[Milsurplus] TS-234A/UP

Tue Aug 18 19:58:52 EDT 2026

Hi,

I was just about to recommend sweeping with a NanoVNA. I have a 
temptiing unit that samples and attenuates signals sent through my Bird 
Wattmeter also made by Bird. I swept it and found that it did nor 
present 50 ohms below about 26 MHz. I have also swept the Drake dummy 
load and other elements I have all flat 50 Ohms into the UHF spectrum. 
Not a problem for VHF/UHF hams. But I am a forty meter ham and get 
nosebleeds starting at 15 meters and I go into paralysis at 10 meters! 
The VNA will help you with confidence in your equipment. I also 
recommend the TinySA. Those two instruments have amazing utility. Owners 
of the big buck famous maker gear tell us the Nano and Tiny are 
remarkably accurate. They also do not cost you your retirement funds.

73,

Bill  KU8H

On 8/18/26 13:51, Jim Whartenby via Milsurplus wrote:
> Francesco
> I wonder how non-inductive the resistors actually are?  This would 
> limit the upper frequency that one can safely use.  I believe what 
> limits the upper frequency of most dummy loads is actually the 
> detector network used to measure input power.
> Do you have a tiny VNA for testing the resistor network?
> Jim
>
> *Logic is a systematic method of coming to the wrong conclusion with 
> confidence.* *Murphy*
>
>
> On Tuesday, August 18, 2026 at 11:50:30 AM CDT, Francesco Ledda 
> <k5urg at yahoo.com> wrote:
>
>
>     Well, my TS-234A is indeed 50 ohm! It has 4 large 200 ohm
>     resistors. There are no signs of manumission and looks original.
>      I am as puzzled as you probably will be. If interested, I can
>     forward a picture of the inside.
>
>     Best, Francesco K5URG
>     Sent from my iPad
>
>>     On Aug 17, 2026, at 19:15, Jim Whartenby via Milsurplus
>>     <milsurplus at mailman.qth.net> wrote:
>>
>>     
>>     16 ohms is 1/3 of 50 ohms so it might be possible that there are
>>     3 each 50 ohm @ 425 watt elements in parallel.
>>     So it might still be useable as a standard 50 ohm load at reduced
>>     power.
>>     Jim
>>
>>     *Logic is a systematic method of coming to the wrong conclusion
>>     with confidence.* *Murphy*
>>
>>
>>     On Monday, August 17, 2026 at 03:58:47 PM CDT, frledda at att.net
>>     <frledda at att.net> wrote:
>>
>>
>>         Thank you, all!
>>
>>         *From:*milsurplus-bounces at mailman.qth.net
>>         <milsurplus-bounces at mailman.qth.net> *On Behalf Of *hwhall---
>>         via Milsurplus
>>         *Sent:* Monday, August 17, 2026 3:51 PM
>>         *To:* k5urg at yahoo.com; milsurplus at mailman.qth.net
>>         *Subject:* Re: [Milsurplus] TS-234A/UP
>>
>>         Can we post images here? Let's see.
>>
>>         Wayne
>>
>>         WB4OGM
>>
>>         On Monday, August 17, 2026 at 02:14:20 PM MDT,
>>         k5urg at yahoo.com <k5urg at yahoo.com> wrote:
>>
>>             Hi All,
>>
>>             I have here a dummy load labeled TS-234A/UP.  It says
>>             1275W, but does not specify the frequency range.
>>
>>             Does anybody have a spec of such thing that can share
>>             with me?
>>
>>             Thank you!
>>
>>             Best, Francesco K5URG
>>
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