venerdì 7 aprile 2017

Modifying the FRG-7000

Introduction

The Yaesu FRG 7000 is a colorful, vintage receiver that is still fun to use. The main drawback when used in AM mode is the availability of only one IF bandwidth, that is way too wide (9kHz at –6dB, measured) in crowded band conditions (What ? “Crowded bands” in 2017 ?). The narrow filter (2.8 kHz at – 6dB) is accessible only in USB/LSB modes.




However, this limitation can be overcome with a very simple modification, that is absolutely not-invasive and completely reversible. With this modification when you select the AM mode the receiver uses the Wide Filter, while when you select the AM-ANL mode the receiver uses the Narrow Filter.


But first let me state it very clearly: do it at your own risk. I will accept no liability for any damage you will do to your radio, to yourself or to this sector of the Universe by following the procedure outlined in this document.

The mod

Since the filters are selected electronically by activating a diode, the modification is very simple: just “cut” a connection on the “mode” switch and rewire it. This will allow you to select the Narrow Filter in AM-ANL mode, while the standard AM mode uses the Wide Filter.

The mode switch is easily accessible from underneath the radio, there is no need to dismount anything apart removing the receiver’s cover; the photo below shows the position of the mode switch (circled in red).




In the schematic below the modification is shown: just “cut” a connection (red cross) on S2(e) switch and rewire it with the blue wire. The section (e) of switch S2 select the desired IF filter (CF01 –wide-  or CF02 –narrow-) by grounding a diode (and hence activating it).

As standard, CF01 is selected for AM and AM-ANL modes, and CF02 for USB and LSB modes. By rewiring section (e), we activate CF01 only for AM, and CF02 for USB/LSB/AM-ANL; as simple as that !





Please note that I kept the ANL circuit operative, since I could hardly notice its effect; if you want, you can disable it but then the modification will be more invasive and you will need to rewire also section (a) of S2.



On the left the band switch before the mod. The connection that need to be interrupted is the one circled in blue, easily accessible, where the white-and-blue wire is connected.
There is no need to dismount the switch.

The two pins of the switch are soldered together; I cut the wire and then used a de-soldering pump to remove the solder and separate them.









On the right the band switch after the mod. Note the added green wire that jumpers the fourth (and last) pin of the switch (AM-ANL position) to the first and second pins (USB/LSB position), i.e. to the white-and-brown wire.


The white-and-blue wire is now connected only to the third pin (AM position).



martedì 25 ottobre 2016

Ascolti milanesi




Ascolti milanesi senza pretese. I canali eritrei "intrusi" nella banda radioamatoriale dei 40 metri sono spesso oggetto di pesante noise-jamming (dall'Etiopia, forse ?), il che rende inutilizzabile una banda larga dai 10 ai 20 kHz attorno alla frequenza centrale dell'emittente... se ne sentiva davvero il bisogno !

 5915 20:16 21/10 Zambia NBC, Lusaka, talk, VV. Fair.  (SIO 344).
 5950 19:53 11/10 Voice of Tugray Revolution, Ethiopia, local music, VV. At 19:58 whiped out by KBS (via France) signing in. Good. SIO (444).
 5995 20:20 21/10 RTV du Mali, Bamako, talk, local music, VV. Fair signal, low modulation. (SIO 343).
 6090 20:17 11/10 Amhara State Radio, Ethiopia, local music, talk, VV. Fair. (SIO 343)
 6110 20:02 11/10 R. Fana, Ethiopia, local music, talk, VV. Good. (SIO 444).
 7145 16:40 21/10 Heavy jamming (against Voice of the Broad Masses, I suppose), spanning almost 20 kHz, extremely strong, messing up the 40 metres ham band.
 7185 16:40 21/10 Heavy jamming, spanning almost 10 kHz, strong, messing up the 40 metres ham band.
11975 16:20 21/10 A.W.R. via Sri Lanka, sermon, EE. Fair. (SIO 343).
12065 20:04 21/10 R.Australia, Shepparton, ABC news, EE. Good. (SIO 444).
15124 16:10 21/10 C.R.I. via Mali, TK, AA. Exactly 1 kHz below nominal frequency. Good. (SIO 354).
15235 16:07 21/10 Channel Africa, South Africa, news, FF. Very good. (SIO 455).
15345 16:12 21/10 R. Cairo (I suppose), just buzzing noise, no modulation, as usual... do they have engineers there ?


73,

Michele IZ2EAS - Milano

RXs (modern) : Perseus, Drake R8E, Icom R72
RXs (vintage): Collins 51S1, Drake R4C, BC348R, Russian R-326
Antenna:    Cushcraft R8 vertical (ham bands, 9 metres high)
More infos: https://www.qrz.com/db/iz2eas
Facebook:   https://www.facebook.com/michele.iz2eas

lunedì 10 ottobre 2016

Qualche ascolto autunnale


Ciao,
un piccolo log con gli ascolti della settimana appena passata. Condizioni così così a Milano, con il solito rumore elettrico sempre presente.



 4765 04/10 19:33 R.Tajikistan, talk, VV. Poor. (SIO 232)
 4835 04/10 19:24 A.B.C. Alice Springs, Australia, talk, EE. Fair-to-poor. (SIO 243)
 6005 07/10 19:28 Radio 700, Germany, pop mx. Fair. (SIO 433)
 6070 05/10 18:20 I.B.C. via Channel 292, posta degli ascoltatori, II. Good. (SIO 454)
 6130 06/10 19:08 Trans World Radio, Swaziland, religious songs, TK, VV. Fair (SIO 343)
 6150 09/10 06:59 Europa 24, Germany, music, ID in German at 07:00, news in German. Good. (SIO 444)
 6180 09/10 06:50 R.Nacional Brasilia, soft songs (lulling listeners to sleep?) ID, PP. Fair. (SIO 344)
 6195 04/10 20:02 V.O.A. via Botswana, African Beat, beautiful African music, EE. Good.(SIO 444)
 6267 07/10 19:48 Mustang Radio, pop mx, ID in EE, e-mail address. Very good. (SIO 544)
 6285 08/10 20:25 Radio Focus International, mx, ID and jingle in EE. Good. (SIO 444)
 6300 09/10 08:02 Radio Quintus, Arnhem, Netherland, music, frequent IDs in EE. Fair. (SIO 343)
 6305 09/10 20:33 TRX Radio, music, multiple ID in English "TRX radio on shortwave". Fair. (SIO 333)
 6320 06/10 18:28 Radio Oleg, two men talking, commenting on what a stupid hobby radio listening is (!), ID, mx, EE. Good. (SIO 444)
11735 04/10 10:46 Zanzibar B.C., Tanzania, African mx, VV. Good. (SIO 454).
15345 06/10 19:40 R.A.E., Argentina, historical news, II. Fair. SIO (353).

73,

Michele IZ2EAS - Milano

RXs (modern) : Perseus, Drake R8E, Icom R72
RXs (vintage): Collins 51S1, Drake R4C, BC348R, Russian R-326
Antenna:    Cushcraft R8 vertical (ham bands, 9 metres high)

giovedì 8 settembre 2016

Ascolti metropolitani

Ascolti fatti in relax, da Milano, in mezzo al rumore cittadino, principalmente con il Drake R8E. Molto attivi i 49 metri al mattino; Radio Habana Cuba ha attive 4 (!) frequenze in parallelo, con il programma in inglese. R. Nacional dal Brasile a bomba.


 6000 08/09 05:16 R. Habana Cuba, talk // 6165, 6100, 6060, EE. Fair (SIO 433).
 6060 08/09 05:11 R. Habana Cuba, talk // 6165, 6100, 6000, EE. Good (SIO 454).
 6100 08/09 05:06 R. Habana Cuba, talk // 6165, 6060, 6000, EE. Very good (SIO 555).
 6135 08/09 05:07 R. Aparecida, talk and music, PP. Fair (SIO 354).
 6165 08/09 05:02 R. Habana Cuba, ID, talk // 6100, 6060, 6000, EE. Good (SIO 454).
 6180 07/09 05:20 R. Nacional Brasil, music program "Madrugada Nacional", PP. Very good (SIO 454) 
15344 07/09 19.05 R. Argentina al Exterior, TK, II. Poor (SIO 242).

Michele IZ2EAS - Milano

RXs (modern) : Perseus, Drake R8E, Icom R72
RXs (vintage): Collins 51S1, Drake R4C, BC348R, Russian R-326
Antenna:    Cushcraft R8 vertical (ham bands, 9 metres high)
More infos: https://www.qrz.com/db/iz2eas
Facebook:   https://www.facebook.com/michele.iz2eas

sabato 9 novembre 2013

Per gli amanti della radio digitale...

I vigili del fuoco olandesi (e non solo) "scaricano" la radio digitale e tornano alla FM analogica.
La ragione? E' talmente inaffidabile da mettere in pericolo la sicurezza di pompieri e civili.

Meditate, talebani del D-Star, meditate !

http://hamgear.wordpress.com/2013/11/09/dutch-fire-department-ditches-c2000/


lunedì 30 settembre 2013

Message in a bottle....

Quando parliamo del nostro "strano" hobby, spesso ti chiedono "ma che gusto ci provi a parlare alla radio ?"
La risposta perfetta è nelle parole di Luca Parmitano, astronauta e neo radioamatore...



When we talk about our "strange" hobby, often people asks "where is the pleasure in talking into a radio ?"
The perfect answer is in the words of Luca Parmitano, astronaut and freshly-licensed ham....

http://blogs.esa.int/luca-parmitano/2013/08/13/message-in-a-bottle/


domenica 28 luglio 2013

La macchina del tempo (the time machine)

La mitica Yaesu FT209RH fu la mia prima radio, la acquistai di seconda mano nel 1985, fresco di licenza (all’epoca ero IK7GDP). La utilizzai tantissimo, prima in fonia (dirette e ponti), poi per il packet radio (chi se lo ricorda ?), finché nel 1994 un guasto irreparabile alla CPU mise fine ai giochi e la radio finì in discarica…

The FT209RH was my very first radio; I bought it in December 1985 when I got my ticket (at that time I was IK7GDP). I used it quite intensively for a few years: first on voice, on local direct and repeater frequencies; later, in 1988, for packet radio - a lot of fun. In 1994 it eventually developed a fault in the CPU module that I was not able to fix, so it was discarded.



The FT290RH open for repair

…avanti veloce ad alcuni mesi fa, quando l’amico Tony I0JX decise di donarmi (grazie !) la sua vecchia FT290RH che non usava più e che era finita in un cassetto. Per me è stato un vero salto nel passato! Dopo circa 30 anni di onorata carriera, la radio aveva bisogno di qualche attenzione ma io ero assolutamente determinato a sistemare tutti i piccoli acciacchi dell’età: con pazienza, in due settimane e lavorando nei ritagli di tempo, ho sostituito tutti i condensatori elettrolitici, i due potenziometri di volume e squelch (andati completamente) e ovviamente la batteria al litio di backup.

Fast forward.... few months ago a friend of mine (Tony I0JX) gave me his old FT209RH, that he wasn't using any longer and that had been sleeping in a drawer for the last few years. For me it was a jump in the past! After almost 30 years of life, the radio needed attention, but I was determined to fix it, no matter what! So I started working on it, and in a few weeks of part-time work I brought it back to its original "splendor"; I had to replace: both potentiometers (on/off-volume and squelch - they had gone bananas), all the electrolytic capacitors (they were leaking or dry) and the lithium back-up battery (flat, of course, after 27 years...).




Per quanto riguarda il pacco batterie, ho deciso di acquistarne uno nuovo su e-bay… si tratta di un pacco NiCd (!) da 1200 mAh, siglato FNB-4 come l’originale Yaesu ma più lungo, con l’inconveniente che la custodia in simil-pelle originale non è più utilizzabile… con pacco nuovo la radio è veramente lunga, quasi 21 cm (antenna esclusa)… molto anni ’80.

The FNB-4 battery pack was exhausted, so I decided to treat me to a brand new one (yes, I could have replaced the elements inside, but the pack itself was quite beaten-up... I kept it for future project). The pack that is available today is a NiCd (!) 12V, 1200 mAh, that is quite good; the only drawback is that it is longer than the original FNB-4, so the original protective case won't fit, and the radio is really loooong (almost 21 cm, without the antenna).... quite funny, it definitely looks vintage !

Naturalmente niente toni subaudio, neanche come opzione, quindi parecchi dei ponti attuali non sono accessibili… poco male, la mia “macchina del tempo” la uso per QSO in diretta dalla stazione fissa, connessa all’antenna esterna (una X50). Questa volta non lascerà lo shack !

Of course, no CTCSS (on the European version they were not even an option)... so a lot of repeaters are not accessible, but who cares... I am using it at home, for QSOs on local VHF frequencies, connected to my external antenna. This time I am going to keep it !