[TenTec] Model 1225 SWR and Wattmeter Kit

Bob McGraw - K4TAX RMcGraw at Blomand.net
Tue Jul 22 08:23:32 EDT 2014


Jim et al;

I can agree that the bare Bird 43 at a hamfest is about a $200 instrument. 
A legit 43P, not with a add on board version, is a bit more expensive.  The 
slug prices I quoted are new and not of unknown hamfest specials.  I too 
have a special slug case with all 24 slots filled, each with a different 
slug, some covering up to 1 GHz.  and power ranges from a few milliwatts to 
2500 watts.  I view this as bench test equipment an not station equipment.

On the CN 801, there's a couple of mods to be done that make the reflected 
value display in the PEP mode.  As to reading the reflected value, any 
amount of AVG of PEP power is an indicator that something can be improved. 
The FWD power in either PEP or PEP HOLD mode is really worthwhile.  The 
going price for a new CN 801 HP is about $175 as I recall.  It covers 1.8 - 
200 MHz with 20W, 200W and 2000W power ranges.

As to the lamps burning out, when I did the mod for REF I added a series R 
that reduced the brilliance of the LED illumination.

I do have the published modification procedure and the Daiwa calibration 
procedure.

In your station and operation it is clear it's needs are different than many 
others needs.   To that end, there are different flavors and different 
tastes, all can be satisfied with their individual choice of the wide range 
of instruments available today.

73
Bob, K4TAX



.


----- Original Message ----- 
From: "Jim Brown" <k9yc at audiosystemsgroup.com>
To: <tentec at contesting.com>
Sent: Tuesday, July 22, 2014 2:27 AM
Subject: Re: [TenTec] Model 1225 SWR and Wattmeter Kit


> On 7/21/2014 10:09 PM, Bob McGraw - K4TAX wrote:
>> To add to that if you wish, a Bird 43P {clean but used late model $375} 
>> add a 250 watt HF slug {250H @ $175 new} and add 2500 watt HF slug {2500H 
>> @$255 new} is all one needs.  Plus if one drops it, it doesn't break.
>
> Bob,
>
> Add those numbers together and tell me what you get. Don't take your shoes 
> off. :) I get $805. An it only goes to 30 MHz. And precision is 5% of full 
> scale. I shopped at hamfests and found a Bird 43 for about $200, and 
> bought a drawer full of slugs for about $100 each. I've got slugs to 
> measure the output of talkies on 2M and 440. :) My Birds (two) are average 
> reading. Actually, one is peak reading, but the required battery has been 
> obsolete for years. :)
>
> Now, add these numbers:  LP100A with a single probe that goes from 1.8-54 
> MHz, up to 3 kW. $450  Have an SO2R station? Want to study input and 
> output of your rig? Add a second probe -- $210. Total cost for TWO rigs is 
> $660. Precision is 5% of the measured value of both power and SWR, NIST 
> traceable. And it's peak-reading.
>
> The W2 is also a bargin -- $250 as a kit for one probe, 1W to 2kW, 1.8-54 
> MHz, $100 for a second probe. It's a conventional SWR and power meter, is 
> peak reading. Accuracy is specified 0.5dB typical. For another $100, you 
> can get a sensor for 144-450 MHz. When used in an SO2R station, it can be 
> set to automatically switch to display the radio that is transmitting. As 
> compared to the LP100A, it does not read Z, so power is subject to error 
> based on Z of the load.
>
> I also have a CN801. The lamps burned out after a year or two. When set 
> for peak reading, reflected power is still average.
>
> For most of us, the most important functions of a power/SWR meter are 1) 
> to tell us if our antenna is broken; 2) telling us approximately where our 
> antennas are resonant, and 3) to tune our power amplifiers for maximum 
> smoke, thus minimizing the trash we transmit. The meters I have allow me 
> to do all of those things, but they don't read real power, so I'm buying 
> an LP100A. And I'm doing that ONLY because I'm a serious contester and 
> want to be as competitive as possible but still legal.
>
> 73, Jim K9YC
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