Re: [Elecraft] Dummy loads for dummies

@mailman.qth.net Subject: Re: [Elecraft] Dummy loads for dummies FWIW, comments to consider about open wire feedline from my experience: Window line has shattered in the cold winter winds. Frost, snow, and ice easily accumulates. It catches the wind easily. On the plus side, window line conductors do

Re: [Elecraft] Dummy loads for dummies

FWIW, comments to consider about open wire feedline from my experience: Window line has shattered in the cold winter winds. Frost, snow, and ice easily accumulates. It catches the wind easily. On the plus side, window line conductors do not fold over on each other. Conductors stay evenly

Re: [Elecraft] Dummy loads for dummies

I guess I'll chime in on the dummy load discussion (pictures below). Over the last few months, I have picked up a couple Bird Termaline Coaxial Resistor dummy loads (these may be the models K9YC is referring to). I got tired of the crappy cantenna style QRO loads that are typical of the current

Re: [Elecraft] Dummy loads for dummies

mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wes Stewart Sent: Tuesday, December 27, 2016 8:00 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Dummy loads for dummies You might be interested in this: http://k6mhe.com/n7ws/Ladder_Line.pdf On 12/27/2016 1:22 PM, Paul C wrote: > He

Re: [Elecraft] Dummy loads for dummies

I also found one of the big oil filled dummy loads at a Hamfest. It handles 500W easily. I bring a phone powered USB powered VNA with me to Hamfests to check things out. You never know what you will find! 73, Mark W7MLG On Dec 28, 2016 8:25 AM, "David Olean" wrote: > It

Re: [Elecraft] Dummy loads for dummies

It always pays to keep your eyes open. The local (and only ) surplus store here has a pile of heat sinks that look just great for a 250 watt solid state PA. The good part is that they also have a pair of SMA connectors, PC boards, and associated flanged 50 ohm resistor good for several

Re: [Elecraft] Dummy loads for dummies

On Wed,12/28/2016 12:26 AM, Edward R Cole wrote: I have a big old Sierra Electronic 500w coaxial load with heat sink and built in power meter; weighs about 40-50 lbs; makes a dandy door stop, too! It is rated to 1000-MHz. I found a nice oil-cooled dummy load with a big heat sink integral to

Re: [Elecraft] Dummy loads for dummies

http://www.kl7uw.com/2M80_inside_1.jpg In the photo the large black square at bottom of the pc board is a surface-mount 56-ohm 35w resistor (good at 2m) and available from Mouser. I believe there were 51-ohm values also. This used in a 23-dB pi-attenuator to take 10w down to 50mw for

Re: [Elecraft] Dummy loads for dummies

Carefull. Are they wire-wound power resisters cased in ceramic. If so they are likely inductive and of marginal use as withvRF they will not be just resistive but somewhat inductive and this will skew your results. Sent from my iPhone ...nr4c. bill > On Dec 27, 2016, at 9:43 AM, Paul C

Re: [Elecraft] Dummy loads for dummies

You might be interested in this: http://k6mhe.com/n7ws/Ladder_Line.pdf On 12/27/2016 1:22 PM, Paul C wrote: Here's another naive idea of mine: I'm planning to use ladder line too. Now I'm waiting for the other shoe to drop, when I realize coax will be my only practical choice. Paul KG5KXG

Re: [Elecraft] Dummy loads for dummies

-Original Message- From: "Jim Brown" <j...@audiosystemsgroup.com> Sent: ‎12/‎27/‎2016 7:13 PM To: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net> Subject: Re: [Elecraft] Dummy loads for dummies On Tue,12/27/2016 12:22 PM, Paul C wrote: > It seems tuff to ge

Re: [Elecraft] Dummy loads for dummies

On Tue,12/27/2016 12:22 PM, Paul C wrote: It seems tuff to get going in QRP. Hi Paul, The only thing "special" about antennas for QRP operation is that BECAUSE you're QRP, you want the most efficient antennas that you can. And the simple answer to that is to study the fundamentals in the

Re: [Elecraft] Dummy loads for dummies

They make similar resistors up to 800 watt or more, see them on ebay all the time, they are even made in 25 ohm or 100 ohm so you can series or parallel them to what you need, easy to make a dummy load that will handle many KW with just a couple. Large heat sink needed. Makes me curious

Re: [Elecraft] Dummy loads for dummies

Clay, Unless things have changed since I tested the Caddock Thick Film Power resistors of other than 50 ohms, I would not parallel 20 1000 ohm resistors to produce a 50 ohm load. Values other than 50 ohms are not guaranteed to be non-reactive. I would put 4 strings of 4 50 ohm resistors in

Re: [Elecraft] Dummy loads for dummies

: Clay Autery <caut...@montac.com> To: elecraft@mailman.qth.net Sent: Tuesday, December 27, 2016 7:16 PM Subject: Re: [Elecraft] Dummy loads for dummies Makes me curious about designing with these TO-220 resistors in the 1000 Ohm size of appropriate power rating...  Parallel 20 of them like

Re: [Elecraft] Dummy loads for dummies

Makes me curious about designing with these TO-220 resistors in the 1000 Ohm size of appropriate power rating... Parallel 20 of them like folks do on the axials that they put in the can type dummy loads with oil. Options: 1) 20 in parallel on a finned copper or bare aluminum sink of sufficient

Re: [Elecraft] Dummy loads for dummies

'Paul C' <paul...@sbcglobal.net>; elecraft@mailman.qth.net Sent: Tuesday, December 27, 2016 3:23 PM Subject: Re: [Elecraft] Dummy loads for dummies For parts, digikey.com and mouser.com are good friends. No minimum order, great prices and huge selection. You've gotten several

Re: [Elecraft] Dummy loads for dummies

AC -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Paul C Sent: Tuesday, December 27, 2016 12:23 PM To: Walter Underwood; elecraft@mailman.qth.net Subject: Re: [Elecraft] Dummy loads for dummies Ok, I won't be using these resistors after all. T

Re: [Elecraft] Dummy loads for dummies

Wes, What you say is true, and how much it matters in practice will vary depending on just how much inductance is present in those wirewound resistors. how much it matters depends of frequency. The higher the frequency, the more it matters - and that is independent of power. The load in

Re: [Elecraft] Dummy loads for dummies

Paul, You've got a lot of hand wringing comments about how those are probably wire wound resistors. They probably are but in practice it might not matter. It all depends on what exactly you are trying to accomplish. You don't say what your usage is or how much power your TX is putting

Re: [Elecraft] Dummy loads for dummies

I use those Caddock Thick Film Power resistors to make my own dummy loads. They make flat dummy loads up to at least 200MHz with normal lead dress, and with care they can be flat up to 500MHz. I have found is that the 50 ohm resistors are non-reactive, but other values may be capacitive.

Re: [Elecraft] Dummy loads for dummies

Paul, For the ladderline vs. coax question, you might want to take a look at the article I wrote for QRP Quarterly some years back. If so, go to my website www.w3fpr.com and look at the Antenna, Transmission Lines and Tuners article. You can also find that article at

Re: [Elecraft] Dummy loads for dummies

] On Behalf Of Walter Underwood Sent: Tuesday, December 27, 2016 12:42 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Dummy loads for dummies If you want a dummy load kit for about as much as you would pay for the box, I highly recommend the Oak Hills Research RFL-100 kit for $40. http

Re: [Elecraft] Dummy loads for dummies

I'm using ladder line to feed a 20m dipole on all bands from 40-10m (actually, it even works on 6m). Using a dipole shorter than 1/2 wavelength can be tricky, but it should work pretty well on the design frequency and higher. You will need to use a balanced antenna tuner, or an unbalanced

Re: [Elecraft] Dummy loads for dummies

For a 10W load, it is hard to beat the OHR kit. It is just two resistors on the back of a connector, but you probably couldn’t buy the three components for $11.50. The Craddock resistors are almost $10 each in small lots. "The CQC RFL-10 Dummy Load Kit consists of two 5 Watt 100 Ohm metal oxide

Re: [Elecraft] Dummy loads for dummies

​Well now I don't think anyone said the wirewounds wouldn't work just that you'd need to check them out. Give it a shot and see if the SWR is as expected. I've used cheap carbon comp resistors in the past​. Heck, a light bulb (incandescent) probably wouldn't do a bad job. As for your other idea,

Re: [Elecraft] Dummy loads for dummies

" <elecraft@mailman.qth.net> Sent: Tuesday, December 27, 2016 11:44 AM Subject: Re: [Elecraft] Dummy loads for dummies Ah, yes, bricks. Like these? https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack# <https://www.radioshack.com/products/

Re: [Elecraft] Dummy loads for dummies

@mailman.qth.net> Subject: Re: [Elecraft] Dummy loads for dummies Ah, yes, bricks. Like these? https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack# <https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#> wun

Re: [Elecraft] Dummy loads for dummies

The good non-inductive resistors are made by Caddock Electronics. Available from some of the catalog dealers. John WB4UHCK3 #2165 On Tuesday, December 27, 2016 2:46 PM, Walter Underwood wrote: Ah, yes, bricks. Like these?

Re: [Elecraft] Dummy loads for dummies

Ah, yes, bricks. Like these? https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack# wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On

Re: [Elecraft] Dummy loads for dummies

They are undoubtedly wire-wound resistors and will have too much inductance to work well as a dummy load. The resistance is fine. If you have an SWR meter, check it with that. SWR below about 1.5 would mean it is usable. It might be OK on 160 or 80 meters but not on higher bands. Vic 4X6GP >

Re: [Elecraft] Dummy loads for dummies

> Mel, K6KBE > > > From: Ryan Noguchi via Elecraft <elecraft@mailman.qth.net> > To: Paul C <paul...@sbcglobal.net>; "elecraft@mailman.qth.net" > <elecraft@mailman.qth.net> > Sent: Tuesday, December 27, 2016 8:16 AM > Subject: Re: [Elecr

Re: [Elecraft] Dummy loads for dummies

>I made my own dummy load last night from two 100 ohm resistors wired in >parallel.  They are rated for 10 watts each and look like little bricks.  I >measured the resistance at 51 ohms.  Do you think this is close enough or >should I reduce it to 50? >Paul KG5KXG If your impedance is

Re: [Elecraft] Dummy loads for dummies

Paul, Kevin is likely correct. If those two resistors have a sand-like finish they're almost certain to be wire wound and therefore will have some inductance, which will cause your load to give "uncertain" results. Your 51 ohm would be OK. Your ohmmeter isn't -that- accurate, after all.

Re: [Elecraft] Dummy loads for dummies

​Plenty close enough. Only issue I can think of (besides the normal safety stuff) is to make sure the resistors are not of the wirewound variety. Kev K4VD __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft

[Elecraft] Dummy loads for dummies

I made my own dummy load last night from two 100 ohm resistors wired in parallel. They are rated for 10 watts each and look like little bricks. I measured the resistance at 51 ohms. Do you think this is close enough or should I reduce it to 50? Paul KG5KXG