Neil, As you have probably found out, low-band VHF isolators are not cheap. Also, they have very little tunable range from the factory-set frequency.
It's one of the annoying marketing practices that seems to come as a surprise to many Hams who receive donated isolators. Case in point: A local radio club received a mint-condition Sinclair I-2213T dual isolator that was pulled from Government service in the 163 MHz band. The initial joy at receiving a dual isolator that is specified as having a frequency range of 132-174 MHz was dampened when the club members learned that a ferrite isolator is field-tunable over a very narrow range- in this case, just +/- 2.5 MHz. That's a LONG ways from the 2m band! The club sent the isolator back to Sinclair for remanufacturing to the exact frequency needed for the 2m repeater, and it cost just $250 to have this done. It took almost three weeks, but when it came back, it was a perfect unit- fully tested and guaranteed. I have never tuned a low-band isolator, but I understand that the tuning range is much narrower than high-band VHF and UHF units. The best course of action, I think, is to contact the manufacturer of the isolator, advise the part number and current frequency, and ask about getting it retuned to a Ham frequency. If the charge is about a third the cost of a new isolator, it's probably a fair charge. 73, Eric Lemmon WB6FLY Neil McKie wrote: > Eric, > What is your opinion about possible retuning of a low-band isolator? I can get the make / model for you but tomorrow. > > Thank you, > > Neil - WA6KLA > > > > Eric Lemmon wrote: > > > > Doug, > > > > Rather than download the entire catalog, those interested in the > > isolators can simply download the 750K portion that applies to > > the UHF isolators at: > > > > <http://www.emrcorp.com/catalog/FullLine/ISOCIRC/ISOCIRC_300_650.pdf> > > > > Ferrite isolators are custom-manufactured to order, and the > > components are ground and/or selected to operate on the exact > > frequency specified. > > > > A UHF isolator can usually be tuned +/- 5 MHz from the original > > frequency it was made for, and still be within specifications. EMR > > will remanufacture both their own and some other brands to operate > > properly in the 70cm Amateur band for a modest fee. > > > > 73, Eric Lemmon WB6FLY > > > > doug wrote: > > > > > > i have the following equipment available @ "best offer" this gets offered > > > here before it goes to fleabay > > > > > > 2 ea EMR CORPORATION UHF double isolators w/ loads p/n 8550-34 link here: > > > > http://emrcorp.com/images/catalogs/Full_Line_Catalog.pdf > > > > > > item is on page 14, WARNING - HUGE 40meg file (full catalog from emr) and > > > > > > 2 ea DB 4332-B UHF harmonic filters w/ N male factory cables > > > > > > link here: http://www.ecwest.com/shopping/buy.asp?prid=301334 > > > > > > These were in service in a UHF data system and were removed when the > > > system > > > was replaced. there is some paint missing on the harmonic filters, > > > probably from banging around against each other in the plastic baggie. > > > > > > pictures to those who really want them. > > > > > > all items are on 461.xxx freqs and from what i can tell in the literature > > > are re-tunable to the ham band (400-520 MHz). > > > > > > email me OFF THE LIST, please. > > > > > > doug > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
