others not far off, if I remember rightly.
I also don't like the 290's tuning knob and dial. There is a distinct
notchy feeling about it and you get the "di-di-di-di" effect when you
tune across a carrier... not the smooth tuning effect you would get
with a non-synthesised rig.
Most of the 290s I've heard have, IMHO, poor TX audio characteristics,
often rough around the edges, probably because the user tends to
swallow the fist mike when speaking into it! Several of my microwave
pals use 290s and they sound rough. (Exception is Mike, G0MJW..if that
is a 290 you use Mike... it sounds vy good!)
The problem of finding a suitably portable low-power prime mover for
driving a microwave transverter is a tough one. Many of us use the
IC202S and put up with its lousy frequency calibration (10kHz per
division!) because at least the RX is quite good and the TX audio is
frequently superb. I would like the FT290's 1kHz readout coupled with
the "proper" VFO of the 202S and the 202S's audio.
Unlike the FT290 it's very easy to reduce the RF output of the 202 to
around 100mW. I feed that to my 10 and 24GHz transverters via 15 feet
of 50 ohm coax. Inside the tranverters are small variable attenuators
to optimise the drive to the microwave mixers. I dont like the idea of
feeding 3 watts into my microwave box only to lose it all in a big
resistor. If you share a portable site with another microwaver he can
hear your 290 on 2m when you are transmitting on 10GHz!
If you put a Mutek front-end in the 290 I think you will have too much
gain at that point in your system. You would almost certainly need an
attenuator in the input (as Mike said in an earlier posting) or you
could experience overload/cross mod when receiving a strong 10GHz
signal (some can pin the S meter!). You need sufficient gain in your
10GHz rx to just perceptibly increase the background noise in the
14MHz IF when you switch on the 10GHz gear. I have seen and heard some
setups where the resting noise on the receiver IF stands at S7 to 8...
no kidding!!
>anyway thats what I have at present along with an FT847 so I can do tests to
>see what is best !!!
Sure... I'm not knocking you Steve... just the 290! Use what you have
until you find something better. It's much better to operate that sit
around waiting for better gear.
I think we would do better if we all homebrewed a dedicated 144MHz
multimode transceiver for microwave use. I believe there could very
well be a kitset in the offing next year...
Of course you dont have to use 144MHz for your prime mover. 50MHz,
70Mhz or even 1.2GHz are alternatives.
>2m tx / rx to drive a 200mw DB6NT transverter. Anyone fancy a sked??????
>qth here is S.E.Essex JO01HO.
I'd like to work you from here in Sheffield but my home location is
very poor. That said I have worked several PA and DL stations from my
bedroom window but that was during exceptional tropo conditions. You
should be able to work across to the Continent everty day from SE
Essex. I have 5 watts RF output on 10GHz to a 1.2m dish and operate
almost 100% from /P locations.
Look on 144.175MHz every Monday evening from around 8pm. You should
find microwavers arranging contacts ... Monday night is microwave
activity night (in theory at least!) You have several local 10GHz ops
near to you ... G8APZ, G4DDK, G3LQR to name a few. They are all
well-equipped stations with several watts of RF and years of
experience.
Every morning, except on Sunday) there is a microwave net on 3625kHz,
staring around 0820 and going on to around 0930. Feel free to call in.
regulars include G3KEU, G0HNW, G3LRP, G3PHO and G4XHS. 3cm contacts
often take place between members of the net while it is in progress!
Good luck with your DB6NT 10GHz transverter. It's a very fine piece of
equipment. For those readers who are not microwaves yet it's a good
way to get on. The kit is available directly from DB6NT and can be put
together in a weekend (at least that is what M5AFG has just done!).
Look at DB6NT's website for full details and download his catalogue:
73 from Peter, G3PHO
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@rl.ac.uk Mike
> them at our local club. None was better than 5dB and a few were as bad
> as 7dB! IC202s were also checked and fared much better... one around
> 2dB and the others not far off, if I remember rightly.
5 dB is enough with 2.5W to a whip, but besides the point for a 10 GHz
driver. At least you know what frequency the IF is at and it does not change
when you squeeze it like my old IC202. You also get FM that is useful in
rainscatter. Regarding the dial - yes. Modify it to improve the feel. 100Hz
steps are not a major problem when the other chap is drifting 1kHz a minute.
Peter of course is rock steady and always on frequency - which is just as
well with my receiver. The bad TX audio can be fixed by adjustment. It is
usually the ones giving 3.5W out, or by setting them to low power. Best
never to use a MK1 290 on low power on SSB.
> (Exception is Mike, G0MJW..if that is a 290 you use Mike... it sounds vy
good!
- thanks Peter - it is a mark 2, I would prefer to use a MK1 for the
ergonomics. I am after one at the right price, as from the circuit, I think
they can be made to work on 4m.
> I think we would do better if we all homebrewed a dedicated 144MHz
> multimode transceiver for microwave use. I believe there could very
> well be a kitset in the offing next year...
Why bother with a VFO at all at the IF. There ought to be more than enough
coverage tuning the microwave LO. 144 MHz is not such a good idea if you
also use that band for talkback. A simple few mW from a fixed tuned Hands
tranceiver would be adequate, low power and cheap.
I will still need 100W and a 7 ele beam for the talkback. Thats where all
the power goes.
steve barrett
I think I will stick with the 290 for now as its early
days for me on 3cms.
still awaiting 1st contact.....................
cheers
steve g4htz