It doesn't seem super cheap esp if you allow for the additional costs of transmit receive relays, sequencer and all that other stuff. Do you have the gear to test it for harmonics etc?
Elecraft gear is usually excellent.
Hi german EE
I don't have the budget for a DE or Elecraft one but I do have a CB amplifier with blown PA transistors
and it will cost more to repair that than its worth, so the plan was to remove the board and put the
transverter and attenuator boards in it.
VK5RC I wasnt aware it needed TX/RX relays or a sequencer, I thought it was just a case of a suitable attenuator
and hook up the external connections to the board, the transverter has a TX connection which needs to be grounded,
I was going to hook that up the my yaesu FT-950 as it has that for connection amplifiers.
Hi Flump
When I posted I was on a mobile and couldn't get pictures of the circuit diagram, you are right, it does have silicon switching so no delay needed. Do you intend to switch out the attenuation on receive?
I must admit to being a bit cautious with transverters and a nice unit like the FT 950!
How does the 950 reduce power? I think the IC 706Mk2G has a nasty habit of of at the beginning of tx being at high power for a very brief period then using the ALC to de-power.
Hmm definitely class C amp. What HF radio would you use it with, Does it have a low level rf output? For the price might be better to get a used 2 meter mobile.
I am with KC9QVL on this. You have to be very careful how you feed the transverter. If you forget to reduce the radio power you will let out the magic smoke. I think your best bet would be a 2 meter mobile radio. The only radios safe for transverters are those that have the ability to automatically reduce the power when the transverter is engaged like the Yeasu FT-1000MP. Besides, the mobile radio will give more power. In the house, I typically set my Kenwood TM-281 to 25 watts output (low power setting) but it is nice to know that I have 65 watts should I need it.
Hi All , thanks for the replies so far.
I have a few radios that work on 2M, yaesu 8800 dualbander , trio 9130 and kenwood ts-711e
i want to drive a transverter with my yaesu ft-950 which does not have a dedicated port for it
so the plan was to built a relay switched attenuator (around 15db) so it is bypassed on RX and being hard wired
inside the unit there wouldnt be a worry of forgetting to switch on the attenuator.
it's more of a project i want to do rather than a need for it.
@Flump One issue could be if the relay is a bit slow in opening, so no attenuator in circuit until it does and if the FT 950 gets power out very shortly after the PTT goes to ground, you might get a spike of unattenuated RF into the transverter. This is where a sequencer can help if you can get it to lower the output of the FT950 for 50mS or so.
If you already have a 2m radio, could I suggest a 'microwave' 1+GHz transverter as an alternative? it will open up some new bands and the only way to get to 2+GHz is with home-brew. in the UK there are some serious microwave groups who I am sure would be willing to help if needed.
I am about to try and bounce a 1.2GHz signal off the moon, I have an Icom 910 (10W) going into a 160W W6PQL PA, with sequencer et al on the transmit side and a UK hams G4DDK low noise pre-amp kit (37dB gain 0.27dB noise factor) on the receive. Planning, designing and testing is most of the fun. I have done some sun-noise tests (VK3UM has a great site for some calculators) and been able to measure it within a dB or so of that calculated.
73 de Robert
@Flump One issue could be if the relay is a bit slow in opening, so no attenuator in circuit until it does and if the FT 950 gets power out very shortly after the PTT goes to ground, you might get a spike of unattenuated RF into the transverter. This is where a sequencer can help if you can get it to lower the output of the FT950 for 50mS or so.
If you already have a 2m radio, could I suggest a 'microwave' 1+GHz transverter as an alternative? it will open up some new bands and the only way to get to 2+GHz is with home-brew. in the UK there are some serious microwave groups who I am sure would be willing to help if needed.
I am about to try and bounce a 1.2GHz signal off the moon, I have an Icom 910 (10W) going into a 160W W6PQL PA, with sequencer et al on the transmit side and a UK hams G4DDK low noise pre-amp kit (37dB gain 0.27dB noise factor) on the receive. Planning, designing and testing is most of the fun. I have done some sun-noise tests (VK3UM has a great site for some calculators) and been able to measure it within a dB or so of that calculated.
73 de Robert
Please post a pic of your antenna array. I like antenna porn.
For a laugh;
The feed horn support pole is a piece of bent exhaust pipe
The support frame for the dish is based around an engine stand
The feed horn consists of a piece of stainless steel flue pipe and a cake tin
The whole assembly can be moved and stowed around the side of the house, unfortunately too many trees to be used there!
For a laugh;
The feed horn support pole is a piece of bent exhaust pipe
The support frame for the dish is based around an engine stand
The feed horn consists of a piece of stainless steel flue pipe and a cake tin
The whole assembly can be moved and stowed around the side of the house, unfortunately too many trees to be used there!
Very nice! Interested to hear how you get on with that setup. FWIW your dish looks about the same size as G4DDK's, I've been to his place quite a few times, he works on some of the space related projects I work on. I live in a flat in the middle of London, so getting BUDs up is not on the menu regretably, but I have managed to put up a dual band feed for 23 and 13cm on a 1.2m homebrew dish for satellite, worked pretty well, until the noise floor made it barely useable due to all the unlicensed stuff on 2.4GHz coming on line in the early/mid 2000's.
G6LVB
QRM is the scourge of the times, cheap switch modes, poorly shielded high speed digital signals are a curse, my hf setup is now deaf as a post with s7 noise on 20m.
My next issue is to try and pick up an eme beacon, if that and a self echo go well I will try a contact with vk3um (a vk eme guru).
I would encourage the OP with home-brew, it's a lot of fun, you learn a lot, especially bl#&dy earth loops!
UT5JCW Is it linear for SSB?
73,
Steve N8KVD
UT5JCW Is it linear for SSB?
73,
Steve N8KVD
YES it is and there you find a pot to change the bias.
The fact you got an RD15HVF1 to work without singing itself to death is impressive. RD16HHF1s? No problem. RD15s? Laaaaaaa<poof>
What you mean? It works fine. It is very durable. Both of them works equal. Getting 10-15 watts easy.
The fact you got an RD15HVF1 to work without singing itself to death is impressive. RD16HHF1s? No problem. RD15s? Laaaaaaa<poof>
Hmmm... looking at the datasheet, they give S-params up to ~GHz, not that there's any gain left up there... but of note... the phase angles are
negative over a generous stretch of that range!
TO-220 is NOT A GOOD PACKAGE for this kind of device...
Tim
Tim
The package has different pinouts compared to a switching MOSFET. The Source is the centre pin and tab so you can easily ground the tab to the heatsink.
The Mitsubishi MOSFETs are not actually intended for linear operation (check datasheet) but give reasonable SSB performance if backed off quite a bit.
You'll notice that none of the datasheets of the RD range mentions its IMD performance.
Tim
The package has different pinouts compared to a switching MOSFET. The Source is the centre pin and tab so you can easily ground the tab to the heatsink.
The Mitsubishi MOSFETs are not actually intended for linear operation (check datasheet) but give reasonable SSB performance if backed off quite a bit.
You'll notice that none of the datasheets of the RD range mentions its IMD performance.
That's all well and good, but my point was, the S params are largely
negative in magnitude...
If such a beast is more stable in class C, I suppose that's something. (Who cares if it oscillates, as long as it oscillates at the desired frequency?
)
Tim
That's all well and good, but my point was, the S params are largely negative in magnitude...
If such a beast is more stable in class C, I suppose that's something. (Who cares if it oscillates, as long as it oscillates at the desired frequency? )
Tim
The RD series are usually pretty linear (for FETs), and I'm pretty successful with the RD16 for my linear Class A/Class AB designs. Every time I try to build with a '15 though, it sings at some high frequency until it burns up. :|
The RD01MUS1s are a bit fussy, but I'm able to tame them okay.
I have actually bought 2 of these transverters. The first one I damaged while mounting in a diecast box. The second seems to be working OK. Be VERY careful with drive power they are easily popped! As far as linearity is concerned all I can say is if they're not overdiven IMD is as good as my DEMI 144/28. Of course with such a basic design don't expect the performance of a $1300 Kuhne. If I were you I'd fix my ancient MM transverter. I still use one on 70cm and it's bombproof! These are still very well respected. Just check the Ebay prices.
73
Geoff
We are a producer of those transverters boards.
Actually no. You are just seller. Real author and producer of transverters from your store is Alex UR3LMZ ashatun@mail.ru
And now you stole almost all of his transverters and started producing yourself.
To the community - please contact Alex UR3LMZ directly if you have any questions related to the transverters as nobody knows the devices better then the author. Be informed that original transverters boards do not have silkscreen.
