Dave Richards AA7EE

September 16, 2014

New “Free” SA602 and SA604 Offer Back – Now With Overseas Shipping

Filed under: Amateur Radio,Ham Radio,QRP — AA7EE @ 6:29 am
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On Saturday, a medium size Priority Mail flat-rate box packed full of IC’s, resistors, transistors and other devices arrived from KV7L. Lynn is the gentleman who made my previous SMT SA602 and SA604 offer possible by shipping me 2 large rolls of SMT SA602’s and SA604’s a few months ago. At a rough guess, that initial shipment contained about 1700 SA602’s and a few hundred SA604’s. Almost all of them went to QRP clubs wishing to sell them to raise funds, people organizing group builds, and the parts bins of individual home-brewers – and all for $4 to cover just the cost of shipping and the Paypal fee.

Now I have another, final shipment from Lynn and can open up this offer again. As well as the SMT 602’s and 604’s, Lynn threw in some bags of 2 and 3 W resistors, some of which will be useful for making QRP dummy loads, as well as some voltage regulators, power MOSFETS, and small signal NPN transistors. A number of people did ask if I could ship overseas, to which I replied that I was trying to keep the distribution process simple (for me) by limiting it to the US only. This time around, I’ll open it up to other countries, though the shipping costs are significantly higher and I’m not sure whether it will be considered worthwhile to those not in the US.

Sprat The QRP Cat wasted no time in thoroughly smelling all the parts. Lynn has dogs so I’m sure there was plenty for Sprat to sniff -

Before detailing the new deal (boy, I feel a little like FDR :-) ), there was something else I wanted to mention. Lynn KV7L said to me on the phone that he’d really like to receive QSL’s from some of the home-brewers who have had some of the parts from him so he can get an idea where his parts are ending up. Although I wasn’t shipping overseas in the last round, one gentleman in India asked if I could ship to a friend in the US who was visiting him in Bangalore in the near future and could deliver the parts. He is an educator who will be using his 602’s to encourage his students to build something. Lynn said he’d love to have a QSL from India, and from all the other places his parts are going so that he can put them up on his wall and get an idea of how his parts are being distributed far and wide.  This is not about tracking them – it’s because Lynn’s only involvement  in this giveaway has been to very kindly ship the parts to me, while I distribute them. He is a bit disconnected from the process and being able to look at QSL’s on his wall will help him feel a bit closer to the whole “free parts” operation. If you have already received parts from him (through me), I know that he’d love to receive a QSL from you. You can either send it to him, or to me – and I will forward it on to him. Both of our addresses are good on QRZ. Lynn’s address is a PO Box, while his actual QTH is in a fantastic radio location. He is miles from his nearest neighbor in rural Eastern Oregon,  and not served by any utility (he is 100% solar-powered). He has 5,000 feet of wire buried in the earth for a ground and his resulting noise level is very low indeed. He is the co-net manager of the Noontime Net on 7268.5KHz daily. It’s a regional net that covers most of California, Oregon and Washington, as well as a few other nearby states when daytime conditions are good and it seems that Lynn, with his fantastic radio location, hears almost everyone who calls into the net.

If you haven’t yet taken advantage of this offer and would like to, please know that Lynn would love to receive a QSL from you as well.  I think it’s a very modest request from a gentleman who has shipped me something like 2,000 SMT SA602’s and 600-800 SA604’s and asked for nothing in return, other than the occasional update on how the giveaway is going. If you don’t have a QSL then don’t worry about it – and please don’t let it deter you from taking advantage of this offer.

This time around, as well as SMT SA602’s and SA604’s, I have a bunch of 2 and 3 watt resistors in low values, some of them suitable for building QRP dummy loads. There are some 160 ohm resistors and some 130 ohm ones. 2 x 160 ohm and 1 x 130 ohm resistor, all in parallel will give you a total effective resistance of 49.5 ohms. If all 3 resistors are 3 watts, then the final dummy load will handle about 9 watts, which is more than enough for the QRP “full gallon” of 5W. Some of the resistors are 2W, and even if you were to use just those, your final dummy load would still handle 6W,  There are also other values of 2 and 3W resistors such as 22 ohms, 27 ohms, and also 50 ohms. I don’t have many of the 50 ohm ones, so you’ll probably only get one of those, but there are more available of the other values.  Actually, the 50 ohm 3W resistor would make a useful dummy load on it’s own. It will handle 5W for short periods of time and of course, if your TX is just 2 or 3W, it will be even more able to handle long key-down periods. If you want to make a “classic” QRP dummy load, you can mount your decided combination of resistors in a mint tin, along with a BNC connector for connecting it to your TX and you’ve got yourself an affordable and useful station accessory.

I also have some LM2575T 12V 1A voltage regulators, in a 5-lead TO-220 package. Datasheet here. There are also some F10P03L P-channel power MOSFETS, datasheet here, as well as some PN4275 NPN switching transistors, for which the datasheet is here.  I may throw in a few general purpose NPN transistors too, if I have any left. They have the number F15103477844 printed on them which I haven’t been able to find any datasheets for but that is not surprising. It is very common for mass-manufactured electronic goods to use parts with parts numbers that were supplied specifically for one production run. They are small signal NPN transistors and they may well be very similar to transistors used in many other products, that had different numbers stamped on them. They’ll most likely work fine in many circuits that call for 2N3904’s, BC109’s or similar.

This photo isn’t exactly what you’ll get in your package, but it’s pretty close. You’ll probably get this, along with a few extra resistors and possibly some extra transistors thrown in. As a bare minimum, you’ll get 15 x SMT SA602’s, 6 SA604’s, an assortment of 2 and 3 W resistors in low values, some of which will be suitable for making up QRP dummy loads, 8 x LM2575T 12V 1A voltage regulators, 6 x F10P03L P-channel power MOSFETS, and a small handful of PN4275 NPN transistors -

My supplies of both 602’s and 604’s are now limited but if you need a few extra for a club project or group build, please ask and I’ll try to accommodate you. The 602’s are particularly limited, but I have a few more of the 604’s, so if you have a group project that uses 604’s, I should be able to provide them.

The last offer was just for 602’s and 604’s and for that I was asking $4. To ship these I need a small box, (as opposed to the padded mailer used previously), which costs a bit more, and the extra weight costs a bit more in shipping, I am now asking $6 payable via Paypal for US builders – and also asking if you can send KV7L a QSL card (either directly to him, or to me so that I can pass it along to him – but don’t write it out to me – write it to Lynn KV7L). If you don’t want to use Paypal, you can mail a check for $5.50 (because I don’t have to pay the Paypal fee) to me. This is quite a handy way to do it, as you can include your QSL card for Lynn in the envelope with the check :-)

Whatever you do, don’t send any money until you have first e-mailed me! My e-mail address on QRZ is good, or you can use mycallsign@arrl.net

If you are anywhere in Europe I will now ship to you, but the shipping costs are significantly higher, I’m afraid.  If you are in Europe, I need to ask for US$17 to cover the shipping box, shipping costs and the Paypal fee. I’d rather not accept personal checks from outside the US, so will have to ask for Paypal for non-US builders, to keep the process relatively simple for me. However, if you are outside the US and are able to mail a QSL card to Lynn (either to Lynn, or to me – but make sure it is written out to Lynn) I will be happy to reimburse you for the postage via Paypal. I’d really love for Lynn to get a whole bunch of QSL’s from many different areas. He’ll love that. In fact, if you’re a US builder who is paying via Paypal, let me know if you plan to send a QSL and I’ll knock 50 cents off the price to cover most of your postage.

If you are outside the US and Europe, I may well be able to ship to you, but will have to get a quote from my local Post Office. It will probably be very close to the price for EU. E-mail me if you seriously intend to take advantage of the offer and I’ll get a price for you.

I hope that all made sense, and that the parts make it worth the expenditure of a few dollars for the shipping. It’s a no-brainer for US builders, and may be worth it to non-US home-brewers too.


73 for now,

Dave  AA7EE

PS – I have 100 of these Molex connector shells. The total width is 1  1/8″  (1.125″). Let me know if you’d like some of these too, but you have to ask as I know that most people won’t want them.

December 31, 2012

The ARRL 10-Meter Contest and Checking In To SSB Nets with QRPp

A few days ago, Bryan Herbert KE6ZGP, posted on Facebook that he’d come first place in his section for Single Op QRP phone in the 2011 ARRL 10-Meter contest and posted a picture of his certificate. I thought it was pretty neat-looking and gave him my congratulations, telling him that I was envious, but happy for him, and also noting that I’d never won anything like that, as 2 hour sprints were about the most I had any kind of stamina for.

Then a little over an hour later, the front doorbell rang.  It was the mailman with a few packages for my neighbors and a large brown envelope for me, containing this -

I had completely forgotten entering the ARRL 10-Meter contest.  It was almost a year ago!  I had participated (casually), submitted my log, and promptly forgotten about it.  Now I know that I am by no stretch of the imagination even a semi-serious contester, so figured that there probably hadn’t been many other QRP CW contenders in my AARL section.  On checking the ARRL site I found that there had been just one other. Nevertheless, I was very happy to have this piece of paper, which is already framed and hanging on the wall.

In other news, I have been doing no home-brew – sorry about that. My INTJ mind is either very pre-occupied with something, or not noticing it at all. Currently, I am engrossed with the task of committing as many music CD’s as possible to hard drive in order to de-clutter my living space. It’s all part of a long-term plan for the future which may include living in an RV, or simply another apartment.  Either way, I want less stuff, and 10,000 music CD’s are awful heavy when it comes to moving time. While busying myself with the task of ripping and scanning during the day, I have had the K2, my main station rig, tuned to 40M and in particular, the Noontime Net on 7268.5 KHz. My mind works in strange ways, and for the 3 years I was into CW, that was all I was interested in.  I had spent plenty of time operating SSB (and FM on the 2-meter band) in the past and it no longer held any interest for me – it really didn’t.  Every now and again, I would tune up to the phone portion of whatever band I happened to be in and after just a few minutes of listening, wonder how anyone could remain interested in amateur radio if SSB was their main mode of operation. I like the mental challenge of decoding a CW signal in my head, and that is as much of an attraction to me as the radio part.  Decoding SSB in my head was a skill I learned when very young, so there’s not much challenge there!

Nevertheless, while busying myself with the task of ripping CD’s and scanning all the artwork, I had the K2 tuned to 7268.5 KHz from about 9:30am – 2pm every day to listen to the Noontime Net.  I have never done a lot of listening to nets before and at first, couldn’t quite understand the attraction of checking in to a net on a regular basis when the main purpose of doing so seemed to be to just check in and then not do much else. However, there is a little bit more to it than that, and after a few weeks of listening, I started to get a feel for it and checking into the net became a welcome part of my daily routine. EDIT: After a few months of checking in daily to the Noontime Net, it has become a very welcome part of my daily routine and to amend what I said a few sentences earlier, there is a lot more going on with a net like this than first meets the ear. It is a very well-run net that manages to check in a lot of people every day, while still having time for the occasional bit of friendly chat. It never wanders into the territory of “clique-ness”. The balance between the business of checking in a lot of people, while retaining a sense of camaraderie and connectivity is perfect. KV7L Lynn is the net manager, and along with every single one of the net controllers, is to be commended for pulling off this feat. It’s not an easy thing to do.

The Noontime Net is a traffic net, and traffic is indeed passed on occasion.   After a few weeks of listening almost daily (at first on the WBR regen receiver when I was still fresh out of building that) I began to recognize the regular characters,  including the very distinctive voice of Clyde AA7WC who took early check-ins daily until his recent illness. I checked in a few times, and then having the radio on and listening to the net in the background as I did other things around the shack, checking in on an almost daily basis started to become a welcome part of my daily routine. Many days, I will check in fairly early, and the re-check later.  It’s also interesting to listen to many of the same stations regularly to see how propagation affects how we all hear each other – and this brings me to the aspect of the net that has interested me the most in the last week or two.

I had been checking in to the Noontime Net with my K2’s full output power of 15W.  About 10 days ago, I decided to dial down the power to see whether I could still check in with one of the net control stations.  On CW, you can turn the power down to 100mW, and on SSB, 1W.  I dialed down to minimum SSB power and called Lynn KV7L in Princeton, Oregon. I thought I was running 100mW but forgot that on SSB, even though the K2 may indicate an output power of 0.1W, it is actually putting out 1W. To my surprise, Lynn gave me a 58 report. He is 412 miles from me. I also got a 59 report from a station in Bakersfield, about 245 miles to the south.  Thinking I was running 100mW, I was ecstatic but in retrospect,  a 58 report from a station 412 miles distant when you’re running 1W of SSB is still pretty good.  Since then, I have regularly checked into the net with just 1W and am heard well by KV7L in Princeton, OR, W6FHZ in Reno, Nevada and N7WH in Boise,  Idaho.

I often received unprompted reports of good audio too, for which much of the credit has to go the K2.

All of this has gotten me quite excited about seeing how low I can take the power and still successfully check in to the Noontime Net. I cannot dial the power on my K2 below 1W on SSB,  so the next step is an attenuator.  Even though I have not been doing any home-brew and am concentrating most of my efforts on non-ham radio pursuits, I think an attenuator is in my immediate future.  I would love to be able to tell net control that I am running just 50mW – or even 10mW! Stay tuned to this space.  Maybe I can get something together in the next few weeks. (EDIT – I ordered an attenuator online before this post was even finished – keep reading.)

The upshot of all of this is that although when people think of QRP, they usually think of CW, and the 13dB disadvantage of SSB compared to CW is well-known, you can still achieve things with QRP SSB. Bryan Herbert KE6ZGP has made many great DX contacts with just 5W of SSB (and even FM during 10M openings) and he told me recently how he thinks the potential of QRP SSB is underestimated.

On another tack, I was in Cost Plus the other day and saw a mint tin that was just crying out to have something built in it.  Some people think of electronic gadgets as boxes of “black magic” and indeed, even us hams think of radio as quite magical.  I like to put as many of my mint tin projects in different looking tins as possible, to make them easier to tell apart from each other. I think this tin fits the bill perfectly. What piece of black magic could I build into this enclosure?

My recent experiences successfully checking into the Noontime Net with just 1W PEP of SSB made me keen to see if I could check in with even less power.  The minimum amount you can dial the power down to on the K2 on SSB is 1W, so to get it down further I would need an attenuator.   I was looking for a cheap way to do this without having to build anything, and settled on this 20dB inline attenuator that I got from eBay for $6.99 including shipping -

I like it because unlike the step attenuators in regular enclosures, I don’t have to come up with an extra BNC to BNC cable.  It’s quick n’ dirty n’ cheap. Without setting up a separate receive antenna, the attenuator also attenuates the signal on receive, but as I plan on initially using it to check in with net control stations that are very strong here, that won’t matter.

In theory, when I set the K2 to 1W and connect the output of it to the attenuator, which is terminated in a 50 ohm load, the 1 watt should be attenuated by 20dB, giving me a final output signal of 10mW into 50 ohm, but when I connected the output of the K2 (set at 1W in CW mode) to my OHR WM-2 QRP Wattmeter, the output of which was terminated  in a 50 ohm load, I measured 40mW and not 10mW.  I do believe the meter to be calibrated accurately  so I am not sure what is going on here.

The next step should be to construct my own attenuation pad to verify these results but for the meantime, the Noontime Net was in progress and I wanted to see if net control could hear me. KD7RTE was taking check-ins and couldn’t hear me, but Lynn KV7L in Princeton, OR gave me an S3. He is 412 miles distant – not bad for 40mW of SSB.

I have gotten into the habit of checking into this net with 1W PEP and I think I will continue to do so, but the quick n’ dirty experiment with QRPp was pleasantly fruitful. I kind of wish it was possible to use the front panel control on the K2 to dial the power all the way down to 100mW on SSB, the way you can on CW – or even lower. QRPp is fun! 40mW is flea power, and it’s especially gratifying for a signal of such low power to be copied 412 miles away on SSB.

In other news, it has become harder to operate the radio, because Sprat The QRP Cat has decided that she likes biting the fingerpieces of my Bencher paddle.  I try to put the K2 in test mode so she doesn’t transmit. When she’s not practicing the code, she just likes to get in the way when I’m trying to operate the radio, and steal the spotlight -

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