logo
Welcome, Guest. Please Login or Register.
14. December 2024, 05:03:30


Home Help Search Login RegisterWIKIUHSDR Download

Amateurfunk Sulingen
Diskussions- und Newsboard des DARC-Ortsverbandes I40  |  allgemeine Kategorie  |  mcHF Projekt Deutsch / English (here you can discuss everything related to mcHF) (Moderators: DF8OE, DL1PQ)  |  Topic: TX Intermod Meausements <- zurück vorwärts ->
Pages: [1] Go Down Print
   Author  Topic: TX Intermod Meausements  (Read 2203 times)
oz4hz
Neuling
*

Offline

Posts: 4



Jeg hænger på!

View Profile
TX Intermod Meausements
« on: 07. November 2022, 09:58:55 »

I have made a lot of TX IMD measurements both with  the original
PIN diode ant. switch and the relay modification.
See pics below

First picture is with the original PIN diode switch
and the second  with the relay modification.

There is quite a difference in IMD

Vy 73 OZ4HZ, Hans
Logged
oz4hz
Neuling
*

Offline

Posts: 4



Jeg hænger på!

View Profile
Re:TX Intermod Meausements
« Reply #1 on: 07. November 2022, 10:00:29 »

IMD with PIN diode
 3.5MHz_5w_PIN.jpg
Logged

oz4hz
Neuling
*

Offline

Posts: 4



Jeg hænger på!

View Profile
Re:TX Intermod Meausements
« Reply #2 on: 07. November 2022, 10:01:11 »

IMD with relay modification
 3.6MHz_5W_Relay.jpg
Logged

DF8OE
Administrator
*****

Offline

Posts: 6280



Stellvertr. OVV I40, Jugend / Nachwuchsreferent

View Profile WWW
Re:TX Intermod Meausements
« Reply #3 on: 07. November 2022, 12:10:55 »

That's the reason I implemented relay switching few years ago...

vy 73
Andreas
Logged

Wenn der Wind des Wandels weht, nageln die einen Fenster und Türen zu und verbarrikadieren sich. Die anderen gehen nach draußen und bauen Windmühlen...
qrz.com-Seite von DF8OE
-----------------------------------------------------
>>>> Die Inhalte meiner Beiträge dürfen ohne meine explizite Erlaubnis in jedwedem Medium weiterverbreitet werden! <<<<
SP9BSL
positron
alter Hase
****

Offline

Posts: 443





View Profile WWW
Re:TX Intermod Meausements
« Reply #4 on: 08. November 2022, 11:08:20 »

Totally agree to remove the PIN diodes.

I have some remarks to your measurement, be careful with measurements of such high signals because:
- you have performed different measurements because of TOI your SA, look at first measurement - you have 30dB attenuator set and signal level is over 3dBm at input mixer. SA itself may produce false intermodulation. With the second measurement, mixer signal is 10dB lower becuse you have 40dB attenuation. It is good to measure or find in manual IMD of SA mixer first to be sure the limits and reliable measurement. Believe me, R&S ESR (very expensive) has significant IMD3 rise at the level of -15dBm at input! Even worse  with cheap Siglent or Rigol...

- if you do not have proper external attenuator you may destroy the SA input mixer/attenuator with 2W power
Logged

73 Slawek
oz4hz
Neuling
*

Offline

Posts: 4



Jeg hænger på!

View Profile
Re:TX Intermod Meausements
« Reply #5 on: 08. November 2022, 16:03:29 »

You are absolutely right, but there is also an external power attenuator of 30dB - so in the first picture the signal is -29dBm at the mixer input. In the pictures you can't see that there is a reference offset of 30dB from the external power attenuator-
.
Vy 73 OZ4HZ
(also eine alte Hase)
Logged
SP9BSL
positron
alter Hase
****

Offline

Posts: 443





View Profile WWW
Re:TX Intermod Meausements
« Reply #6 on: 08. November 2022, 18:28:07 »

Thank you for clarification - now everything is ok
Logged

73 Slawek
Pages: [1] Go Up Print 
Diskussions- und Newsboard des DARC-Ortsverbandes I40  |  allgemeine Kategorie  |  mcHF Projekt Deutsch / English (here you can discuss everything related to mcHF) (Moderators: DF8OE, DL1PQ)  |  Topic: TX Intermod Meausements <- zurück vorwärts ->
Jump to: 


Login with username, password and session length

 Es wird die Verwendung von Browsern die auf der "Blink"-Engine basieren und mindestens
1024x768 Pixel Bildschirmauflösung für die beste Darstellung empfohlen
 
Amateurfunk Die Beiträge sind, sofern nicht anders vermerkt, unter der folgenden Lizenz veröffentlicht:
GNU Free Documentation License 1.3 GNU Free Documentation License 1.3
verbindet!
Powered by MySQL Powered by PHP Diskussions- und Newsboard des DARC-Ortsverbandes I40 | Powered by YaBB SE
© 2001-2004, YaBB SE Dev Team. All Rights Reserved.
- modified by Andreas Richter (DF8OE)
Impressum & Disclaimer
Valid XHTML 1.0! Valid CSS!