[600MRG] 600MRG Digest, Vol 80, Issue 2

Dave Riley dave.riley3 at verizon.net
Fri Dec 1 14:50:07 CST 2017 

Add to the fact that the Tesla coil antenna has a very narrow bandpass 
in and of itself, call it a series Tesla filter between the low Z 
current and the high volts corona generator...

You put the amps in one side and the volts come out on the other side of 
the vario... Your rig is matched to the ether...

I use a relatively short loop so the HV at the tuning cap with NE-2s 
mounted on one side of the cap tells me when the volts are there and 
W1TAG's RF ammeter lets me see the amps going in to the loop...

I use a vario in the plate circuit of this tube amp with 6 turns wound 
on the cold side in series with the loop, it can not be any simpler, 
call me Dave the burnt no more...

I must retune when QSYing from 472 to 474 so that's a clue to the Q... A 
very selective antenna filter...

Ovah...  de DaveR aa1a




On 12/1/2017 3:14 PM, 600mrg-request at w7ekb.com wrote:
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> Today's Topics:
>
>     1. Re: Quick and cheap rig to get on 630m CW
>        (lstoskopf at cox.net lstoskopf at cox.net)
>     2. Re: A couple of crude Antenna Matching techniques - will
>        either one work (lstoskopf at cox.net lstoskopf at cox.net)
>     3. Re: A couple of crude Antenna Matching techniques - will
>        either one work (eric)
>     4. Re: A couple of crude Antenna Matching techniques - will
>        either one work (John Andrews)
>     5. Radiated power (Rudy Severns)
>     6. Re: A couple of crude Antenna Matching techniques - will
>        either one work (Frank Lotito)
>     7. the neon bulb (Rudy Severns)
>     8. Re: A couple of crude Antenna Matching techniques - will
>        either one work (eric)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 1 Dec 2017 13:02:09 -0500 (EST)
> From: "lstoskopf at cox.net lstoskopf at cox.net" <lstoskopf at cox.net>
> To: 600MRG Reflector <600mrg at w7ekb.com>, michael polia
> 	<ab1aw at yahoo.com>
> Subject: Re: [600MRG] Quick and cheap rig to get on 630m CW
> Message-ID: <1823641950.12435.1512151330054 at myemail.cox.net>
> Content-Type: text/plain; charset=UTF-8
>
> We all know that Dave is a master designer with minimalist ideals.  Now for one for 630M with on board spiral inductors! Almost afraid to mention that.  The FCC will have a million (or so) applications for a ticket for the Ozark location for next year.  N0UU
>
>>      On December 1, 2017 at 12:16 PM michael polia <ab1aw at yahoo.com> wrote:
>>
>>      I've mated the MF Solutions down-converter with the Cricket 80a CW transceiver from the Four State QRP Group http://www.4sqrp.com/cricket.phpSince the Cricket 80a is XTAL controlled too, I've slightly modified the MF Solutions; replaced the crystal with caps and coil to allow tuning of the SA612 across the band.Together they give me a good 30W output.
>>
>>      73MikeAB1AW
>>
>>      _______________________________________________
>>      600MRG mailing list
>>      600MRG at w7ekb.com
>>      http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com
>>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 1 Dec 2017 13:19:19 -0500 (EST)
> From: "lstoskopf at cox.net lstoskopf at cox.net" <lstoskopf at cox.net>
> To: n6lf at arrl.net, Rudy Severns <n6lf at epud.net>, 	Andy - KU4XR
> 	<ku4xr at yahoo.com>
> Cc: 600MRG <600mrg at w7ekb.com>
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques -
> 	will either one work
> Message-ID: <617403695.13208.1512152360100 at myemail.cox.net>
> Content-Type: text/plain; charset=UTF-8
>
> I threw this out to one of the other antenna gurus and never got a reply.  Probably because of insanity here!
>
> On 630M we are limited on EIRP, not TX power.  And the EIRP is low compared to what we can generate.
>
> Why not put a hefty directional couple at the antenna input.  Pass the power from the rig to the antenna.  Dump the reflection into a dummy load.  The antenna has the same standing wave, but the transmitter just sees a load.
>
> And my perpetual motion machine is next.
>
> N0UU
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 1 Dec 2017 10:17:41 -0900
> From: eric <kl7aj at acsalaska.net>
> To: 600mrg at w7ekb.com
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques -
> 	will either one work
> Message-ID: <d5d2711d-3fe9-85ad-8aa6-c9b004dbc2bc at acsalaska.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Check out my Feb. 2009 QST article, "Keeping Current with Antenna
> Performance."?? For the first half of ham radio history, the RF ammeter
> was just about the only instrument any ham had at his disposal. :)
>
> Eric the Old
>
>
>
> On 12/1/2017 8:58 AM, Rudy Severns wrote:
>> In the early days of radio Andy's problem had to be addressed by most
>> everyone with nothing more than an RF ammeter.  The answer is simple: tune
>> for maximum antenna current with the power available.  While that's very
>> simple advice, sometimes it takes a good deal of fiddling to find the magic
>> "maximum" but with some experience early hams and pro's for that matter,
>> made it work.
>>
>> The first step is to make sure you have enough inductance to resonate.  That
>> can be estimated pretty closely either from modeling or with the
>> calculations shown in chapter 3 of my notes.  Assuming you have enough L the
>> usual procedure is to have taps on the coil in two places, one set near the
>> top which you adjust for resonance and one set for matching maybe 10-20% up
>> from the bottom.  You the alternated taps, first the top taps for max
>> current then the bottom taps again for max current, etc, etc, etc until
>> there's no improvement.  As long as you have enough L to start with this
>> procedure usually converges.  If you don't have enough L then the procedure
>> should end with the tap at the top of the coil indicating more L is needed.
>>
>> The equation for inductance is also very simple: L=(D^2 N^2)/(18D+40l),
>> where D= diameter in inches, l= winding length in inches, N=number of turns
>> and L is in uH.
>>
>> GL and 73, Rudy N6LF
>>
>>
>>
>> _______________________________________________
>> 600MRG mailing list
>> 600MRG at w7ekb.com
>> http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com
>>
>>
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> ------------------------------
>
> Message: 4
> Date: Fri, 1 Dec 2017 14:47:58 -0500
> From: John Andrews <w1tag at charter.net>
> To: 600mrg at w7ekb.com
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques -
> 	will either one work
> Message-ID: <bea06a96-df4d-0b42-5441-4fb671d1f74e at charter.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> In case it would be of any use, here's the schematic of an LF-MF SWR
> bridge that I have been using for years:
> http://www.w1tag.com/files/LF_SWR_Bridge.jpg
>
> It's designed toward the QRO side of things, let's say 100w and up. I
> could make some suggestions for something more QRP-oriented.
>
> John, W1TAG
>
>
>
> ------------------------------
>
> Message: 5
> Date: Fri, 1 Dec 2017 11:54:17 -0800
> From: "Rudy Severns" <n6lf at epud.net>
> To: "600MRG" <600mrg at w7ekb.com>
> Subject: [600MRG] Radiated power
> Message-ID: <001201d36ade$2c6bc2a0$854347e0$@net>
> Content-Type: text/plain;	charset="us-ascii"
>
> Yep, the RF ammeter is the original "must have" instrument and for many hams
> that was pretty much it until after WWll.
>
>   
>
> The radiated power (Pr) is the product of the square of the base current
> (Io) times the radiation resistance (Rr, referred to the base).  Once you've
> finished building the antenna, Rr is what it is.  All you can do to increase
> Pr is to increase Io.  This is done by tuning for maximum Io with a given
> transmitter output power.  To increase Pr further still you'll need either
> more power or improvements to your antenna.
>
>   
>
> GL and 73, Rudy N6LF
>
>
>
> ------------------------------
>
> Message: 6
> Date: Fri, 1 Dec 2017 20:02:48 +0000
> From: Frank Lotito <k3dz at live.com>
> To: 600 / 630 meter research group <600mrg at w7ekb.com>
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques -
> 	will either one work
> Message-ID:
> 	<DM5PR13MB088955BE0D459B274B967656E5390 at DM5PR13MB0889.namprd13.prod.outlook.com>
> 	
> Content-Type: text/plain; charset="iso-8859-1"
>
> A question - With certain transmitter designs the output can be quite rich in harmonics. Definitely when we opt for simple minimal output filter solid state designs, and simple single tuned and even double tuned link coupled OT and OOT designs.  Specifically, using no low-pass PI network. Is the simple ammeter technique really prudent to recommend?  Maybe not when the 630 meter second and third harmonis fall in the AM Broadcast Band.
> ..
> In my mind, the simple "tune for max current" runs the risk of tuning up "on the wrong harmonic."  Using a nearby monitor receiver as a "poor man's spectrum analyzer" does not proove much w.r.t. tuning on the correct harmonic, e.g., the fundamental.  I think we should be careful with our advice unless we know for sure the transmitter has a more than adequate low-pass output filter.
> ..
> 73 Frank K3DZ / starting to become a moot point WH2XHA
> ________________________________________
> From: 600MRG <600mrg-bounces at w7ekb.com> on behalf of eric <kl7aj at acsalaska.net>
> Sent: Friday, December 1, 2017 2:17 PM
> To: 600mrg at w7ekb.com
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques - will either one work
>
> Check out my Feb. 2009 QST article, "Keeping Current with Antenna
> Performance."?? For the first half of ham radio history, the RF ammeter
> was just about the only instrument any ham had at his disposal. :)
>
> Eric the Old
>
>
>
> On 12/1/2017 8:58 AM, Rudy Severns wrote:
>> In the early days of radio Andy's problem had to be addressed by most
>> everyone with nothing more than an RF ammeter.  The answer is simple: tune
>> for maximum antenna current with the power available.  While that's very
>> simple advice, sometimes it takes a good deal of fiddling to find the magic
>> "maximum" but with some experience early hams and pro's for that matter,
>> made it work.
>>
>> The first step is to make sure you have enough inductance to resonate.  That
>> can be estimated pretty closely either from modeling or with the
>> calculations shown in chapter 3 of my notes.  Assuming you have enough L the
>> usual procedure is to have taps on the coil in two places, one set near the
>> top which you adjust for resonance and one set for matching maybe 10-20% up
>> from the bottom.  You the alternated taps, first the top taps for max
>> current then the bottom taps again for max current, etc, etc, etc until
>> there's no improvement.  As long as you have enough L to start with this
>> procedure usually converges.  If you don't have enough L then the procedure
>> should end with the tap at the top of the coil indicating more L is needed.
>>
>> The equation for inductance is also very simple: L=(D^2 N^2)/(18D+40l),
>> where D= diameter in inches, l= winding length in inches, N=number of turns
>> and L is in uH.
>>
>> GL and 73, Rudy N6LF
>>
>>
>>
>> _______________________________________________
>> 600MRG mailing list
>> 600MRG at w7ekb.com
>> http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com
>>
>>
>
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>
> ------------------------------
>
> Message: 7
> Date: Fri, 1 Dec 2017 12:08:49 -0800
> From: "Rudy Severns" <n6lf at epud.net>
> To: "600MRG" <600mrg at w7ekb.com>
> Subject: [600MRG] the neon bulb
> Message-ID: <000001d36ae0$3452da60$9cf88f20$@net>
> Content-Type: text/plain;	charset="us-ascii"
>
> I just remembered my solution (and other peoples too) for this problem when
> I was a boy first getting started in ham radio (>60 years ago).  I couldn't
> afford an RF ammeter.  On the advice of a older mentor I used a simple neon
> bulb with a loop of wire between the terminals.  In the initial tuning I
> placed the bulb fairly close to the base and tuned for maximum brightness.
> Very soon the brightness saturates but all I had to do was progressively
> move the bulb/loop further away to keep the sensitivity.  In my case I was
> using a tuner and I could see the antenna base from the shack window.
> Working at night so I could see the brightness at a distance, the bulb/loop
> worked like a charm, with a few trips to and fro.
>
>   
>
> John's suggestion of an SWR bridge is very post WWll but also a very good
> idea and well worth the small effort required.  I seem to remember some of
> the older ham, who were still using open wire lines, using two bulbs and
> some wire loops to create an SWR indicator.  Cheap, cheap, cheap!
>
>   
>
> 73, Rudy N6LF
>
>   
>
>   
>
>
>
> ------------------------------
>
> Message: 8
> Date: Fri, 1 Dec 2017 11:13:55 -0900
> From: eric <kl7aj at acsalaska.net>
> To: 600mrg at w7ekb.com
> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques -
> 	will either one work
> Message-ID: <8b9e5c1f-65ad-c99d-876a-7516470c0350 at acsalaska.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Hi Frank:
>
>   ?? You certainly bring up a valid point, and it's always important to
> verify a clean signal before performing any measurements.? (This is
> ESPECIALLY true with a monimatch type SWR meter which is FAR more
> sensitive to harmonics than the fundamental!)
>
>   ? So, before tuning for maximum smoke, it is good to have some other
> indicator that you are indeed tuning the fundamental.
>
>
> Eric
>
>
> On 12/1/2017 11:02 AM, Frank Lotito wrote:
>> A question - With certain transmitter designs the output can be quite rich in harmonics. Definitely when we opt for simple minimal output filter solid state designs, and simple single tuned and even double tuned link coupled OT and OOT designs.  Specifically, using no low-pass PI network. Is the simple ammeter technique really prudent to recommend?  Maybe not when the 630 meter second and third harmonis fall in the AM Broadcast Band.
>> ..
>> In my mind, the simple "tune for max current" runs the risk of tuning up "on the wrong harmonic."  Using a nearby monitor receiver as a "poor man's spectrum analyzer" does not proove much w.r.t. tuning on the correct harmonic, e.g., the fundamental.  I think we should be careful with our advice unless we know for sure the transmitter has a more than adequate low-pass output filter.
>> ..
>> 73 Frank K3DZ / starting to become a moot point WH2XHA
>> ________________________________________
>> From: 600MRG <600mrg-bounces at w7ekb.com> on behalf of eric <kl7aj at acsalaska.net>
>> Sent: Friday, December 1, 2017 2:17 PM
>> To: 600mrg at w7ekb.com
>> Subject: Re: [600MRG] A couple of crude Antenna Matching techniques - will either one work
>>
>> Check out my Feb. 2009 QST article, "Keeping Current with Antenna
>> Performance."?? For the first half of ham radio history, the RF ammeter
>> was just about the only instrument any ham had at his disposal. :)
>>
>> Eric the Old
>>
>>
>>
>> On 12/1/2017 8:58 AM, Rudy Severns wrote:
>>> In the early days of radio Andy's problem had to be addressed by most
>>> everyone with nothing more than an RF ammeter.  The answer is simple: tune
>>> for maximum antenna current with the power available.  While that's very
>>> simple advice, sometimes it takes a good deal of fiddling to find the magic
>>> "maximum" but with some experience early hams and pro's for that matter,
>>> made it work.
>>>
>>> The first step is to make sure you have enough inductance to resonate.  That
>>> can be estimated pretty closely either from modeling or with the
>>> calculations shown in chapter 3 of my notes.  Assuming you have enough L the
>>> usual procedure is to have taps on the coil in two places, one set near the
>>> top which you adjust for resonance and one set for matching maybe 10-20% up
>>> from the bottom.  You the alternated taps, first the top taps for max
>>> current then the bottom taps again for max current, etc, etc, etc until
>>> there's no improvement.  As long as you have enough L to start with this
>>> procedure usually converges.  If you don't have enough L then the procedure
>>> should end with the tap at the top of the coil indicating more L is needed.
>>>
>>> The equation for inductance is also very simple: L=(D^2 N^2)/(18D+40l),
>>> where D= diameter in inches, l= winding length in inches, N=number of turns
>>> and L is in uH.
>>>
>>> GL and 73, Rudy N6LF
>>>
>>>
>>>
>>> _______________________________________________
>>> 600MRG mailing list
>>> 600MRG at w7ekb.com
>>> http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com
>>>
>>>
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>
>
>
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>
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> End of 600MRG Digest, Vol 80, Issue 2
> *************************************
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