EMRFD Message Archive 7275
Message Date From Subject 7275 2012-02-20 13:44:34 Donald 2SC1307, 2SC1969
I like this power level and basic design and have used it numerous times but the 2SC1307 (or 2SC1969) is no longer manufactured. RF Parts has the 2SC1969 for $12.95 each.
Ebay shows 2SC1307 and 2SC1969 transistors at very inexepensive prices. I am a little fearful quality is not the same as older devices.
Does anyone have a suggestion for a substitute NPN in the 16 to 20W range? I ordered some of the cheap replacement ones on EBAY to test them. Perhaps it would be nice to try something newer or different.
Thanks
Don7276 2012-02-20 13:57:44 Jim Kortge Re: 2SC1307, 2SC1969 7279 2012-02-22 04:03:49 Tim Re: 2SC1307, 2SC1969
Going to E-bay for CB final parts... I am personally dubious. Many of the TO-220 parts being sold to CB'ers7280 2012-02-22 04:39:41 Silva Re: 2SC1307, 2SC1969
take a look on
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_209234_-1.
The IRF510 costs just $0.79 each there!!!
It works great up 50MHz!!!
Best 73's,
Silva.
On 22-02-2012 09:03, Tim wrote:
>
> RD16HHF1 is an N-channel RF MOSFET, about $5 a pop. From
> kitsandparts.com or rfparts.com. These go all the way to 30MHz just fine.
>
> Going to E-bay for CB final parts... I am personally dubious. Many of
> the TO-220 parts being sold to CB'ers7281 2012-02-22 08:06:57 Donald Re: 2SC1307, 2SC1969 7282 2012-02-22 08:35:42 Ashhar Farhan Re: 2SC1307, 2SC1969
are cheaper choices like the BD139/BD137/BD135s which are more robust
and forgiving than the IRF51Xs.
The RD series are more expensive but stable.
Be aware of 2SC1969s. There are a number of spurious items being
pedalled on ebay. Especially, the low priced ones. There are some nice
writeups on the net about identifying them.
Now, a shameless plug. Checkout my jbot amp on
www.phonestack.com/farhan it works with a large selection of
transistors and it is pretty stable.
- farhan
7283 2012-02-22 08:37:17 Donald Re: 2SC1307, 2SC1969 7284 2012-02-22 11:16:36 Donald Re: 2SC1307, 2SC1969 7285 2012-02-23 06:36:22 cbayona Re: 2SC1307, 2SC1969
quantities, these are bought from authorized distributors not from
China, it goes the same for all semiconductors.;
<
<http://thepartsplace.k5nwa.com/index.php?route=product/category&path=36_37>http://thepartsplace.k5nwa.com/index.php?route=product/category&path=36_37
>At 06:03 AM 2/22/2012, you wrote:
>RD16HHF1 is an N-channel RF MOSFET, about $5 a pop. From
>kitsandparts.com or rfparts.com. These go all the way to 30MHz just fine.
>
>Going to E-bay for CB final parts... I am personally dubious. Many
>of the TO-220 parts being sold to CB'ers7286 2012-02-23 07:42:23 William Carver Re: 2SC1307, 2SC1969
W7AAZ7287 2012-02-23 07:55:26 cbayona Re: 2SC1307, 2SC1969
>OK Cecil, will try some RD15HVF1Those guys are usable to 560MHz, some have used them for making 20W
>W7AAZ
to 30W linear amplifiers from 180M to 6M, they are very nice devices
that are easy to use.
I took me a while to get them, finding a factory distributor source
that sold them at the quantities I could afford, but now that we are
there it's easier to continue carrying them, in a couple of months I
will be carrying the 6Watt UHF version also RD06HVF1 device.
--
Cecil
k5nwa
http://www.softrockradio.org/
http://thepartsplace.k5nwa.com/
http://parts.softrockradio.org/
Never take life seriously. Nobody gets out alive anyway.7288 2012-02-23 08:36:28 William Carver Re: 2SC1307, 2SC1969
amplifier, gain dropped at 21-30 MHz. Trying to maintain the same output
by increasing drive resulting in a dramatic, unacceptable, increase in
third order IMD.
It will be interesting to see if I can get "flat" performance over
1.8-30 MHz with the RD15HVF1.
W7AAZ
On Thu, 2012-02-23 at 09:55 -0600, cbayona wrote:
>
> At 09:42 AM 2/23/2012, you wrote:
> >OK Cecil, will try some RD15HVF1
> >W7AAZ
>
> Those guys are usable to 560MHz, some have used them for making 20W
> to 30W linear amplifiers from 180M to 6M, they are very nice devices
> that are easy to use.
>
> I took me a while to get them, finding a factory distributor source
> that sold them at the quantities I could afford, but now that we are
> there it's easier to continue carrying them, in a couple of months I
> will be carrying the 6Watt UHF version also RD06HVF1 device.7289 2012-02-23 08:53:29 cbayona Re: 2SC1307, 2SC1969
160M to 6M. Did you have negative feedback to flatten the output
across your frequency range?
Chevrolet made the Corvette and Malibu SS but they also made the
Corsair, you can't win them all.
At 10:36 AM 2/23/2012, you wrote:
>My personal experience with a pair of RD15HHF1, as a 20W linear--
>amplifier, gain dropped at 21-30 MHz. Trying to maintain the same output
>by increasing drive resulting in a dramatic, unacceptable, increase in
>third order IMD.
>
>It will be interesting to see if I can get "flat" performance over
>1.8-30 MHz with the RD15HVF1.
>
>W7AAZ
>
>
>On Thu, 2012-02-23 at 09:55 -0600, cbayona wrote:
> >
> > At 09:42 AM 2/23/2012, you wrote:
> > >OK Cecil, will try some RD15HVF1
> > >W7AAZ
> >
> > Those guys are usable to 560MHz, some have used them for making 20W
> > to 30W linear amplifiers from 180M to 6M, they are very nice devices
> > that are easy to use.
> >
> > I took me a while to get them, finding a factory distributor source
> > that sold them at the quantities I could afford, but now that we are
> > there it's easier to continue carrying them, in a couple of months I
> > will be carrying the 6Watt UHF version also RD06HVF1 device.
Cecil
k5nwa
http://www.softrockradio.org/
http://thepartsplace.k5nwa.com/
http://parts.softrockradio.org/
Never take life seriously. Nobody gets out alive anyway.7290 2012-02-23 19:24:59 kb1gmx Re: 2SC1307, 2SC1969 7291 2012-02-23 20:51:54 William Carver Re: 2SC1307, 2SC1969
good up to 20m, the open loop gain drops at high frequencies so the
feedback is less effective in reducing IMD above 21 MHZ. I was seeing
third order IMD 20 dB below one tone at 15W output.
Haven't looked at Kees amplifier. He is a very good designer of other
things, I'll go take a look.
> Chevrolet made the Corvette and Malibu SS but they also made theI presume you meant "Corvair". Yes, it was a little tail happy and the
> Corsair, you can't win them all.
heads warped easily. So I drive a C6.
W7AAZ
P.S. My rig will eventually drive a 4CX1500B so my "requirement" for
the 20W exciter is IMD 45 dB below one tone. I'm willing to run a class
A exciter to get that.
>
>
>
>
>
>7292 2012-02-24 06:13:30 gi0gdp Re: 2SC1307, 2SC1969 7293 2012-02-24 07:26:01 William Carver Re: 2SC1307, 2SC1969
> I have been using these devices at 70 MHz, in general the To220 typesThird order of -15 dBc is as bad as the worst of the commmercial rigs,
> all have excellent gain and fairly poor 3rd order IMD at 70 MHz
> This is true for the HF and VHF types.
> However the flanged types seem to be much better but not as good as
> one would have hoped for.
> Bias currents have varied from 0.5A to 1A but in general the 3rd
> orders have been poor often -15dB below carrier.
>
> regards
> Geoff
> GI0GDP
and a good 12 dB below what was considered acceptable 30-40 years ago.
In their defense, they don't specify IMD in any of the data sheets.
It's amusing how we work on receiver intercepts while transmitters
degrade without even comments, in most cases, in equipment "test"
reviews.
I'll see what I can do in class A. Also I have a pair of 28V 40W devices
from MaCom/PHI to try, but pre-regulator voltage is only about 20V.
Let's see....I could make a buck regulator to get 6.3V and a boost to
get screen and plate voltages for a 6146.....
W7AAZ7294 2012-02-24 08:08:21 gi0gdp Re: 2SC1307, 2SC1969 7295 2012-02-24 08:39:03 Ashhar Farhan Re: 2SC1307, 2SC1969
techniques used in audio power amps at rf ?
Agreed that efficiency will low but I am willing to sacrifice it for
10 watts from my base station considering that the desk lamp is 60
watts...
- farhan
7296 2012-02-25 04:43:17 Tim Re: 2SC1307, 2SC1969
Isn't the primary market for VHF/UHF PA transistors these days FM or digital trunking and thus class C anyway? Like you point out Bill the datasheets never say anything about IMD3 and the Pout vs Pin curves compared to the datasheet title make it clear that class C operati7297 2012-02-25 11:05:30 kb1gmx Re: 2SC1307, 2SC1969 7298 2012-02-25 12:05:05 scriabini Re: 2SC1307, 2SC1969 - IMD or HD?
In this application is the measured
distortion of the signal truly
Inter-Modulati7299 2012-02-25 12:20:23 Dan Mills Re: 2SC1307, 2SC1969 - IMD or HD?
> Technical Question:Typically both are present, but it is the IMD that we care about because
>
> In this application is the measured
> distortion of the signal truly
> Inter-Modulation Distortion?
>
> Or, is it Harmonic Distortion?
the harmonic distortion is removed to a very great extent by the output
filters, where the odd order IMD products have a nasty tendency to fall
in band and thus cannot be filtered out.
The usual test is to inject two non harmonically related tones each
causing output at -6db below rated PEP (so the total peak power is rated
PEP), then look at the output spectrum and quote the level of the
highest IMD product.
It is the worst way to test apart from all the others, and it does at
least give numbers that are repeatable for all that they sometimes mean
less then some think (The rate the mess decreases with higher order
products matters too).
Regards, Dan.7308 2012-03-03 17:39:41 William Carver Re: 2SC1307, 2SC1969
> Like you point out Bill the datasheets never say anything about IMD3Although they never give an IMD number, I don't think the data sheet is
> and the Pout vs Pin curves compared to the datasheet title make it
> clear that class C operation was a goal.
focused totally on class C. For example at 520 MHz they show Pout v.s.
Pin with 1/2A quiescent current...so it's not class C.
And the Po/Pi is a pretty straight line to 10 watts (+40 dBm) output.
But "pretty straight" isn't as meaningful as a third order IMD number at
a specific PEP output.
I've been in Colorado skiing, the transistors from Cecil were here when
I got home, and will see what kind of performance I can get7310 2012-03-05 12:22:00 Tim Re: 2SC1307, 2SC1969
I used a search engine to look for it again today but the googles, they do nothing!!!! Without any actual IMD numbers we can sit around all day and pretend something will work :-)
Bill, have you tried, does source degeneration help as much with MOSFETs as the analogous emitter degeneration does with bipolars? I've done both but only at the 10W level and while the single tone cyrves with the MOSFETs looked nice I was less than impressed with IMD.
Tim N3QE
7311 2012-03-05 13:05:36 William Carver Re: 2SC1307, 2SC1969
now, but do have the Mitsubishi FETS (as well as MRF136, MRF137 and some
others) and will try everything I can think of.
It's difficult for most homebrewers to generate an accurate IMD number
so its missing from many efforts. I have an 8560E so can measure it as
soon as I get back on the bench.
Bill
On Mon, 2012-03-05 at 20:21 +0000, Tim wrote:
>
> Somewhere associated with Softrock stuff, I once found a kit for PSK31
> operation that used Mitsubishi RRD16HF1's biased for low IMD
> operation. I seem to recall that from a push-pull pair, they were
> satisfied with IMD at the 10W ballpark.
>
> I used a search engine to look for it again today but the googles,
> they do nothing!!!! Without any actual IMD numbers we can sit around
> all day and pretend something will work :-)
>
> Bill, have you tried, does source degeneration help as much with
> MOSFETs as the analogous emitter degeneration does with bipolars? I've
> done both but only at the 10W level and while the single tone cyrves
> with the MOSFETs looked nice I was less than impressed with IMD.
>
> Tim N3QE
>
>7312 2012-03-05 14:34:00 kb1gmx Re: 2SC1307, 2SC1969 7313 2012-03-05 15:11:29 kb1gmx Re: 2SC1307, 2SC1969 7314 2012-03-05 20:07:19 Ashhar Farhan Re: 2SC1307, 2SC1969
A sample of amp's output was fed to a simple direct conversion
receiver without any af filtering at all. Using a standard common
emitter audio preamp, the output was fed to a bose audio system.
I played tones, speech and music through the bitx tx to hand tune each
stage for best sound. A pc bases audio spectrum anaylzer came handy to
eliminate harmonic distortion. After all, the end purpose was a) to
get out a great modulation and b) keep within the allowed limits.
- farhan